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Higher Biology Flashcards

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1
Q

What is DNA

A

An organism’s inherent genetic material, that is used to code for its specific characteristics.

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2
Q

Where is DNA found in animal, plant and fungi cells

A

The nucleus

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3
Q

Where is DNA found in bacterial cells

A

Plasmids (ring-like structures of DNA) or the nucleus

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4
Q

What are the large molecules that DNA strands are collectivised and packaged into

A

Chromosomes

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5
Q

What is the name for a section of DNA that codes for a certain characteristic

A

A gene

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6
Q

What are the building blocks of DNA

A

Nucleotides

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7
Q

What do nucleotides comprise of

A

+ a deoxyribose sugar
+ a phosphate group
+ a base

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8
Q

How many strands does a DNA molecule have

A

2

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9
Q

What can each DNA strand be referred to as

A

A sugar-phosphate backbone

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10
Q

Within a sugar-phosphate backbone, what deoxyribose carbon is bound to a phosphate group

A

3’

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11
Q

What are the four bases

A

+ Adenine
+ Thymine
+ Guanine
+ Cytosine

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12
Q

What are the base pairing rules

A

Adenine-Thymine

Guanine-Cytosine

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13
Q

What bond forms between adjacent, complementary bases

A

Hydrogen bonds

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14
Q

A DNA molecule has an … structure

A

Antiparallel

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15
Q

What do DNA molecules coil around

A

Associated proteins/histones

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16
Q

What does the DNA’s antiparallel structure look like

A

One of the DNA strands has a loose phosphate group at its end, whilst the other end has a deoxyribose sugar.

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17
Q

What end features a deoxyribose sugar

A

3’

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18
Q

What is a prokaryote

A

The collective term used to describe bacterial organisms or cells.

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19
Q

What is a eukaryote

A

The collective term used to describe animal, plant or fungi organisms or cells

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20
Q

Characteristic of eukaryotes:

A

+ features a nucleus
+ linear chromosomes (in nucleus)
+ some DNA found in chloroplasts and mitochondria

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21
Q

Give an example of an abnormal eukaryote

A

Yeast cells (feature plasmids)

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22
Q

What is DNA replication

A

The synthesising of an identical, complementary copy of a DNA molecule - allowing cell division to occur

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23
Q

Why must cell division/DNA replication occur

A

To maintain an average quantity of bodily cells, as huge quantities die

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24
Q

What is DNA polymerase

A

The enzyme commonly used during replication, which monitors the addition and conjoining of nucleotides - to create a complementary strand.

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25
Q

From what end of a DNA strand does DNA polymerase add nucleotides

A

3’

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26
Q

Process of DNA replication (leading strand)

A

1: DNA molecule unwinds, as hydrogen bonds break
2: Primer attaches to 3’ end of ‘leading strand’
3: loose nucleotides align with complementary bases, from 3’ to 5’
4: DNA polymerase binds them together - creating a complementary DNA strand
5: The initial primer is removed and replaced with nucleotides
6:

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27
Q

Process of DNA replication (lagging strand):

A

1: primers place down the strand, allowing fragments of loose nucleotides to bind
2: DNA polymerase binds the nucleotides within the fragments
3: DNA ligase binds the fragments together

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28
Q

What are the five requirements of DNA replication

A 
\+ template strand of DNA
\+ primers
\+ nucleotides with all four bases
\+ enzymes (ligament and polymerase)
\+ a wealth of ATP
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29
Q

DNA replication allows growth and maintains the…

A

Chromosome complement

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30
Q

What does PCR stand for

A

Polymerase chain reaction

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31
Q

What is the goal of PCR

A

To amplify the quantity of a target DNA strand

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32
Q

What are the 5 requirements for PCR:

A 
\+ template section of DNA
\+ a buffer solution
\+ Taq polymerase enzyme
\+ nucleotides with all four bases
\+ primers
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33
Q

What is:

a) a buffer solution
b) Taq polymerase

A

a) a solution that the target strand of DNA is initially added to, maintaining a constant pH level
b) the enzyme used during PCR that is resistant to extremely high temperatures. It anneals loose nucleotides.

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34
Q

Describe the process of PCR

A

1: target DNA molecule is heated to 95 degrees Celsius, breaking the hydrogen bonds and separating the two strands
2: the molecule is the. Called to 55-60 degrees Celsius, allowing primers to anneal to the 3’ end of each strand
3: the molecule is heated to 70 degrees Celsius and Taq polymerase aligns and joins complementary nucleotides, from the 3’ end
4: the joined nucleotides form two new strands of DNA

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35
Q

What are three uses of PCR

A

+ DNA fingerprinting
+ Diagnosis of genetic disorders
+ Solving parental issues

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36
Q

What is an organism’s genome

A

Their entire store of genetic information

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37
Q

What is gene expresssion

A

The process by which the information from a gene is used to synthesis specific protein molecules

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38
Q

How do organisms differentiate

A

By masking the effects of certain genes, meaning only some proteins are produced - dictating the organism’s characteristics

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39
Q

What are the 5 main functions of proteins

A 
\+ enzymes
\+ antibodies
\+ replication monitors
\+ structural 
\+ hormones
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40
Q

What is an organism’s…

a) phenotype
b) genotype

A

a) the physical appearance of an organism, based on its genotype
b) the organism’s internal genetic information and sequence

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41
Q

What does gene expression require

A

RNA molecules

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42
Q

What are 3 structural differences between DNA and RNA molecules

A

+ RNA nucleotides contain a uracil base, instead of thymine
+ RNA nucleotides confiance ribose sugars, instead of deoxyribose
+ RNA molecules are single-stranded

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43
Q

What are the three types of RNA molecule:

A

+ mRNA
+ tRNA
+ rRNA

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44
Q

What is the role of mRNA

A

It synthesis a complementary copy of the nucleus’s DNA and transports it to the cell’s ribosome- as DNA molecules are too large to leave the nucleus.

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45
Q

What is the role of tRNA

A

Used during gene expression, as it locates loose amino acids and carries them to the ribosome

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46
Q

What is the structure of a tRNA molecule

A

3D and Clover-shaped, due to self-adjoining hydrogen bonds

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47
Q

What is the role of rRNA

A

Combines with structural proteins to form the ribosome

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48
Q

What is the first stage of gene expression and where does it occur

A

Transcription

Occurs in the nucleus

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49
Q

Process of transcription:

A

+ an RNA polymerase enzyme breaks the hydrogen bonds and unwinds a DNA molecule
+ RNA nucleotides align with their complementary DNA bases
+ hydrogen bonds form between the complements
+ an RNA polymerase joins the adjacent RNA nucleotides together and breaks their complementary hydrogen bonds
+ a single strand of ‘primary’ mRNA has now formed

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50
Q

What is required to initiate transcription

A

A start codon (a sequence of 3 bases that indicates to the nucleotides to join here)

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51
Q

What is required to end transcription

A

A stop codon

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52
Q

What is the second stage of RNA splicing and where does it occur

A

RNA splicing

Occurs in the nucleus

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53
Q

What happens during RNA splicing

A

Introns (non-coding DNA regions) are removed, whilst exons (coding DNA regions) are spliced back together.

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54
Q

What forms as a result of RNA splicing

A

A mature mRNA transcript, that features the exons in their officinal sequence

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55
Q

What is the process by which different mature mRNA transcripts are created

A

Alternative RNA splicing

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56
Q

What occurs during alternative RNA splicing

A

The same exons are spliced together, but in a different order OR old introns are now used as exons

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57
Q

What is the final stage of gene expression and where does it occur

A

Translation

Occurs in the ribosome

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58
Q

Process of translation:

A

+ 5’ end of mature mRNA binds to the ri so some
+ start codon begins translation
+ certain codons tell a tRNA molecule to retrieve a corresponding amino acid from the cytoplasm
+ codon and anti-codon from the acid and RNA form a weka hydrogen bond
+ tRNA molecules unbinds and repeat process
+ multiple amino acids form next to one another and join, forming a peptide bond
+ polypeptide of multiple acids forms, that folds in a certain way to create a specific protein and function

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59
Q

What is cellular differentiation

A

The process by which bodily cells specialise and gain specific function and characteristics

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60
Q

What must genes do during cellular differentiation

A

‘Switch’ on or off

Depending on their function, they require or do not require certain proteins, which require or don’t require certain genes

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61
Q

What are the undifferentiated areas of plant organisms known as

A

Meristems

They divide and specialise through mitosis

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62
Q

What are the two main types of meristem

A

+ Apical

+ Lateral

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63
Q

Where are apical meristems located and what is their function

A

Located in the roots and shoots of a plant

Primary site of vertical growth

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64
Q

Where are lateral meristems located and what is their function

A

Located in the stem of a plant

Secondary site of horizontal growth

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65
Q

Give two examples of specialised plant cells

A

+ xylem (lignin spirals)

+ phloem (sieve cells)

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66
Q

What are undifferentiated cells known as in animals

A

Stem cells

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67
Q

What are the two main types of stem cell

A

+ embryonic

+ tissue/adult

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68
Q

Where are embryonic stem cells found

A

In the blastocyst of an animal embryo. This is the bundle of cells formed before foetal development.

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69
Q

Where are tissue stem cells found

A

In all of the organism’s bodily tissue

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70
Q

Why are embryonic stem cells pluripotent

A

As they have the capacity to specialise into all cell types, found within the organism

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71
Q

Why are tissue stem cells multipotent

A

As they only have the capacity to to specialise into a select, finite number of closely-related cells, based on their function.

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72
Q

What are the therapeutic uses of stem cells

A

+ treatment of leukaemia - through a bone marrow transplant

+ treatment of skin grafts - healthy cells replaced damaged ones

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73
Q

What are the research-based uses of stem cells

A

+ test the effects of newly developed drugs on an organism cells
+ causes of disease can be determine day examining diseased stem cells
+ develop understanding of growth and development

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74
Q

What are the ethical issues of stem cells

A

The use of embryonic stem cells, during research, requires the destruction of an embryo - which has the potential for human life. The foetus must be destroyed before 14 days of existence, or else it may develop vital organs and conscious thought

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75
Q

What does it mean if a cellular process is carried out “in vitro”

A

It occurs outside its natural location or situation

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76
Q

What are coding genetic sequences known as and what is their function

A

Genes or exons

Code for the synthesis of proteins

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77
Q

What are non-coding genetic sequences known as and what is their function

A

Introns

Regulate transcription OR form rRNA or tRNA as they wer etranscribed but never translated

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78
Q

What is a mutation

A

A sudden, random alteration to the genetic material of an organism

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79
Q

How do mutation manifest themselves

A

By changing the organism’s genetic base sequence, resulting in the creation of different proteins

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80
Q

How can the rate of mutation be increased

A

By introducing mutagenic agents, such as chemical radiation

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81
Q

What is a single gene mutation (SGM)

A

When only one of the DNA molecule’s genes is affected by the mutation, and its protein is altered or removed

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82
Q

What are the three main types of single gene mutation

A

+ substitution
+ insertion
+ deletion

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83
Q

What is a substitution SGM

A

When one of the bases, within a genetic sequence, is directly swapped for another.

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84
Q

What are the three types of substitution SGM

A

+ missense
+ nonsense
+ splice-site

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85
Q

What is a missense substitution

A

When a base is substituted, meaning a different amino acid forms

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86
Q

What is a nonsense substitution

A

When a base is substituted, meaning the resultant protein is shortened - as a premature stop codon forms

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87
Q

What is a splice-site substitution

A

When the splice site of the genome does not function properly, as a base has been substituted, altering the shape and function of the resultant proteins

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88
Q

What is a frame-shift mutation

A

When the alteration of one base leads to a domino effect of alterations- affecting all subsequent bases.

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89
Q

What is an insertion SGM

A

When a base is inserted randomly into a genetic sequence. This forces all subsequent bases to move down one, changing all the codons and the resultant protein. FRAME-SHIFT

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90
Q

What is a deletion SGM

A

When a singular base is removed from a genetic sequence. This forced all previous bases to move down one, altering the resultant codons and proteins. FRAME-SHIFT

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91
Q

What is a chromosome structure mutation (CSM)

A

When large parts of a chromosome are changed, meaning multiple genes and their resultant proteins are altered

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92
Q

What are the four main types of CSM

A

+ Duplication
+ Deletion
+ Inversion
+ Translocation

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93
Q

What is a duplication CSM

A

When a section of chromosome is replicated and this replica joins the structure

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94
Q

What is a deletion CSM

A

When a section of the chromosome or multiple genes are removed

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95
Q

What is an inversion CSM

A

When a section of the chromosome detached, rotates 180 degrees and rejoins the structure

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96
Q

What is a translocation CSM

A

When a section of chromosome detached and joins a separate chromosome

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97
Q

How do mutations contribute to the evolution of a species

A

They create variation amongst a species, as new alleles are created. This allows natural selection to occur as mutations may hinder or boost the organism’s ability to survive and reproduce - allowing the advantageous mutations to increase in frequency amongst the population.

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98
Q

What CSM allows evolution

A

Duplication

The replica is free from selection pressures, meaning there is an increased chance of further advantageous mutation

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99
Q

What is evolution

A

Th term used to describe alterations in the genetic material of an organism, due to generations of genomic variation.

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100
Q

What three processes does evolution involve

A

Inheritance, selection and speciation

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101
Q

Inheritance is…

A

The sole method of genetic transfer, between organisms of different or similar species

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102
Q

What are the two types of genetic transfer

A

+ vertical

+ horizontal

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103
Q

What is vertical gene transfer

A

Is the typical, textbook form of inheritance, as parents reproduce and transfer identical copies of their genetic material to their offspring

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104
Q

What is horizontal gene transfer

A

When prokaryotes undergo cell division, whilst maintaining the chromosome complement. Therefore, in the same generation there may be multiple copies, in tasing the likeliness of evolution.

105
Q

Vertical transfer is carried out by…

Horizontal gene transfer is carried out by…

A

Eukaryotes and prokaryotes

Prokaryotes only

106
Q

What is natural selection

A

A non-random process by which the frequency of advantageous genomes, that increase the chance of survival increase, whilst disadvantageous genome frequency decreases

107
Q

How does natural selection occur

A

Organism whom possess advantageous DNA survive and reproduce, meaning their offspring inherent this genome. On the other hand, those without the advantageous DNA are killed off. This means that, over time, the majority of the population has the advantageous DNA sequence.

108
Q

What are the three modes of selection

A

+ stabilising
+ directional
+ disruptive

109
Q

What is stabilising selection

A

When the extreme DNA sequences are discriminated

This results in reduced diversity, as those who survive all possess average traits

110
Q

What is directional selection

A

When one DNA extreme is benefited

This results in a highly unique population, as the average and opposite extreme individuals are discriminated and killed.

111
Q

What is disruptive selection

A

When both DNA extremes are benefited

This produce a highly varied population, as there are no normal or average individuals - as they have been discriminated and killed

112
Q

What is a species

A

A group of organisms who have the ability to interbreed with one another, to produce fertile offspring

113
Q

What is speciation

A

The process by which new species emerge, as a result of evolution

114
Q

What are the two main types of speciation

A

+ Allopatric

+ Sympatric

115
Q

What is an isolation barrier

A

A geographical, behavioural or ecological obstruction that separates a population indefinitely

116
Q

Characteristics of prokaryotes:

A

+ features no nucleus
+ circular chromosomes
+ plasmids

117
Q

What is allopatric speciation

A

When the population of a singular species is separated by a geographical isolation barrier.

118
Q

What is sympatric speciation

A

When the population of a singular species is separated and isolated by behavioural (lifestyle) or ecological (niche) isolation barriers.

119
Q

Which form of speciation occurs more regularly, in the modern world

A

Allopatric, due to man’s gentrification of the globe

120
Q

What is genomics

A

The study of an organism’s genome, by determining its DNA base sequence and the resultant proteins formed

121
Q

What are the three research and therapeutic uses of genomics

A

+ identification and treatment of conditions
+ likeliness of disease predicted
+ reception to drugs predicted (pharmacogenetics)

122
Q

What is the ethical issue of such uses of genomics

A

It is not decided wether this information should be made available to people, such as employers or children - to prepare for the future.

123
Q

Describe speciation

A

+ species population is separated into two sub-populations by a geographical, behavioural or ecological barrier
+ sub-populations expérience random mutation
+ evolution occurs in each sub-population, meaning these different mutations manifest themselves and changes the individuals in each
+ sub-populations evolve differently to a point where they can no longer interbreed to produce fertile offspring, melanin two new species have formed

124
Q

What end features a loose phosphate group

A

5’

125
Q

What is bioinformatics

A

The study of the determined genome, using computer technology and statistical analysis. This involves comparative genomics, as the genomes of similar species are compared to determine what causes their differences.s

126
Q

What is an example of mass genomics

A

The human genome project

An initiative, launched in 1990, that aimed to sequences all 3 billion bases in a typical human genome. It was finally completed in 2003.

127
Q

What is phylogenetics

A

The study of how closely relayed certain organisms are, based on their evolutionary status

128
Q

What two sources of information are required during phylogenetic

A

+ fossil evidence

+ genome sequence data

129
Q

What is the underlying rule of phylogenetic

A

As the genomes of two organisms increases in similarity, so too does their evolutionary relatedness. This means that as the number of mutations increases, they become increasingly distant

130
Q

What graph indicates the evolutionary relatedness, based on the time since they shared a common ancestor

A

A phylogenetic tree

131
Q

What does the molecular clock state

A

The higher the number of mutation observed, between two organisms, the greater the time since they shared a common ancestor

132
Q

Based off the molecular clock, what are the three domains of life that split from the first common ancestor

A

+ Bacteria
+ Archaea (extreme prokaryotes)
+ Eukaryotes

133
Q

Sequence of life:

A

Prokaryotes formed —> eukaryotes evolved from prokaryotes —> eukaryotes evolved into multicellular organisms—> vertebrae evolved —> land plants evolved

134
Q

What acronym can be used to remember the sequence of life

A 
Percy                    Prokaryotes 
Emma                  Eukaryotes
Matthew              Multicellular organisms
And                       Animals
Violet                   Vertebrae
Left together      Land plants
135
Q

What is an organism’s metabolism

A

The collective term used to describe all the chemical processes that occur within the organism.

136
Q

What is a metabolic pathway

A

A sub-section of the organism’s overall metabolism, that concerns a series of interconnected reactions.

137
Q

What are metabolic pathways controlled by

A

Enzymes

138
Q

What are the two types of metabolic pathway

A

+ anabolic

+ catabolic

139
Q

Describe an anabolic reaction

A

+ one large molecules is synthesised from two smaller ones

+ energy/ATP is required

140
Q

Describe a catabolic reaction

A

+ a large molecule is broken down into two or more smaller molecules
+ energy/ATP is released

141
Q

What is the role of ATP, in metabolic pathways

A

It transfers energy between anabolic and catabolic reactions

142
Q

Where are metabolic pathways localised

A

Cell or organelle membranes

143
Q

Describe the plasma membrane

A

+ fluid mosaic model
+ phospholipid balayer
+ irregular proteins

144
Q

Within metabolic pathways, what are the three types of possible protein

A

+ pores
+ pumps
+ enzymes

145
Q

What is a protein pore

A

A membrane protein that features a hollow, internal channel. Allows large molecules to pass through the membrane.

146
Q

What is a protein pump

A

A membrane protein that carries substances across the membrane itself. They do so by carrying out active transport, using up ATP

147
Q

What are enzymes

A

Biological catalysts, that increase the rate of a chemical reaction, without being used up in the process.

148
Q

What is a chemical reaction’s activation energy

A

The amount of energy required to convert reactants into products

149
Q

What is the effect of introducing an enzyme in a reaction’s activation energy

A

It decreases

150
Q

What is the process by which enzymes and substrates interact

A

Enzyme action

151
Q

Describe enzyme action

A

+ enzymes locate their specific substrate
+ they bind at their complementary active sites
+ enzyme-substrate complex forms

152
Q

What is enzyme-substrate affinity

A

The level of specificity between the two molecules (the measure of how complementary their active sites are)

153
Q

What do enzymes create, in an attempt to increase their substrate affinity

A

An induced fit

154
Q

Describe the process of induced fit

A

+ enzyme and substrate bind at complementary active site
+ small molecule fill tiny gaps between active sites
+ orientation of substrate, within the complex, alters
+ affinity of the enzyme-substrate complex increases, as they are brought into closer contact.

155
Q

What are the 4 ways to alter the rate of a metabolic reaction/pathway

A

+ alter the substrate concentration
+ alter the enzyme concentration
+ change the temperature (enzyme optimum)
+ change the pH (enzyme optimum)

156
Q

What is the process by which enzyme action is stopped or hindered

A

Inhibition

157
Q

What are the 3 main types of inhibition

A

+ competitive
+ non-competitive
+ feedback

158
Q

Describe competitive inhibition

A

+ inhibitor molecule binds to enzyme active site
+ substrate cannot enter or bind
+ reaction does not take place

159
Q

What can competitive inhibition be reversed or reduced by

A

The increase of the reaction’s substrate concentration, as substrates are now more likely to reach the enzyme before the inhibitor

160
Q

Describe non-competitive inhibition

A

+ inhibitor binds to the enzyme, at a site located away from the active site
+ shape of the enzyme alters, altering the active site shape
+ enzyme active site is no longer complementary to substrate’s
+ molecules cannot bind, meaning the reaction can not occur

161
Q

Is non-competitive inhibition reversible

A

No

162
Q

Describe feedback inhibition

A

+ final product of metabolic pathway is over-produced to a critical concentration
+ product used as a non-competitive inhibitor of earlier enzyme
+ pathway cannot proceed

163
Q

What is respiration

A

A series of metabolic pathways that produced energy (in the form of ATP) from food/glucose

Present in all living organisms and domains of life

164
Q

What is ATP

A

Adenine tri-phosphate is a molecule that stores internal energy within cells

165
Q

What is the process by which ATP forms and what are the two reactants

A

Phosphorylation

ADP + Pi (adenine di-phosphate + phosphate)

166
Q

What is the role of dehydrogenase enzymes, during respiration

A

They remove hydrogens and elections from molecules and pass them co-enzyme NAD. This then forms NADH

167
Q

What is the first stage of respiration and where does it occur

A

Glycolysis

Occurs in the cell’s cytoplasm

168
Q

What occurs during glycolysis

A

+ Glucose is broken down into intermediate enzymes
- ADP + Pi are produced from ATP (energy investment)

+ Intermediate enzymes are broken down into pyruvate

- ATP is produced from ADP + Pi (energy investment)
- NADH is produced from NAD
169
Q

What is the second stage of respiration and where does it occur

A

The fate of pyruvate

Occurs in the matrix of the cell’s mitochondria

170
Q

Describe the fate of pyruvate

A

+ pyruvate is brown. Down into acetyl co-enzyme a

+ CO2 is produced

171
Q

What is the third stage of respiration and where does it occur

A

The citric acid cycle

Occurs in the matrix of the mitochondria

172
Q

Describe the citric acid cycle

A

+ oxalo-acetate and acetyl co-enzyme a combine to form citrate
+ intermediate enzymes form from citrate
+ CO2 is produced twice
+ NADH is produced twice from NAD
+ ATP is produce from ADP + Pi

173
Q

What is the fourth stage of respiration and where does it occur

A

The electron transport chain

Occurs in the inner mitochondrial membrane

174
Q

What does NADH transfer to the electron transport chain

A

Hydrogen ions and electrons

175
Q

What do electrons do during the electron transport chain

A

They release energy by flowing through protein acceptors

176
Q

Describe the route of hydrogen ions during the electron transport chain

A

They first travel across the membrane, through protein pumps, before returning back through a protein pore. They then combine with the present oxygen and electrons - forming water.

177
Q

What is the protein pore that returns the hydrogen ions back across the membrane

A

ATP synthase

Rotates, propelling the ions across the membrane and producing ATP from ADP + Pi

178
Q

What is hydrogen known as, within the process of respiration

A

The final hydrogen and electron acceptor

179
Q

What is the alternative process that occurs, instead of respiration, if oxygen is not present

A

Fermentation

180
Q

Describe fermentation

A

Glycolysis occurs, before the final product are synthesised from pyruvate

181
Q

What is the product of fermentation in animals

A

Lactate

182
Q

What are the products of fermentation in plants

A

Ethanol and CO2

183
Q

What are the differences between fermentation and respiration

A

+ 2 molecules of ATP produce din fermentation, 38 in respiration
+ fermentation is anaerobic

184
Q

What is an organism’s metabolic rate

A

The amount of energy used up by the organism in a given time interval (speed of metabolism)

185
Q

What are the three ways by which metabolic rate can be determined

A

+ rate of oxygen consumption
+ rate of carbon dioxide production
+ rate of heat energy production

186
Q

As an organism’s mass increases, its metabolic rate…

A

Increases

187
Q

How many times does blood pass through the heart in the circulatory system of a…

a) fish
b) amphibians or reptile
c) bird or mammal

A

a) 1
b) 2
c) 2

188
Q

What is the pressure of blood at gas exchange capillaries in the circulatory system of a…

a) fish
b) amphibian or reptile
c) bird or mammal

A

a) high
b) high
c) high

189
Q

What is the pressure of blood at body tissue capillaries in the circulatory system of a…

a) fish
b) amphibian or reptile
c) bird or mammal

A

a) low
b) medium
c) high

190
Q

How many atria does the heart have in the circulatory system of a…

a) fish
b) amphibian or reptile
c) bird or mammal

A

a) 1
b) 2
c) 2

191
Q

How many ventricles does the heart have in the circulatory system of a…

a) fish
b) amphibian or reptile
c) bird or mammal

A

a) 1
b) 1
c) 2

192
Q

What type of system is found in the circulatory system of a…

a) fish
b) amphibian or reptile
c) bird or mammal

A

a) single
b) double incomplete
c) double complete

193
Q

How much mixing of oxygenated and deoxygenated blood is there in the circulatory system of a…

a) fish
b) amphibian or reptile
c) bird or mammal

A

a) low
b) high
c) low

194
Q

What is the efficiency of the circulatory system in…

a) fish
b) amphibians and reptiles
c) fish and mammals

A

a) low
b) medium
c) high

195
Q

What is the metabolic rate of…

a) fish
b) amphibians and reptiles
c) birds and mammals

A

a) low
b) medium
c) high

196
Q

Name 3 external factors that may affect an organism’s metabolic rate

A

+ surrounding pH
+ surrounding salinity
+ surrounding temperature

197
Q

Based on their response to external factors, what are the two categories of organism

A

+ Conformers

+ Regulators

198
Q

What is a conformer

A

An organism that changes its internal environment, as the external environment changes

199
Q

What is a regulator

A

An organism’s that maintains a constant internal environment, regardless of the external environment - suing physiological mechanisms

200
Q

How do conformers adapt to changing external environments

A

By using behavioural adaptations that alter their internal environment

E.g. basking in the sun to increase their body temperature, as the surroundings become cooler

201
Q

How do regulators adapt to cheating external conditions

A

Through a high energy process known as homeostasis (a form of negative feedback)

202
Q

Describe homeostasis/negative feedback

A

External conditions deviate —> organism’s receptor cells detect the change —> effector organ produces appropriate internal change

203
Q

Can conformers or regulators assume a wider range of niches and habitats

A

Regulators

204
Q

Give another example of negative feedback

A

Thermoregulation - the maintenance of the body’s core temperatures within a tolerable range

205
Q

What region of the brain controls thermorégulation

A

The hypothalamus

206
Q

What are the cells that detect external changes in temperature

A

Thermo-receptors

207
Q

What happens to animals, as their external temperature increases

A

+ blood vessels widen (vasodilation)
+ sweat glands release more perspiration, increasing heat evaporation
+ decrease in metabolic rate, decreasing heat production

208
Q

What happens to animals, as their external temperature decreases

A

+ blood vessels narrow (vasoconstriction)
+ hair erector muscles contract and flatten, trapping warm air
+ metabolic rate increases, increasing heat production
+ shivering occurs

209
Q

Why must mammals and birds maintain a body temperature of around 37 degrees Celsius

A

This is the optimum temperature for the majority of their reaction-controlling enzymes

210
Q

How is information relayed between muscles, during negative feedback

A

As electric impulses, within nerves

211
Q

What are the two mechanisms that reduce an organism’s metabolic rate

A

+ dormancy

+ torpor

212
Q

What is dormancy

A

An annual occurence, as an organism decreases its metabolic rate to conserve energy and heat - by decreasing its amount of action and movement. This occurs in response to adverse conditions and often appears as a period of extended rest or sleep.

213
Q

What are the two types of dormancy

A

+ predictive

+ consequential

214
Q

What is predictive dormancy

A

When an organism enters dormancy prematurely, before the adverse conditions arrive.

215
Q

What is consequential dormancy

A

When an organism enters dormancy, as a result of the arrival of adverse conditions. Allows the animals to make full use of all available resources, but increases their chance of death.

216
Q

What is aestivation

A

A form of dormancy, during which animals enter this period of lowered activity and metabolic rate, in response to high temperatures in summer months.

217
Q

Give an example of two animals that enter aestivation

A

Crocodiles and frogs

218
Q

What is hibernation

A

A form of dormancy, during which animals enter this period of lowered activity and metabolic rate, in response to low temperatures and food scarcity in winter months.

219
Q

Give an example of two animals that undergo hibernation

A

+ hedgehogs

+ field mice

220
Q

What is torpor

A

A similar process to dormancy, during which an organism’s metabolic rate and activity decrease. However, this process usually involved the organism’s metabolic activity event reduced for a shorter time

221
Q

What 4 changes occur during torpor

A

+ breathing rate decreases
+ body temperature falls
+ heat production decreases
+ oxygen consumption decreases

222
Q

What is daily torpor

A

When animals enter a state of torpor for short amounts of the day, increasing their energy content when they are awake and active

223
Q

Give an example of when daily torpor may occur

A

Migration

Allows organisms to travel at increased speeds when active

224
Q

What is migration

A

The long distance movement of a population or individual, a steely move from adverse conditions to favourable one’s - that are increasingly suited to the organism’s niche.

225
Q

What are the 4 factors that trigger migration

A

+ a decreasing number of daylight hours
+ changes in surrounding temperature
+ changes in food availability
+ genetic factors

226
Q

What are the three methods by which scientists may track an organism’s migration route

A

+ Banding - attach a metal band to an individual, and identify them as they complete the migration

+ Tagging - same as banding but with a tag

+ Transmission - microchips are fitted in the organism, relaying their location via satellite

227
Q

What is an innate migration

A

An inherited migration that is carried out by all members of a species, during adverse conditions

228
Q

What is a learned migration

A

One that develops amongst certain individuals, due to their experience

229
Q

What is an extremophile

A

An organism that exist and thrives in adverse or extreme conditions

E.g. Taq Polymerase enzyme

230
Q

What is a microorganism

A

Minuscule forms of life, found in all three domains of life

231
Q

Why are micro-organisms used for research and industry

A

+ easy to culture
+ reproduce rapidly
+ create a variety of useful products

232
Q

What is a micro-organism’s growth medium

A

The object or substance that supports the life of the micro-organism, by providing raw materials and energy for growth

233
Q

Why do some substances require complex additions to their growth medium

A

As they are unable to produce the complex substances required for biosynthesis, such as amino acids

234
Q

Give an example of a substance that may be added to such micro-cultures, to supply complex substances

A

Beef extract

235
Q

What 4 factors must be controlled to ensure that the growth medium is optimum for microorganism growth

A

+ sterility
+ temperature
+ pH
+ oxygen concentration

236
Q

How does one control the…in a bioreactor

a) sterility
b) temperature
c) pH
d) oxygen concentration

A

a) ensure aseptic techniques are carried out
b) increase the flow of warm/cold water
c) introduce a buffer or add acid/alkali
d) allow increased amounts of air to enter the reactor

238
Q

What is a micro-organism’s mean generation time

A

The time taken for the organism’s cells to divide once

239
Q

What are the 4 stages of micro-organism growth

A

+ lag
+ log
+ stationary
+ death

240
Q

What is the lag phase

A

As the micro-organism adjusts to the conditions of the growth medium, it does not divide. Biosynthesis occurs as cells combine nucleic acids and enzymes.

241
Q

What is the log phase

A

When the micro-organism divides at its maximum rate, meaning the culture population doubled at regular intervals

242
Q

What is the stationary phase

A

As the micro-organism begins to exhaust its substrate wealth and a toxic concentration of secondary metabolites forms, the cell death rate equals the cell growth rate

243
Q

What is the death phase

A

When the culture fully exhausts its substrate concentration and the toxic secondary metabolites kill the cells, the death rate finally exceeds the growth rate

244
Q

What is a primary metabolite

A

A metabolite that is produced during periods of active micro-organism growth (lag or log) and concerns the biosynthesis of microbes.

245
Q

What is a secondary metabolite

A

A metabolite that is not produced until cells have established themselves in the medium (log, stationary, death). They confer an ecological advantage and are often highly useful to humans. However, they can also be toxic and dangerous

246
Q

How can metabolite production be increased, at a controlled rate

A

+ precursors (increased primary metabolite conc.)
+ enzyme inducers
+ enzyme inhibitors

247
Q

What are the two methods by which wild micro-organisms are altered, for human benefit

A

+ mutagenesis

+ recombinant DNA

248
Q

What is mutagenesis

A

When micro-organisms are exposed to mutagens (agents that increase the rate of mutation) in an attempt to improve their genome through a mutation

249
Q

Give an example of a mutagen

A

Ultraviolet light

250
Q

What is a disadvantage of mutagenesis

A

Once mutated, the wild micro-organisms often revert to their original state and are harmful in these civilised environments

251
Q

What is recombinant DNA technology

A

When the DNA of a plant or animal is placed inside that of a bacteria, in an attempt to increase the rate of production of the plant or animal protein - as the bacteria reproduce quickly

252
Q

Describe the process of recombinant DNA technology

A

+ animal/plant gene is extracted rim chromosome, using endonuclease enzyme
+ enzyme recognised restriction sites and cuts gene out
+ enzyme repeats process with section of bacterial plasmid
+ complementary sticky ends bind, with the help of DNA ligament enzyme
+ plasmid features animal/plant gene and produces its protein in excess

253
Q

What is a plasmid an example of..

A

A micro-organism vector, as it simply acts as a body of transfer for the plant/animal gene

254
Q

What else is a vector

A

Artificial chromosomes which act in the same way as plasmids but can carry larger sections of DNA

255
Q

What is a restriction site

A

A sequence of DNA bases that indicates to the endonuclease enzyme to extract this section of DNA

256
Q

What is the origin of replication

A

The site of a plasmid where DNA synthesis begins, as it contains genes that control self-replication. Furthermore, it contains regulatory sequences, which carry out self-replication

257
Q

What are marker genes

A

Genes in a plasmid that indicate wether or not the plasmid has taken up the animal/plant gene

E.g. antibiotic resistant gene

258
Q

Why might a recombinant protein be non-functional

A

As eukaryotic proteins are often mis-shapen, when cultured in a bacterial cell, as RNA splicing does not occur properly

259
Q

What is the way to prevent recombinant proteins from becoming non-functional

A

Use a yeast cell, as it is eukaryotic but acts similarly to a bacterial cell OR use artificial chromosomes. Both options ensure that the resultant protein is shaped correctly and, therefore, functional

Biology (9 decks)

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