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DAT > SNS - Biology > Flashcards

SNS - Biology Flashcards

1
Q

Kin Selection

A

Altruistic behaviour is selected for evolutionarily as it increases the fitness of closely related individuals

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2
Q

Ethology

A

Behavioual science - explores the way in which animals respond to their environment - how and why an animal reacts to a stimulas in a certain way and why a particular behaviour was evolutionarily favoured

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3
Q

Fixed Action Potentials, FAPs

A

Inherited behaviours, neither learned nor changeable but hard-wired into the neural circuitry of the organism. Occurs when an environmental stimulus consistently triggers a programmed response sequence. eg an insect building a nest, a hatchling opening its mouth for food

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4
Q

Imprinting

A

A type of learning that combines inherited and learned behaviours. Happens during a critical period in an animal’s development when an innatr behaviour is customised to environmental information

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5
Q

Habituation

A

Simple form of learning in which an animal stops reacting to unimportant stimuli over a period of time

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6
Q

Associative learning

A

Involves the association of one thing in the environment with another. The two types are classical and operant conditioning

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7
Q

Classical conditioning

A

Whereby an animal associated a neutral stimulus with another non-neutral stimulus. eg bell and food

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8
Q

Operant conditioning

A

WHereby an animal learns to associate a behaviour with a reward or punishment

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9
Q

Ecosystem

A

Comprises all living and non-living parts of a community including animals, plants, fungi, bacteria, rock, air, water sources etc

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10
Q

Primary producers

A

Organisms are classed as either producers or consumers. Primary producers - plants - are self-feeding (autotrophs) capturing energy from inorganic nutrients. Represent the first trophic level in the food web

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11
Q

Primary consumers

A

Consumers are heterotrophs - cannot make their own food. They obtain it by eating producers or other heterotrophs. Primary consumers are herbivores and directly eat the primary producers. Represent the second trophic level in the food web

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12
Q

Secondary consumers

A

carnivores - eat primary consumers

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13
Q

Tertiary consumers

A

carnivores - eat secondary consumers

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14
Q

Decomposers

A

Or Detritivores. Mostly fungi and bacteria. Occupy the trophic level that return the energy to the producers when organisms die,

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15
Q

10% Rule

A

States that only 10% of energy transfers from a lower trophic level to a higher one

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16
Q

Nitrogen cycle

A

x

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17
Q

Carbon cycle

A

x

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18
Q

Interspecific interactions

A

Sets of relationships that can occur between different species in a community. Can have a positive or negative effect on each of the species involved 1. competition 2. predation-prey oscillations 3. symbiosis

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19
Q

Interspecific interactions Competition

A

When a specific resource is scarce and needed by two different species, these compete. Can lead to conpetitive exclusion with local extinction of one of the species or niche differentiation with one of the species redefining its ecological niche so that they are no longer in competition Competition is a negative interaction for both species involved

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20
Q

Interspecific interactions Predation-Prey Oscillations

A

Negative for one species (prey), positive for the other (predator)

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21
Q

Interspecific interactions Symbiosis

A

Close association between two species in a community. Parasitism is one relationship in which one species (the parasite) benefits and the other (the host) is harmed. In mutualism both organisms benefit from the interaction Commensalism is a relationship in which one organism benefits but the other is neither helped nor harmed

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22
Q

Niche

A

The sum of all resources that a species uses in a community is called its niche. Refers to an organisms habitat. Is also defined by the conditions under which the organism can live and the way in which it utilises the resources in its environment. Temp range, moisture levels and food preferances are examples of factors that shape an organism’s niche

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23
Q

Competetive exclusion principle

A

States that no two species can occupy the same niche in the same place and time. For this reason organisms are likely to exploit different resources and develop varying niches

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24
Q

Succession

A

Refers to the gradual process by which the species composition within an area can change as one community gives way to another

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25
Q

Communities

A

An assembly of different species, eg different types of coral, fish, arthropods etc in a coral reef

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26
Q

Population

A

A group of orgainisms from the same species that lives in the same niche. Highly dynamic and can fluctuate dramatically in number

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27
Q

Population ecology

A

the study of population dynamics

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28
Q

Carrying capacity, K

A

The limit to the number of individuals of a species. Based on the concept that a niche has a finite amount of resources to support a population

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29
Q

K-selected species

A

Those that have few offspring and invest heavily in parental care

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30
Q

r-selected species

A

Those that have a large number of offspring and provide little parental investment

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31
Q

The founder effect

A

Extreme example of genetic drift. Whereby a small number of individuals branch off from the main population and colonise a new habitat. When a population becomes reproductively isolated, the ‘colonising group’ becomes the ‘founder’ of a new species

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32
Q

Allopatric speciation

A

Arises from the geographical separation of population preventing gene flow and resulting in natural selection operating differently on the two populations

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33
Q

Parapatric Speciation

A

Occurs when a small part of a larger population branches off in the absence of geographical barriers

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34
Q

Sympatric Speciation

A

Whena new species originates within a larger population, usually resulting from a genetic mutation. Occurs frequently in plants with chromosome doubling

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35
Q

Genetic drift

A

Mutations can by chance, rapidly change the genetic composition of a small population

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36
Q

Hardy-Weinberg Law

A

A hypothetical model that examines circumstances that cause evolution. If random sexual selection is the only factor affecting allele frequencies, no evolution would occur - a situation known as the Hardy-Weinberg equilibrium. If, however, there are mutations or unequal reproductive successes among individuals within a population, allele frequencies will not match those for the Hardy-Weinberg equilibrium and evolution will occur

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37
Q

Evolution

A

CHanges in the allele frequency within a population

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38
Q

The Hardy-Weinberg Equation

A

p^2 + 2pq + q^2 = 1 Where p = the frequency of the dominant allele, and q = is the frequency of the recessive allele in a given population

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39
Q

Analogous Evolution

A

Or convergent evolution. Independent evolution of similar structures in species which do not have similar lineages

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40
Q

Homologous Evolution

A

Or divergent evolution. Gives rise to similar structures in species from a common ancestral lineage

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41
Q

Cladistics

A

The study of the groupings of organisms. An ancestor and all of its descendents are grouped into a clade

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42
Q

Phylograms vs Cladograms

A

Length of branches in a phylogram indicate the number of genetic changes that have occured since a common evolutionary ancestor. Therefore give infomation on evolution. Cladograms give information on groupings of organisms

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43
Q

Evolution Natural Selection

A

Tends to select for characteristics of an organism which make it better suited to its environment

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44
Q

Evolution

A

The process by which the genetic makeup of populations change over time

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45
Q

Evolution Fitness

A

Determined by the ability to produce viable offspring

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46
Q

Evolution Adaptation

A

A change over time in the genetic makeup of a population that increases its fitness

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47
Q

DNA Replication Direction of Replication

A

The two DNA strands are antiparallel: one 5’ to 3’ and the other 3’ to 5’. During replication bases are added to the 3’ end of the template, making the overall direction fo replication 5’ to 3’

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48
Q

DNA Replication Leading Strand

A

Because strands are antiparallel and only one portion of the DNA is unwound at a time, only one strand - the leading stand- will alllow for the 5’ to 3’ directional addition

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49
Q

DNA Replication Okazaki Fragments

A

Small fragment of DNA transcribed from the lagging strand in the 5’ to 3’ direction and joined together

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50
Q

DNA Transcription

A

Process by which the portion of DNA encoding a specific protein is base paired with RNA nucleotides creating a complementary strand of RNA called mRNA

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51
Q

DNA Translation Sense strand

A

Strand of DNA that permits the mRNA strand to grow in a 5’ to 3’ direction

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52
Q

DNA Translation Anti-sense strand

A

Strand of DNA that isn’t used as a template

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53
Q

DNA Translation Complementary mRNA

A

Base pair inverted form of the original DNA sense strand containing U in place of T

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54
Q

DNA Replication Steps

A
  1. DNA helicase unwinds the two DNA strands 2. Single stranded binding protein helps stabilise the unwound DNA strands 3. A small piece of RNA acts as a primer, which is necessary to begin replication process. Only one primer is necessary for replication of the leading strand while multiple primers are needed for replication of the lagging strand 4. DNA polymerase III adds nucleotides to the 3’ end of the primer following the base pairing of nucleotides. Also corrects base pairing errors 5. DNA polymerase replaces the RNA primer with DNA nucleotides 6. DNA ligase joins the Okazaki fragments of the lagging strand as well as the DNA replacing the RNA primer in the leading strand 7. Following replication, each new helix is composed of one parent strand and one newly replicated strand
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55
Q

DNA Transcription Phases

A
  1. Initiation 2. Elongation 3. Termination
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56
Q

DNA Transcription Initiation

A

Begins when the promoter protein binds to the DNA at the starting point of transcription, unwinding the DNA

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57
Q

DNA Transcription Elongation

A

Occurs when RNA polymerase adds RNA nucleotides, again following the base pairing rule

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58
Q

DNA Transcription Termination Eukaryotes

A

Different in prokaryotes and eukaryotes In eukaryotes a specific sequence of nucleotides indicates the end of transcription is near. RNA polymerase continues to add 50-250 base pairs before cutting the mRNA free. The mRNA then receives a cap of modifies guanine and a tial of 50-250 adenine nucleotides. Exons, the coding portions, are spliced tgether while the non-coding introns are excised

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59
Q

DNA Transcription Post-transcriptional modification

A

The newly-transcribed mRNA then receives a cap of modifies guanine and a tial of 50-250 adenine nucleotides. Exons, the coding portions, are spliced together while the non-coding introns are excised. The modified mRNA exits the nucleus and enters the cytoplasm where it will be translated into a protein

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60
Q

RNA Translation

A

The bases on a strand of mRNA code for different amino acids which assemble to form proteins during the process of translation. Different codons - combinations of three base pairs - correspond to each of the 20 amino acids. tRNA is responsible for decoding the message and adding the appropriate amino acids. Ends when a tRNA reaces a stop codon on the mRNA such as UGA which doesn’t code for an amino acid

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61
Q

RNA Translation Transfer RNA

A

tRNA is responsible for decoding the message and adding the appropriate amino acids. Each has an anticodon sequence that is complementry to the mRNA. The other end has a specific amino acid attached to it

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62
Q

RNA Translation Ribosomes

A

Moves along the mRNA strand. Responsible for holding the tRNA in place while the peptide bond between amino acid is taking place. Have three distinct regions: E site, P site and A site. Proteins that are bound for extracellular release, such as neurotransmitters are translated on ribosomes in the rough ER. Proteins destined to stay within the cell are translated in free ribosomes

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63
Q

RNA Translation Ribosomes E site

A

exit site for the tRNA that has just finished adding its amino acid

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64
Q

RNA Translation Ribosomes P site

A

For the tRNA that is actively creating a peptide bond int eh growing polypeptide chain

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65
Q

RNA Translation Ribosomes A site

A

For tRNA that is bringing the amino acid to be added after that occupying the P site

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66
Q

Gene Structure Nucleotide

A

Composeed of one molecule of the sugar deoxyribose, one phosphate group and one of four nitrogenous bases: adenine, cytosine, guanine or thymine

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67
Q

Gene Structure DNA Structure

A

Double helix witha sugar-phosphate backbone and rings of paired nucleotide bases. Two hydrogen bonds link A and T while three join G and C

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68
Q

Gene Structure RNA Structure

A

Can be single or double stranded. Different to DNA in its composition in that the sugar ribose replaces deoxyribose and the nitrogenous base Uracil replaced thymine

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69
Q

Independent Assortment

A

During metaphase I of meiosis when chromosomes line up at the metaphase plate, there is no force that governs maternal chromosomes to orient themselves towards one pole and paternal chromosomes towards the other. For each homolougous pair, there is a 50% chance that the maternal chromosome will situate itself at a particular pole. Chromosome1 has no effect on the positioning of chromosome 7 - they are independent. Without considering crossing-over, the number of combinations of a daughter cell formed by meiosis of a parent cell with two homologous pairs of chromosomes is four

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70
Q

Linkage

A

Means genes for two given traits are linked on the same chromosome and will not follow Mendalian laws for independent assortment. Genes that are close together on the same chromosome are more likely to be inherited together. Genes that are farther apart are more likely to be separated by crossing=over and exchange

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71
Q

Recombination Frequency

A

The rate at which two genes become unlinked. By establishing this, it is possible to create genetic maps which show the locations of the various alleles on the chromosome

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72
Q

Sex-linked genes

A

Located on sex chromosomes. The X chromosome is much larger than the Y and carries these genes. As females have two X chromosomes, the dominant sex-linked allele is expressed and the recessive is not. In males any allele on the one X chromosome is expressed

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73
Q

Sex-linked genes -Inheritance

A

A woman can be heterozygous for a recessive sex-linked disease and act as a carrier. She is not affected but there i a 50% probability that her sons will suffer from the disease. The male X chromosome is passed onlyto female offspring. Therefore an affected male can pass the condition to female but not male offspring. If a daughter is homozygous for the recessive allele she will suffer from the condition. If she is heterozygous, she will act as a carrier

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74
Q

Sex-linked genes -Pedigrees

A

Depict the pattern of inheritance of a particular trait in a family and gives information on gene transfer. Females are represented as circles and males as squares. Solid coloured shapes indicate that an individial has the trait/disease tracked.A dot or partially shaded shape indicates that an individual is a carrier

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75
Q

Asexual Reproduction

A

Many unicellular and some multicellular organisms reproduce via asexual reproduction. The process results in offspring that are genetically identical to the parent. There are three types: 1. Binary fission 2. Budding 3. Fragmentation

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76
Q

Asexual Reproduction Binary fission

A

Occurs in some single-celled organisms such as bacteria and amoeba. Genetic material within the parent cell is replicated while the cell elongates After the DNA is duplicated, the cell dives in half producing two identical daughter cells.The process is similar to mitosis but the latter involves nuclear disintegration and guidance of chromosomes by microtubules

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77
Q

Asexual Reproduction Budding

A

Yeast cells. Small bud cells are pinched off of from the parent by cell division

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78
Q

Asexual Reproduction Fragmentation

A

eg earthworms and plantsWhereby an organism may become fragmented into multiple pieces. Some or all of these fragments may grow into complete adults

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79
Q

Prokaryotic Genetic Diversity

A
  1. Mutations 2. Transformation 3. Transduction 4. Conjugation
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80
Q

Prokaryotic Genetic Diversity Transformation

A

Naked DNA from the environment is taken up by the prokaryotic cell and incorporated into its chromosome

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81
Q

Prokaryotic Genetic Diversity Transduction

A

Bacteriophages (viruses that infect bacteria) carry pieces of DNA from one bacteria to another

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82
Q

Prokaryotic Genetic Diversity Conjugation

A

Involves direct one-way transfer of genetic material from one organism to another. The donor extends a sex pilus to the recipient. A cytoplasmic bridge then forms between the two cells. A single strand of DNA from the donor’s bacterial chromosome or plasmid is transfered to the recipient. The bridge then breaks and the transferred DNA is taken up by the recipient’s bacterial chromosome or plasmid

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83
Q

Sexual Reproduction

A

Combines genetic material from two different sources to create offspring. Specialised germ cells undergo meiotic division and come together to form new individuals with new genetic combinations. Unlike mitosis which produces diploid cells (2N), meosis produces haploid gamete cells (1N). Even greater genetic diversity can be generated as genes are exchanged between chromosomes during crossing over during prophase I or meosis

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84
Q

Diploid Species

A

Have two sets of chromosomes, one from each parent

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85
Q

Gametes

A

Have half the chromosome number. Referred to as haploid

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86
Q

Chromosome Number in humans

A

The full complement of genetic material includes 22 chrmosome pairs called autosomes which don’t differ between the sexes and an additional pair of sex chromosomes. Total of 23 pairs

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87
Q

Inheritance Polymorphic traits

A

For example coat colour in rabbits - multiple alleles with varying degrees of dominance determine the resulting coat colour

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88
Q

Inheritance Polygenic traits

A

Traits determined by the additive effect of two or more genes

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89
Q

Inheritance Pleiotropic genes

A

Affect more than one phenotypic characteristic

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90
Q

Inheritance Incomplete dominance

A

Situation in which one allele doesn’t completely block the expression of another and alleles blend to form the phenotype. eg petal colour in snapdragons. If red (RR) and white (rr) floering plants are produced, the offspring will have pink flowers (Rr)

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91
Q

Inheritance Codominance

A

Where a heterozygous phenotype expresses both alleles equally. For example, blood types - determined by the alleles IA, IB and i corresponding to different types of antigens in the blood. An individual who is homozygous for IA or IB has an A or B phenotype. An individual who is heterozygous for IA and IB has an AB phenotype

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92
Q

Alleles

A

Alternative forms of a single gene. For any inherited trait, an individual possesses an allele from each parent

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93
Q

The Principle of Segregation

A

States that during meiosis, the two alleles from each parent segregate from each other resulting in gametes that each carry one allele for each trait

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94
Q

The Principle of Dominance

A

States that if the two alleles for a trait are different one allele will be dominant (fully expressed in the individual) and the other will be recessive (will not show itself)

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95
Q

Genotype

A

The genetic makeup of an organism

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96
Q

Phenotype

A

Actual physical characteristics of an organism

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97
Q

Test Cross Ratios 1. 100% Bb 2. 50% Bb, 50% bb 3. 25% BB, 50% Bb, 25% bb

A

1, BB x bb 2. Bb x bb 3. Bb x Bb

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98
Q

Dihybrid cross ratio

A

A 9:3:3:1 ratio is characterisic of crosses between individuals that are either homozygous recessive or homozygous dominant for two different independently assorting traits

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99
Q

Embryology Fetus

A

After eight weeks of growth, an embryo is known as a fetus

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100
Q

Embryology Development of the Fetus

A
  1. In the first few weeks, the placenta and unbilical cord form and become the specialised circulatory system between mother and fetus. This system provides nourushment via oxygenated blood in the unmbilical vein and removes metabolic waste via the umbilical arteries
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101
Q

Embryology Umbilical cord development

A

Develops from two embryonic sacs - the yolk sac ( the site of early blood vessel development) and the allantois (an outpocketing of the gut that contains many blood vessels)

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102
Q

Embryology Placenta

A

Formed when part of the chorion fuses to the uterine walls. In addition to supplying nutrients and removing waste, prevents toxins and drugs from entering the fetus and functions as an exocrine gland, producing the essential hormones of pregnancy: oestorgen, progesterone and hCG

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103
Q

Embryology Chorion

A

A membrane that surrounds the amnion

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104
Q

Embryology Amnion

A

The strong sac that houses the fetus and contains amniotic fluid

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105
Q

RNA Translation Ribosomes E site

A

exit site for the tRNA that has just finished adding its amino acid

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106
Q

RNA Translation Ribosomes P site

A

For the tRNA that is actively creating a peptide bond int eh growing polypeptide chain

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107
Q

RNA Translation Ribosomes A site

A

For tRNA that is bringing the amino acid to be added after that occupying the P site

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108
Q

Gene Structure Nucleotide

A

Composeed of one molecule of the sugar deoxyribose, one phosphate group and one of four nitrogenous bases: adenine, cytosine, guanine or thymine

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109
Q

Gene Structure DNA Structure

A

Double helix witha sugar-phosphate backbone and rings of paired nucleotide bases. Two hydrogen bonds link A and T while three join G and C

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110
Q

Gene Structure RNA Structure

A

Can be single or double stranded. Different to DNA in its composition in that the sugar ribose replaces deoxyribose and the nitrogenous base Uracil replaced thymine

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111
Q

Independent Assortment

A

During metaphase I of meiosis when chromosomes line up at the metaphase plate, there is no force that governs maternal chromosomes to orient themselves towards one pole and paternal chromosomes towards the other. For each homolougous pair, there is a 50% chance that the maternal chromosome will situate itself at a particular pole. Chromosome1 has no effect on the positioning of chromosome 7 - they are independent. Without considering crossing-over, the number of combinations of a daughter cell formed by meiosis of a parent cell with two homologous pairs of chromosomes is four

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112
Q

Linkage

A

Means genes for two given traits are linked on the same chromosome and will not follow Mendalian laws for independent assortment. Genes that are close together on the same chromosome are more likely to be inherited together. Genes that are farther apart are more likely to be separated by crossing=over and exchange

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113
Q

Recombination Frequency

A

The rate at which two genes become unlinked. By establishing this, it is possible to create genetic maps which show the locations of the various alleles on the chromosome

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114
Q

Sex-linked genes

A

Located on sex chromosomes. The X chromosome is much larger than the Y and carries these genes. As females have two X chromosomes, the dominant sex-linked allele is expressed and the recessive is not. In males any allele on the one X chromosome is expressed

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115
Q

Sex-linked genes -Inheritance

A

A woman can be heterozygous for a recessive sex-linked disease and act as a carrier. She is not affected but there i a 50% probability that her sons will suffer from the disease. The male X chromosome is passed onlyto female offspring. Therefore an affected male can pass the condition to female but not male offspring. If a daughter is homozygous for the recessive allele she will suffer from the condition. If she is heterozygous, she will act as a carrier

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116
Q

Sex-linked genes -Pedigrees

A

Depict the pattern of inheritance of a particular trait in a family and gives information on gene transfer. Females are represented as circles and males as squares. Solid coloured shapes indicate that an individial has the trait/disease tracked.A dot or partially shaded shape indicates that an individual is a carrier

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117
Q

Asexual Reproduction

A

Many unicellular and some multicellular organisms reproduce via asexual reproduction. The process results in offspring that are genetically identical to the parent. There are three types: 1. Binary fission 2. Budding 3. Fragmentation

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118
Q

Asexual Reproduction Binary fission

A

Occurs in some single-celled organisms such as bacteria and amoeba. Genetic material within the parent cell is replicated while the cell elongates After the DNA is duplicated, the cell dives in half producing two identical daughter cells.The process is similar to mitosis but the latter involves nuclear disintegration and guidance of chromosomes by microtubules

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119
Q

Asexual Reproduction Budding

A

Yeast cells. Small bud cells are pinched off of from the parent by cell division

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120
Q

Asexual Reproduction Fragmentation

A

eg earthworms and plantsWhereby an organism may become fragmented into multiple pieces. Some or all of these fragments may grow into complete adults

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121
Q

Prokaryotic Genetic Diversity

A
  1. Mutations 2. Transformation 3. Transduction 4. Conjugation
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122
Q

Prokaryotic Genetic Diversity Transformation

A

Naked DNA from the environment is taken up by the prokaryotic cell and incorporated into its chromosome

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123
Q

Prokaryotic Genetic Diversity Transduction

A

Bacteriophages (viruses that infect bacteria) carry pieces of DNA from one bacteria to another

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124
Q

Prokaryotic Genetic Diversity Conjugation

A

Involves direct one-way transfer of genetic material from one organism to another. The donor extends a sex pilus to the recipient. A cytoplasmic bridge then forms between the two cells. A single strand of DNA from the donor’s bacterial chromosome or plasmid is transfered to the recipient. The bridge then breaks and the transferred DNA is taken up by the recipient’s bacterial chromosome or plasmid

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125
Q

Sexual Reproduction

A

Combines genetic material from two different sources to create offspring. Specialised germ cells undergo meiotic division and come together to form new individuals with new genetic combinations. Unlike mitosis which produces diploid cells (2N), meosis produces haploid gamete cells (1N). Even greater genetic diversity can be generated as genes are exchanged between chromosomes during crossing over during prophase I or meosis

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126
Q

Diploid Species

A

Have two sets of chromosomes, one from each parent

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127
Q

Gametes

A

Have half the chromosome number. Referred to as haploid

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128
Q

Chromosome Number in humans

A

The full complement of genetic material includes 22 chrmosome pairs called autosomes which don’t differ between the sexes and an additional pair of sex chromosomes. Total of 23 pairs

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129
Q

Inheritance Polymorphic traits

A

For example coat colour in rabbits - multiple alleles with varying degrees of dominance determine the resulting coat colour

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130
Q

Inheritance Polygenic traits

A

Traits determined by the additive effect of two or more genes

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131
Q

Inheritance Pleiotropic genes

A

Affect more than one phenotypic characteristic

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132
Q

Inheritance Incomplete dominance

A

Situation in which one allele doesn’t completely block the expression of another and alleles blend to form the phenotype. eg petal colour in snapdragons. If red (RR) and white (rr) floering plants are produced, the offspring will have pink flowers (Rr)

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133
Q

Inheritance Codominance

A

Where a heterozygous phenotype expresses both alleles equally. For example, blood types - determined by the alleles IA, IB and i corresponding to different types of antigens in the blood. An individual who is homozygous for IA or IB has an A or B phenotype. An individual who is heterozygous for IA and IB has an AB phenotype

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134
Q

Alleles

A

Alternative forms of a single gene. For any inherited trait, an individual possesses an allele from each parent

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135
Q

The Principle of Segregation

A

States that during meiosis, the two alleles from each parent segregate from each other resulting in gametes that each carry one allele for each trait

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136
Q

The Principle of Dominance

A

States that if the two alleles for a trait are different one allele will be dominant (fully expressed in the individual) and the other will be recessive (will not show itself)

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137
Q

Genotype

A

The genetic makeup of an organism

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138
Q

Phenotype

A

Actual physical characteristics of an organism

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139
Q

Test Cross Ratios 1. 100% Bb 2. 50% Bb, 50% bb 3. 25% BB, 50% Bb, 25% bb

A

1, BB x bb 2. Bb x bb 3. Bb x Bb

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140
Q

Dihybrid cross ratio

A

A 9:3:3:1 ratio is characterisic of crosses between individuals that are either homozygous recessive or homozygous dominant for two different independently assorting traits

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141
Q

Embryology Fetus

A

After eight weeks of growth, an embryo is known as a fetus

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142
Q

Embryology Development of the Fetus

A
  1. In the first few weeks, the placenta and unbilical cord form and become the specialised circulatory system between mother and fetus. This system provides nourushment via oxygenated blood in the unmbilical vein and removes metabolic waste via the umbilical arteries
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143
Q

Embryology Umbilical cord development

A

Develops from two embryonic sacs - the yolk sac ( the site of early blood vessel development) and the allantois (an outpocketing of the gut that contains many blood vessels)

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144
Q

Embryology Placenta

A

Formed when part of the chorion fuses to the uterine walls. In addition to supplying nutrients and removing waste, prevents toxins and drugs from entering the fetus and functions as an exocrine gland, producing the essential hormones of pregnancy: oestorgen, progesterone and hCG

145
Q

Embryology Chorion

A

A membrane that surrounds the amnion

146
Q

Embryology Amnion

A

The strong sac that houses the fetus and contains amniotic fluid

147
Q

Embryology Cleavage

A

~24 hrs after fertilisation, the zygote develops by rapid mitotic cell divisions, the first of which are called cleavages. During the first three divisions, the cells continue to become smaller. ~ day three, the fourth division occurs creating the 16-cell morula

148
Q

Embryology Cleavage Indeterminante Cleavage

A

In mammals and other animals along the deuterostome evolutionary line, cleavage is indeterminate, meaning that each cell can develop into a separate organism

149
Q

Embryology Cleavage Determinante Cleavage

A

Occurs in the protostome evolutionary line (insects, crabs, snails) in which cells specialise early in development

150
Q

Embryology From Morula to Blastula

A
  1. As the morula passes from the fallopian tubes into the uterine cavity, fluid penetrates the ball of cells and pushes them to the outer rim, with a small collection of cells at one end of the sphere. 2. The inside of the ball becomes fluid-filled in a process called blastulation. At this stage the embryo is called a blastula or blastocyst and the fluid-filled centre is called the blastocele 3. The blastula develops two specialised parts: the inner cell mass which will later become the embryo, and the trophoblast which will become the placenta 4. The blastula now becomes implanted in the uterine wall and continues to undergo mitotic cell divisions
151
Q

Embryology Process

A
  1. Cleavage 2. From morula to blastula 3. Gastrulation
152
Q

Embryology Gastrulation

A

The cells of the blastulaseparate into three distinct layers: 1. ectoderm - outermost layer 2. mesoderm - middle layer 3. endoderm - innermost layer When the three different layers have become apparent, the assembly is called a gastrula

153
Q

Embryology Gastrulation and embryo types

A

Gastrulation differs among different embryo types. In amphibians, the ball of cells invaginates to create an inner space, the archenteron which becomes the digestive tract and an opening called a blastopore which becomes the anus In mammals the rapid migration of cells from the ectoderm forms the endoderm and the mesoderm from which structures arise

154
Q

Embryology Gastrulation Ectoderm

A

Later forms: S - sweat glands E - epidermis of the skin E - eye - lens and cornea N - nervous system T - tooth enamel H - hair E - epithelial lining of mouth/rectum N - nails

155
Q

Embryology Gastrulation Mesoderm

A

Later forms: S - skeletal system M - muscle (skeletal) A - adrenal cortex L - lining of the body cavity L - lymphatic system R - Reproductive organs E - excretory system D - dermis of the skin M - muscular layer of the digestive tract C - circulatory system

156
Q

Embryology Gastrulation Endoderm

A

Later forms: P - pancreas E - epithelial lining of digestive tract T - thyroid R - reproductive tract lining U - urinary tract lining L - liver E - epithelial lining of respiratory tract

157
Q

Embryology Neurulation

A

Following gastrulation, the nervous system begins to develop. A hollow cord of cells in the mesoderm develops into the notochord which later becomes part of the spinal column. Ectodermal cells above the notochord fuse to become the neural tube which gives rise to the brain and spinal cord. Some ectodermal cells break off the neural tubes and become neural crest cells. These move throughout the body and develop into many parts of the peripheral nervous system such as sensory neurons and glial cells

158
Q

Male Reproduction Androgens

A

Sex hormones. Regulate the pattern of male reproduction. Testerone is the most important

159
Q

Male Reproduction Androgens Testosterone

A

In addition to regulating spermatogenesis, accounts for secondary male sex characteristics (pubic hair, facial hair, muscle growth) and determines certain sexual behaviours (sex drive, aggressiveness)

160
Q

Male Reproduction Gonadotrophins

A

Regulate function of the gonads LH - secreted by the anterior pituitary gland, stimulates the Leydig cells of the testes to produce testosterone FSH - acts with testosterone to continuosly produce sperm

161
Q

Female Reproduction The menstrual cycle

A

Divided into three main parts: 1. Follicular phase 2. luteal phase 3. menstruation

162
Q

Female Reproduction The menstrual cycle Follicular phase

A
  1. GnRH from the hypothalamus stimulates the anterior pituitary to release FSH and LH 2. FSH and LH trigger the growth of the follicle which begins to produce oestrogen at low levels 3. Oestrogen causes the endometrium to thicken 4. As the amount of oestrogen rises, a positive feedback system causes a surge in LH and FSH 5. A day after the LH surge, ovulation occurs ending the follicular phase
163
Q

Female Reproduction The menstrual cycle Luteal phase

A
  1. LH stimulates the follicle to become the corpus luteum which continues to produce oestrogen and progesterone 2, Endometrial arteries enlarge and glands begin to secrete nutrients
164
Q

Female Reproduction The menstrual cycle Menstruation

A

If the egg is not fertilised. the corpus luteum disintegrates resulting in a drop in oestrogen and progesterone causing spasm and rupture of the endometrial arteries, sloughing and menstruation. The follicular phase then begins

165
Q

Female Reproduction The menstrual cycle Conception

A

The point at which the egg becomes fertilised by a sperm cell. Occurs in the fallopian tubes (or oviducts). The fertilised egg (zygote) then travels via the oviduct to the uterus where it implants on the endometrium and develops into a fetus

166
Q

The Female Reproductive System Ovaries

A

The female gonads. Suspended within the abdominal cavity. Composed of hundreds of thousands of follicles, each containing an egg

167
Q

The Female Reproductive System Oogenesis

A

Begins in the embryo. Oogonia in the ovaries begin the first cycle of meosis stopping at prophase I. 2. These primary oocytes are reactivated by hormones at puberty. FSH encourages development of follicles inducing the completion of the first meotic cycle and begins meiosis II. The unequal division of cytoplasm results in one haploid secondary oocyte, which goes on to from an egg, and one secondary body which can’t form a viable gamete 3. Meosis is again halted, this time at metaphase II. 4. Each month from puberty until menopause, one follicle will mature and release its secondary oocyte. If this ovulated oocyte is penetrated by a sperm cell, meosis II is completed resulting in a fertilised egg (a zygote) and a second polar body

168
Q

The Male Reproductive System Testes

A

The male gonad. Composed of tightly wound seminiferous tubules. Housed outside the abdominal cavity in the scrotum, where they are kept 2 degrees celcius cooler that the rest of the body permitting healthy sperm production

169
Q

The Male Reproductive System Sertoli Cells

A

Specialised cells of the seminiferous tubules of the testes. Site of spermatogenesis

170
Q

The Male Reproductive System Leydig cells

A

Dispersed throughout the seminiferous tubules of the testes. Produce testosterone and other androgens

171
Q

The Male Reproductive System Spermatogenesis

A
  1. Spermatogonia undergo two cycles of meiosis. After the first, the germ cells are called primary spermatocytes and are still diploid. 2. A second cycle produces haploid secondary spermatocytes 3. These then continue to mature into spermatids. 4, Spermatids then lose their cytoplasmic bridge connections, gain a flagellum tail and become individual sperm cells 5. Spermatozoa then travel along the seminiferous tubules into the epididimus where they become motile 6. From the epididimus, they travel through the vas deferens, ejaculatory duct and urethra. Along the way, secretions from the bulbourethral gland, prostate gland and seminal vesicles create semen
172
Q

Gametes

A

Germ cells produced by the gonads. Have a haploid number of chromosomes (23).

173
Q

Differences Between Male and Female Gamete Production

A
  1. Spermatogonia continue to divide mitotically throughout a mature adult’s lifetime. Allows a male to produce up to 600 million sperm on a daily basis. Oogonium only divide mitotically in the embryo 2. Oogenesis has resting periods: meosis begins in the embryo and is then halted until puberty. Spermatogenesis begins at puberty and is continuous 3. In oogenesis, cytokinesis is uneven, giving rise to only one viable gamete. Spermatogenesis involves equal cytokinesis and the production of four sperm 4. In spermatogenesis the daughter cells of the meiotic cycle are connected via cytoplasmic bridges until the last stage in development
174
Q

Endocrine system

A

Unlike the nervous sytem which relies upon electrical impulses to trigger rapid responses, the endocrine system uses chemical signals (hormones) to coordinate longer lasting activities such as growth and reproduction

175
Q

Endocrine System Hypothalamus

A

Brain region that connect the nervous system with the endocrine system. Receives information from nerves throughout the body and initiates an appropriate response, regulating body temp, hunger, thirst etc. Composed of neurosecretory cells that control the activity of the pituitary gland

176
Q

Endocrine System Pituitary

A

Sits just under the hypothalamus. Has two parts: anterior (adenohypophysis) and posterior (neurohypophysis)

177
Q

Endocrine system Hormones

A

Secreted by endocrine glands directly into the blood and travel via the circulatory system to their target organs and cells. There are several classes: 1. Steroid 2. Proteins and Peptides 3. Amino acid derivatives

178
Q

Endocrine system Hormones Steroid

A

eg oestrogen, testosterone Lipids. Can easily travel through cell membranes to bind with intracellular receptors

179
Q

Endocrine system Hormones Proteins and peptides

A

eg GH - peptide Cannot traverse the cell membrane but bind to receptors on the cell surface

180
Q

Endocrine system Hormones Cascading effect

A

Each hormone that successfully binds to its receptor activates a series of second messengers which in turn activate multiple enzymes. For this reason, very small amounts of a hormone in the bloodstream can cause dramatic changes in physiology

181
Q

Endocrine System Pituitary Anterior

A

The main hormone products are: F - FSH L - LH A - ACTH T - TSH - secreted in response to TRH from the hypothalamus

182
Q

Endocrine System Pituitary Posterior

A

The main hormone products are: P - Prolactin G - GH

183
Q

Endocrine System Pituitary Storage

A

Oxytocin and ADH are made in the hypothalamus but are stored and secreted by the posterior pituitary

184
Q

Endocrine System Pituitary Hormones that are not part of the hypothalamic-pituitary axis

A
  1. Calcitonin - parathyroid, calcium deposition 2, glucagon - alpha cells of the pancreas 3. insulin - beta cells of pancreas 4. parathyroid hormone - parathyroid, calcium release
185
Q

Central Nervous System

A

Brain and spinal cord

186
Q

Central Nervous System Brain

A

Center of complex neural integration. Composed of three main parts: 1. cerebrum - largest part, controls memory, thought, sensation and movement 2. cerebellum - coordinates and controls movement 3. brainstem - composed of the medulla oblongata, pons and midbrain. Responsible for homeostasis and autonomic functions such as breathing, swalllowing, heart muscle activity and digestion

187
Q

Central Nervous System Spinal Cord

A

Has two functions: to relay information to the brain and to process simple stimuli. Primarily integrates by way of reflex a connection of two or three neurons that unconsciously reacts to a simple stimulus eg the knee jerk reaction

188
Q

Peripheral Nervous System

A

Collects and distributes information. Made up of sensory organs, motor (efferent) nerves and sensory (afferent) nerves

189
Q

Peripheral Nervous System Motor

A

Divided into: 1. Somatic - controls skeletal muscle 2. Autonomic - regulates smooth and cadiac muscles and organs of the digestive, CV, urinary and endocrine systems. Can be further divided into sympathetic and parasympathetic

190
Q

Neurons Summation

A

Many impulses come together to make a neuron fire. A single impulse doesn’t necessarily trigger the transmission of an action potential. Certain impulses may even have an inhibitory effect

191
Q

Neurons Synapse

A

The junction between the axon of a presynaptic neuron and the soma of another neuron or an effector membrane such as muscle. There are two types of synapses: 1. Electric synapses 2. Chemical synapses

192
Q

Neurons Synapse Electric synapses

A

Or gap junctions. Protein channels that allow ions to flow freely from one cell to another and thus to function as a unit

193
Q

Neurons Synapse Chemical synapses

A

Whereby a cell relays an impulse to another cell by converting the impulse into a chemical message, a neurotransmitter

194
Q

Neurons Action Potentials Propagation

A

As Na+ rush into the neuron, they cause the electrical potential of the adjacent region to change. The adjacent portion reaches a threshold potential which quickly initiates an AP in theat area. Meanwhile, the original area returns to its resting potential.

195
Q

Neurons Action Potentials Propagation Factors affecting speed of conduction

A
  1. Diameter - The wider the axon, the greater the speed of the AP 2. Myelination - speed conduction velocity of the impulse. Insulate sections of the membrane so that impulses jump quickly between nodes of Ranvier - saltatory conduction
196
Q

Neurons Action Potentials

A
  1. Cell at resting potenial of -40mV 2. Stimulus changes the permeability of the neuronal membrane. Na+ enter making the charge inside the cell more positive 3. Threshold potential reached, opening VGSCs and rapidly increasing charge to +70mV in a small segment of the axon 4. VGSCs close, VGPCs open and resting potential is restored
197
Q

Neurons Resting Potential

A

When a neuron is not active, it is polarised, meaning that the intracellular electrical charge differs from the extracellular charge. The sodium-potassium pump creates this difference in charge by pumping 3Na+outwards for 2K+ inwards. Membrane is also selectively permeable to K+, allowing this to leak outmore readily than Na+ inwards. The result is a negative charge to the inner surface of the cell membrane relative to its outside

198
Q

Neurons Types

A
  1. Sensory neurons (afferents) 2. Interneurons 3. Motor neurons (efferents)
199
Q

Neurons Nerves

A

Bundles of axons and dendrites

200
Q

Neurons Components

A

1, Soma - cell body, contains nucleus and organelles 2. dendrties - extensions of the cytoplasm that carry signals to the soma 3. axon

201
Q

Urinary System Functions

A
  1. To remove metabolic waste from the body - eg ammonia - highly toxic nitrogenous by-product of cell metabolism. Converted in liver to soluble urea which is then removed by the kidneys 2. To osmoregulate the amount of salts and water in the circulatory system
202
Q

Urinary System Filtration, Secretion and Reabsorption Filtration

A
  1. Blood enters via the renal artery 2. Travels via the arterioles into the capillaries 3. A ball of capillaries called the glomerulus is selectively porous allowing water and small solutes such as amino acids, salts and waste products to be filtered out. 4. Red blood cells and plasma proteins continue to circulate through the blood vessels, exiting the kidney via the renal vein
203
Q

Urinary System Filtration, Secretion and Reabsorption Secretion and Reabsorption

A
  1. The filtrate enters part of the nephron called the Bowman’s capsule 2. Travels through the rest of the nephron: the proximal convoluted tubule, the descending and ascending limbs of the Loop of Henle, distal convoluted tubule and the collecting duct 3. Substances are either secreted into the filtrate (H+ to maintain pH) or reabsorbed by the surrounding capillaries (sugars, amino acids, nutrients) 4. The collecting ducts of each nephron open onto a larger opening - the calyx 5. Calyces join the from the renal pelvis, leading into the ureter connecting the kidney to the bladder
204
Q

Digestive System Large Intestine

A

Water is reabsorbed from the chyme. Salts are actively transportedmfrom the large intestine and water follows by osmosis leaving dense faeces

205
Q

Digestive System Small Intestine

A

Food is broken down in the duodenum Nutrients are reabsorbed in the jejunum and the ileum The lining of the lower small intestine is covered with projections - microvilli - which maximise surface area for diffusion and active transport of molecules The network of blood vessels surrounding the lower small intestine collect the nutrients and transport them to the liver which regulates their release to the heart and other parts of the body

206
Q

Digestive System Pancreas

A

Two glands - the pancreas and the liver - secrete into the duodenum substances crucial for digestion The exocrine pancreas secretes molecules via ducts into the duodenum - hydrolytic enzymes that break down fats, proteins and carbohydrates and a strongly alkaline bicarbonate solution which neutralises the highly acidic chyme This is as opposed to the endocrine pancreas which secretes products (eg insulin) directly into the bloodstream

207
Q

Digestive System Liver

A

Two glands - the pancreas and the liver - secrete into the duodenum substances crucial for digestion The liver produces bile, a mixture containing no digestive enzymes but salts and lipids that aid in fat processing. Also contains pigments - by-products of the liver’s breakdown of red blood cells

208
Q

Digestive System Gallbladder

A

Stores bile until needed

209
Q

Digestive System Stomach

A

Large muscular organ Capable of storing large volumes of food before moved on to other parts of the digestive system Digestive enzymes and high concentrations of HCl (pH ~2) begin to digest proteins and to break down food into small particles. Food becomes known as the nutrient-rich broth chyme which is slowly released into the duodenum

210
Q

Digestive System Pharynx

A

Throat - passageway that channels food to the oesophagus and air to the trachea

211
Q

Digestive System Oesophagus

A

Forces food to the stomach by way of muscular contraction of the oesophageal wall - peristalsis

212
Q

Digestive System Mouth

A
  1. Mechanical breakdown of food by the teeth 2. Saliva is secreted by the salivary glands and increases moisture and begins the chemical breakdown of carbohydrates via the enzyme salivary amylase 3. The tongue manupulates food, pushing the bolus to the pharynx to be swallowed
213
Q

Cells of the Immune System Lymphocytes Origin

A

Bone marrow

214
Q

Cells of the Immune System Lymphocytes B-lymphocytes

A

Found mainly in the bone marrow Involved with humoral immunity Can specialise into plasma cells

215
Q

Cells of the Immune System Lymphocytes T-lymphocytes

A

Originate in the bone marrow but travel to the thymus to mature Involved in cell-mediated imune response Are three forms - helper, killer and suppressor T cells

216
Q

Cells of the Immune System Lymphocytes Memory Cells

A

After an large immune response, many memory B and T cells persist in the spleen. Result is permanent immunity After a mild response, there is temporary immunity

217
Q

Cells of the Immune System Phagocytic Cells

A
  1. Macrophages 2. Neutrophils 3. Eosinophils 4. Basophils 5. Dendritic cells
218
Q

Cells of the Immune System Natural Killer Cells

A

Not very specific. Recognize harmful sequences in virus-infected and cancer cells releasing chemicals that cause these cells to undergo apoptosis

219
Q

Cells of the Immune System Mast Cells

A

Store histamine Activate an inflammatory response follwoing physical injurt or invasion by pathogens

220
Q

Events Of The Immune Response Self vs Non-self

A

MHC proteins identify body’s own cells. Unique to each individual and occur in every nucleated cell of the body Autoimune diseases occur when the body is unable to discriminate between self and ononself and the immune system attacks it’s own cells

221
Q

Bacterial Diseases

A
  1. TB 2. Syphilis 3. Leproust
222
Q

Protozoan Diseases

A
  1. African sleeping sickness 2. Malaria
223
Q

Viral Diseases

A
  1. Smallpox 2. Herpes 3. Measles 4. AIDS
224
Q

Viruses vs Retroviruses

A

Viruses enter the cell and change its biochemistry to produce thousands of viral progeny. Generally uses its own resources to copy its DNA and produce viral RNA Retroviruses eg AIDS contain RNA material. Create an intermediate copy of DNA within the host which is copied to form viral RNA

225
Q

The lymphatic system

A

Link between the circulatory and immune systems There is a net movement of fluid and molecules in the blood from the capillaries to the interstitial fluid. One of the functions of the lymphatic system is to absorb the excess fluid and conduct it in tiny lymph vessels via the lymph nodes to the circulatory system Also plays a crucial role in immunity via production of lymphocytes and transport of WBCs

226
Q

Circulatory System Pulmonary Circuit

A
  1. Deoxygenated blood enters the RA via the superior vena cava 2. Tricuspid valve opens allowing blood to enter the RV 3, Blood passes through the pulmonary valve and into the pulmonary artery 4. Blood flows through the pulmonary arteries, arterioles and capillaries. Carbon dioxide is unloaded and oxygen enters the blood 5. Returns to the heart via the pulmonary vein. Enters the LA.
227
Q

Circulatory System Systemic Circuit

A
  1. Blood enters the LA 2. Via mitral valve, enters LV 3. Forcefully pumped via the aortic valve into the aorta
228
Q

Circulatory System Systolic Blood Pressure

A

Maximum pressure attained during arterial pulse

229
Q

Circulatory System Diastolic Blood Pressure

A

Lowest pressure attained during arterial pulse

230
Q

Circulatory System Blood Composition

A

55% plasma 45% cells

231
Q

Circulatory System Blood Composition Plasma

A

92% water inorganic salts proteins (eg clotting proteins fibrinogen and prothrombin, immune immunoglubulins, BP regulating albumins) hormones nutrients waste products fats gases

232
Q

Circulatory System Blood Composition Cells

A
  1. 99% RBCs 2. phagocytes 3. lymphocytes 4. platelets - fragments of cells. attach to fibrin at the site of injury to form clots
233
Q

Muscular System Sliding Filament Model

A
  1. AP triggers the release of stored Ca2+ 2. Ca2+ expose binding sites in the actin filament 3. At these sites, a head of myosin attaches and pulls the thinner actin filament inward - power stroke - ADP and Pi released 4. ATP attaches to the myosin head and triggers its release 5. ATPase on the myosine head cleaves bound ATP. ADP and Pi remains bound to the myosin. Myosin head is now free to reattach to the actin filament 5. The repeated attachment and release of many heads continues as long as there is stimulation or until the muscle fatigues
234
Q

Muscular System Skeletal Muscle Structure

A
  1. Basic unit is the myofibril composed of thin (predominently three types of actin) and thick (myosin) filaments that slide across each other during muscle contraction. Surrounding these filaments are two types of network - sarcoplasmic reticulum and T-tubules 2. Many closely packed myofibrils make up each fibre. 3. Fibres are surrounded by an endomysium and grouped into fascicles 4. Fascicles are surrounded by perimyceum. Groups of fascicles surrounded by epimyceum make up the total muscle
235
Q

Muscular System Skeletal Muscle Structure Tendons

A

Attach skeletal muscle to bone or other mucle

236
Q

Muscular System Skeletal Muscle Structure Sarcoplasmic Reticulum

A

Stores Ca2+

237
Q

Muscular System Skeletal Muscle Structure T-tublues

A

Help to conduct nerve impulses

238
Q

Muscular System Skeletal Muscle Structure Sarcomeres

A

Units of overlapping thin and thick filaments. Single sarcomere is defined from one Z-line to the next.

239
Q

Muscular System Skeletal Muscle Structure Z-line

A

Alpha actinin, Binds sarcomeres together

240
Q

Muscular System Skeletal Muscle Structure A-band

A

Thick (myosin) filaments Overlaps at edges with thin (actin) filaments Is constant during muscle contraction

241
Q

Muscular System Skeletal Muscle Structure H-band

A

Area of thick (myosin) filaments that doesn’t overlap with actin. Shrinks during muscle contraction

242
Q

Muscular System Skeletal Muscle Structure I-band

A

Area of thin (actin) filaments that doesn’t overlap with myosin. Shrinks during muscle contraction

243
Q

Muscular System Types of muscle

A
  1. Skeletal 2. Smooth 3. Cardiac
244
Q

Muscular System Types of muscle Smooth

A
  1. Lacks striations of skeletal muscle 2. Generally not under voluntary control 3. One nucleus per cell
245
Q

Muscular System Types of muscle Cardiac

A
  1. Striated 2. Controlled by the autonomic nervous system 3. Between cells, are electrical connections - intercalated discs which relay impulses during a heartbeat 4. One nucleus per cell
246
Q

Muscular System Types of muscle Skeletal

A
  1. Striated 2. Composed of two distinct fibre types: red (slow-twitch, contain many mitochondria and myoglobin) and white (fast-twitch, contract with greater force than slow twitch but fatigue more rapidly) 3. Multiple nuclei per cell
247
Q

Skeletal System Joints Synarthroses

A

Immovable joints eg suture in the skull

248
Q

Skeletal System Joints Types

A
  1. Synarthroses 2. Amphiarthroses 3, Diarthroses
249
Q

Skeletal System Joints Amphiarthroses

A

Cartilagenous joints found throughout the axial skeleton eg between vertibrae Absorb shock

250
Q

Skeletal System Joints Diarthroses

A

Synovial joints found throughout the appendicular skeleton. Vary in form depending on location Strong, with free movement. Lubricated by synovial fluid

251
Q

Skeletal System Connective Tissues

A
  1. Cartilage - At birth most of the skeleton is cartilage. Later replaced by bone in process of endochondral ossification. Bones that don’t form from a cartilage template undergo intermembranous ossification 2. Tendons 3. Ligaments - attach bones together at joints
252
Q

Skeletal System Epiphyseal Plate

A

Junction of bone and cartilage in the long bones. Is the location of continued growth of the long bones

253
Q

Skeletal System Types of Bone Tissue

A
  1. Cancellous 2. Compact Outer potion of any given human bone is formed from compact bone. The inner portion is cancellous bone
254
Q

Skeletal System Types of Bone Tissue Cancellous

A

Spongy bone Consists of a network of supporting elements called trabeculae

255
Q

Skeletal System Types of Bone Tissue Compact

A

Composed of dense material made up of structural units called osteons - cylindrical sections at the centre of which is a Haverian canal (tube housing bundles of blodd vessels and nerves). Lamallae - oncentric rings of bony tissue containing osteoblasts surround these canals. Parallel osteons are connected by Volksmann’s canals between Haversian canals

256
Q

Skeletal System Types of Bone

A
  1. Long - arms, legs, toes, fingers. Curve slightly to absorb shock and have long ends 2. Short - wrist, ankle. 3. Flat - skull, ribs, hips, sternum, scapula. Broad plates 4. Irregular - vertibrae, parts of the face 5. Sesamoid - eg kneecap. embedded within tendons
257
Q

Integumentary System

A

Skin. DIvided into dermis and epidermis

258
Q

Epidermis

A

Thin outer skin layer composed of stratified squamous epithelial cells - keratinocytes. Undergo progessive maturation through the layers changing shape and becoming filled with keratin. Stratum corneum composed of flattened, dead keratinocytes filled with keratin Has no BVs or nerves Has five layers Also contains melanocytes and Langerhans cells

259
Q

Epidermis -Layers

A

From outer to innner: 1. stratum corneum 2. stratum lucidem 3. stratum granulosum 4. stratum spinosum 5. stratum basale

260
Q

Dermis

A

Deep skin layer composed of connective tissue including collagen and elastin, sparse cells and ground substance Fibroblasts are the most abundant cell type but there are immune cells including mast cells, lymphocytes and macrophages present Also contains BVs, nerve endings (pacinian, meisner’s corpuscles), hair follicles, sweat glands and sebaceous glands

261
Q

Subcutanous layer

A

Below dermis. Filled with adipose tissue, BVs, lymphatics and nerves

262
Q

Taxonomy Linnaeus Classification

A
  1. Kingdom 2. Phylum 3. Class 4. Order 5. Family 6. Genus 7. Speces
263
Q

Taxonomy Five Kingdoms

A
  1. Monera 2. Protista 3. Fungi 4. Plantae 5. Animalia
264
Q

Taxonomy Five Kingdoms Vertibrates

A

95% animals are vertibrates. Fall into the phyla Phordata - all have, in some stage of their developement, a notochord, a nerve chord and pharyngeal slits eg humans, fish, reptiles, birds

265
Q

Taxonomy Five Kingdoms Invertibrates Lower Invertibrates

A
  1. Porifera - spongescellular level of design (no specialised tissues or organs) 2. Cnidarians - corals, sea anemones and jellyfish. Tissue level of design (no organs) 3. Platyhelminthes - flukes, flatworms and tapeworms. Exhibit cephalisation (presence of head and tail regions) 4. Nematoda - roundworms
266
Q

Taxonomy Five Kingdoms Invertibrates Higher Invertibrates

A

Have a coelom (lined body cavity that aids in movement, nutrient transport and gamete muturation) at some stage of development 1. Annelidae - segmented worms 2. Arthropoda - includes spiders, insects and lobsters. Characterised by jointed appendages and an exoskeleton 3. Echinodermata - starfish, urchins, sea cucumbers and sand dollars. Have pentaradial symmetry 4. Mollusca - snails, clams and squid. Earliest protostome phylum

267
Q

Taxonomy Five Kingdoms Cell Sizes

A

Monera - small 1-10um Protista - large - 10-100um Fungi - large - 10-100um Plantae - large 10-100um Animalia - large 10-100um

268
Q

Taxonomy Five Kingdoms Cell Types

A

Monera - prokaryotic Protista - eukaryotic Fungi - eukaryotic Plantae - eukaryotic Animalia - eukaryotic

269
Q

Taxonomy Five Kingdoms Nuclei

A

Monera - absent Protista - present Fungi - present Plantae - present Animalia - present

270
Q

Taxonomy Five Kingdoms Chromosome Structure

A

Monera - nucleoid (single naked circle of DNA) Protista - chromosomes made of DNA, RNA and protein Fungi - chromosomes made of DNA, RNA and protein Plantae - chromosomes made of DNA, RNA and protein Animalia - chromosomes made of DNA, RNA and protein

271
Q

Taxonomy Five Kingdoms Mitochondria

A

Monera - absent Protista - sometimes present Fungi - sometimes present Plantae - present Animalia - present

272
Q

Taxonomy Five Kingdoms Respiration

A

Monera - obligate and facultative anaerobes, obligate aerobes Protista - most obligate aerobes Fungi - most obligate aerobes Plantae - most obligate aerobes Animalia - most obligate aerobes

273
Q

Taxonomy Five Kingdoms Photosynthesis

A

Monera - if present, enzymes bound to cell membrane. Large variations in metabolic raw materials and end products Protista - if present, enzymes packaged into plastids Fungi - absent Plantae - generally present. Enzymes packaged into chloroplasts Animalia - absent

274
Q

Taxonomy Five Kingdoms Metabolism

A

Monera - many variations Protista - sometimes present Fungi - oxidative metabolism, glycolysis, Kreb’s cycle, electron transport chain Plantae - oxidative metabolism, glycolysis, Kreb’s cycle, electron transport chain Animalia - oxidative metabolism, glycolysis, Kreb’s cycle, electron transport chain

275
Q

Taxonomy Five Kingdoms Cell wall

A

Monera - polysaccharide-amino acid or peptidoglycans Protista - some forms, various types Fungi - chitin Plantae - cellulose Animalia - absent

276
Q

Taxonomy Five Kingdoms Genetic Recombination

A

Monera - rare: conjugation, transduction, transformation Protista - common: fertilisation and meiosis Fungi - common: fertilisation and meiosis Plantae - common: fertilisation and meiosis Animalia - common: fertilisation and meiosis

277
Q

Taxonomy Five Kingdoms Nutrition

A

Monera - autotrophic (photo- or chemosynthesis) and/or heterotrophic Protista - autotrophic (photosynthesis) and/or heterotrophic Fungi - heterotrophic absorption Plantae - autotrophic photosynthesis Animalia - heterotrophic digestion

278
Q

Taxonomy Five Kingdoms Motility (single cell)

A

Monera - bacterial flagellae Protista - undulipodia, ameboid Fungi - flagella only in zoospore gametes. All others non motile Plantae - undulipodia only in some gametes Animalia - undulipodia

279
Q

Taxonomy Five Kingdoms Cellularity

A

Monera - unicellular or colonial Protista - unicellular, multicellular or colonial Fungi - unicellular (yeast) or multicellular Plantae - multicellular Animalia - multicellular

280
Q

Taxonomy Five Kingdoms Cell division

A

Monera - mostly binary fission. No centrioles, mitotic spindle or microtubules Protista - mitosis. Centrioles, mitotic spindle present Fungi - mitosis. Centrioles, mitotic spindle absent Plantae - mitosis. Centrioles, mitotic spindle absent Animalia - mitosis. Centrioles, mitotic spindle present

281
Q

Taxonomy Five Kingdoms Development

A

Monera - N/A Protista - varies Fungi - spores Plantae - multicellular embryo enclosed in maternal tissues Animalia - blastula

282
Q

Taxonomy Five Kingdoms Plantae Growth

A

Unlike animls, can continue to grow throughout entire lifetime, This indeterminate growth occurs at the embryonic tissue called the meristem. Primary growthoccurs in the vertical directionvia apical meristemsat the tip of the stem and root. Seconary, lateral, growth occurs at the lateral meristem

283
Q

Taxonomy Five Kingdoms Plantae Reproduction

A

Called alternation of generations. In animals the only haploid cells are gametes.In plants, an entire mature haploid organism is part of the life cycle. The haploid generation, called the gametophyte, undergoes mitosis producing gametes which fuse in fertilisation to become a zygote which grows into a mature diploid plant called the sporophyte. The sporophyte undergoes meiosis to produce haploid gametescalled spores. These develop into mature gametophytes

284
Q

Taxonomy Five Kingdoms Plantae Angiosperms

A

Flowering plants Account for ~90% plants House their reproductive organs within the flower The male reproductive organ is called the stamen and the female the carpel. Pollinisation by wind, animals etc brings the male gametes to the female gametes. Fertilisation occurs, the ovule devlops into a seed and the ovary into a fruit

285
Q

Taxonomy Five Kingdoms Fungi

A

Heterotrophic but don’t ingest their food. Many - detritivores - decompose the organic remains and waste of plants and animals. Some are parasitic. Others are micorrhizae - have a mutualistic, symbiotic relationship with plant roots

286
Q

Taxonomy Five Kingdoms Fungi Multicellular

A

Composed of hyphae which form an underground network called the mycelium which may give rise to above-ground fruiting bodies such as mushrooms. Hyphae can be composed of separated cells - separated by cell walls called septa which contain large pores for passage of cytoplasm and organelles from cell to cell. Other Hyphae may have no septa and be composed of one large syncytium of cytoplasm and nuclei - undergo mitosis but not cytokinesis Some fungi have hyphae that can penetrate cell walls of organisms with which they have a parasitic or symbiotic relationship - called haustoria.

287
Q

Taxonomy Five Kingdoms Fungi Unicellular

A

Yeast - reproduce by budding. Replicate their genetic material and then pinch off a portion of the membrane and cytoplasm to form a new cell

288
Q

Taxonomy Five Kingdoms Fungi Multicellular Sexual Reproduction

A

Can undergo asexual or sexual reproduction depending on environmental conditions. Spend most of their lives as haploid organisms 1. Sexual reproductive cycle begins when one fungi releases hormones which cause the hyphae of the mating fungi to grow toward each other 2. They then fuse ctoplasm - called plasmogamy. 3. Nuclei then fuse in karyogamy creating a diploid organism. 4. This is followed by meiosis creating haploid spores which then grow into mycelium of new organisms

289
Q

Taxonomy Five Kingdoms Fungi Multicellular Asexual Reproduction

A

Simply involves mitosis forming clones in the form of spores. These can travel by air, water or flagella in the case of zoospores and can produce new organisms

290
Q

Taxonomy Five Kingdoms Protista

A

Used to refer to eukaryotic organisms that are not plants, fungi or animals. Extremely diverse - thought to be the result of endosymbiosis whereby one unicellular organism engulfs another without destroying it Most are unicellular, some are autotrophs, some heterotrophs and others mixotrophs (can be either) Some adhere to asexual reproduction, others engage in some form of sexual reproduction

291
Q

Taxonomy Five Kingdoms Monera

A

Include all prokaryotes but there are two distinct groups: bacteria and archaea Three commmon cell shapes are rods (bacilli), spheres (cocci) and spirals Almost all have a cell wall and many also have a capsule that surrounds the cell wall A nucleoid region contains a single circular chromosome with very few associated proteins. Many also contain a smaller ring of DNA - a plasmid - which replicate independently of the cell’s chromosome

292
Q

Taxonomy Five Kingdoms Monera Bacteria vs Archaea

A

A key difference is in the structure of the cell wall - ain archaea these contain a variety of polysaccharides and proteins. Bacterial cell walls are composed of peptidoglycans - sugar polymers cross linked by peptide bonds Many archaea - extremophiles have adapted to harsh environments where few other organisms can survive

293
Q

Meiosis Process Meiosis I

A
  1. Meiosis I - nuclear membrane disintegrates and homologous chromosomes find each other forming tetrads 2. Chromosomes line up gene by gene, oftentimes cross-crossing to form chiasmata and exchanging genetic materialwith their homologues 3. Homologous chromosomes line up at the metaphase plate and are sparated from each other during anaphase I 4. In some species, nulclear membranes reform during telophase I and cytokinesis completes the division resulting in two haploid cells
294
Q

Meiosis Meiosis I

A

The first of two cell divisions then occur during meiosis. Referred to as reduction division because the resultant daughter cells are haploid.

295
Q

Meiosis Meiosis II

A

The second cycle of meiosis. Referred to as equatorial division as the haploid cells give rise to more haploid cells

296
Q

Meiosis Process Meiosis II

A
  1. No DNA replication occurs before meiosis II but the replication that occured prior to meiosis I created two sister chromatids for each chromosome. In prophase II the nuclear membrane of each daughter cell disintegrates 2. Sister chromatids line up in metaphase II 3. These are pulled apart in anaphase II 4. Nuclear membranes are re-formed in telophase II and cytokinesis completes the formation of four haploid cells
297
Q

Meiosis Non-disjunction

A

Occurs if cell don’t separate properly. Produces one cell with too many copies of a particular gene (polyploidy) and another without any copies (aneuploidy). Down’s syndrome is caused by non-disjunction resulting in three copies of chromosome 21

298
Q

Mitosis

A
  1. Interphase 2. Prophase 3. Metaphase 4. Anaphase 5. Telophase 6. Cytokinesis
299
Q

Mitosis Interphase

A
  1. G1 phase - growth 2. S phase - when chromosomes replicate 3. G2 phase - growth
300
Q

Mitosis Prophase

A
  1. Nuclear envelope begins to disintegrate 2. Chromosomes condense - each consists of two sister chromatids held together by a centromere 3. Microtubules appear forming the mitotic spindle near the centrioles
301
Q

Mitosis Metaphase

A
  1. Centrioles gravitate towards opposite ends of the cell 2. Mitotic spindle - composed of microtubules extending from the centrioles - attach to the centromere of each chromosome helping to align the chromosomes in the middle of the cell
302
Q

Mitosis Anaphase

A
  1. Chromosomes begin to separate, centromeres split and the spindle fibres pull the chromatids to opposite ends of the cell
303
Q

Mitosis Telophase

A
  1. When the chromatids are at opposite ends of the dividing cell, they become less condensed 2. mitotic spindles disappear 3. Nuclear membranes begin to form in each daughter cell
304
Q

Mitosis Cytokinesis

A

Usually occurs simultaneously with telophase. The cytoplasm is divided between the two daughter cells. Rearrangements of microfilaments within the cytoplasm creates a cleavage furrow which progress to split the cell into tow distinct daughter cells. The cell membrane develops around the two new cells each containing identical genetic information

305
Q

Mitosis Plants

A

In plant cells, cell walls prevent formation of the cleavage furrow. Instead vesicles from the Golgi apparatus carrying components of the new cell wall move towards the midline of the cell. There they coalesce to from the cell plate and a new cell wall is formed.

306
Q

Mitosis Control of cell division

A
  1. contact inhibition - physical contact with neighbouring cells signals a halt to reproduction 2. Mitogens - chemicals produced by the body. Can stimulat or inhibit cell division
307
Q

Eukaryotic Cells

A

Contain a membrane-bound nucleus and a number of other organells suspended
within the protein-rich cytoplasm and mostly surrounded by membranes.

308
Q

Eukaryotic Cells

Nucleus

A

Contains almost all of the cell’s DNA
Resposible for activities including DNA replication, RNA synthesis and responses to changes in the cell’s environment
Contains condensed material - chromatin - consisting mainly of DNA and protein
May contain one or more nucleoli - specialised areas that rpoduce ribosomal RNA and help to assemble proteins

309
Q

Eukaryotic Cells

Ribosomes

A

Small, non-membrane bound particles contisting mainly of rRNA. Contain a small
and large subunit. Either bound to the ER membrane or free in the
cytoplasm

310
Q
A

Highly convoluted bilayer membrane
Secretes enzymes and produces other bilayer membranes.
Either rough or smooth. Former involved in export of proteins destined
to fuse with cell membrane or other organelles. Latter involved in the
synthesis of lipids. metabolism of carbohydrates and detoxification of
drugs or other toxic substances. Liver cells have abundant amounts of
smooth ER

311
Q

Eukaryotic Cells

Golgi

A

Extensive network of flattened membrane-bound vesicles. Closely linked with the
ER. Golgi apparatus and all of its vesicles contain a bilayer membrane.
cis face to the Golgi stack receives transport vesicles from the rough
ER. Sorts, modifys and stores the ER-made proteins. When ready to be
secreted, trans side buds into a vesicle and transports the protein to
its final destination. If the protein is to be sectreted from the cell
(exocytosis), the vesicle is called a secretory vesicle rather than a
transport vesicle

312
Q

Eukaryotic Cells

Peroxisomes

A

Single-membrane-bound
Contain enzymes that create hydrogen peroxide which can catabolize large molecules and toxins.
Also contain enzymes that converts the H2O2 into water

313
Q

Eukaryotic Cells

Vacuoles

A

Found in plant cells
Large membranous sacs that store food, minerals, waste and other chemical products
Similar to lysosomes in that they originate from the ER and they carry out hydrolysis
Large, central vacuole is enclosed by a membrane called the tonoplast
Larger vaculoes arise from coalescence of several smaller ones
Can contract and expe water out of a cell or expand and play a role in cellular elongation

314
Q

Eukaryotic Cells

Mitochondria

A

Site of many steps of cellular respiration, eg ATP synthesis
Composed of a deeply folding inner membrane surrounded by an outer membrane

315
Q

Eukaryotic Cells

Chloroplasts

A

Contain chlorphyll and other molecules that absorb the radiant energy of
sunlight. Drives the light-dependent reactions of photosynthesis.
Like the mitochondria, has two membranes.
In addition, contains a number of thylakoids - flattened membrane-bound
sacs separating the chroloplast into two main spaces: the thylakoid
space and the stroma

316
Q

Eukaryotic Cells

Cytoskeleton

A

Support structure of the cell. Network of criss-crossing fibres that maintain and change the cell’s shape
Composed of microtubules, intermediate filaments and microfilaments

317
Q

Eukaryotic Cells
Cytoskeleton
Microtubules

A

Largest type of fibre that makes up the cytoskeleton
Thick, hollow rods found mostly in the cytoplasm
Some microtubules within the cytoplasm create tracks along which
transport vesicles from the ER and golgi can move
Also form cilia and flagella, comprised of nine doublets of microtubules
with two single ones at the centre of the structure (9+2 arrangement)

318
Q

Eukaryotic Cells
Cytoskeleton
Microtubules
Centrosomes and centrioles

A

Centrosome is the microtubule organising centre,
In some cells may be a pair of centrioles, composed of nine sets of
triplet microtubules arranged in a ring
Centrosomes and centrioles are the components of the cytoskeleton that
play a role in the separation of chromosomes during cell division

319
Q

Eukaryotic Cells
Cytoskeleton
Intermediate filaments

A

Midsize protein fibres
Maintain the structural integrity and shape of the cell and the arrangement of organelles within it
While microtubules and microfilaments rearrange themselves, intermediate filaments are more permanent
The nucleus is ofter surrounded by a network of intermediate filaments holding it in place within the cytosol

320
Q

Eukaryotic Cells
Cytoskeleton
Microfilaments

A

Smallest type of fibre
Composed of a twisted double chain of actin
Assist the cell in changing shape. In muscle cells, are responsible for
contraction. In cells that move by crawling along their surface, are
responsible for pseudopod formation. Finally, form the cleavage furrow
in cell division

321
Q

Prokaryotic Cells

A

No true nucleus or membrane-bound organelles
Far simpler and smaller than eukayotic cells.
Contain cytoplams bound by a plasma membrane. Within the cytoplasm,
genetic material is contained in a dense ball of DNA called the
nucleoid. Ribosomes are suspended throughout the cytoplasm. Can also
contain pili, cell walls, flagella and output capsule

322
Q

Dehydration synthesis

A

Formation of biological macromolecules - lipids, proteins, carbohydrates, nucleic
acids - requires this. For each covalent bond formed, a molecule of
water is lost. Conversely the addition of water molecules t a system can
break covalent bonds - hydrolysis reaction

323
Q

Lipids

A

Insoluble in water
Many are made up of glycerol and fatty acids (long hydrocabon chains
with a carboxyl group at one end)
Used as energy store, phospholipids are principal components in cell
membranes, steroids such as oestogen and testosterone play key roles in
hormonal regulation

324
Q

Carbohydrates

A

Carbon compounds that fit the formula ratio 1:2:1 for carbon, hydrogen and oxygen

325
Q

Carbohydrates
Monosaccharides

A

eg glucose
Individual sugar molecule

326
Q

Carbohydrates
Disaccharides

A

eg sucrose
Molecule formed forom two joined sugar molecules

327
Q

Carbohydrates
Polysaccharides

A

eg starch, cellulose, chitin
Complex carbohydrates composed of varying numbrs of covalently bound sugar molecules

328
Q

Proteins

A

Functions include structural support (keratin), transport (haemoglobin), movement (actin, myosin) and hormonal coordination (insulin)
Large number are enzymes
Composed of amino acids linked via peptide bonds to form polypeptide chains

329
Q

Proteins
Primary Structure

A

Amino acid sequence

330
Q

Proteins
Secondary Structure

A

The folding of a polypeptide chain into alpha helices or beta sheets based on hydorgen bonds of the polypeptide backbone

331
Q

Proteins
Tertiary Structure

A

Large-scale folding of the protein involving various forms of bonding resulting in its 3D shape

332
Q

Proteins
Quaternary Structure

A

Binding of number of polypeptide chans together to form a protein’s overall shape

333
Q

Nucleic Acids

A

DNA and RNA
Nucleic acids are composed of chains of nucleotides, each of which is made up of a five carbon sugar ribose or deoxyribose, covalently bonded to a phosphate group and one of five nitrogenous bases

334
Q

Enzymology
Exergonic reactions

A

Release energy. Still require activation energy to initiate, eg heat.
In living cells, usually provide the energy for endergonic reactions

335
Q

Enzymology
Endergonic reactions

A

Require energy

336
Q

Enzymology
Cofactors

A

Many enzymes require an additional molecule to function. If this molecule is inorganic, it is a cofactor

337
Q

Enzymology
Coenzymes

A

Many enzymes require an additional molecule to function. If this molecule is organic, it is a coenzyme. eg vitamins

338
Q

Respiration
Aerobic Respiration Equation

A

C6H12O6 + O2 -> H2O + CO2 +ATP

339
Q

Respiration
Glycolysis

A

Takes place in cytosol
Exergonic
Ten step series of reactions by which 6-carbon glucose converted into 3-carbon pyruvate catalysed by enzymes at each step
Releases a small amount of ATP.
In the presence of oxygen is followed by the Krebs cycle and electron transport chain in the mitochindria. In the absence of oxygen, products of glycolysis are further fermented into lactate or ethanol but no additional ATP is produced

340
Q

Respiration
Glycolysis
Reactions

A
  1. Glucose + ATP -> glucose-6-phosphate
  2. glucose-6-phosphate -> Fructose-6-phosphate
  3. Fructose-6-phosphate + ATP -> fructose-1,6-diphosphate
  4. fructose-1,6-diphosphate -> 2 x glyceraldehyde-3-phosphate
  5. 2 x glyceraldehyde-3-phosphate + 2NAD -> 2 x 1,3-diphosphoglycerate + 2NADP
  6. 2 x 1,3-diphosphoglycerate + 2ADP -> 2 x 3-phosphoglycerate + 2ATP
  7. 2 x 3-phosphoglycerate -> 2 x 2-phosphoglycerate
  8. 2 x 2-phosphoglycerate -> 2 x phosphoenolpyruvate + 2H2O
  9. 2 x phosphoenolpyruvate + 2ATP -> 2 x pyruvate + 2ATP
341
Q

Respiration
Glycolysis
Net Products

A

2 x pyruvate
2 x ATP
2 x NADH

342
Q

Respiration
Krebs Cycle

A

Takes place in the mitochondrial matrix
The two molecules of pyruvate yield
6 x NADH
2 x FADH
CO2
GTP

343
Q

Respiration
Electron Transport Chain

A

Takes place in the mitochondiral inner membrane
High energy products of the Krebs Cycle NADH and FADH2 are passed down a series of electron acceptors (reducing agents), which are then oxidised. Most are proteins including the large protein complexes I, II, II and IV embedded in the membrane and mobile transporters such as the cytochromes
The only electron acceptor that isn’t a protein is ubiquinone (coenzyme Q) which is a small hydrophobic molecule
Oxygen is the final electron acceptor
The energy released in this process drives the production of ATP by chemiosmosis
Entire process is called oxidative phosphorylation

344
Q

Respiration
Photosynthesis
Equation

A

6H2O + 6CO2 + ATP -> C6H12O6 + 6O2

345
Q

Respiration
Photosynthesis

A

Occurs in the chloroplasts
Are two main stages: light reactions which occur in the thylakoid membrane and the light dependent Calvin-Benson cycle which occurs in the stroma

346
Q

Respiration
Photosynthesis

A
  1. Chlorophyll in the thylakoid membranes absorbs light energy in the unit of a photon
  2. The photon is passed from one to the next pigment molecule until it reaches chlorophyll a
  3. The photon first reaches P680 in PSII exciting the chlorophyll’s electrons which are captured by the primary electron acceptor leaving the P680 chlorophyll a as a stron oxidising agent
  4. A molecule of water is enzymatically split into two electrons (which are supplied to P680), two H+ and an O2- which immediately combines with another to form O2.
  5. The electrons that reach the primary electron acceptor are shuttled to PSI via an electron transport chain similar to that of oxidative phosphorylation producing ATP along the way
  6. A separate photon excites electrons in P700 of PSI which are captured by its own primary electron acceptor. The electrons shuttled from PSII replace these.
  7. The P700 electronscan follow one of two routes noncyclical or cyclical electon flow
347
Q

Respiration
Photosynthesis
Light Reaction
Light harvesting complex

A

Specialised structure which surrounds chlorophyll a
There are two main types of light harvesting complex whose chlorophyll a molecules absorb light of slightly different wavelengths - Photosystem II’s chlorophyll a is called P680. Photosystem I’s chlorophyll a is called P700

348
Q

Respiration
Photosynthesis
Light Reaction
Non-cyclical electon flow

A

Dominant route for electrons from P700 of PSI
Electrons are transferred to NADP+ to form NADPH

349
Q

Respiration
Photosynthesis
Light Reaction
Cyclical electon flow

A

Electrons from P700 are shuttled back to the electron transport chain producing more ATP but not producing NADPH. This is significant as the Calvin-Benson cycle requires more ATP than NADPH

350
Q

Respiration
Photosynthesis
Calvin-Benson Cycle

A

In the stroma, ATP and NADPH released. Calvin-Benson cycle converts 3 x CO2, 6xATP and 6xNADPH into 6 x glyceraldehyde-3-phosphate one of which exits the cycle and is used for food
The remaining 5 molecules are recycled in the cycle using three more molecules of ATP. In summary, for the production of one molecule of sugar, nine ATP and six NADPH are used

351
Q

Chemical Energy

A

Form of potential energy.
The potential energy is stored in the bonds between molecules

352
Q

First Law of Thermodynamics

A

States that energy can neither be created nor destroyed - also known as the principle of the conservation of energy

353
Q

Second Law of Thermodynamics

A

When energy is transformed from one form to another, a small amount is lost as unusable energy eg heat
Such loss of usable energy increases the disorder, or entropy, of the universe

354
Q

Passive Transport
Forms

A
  1. Diffusion
  2. Osmosis
355
Q

Hypotonic

A

Solution containing a lower concentration of solute (water will tend to diffuse into this solution by osmosis)

356
Q

Isotonic

A

same concentration of solute

357
Q

Hypertonic

A

greater concentration of solute

358
Q

Osmotic Pressure

A

Force generated by the osmotic movement of particles. A cell must balance this (osmoregulation) or will continue to take in water in a hypotonic environment or will continue to lose water in a hypertonic environment

DAT (53 decks)

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