Biology - Unit 4 Flashcards

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1
Q

What are photoautotrophs?

A

Organisms which make organic molecules using light energy

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2
Q

What are chemoautotrophs?

A

Organisms which make organic molecules using chemical energy

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3
Q

What are heterotrophs?

A

Organisms which rely on ready-made energy-storing organic molecules from other organisms

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4
Q

Where does the light dependent reaction take place?

A

Thylakoid membrane site

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5
Q

Where does the light independent reaction take place?

A

Stroma

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6
Q

What is the Rf value of a pigment?

A

Distance moved by pigment/Distance moved by solvent

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7
Q

What are the names of the five pigments in chlorophyll?

A
Beta carotene
Phaeophytin
Xanthophyll
Chlorophyll a
Chlorophyll b
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8
Q

What occurs in photoexcitation?

A

Electrons get excited by light and move away from molecule

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9
Q

What occurs in photoionisation?

A

Electrons get too excited by light and leave the molecule

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10
Q

What is the method of cyclic photophosphorylation?

A

Electron in PS1 excited by light

Electron passed down ETC generating ATP

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11
Q

What wavelength of light does PS1 absorb?

A

700

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12
Q

What wavelength of light does PS2 absorb?

A

680

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13
Q

What does cyclic photophosphorylation produce?

A

ATP

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14
Q

What is the method of non-cyclic photophosphorylation?

A

Water splits in to proton and hydroxide ion
Oxygen produced and electron passed on
Electron enters PS2
PS2 hit by light and electron passed onto electron acceptor
Electron passed down ETC into PS1 producing ATP
PS1 hit by light and electron excited into NADP
Proton from the water accepted by NADP to form reduced NADP

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15
Q

What occurs in the Calvin Cycle?

A

GALP turned into RuBP
Reaction between RuBP and carbon dioxide catalysed by RUBISCO to produce a 6-carbon compound
6C compound splits into 2 molecules of GP
NADP formed and ATP broken up to form 2 GALP molecules
Some GALP used to produce amino acids and glucose and some fed back into the cycle

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16
Q

What is ecology?

A

The study of the interactions that determine the distribution and abundance of organisms within a particular environment

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17
Q

What is a habitat?

A

The place where an organism lives

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18
Q

What is a population?

A

A group of organisms of the same species, living and breeding together in a habitat

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19
Q

What is a community?

A

All the populations of the different species of organisms living in a habitat at any one time

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20
Q

What is a niche?

A

The role of an organism in its community

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21
Q

What are abiotic factors?

A

The non-living elements of the habitat of an organism

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22
Q

What are biotic factors?

A

The living elements of a habitat which affect the ability of a group of organisms to survive there

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23
Q

What is the process of primary succession?

A
Empty inorganic surface
Opportunists - Lichens, algae, mosses
Rock broken into grains to form humus
Grasses and ferns establish root systems
Death and decay adds nutrients
Larger species supported
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24
Q

What is a climax community?

A

Where the biodiversity and range of species is generally constant

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25
Q

What is the process of secondary succession?

A
Bare earth, grass, weeds
Grass stage
Grass and shrubs
Young forest
Mature forest
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26
Q

What is a plagioclimax?

A

A final community which is partially the result of human intervention

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27
Q

What are examples of abiotic factors?

A
Light
Temperature
Wind and water currents
Water availability
Oxygen availability
Edaphic factors - Soil structure and mineral content
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28
Q

What are examples of biotic factors?

A
Predation
Finding a mate
Territory
Parasitism and disease
Competition
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29
Q

What is the effect of light on organisms?

A

Plants are dependent on light for photosynthesis
Plants in low light levels need adaptations to cope - Earlier reproduction, Extra chlorophyll
Animals are affected as a result of plant distribution

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30
Q

What is the effect of temperature on organisms?

A

Range of temperature in which an organism can grow and successfully reproduce
Extremes not average determine habitat
Many animals have adaptations to cope

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31
Q

What is the effect of wind and water currents on organisms?

A

Wind increases heat and water loss
Less likely to survive in strong winds
Habitats can be destroyed

In water currents, have to flow with the current, be strong swimmers or hang on tight
Can be sudden increase due to flooding

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32
Q

What is the effect of water availability on organisms?

A

Affected by amount of precipitation, rate of evaporation and edaphic factors like loss through drainage
Can die if not adapted and severe water stress
Sudden increase can lead to a huge habitat change so population sizes increase

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33
Q

What is the effect of oxygen availability on organisms?

A

When water is cold or fast flowing, sufficient oxygen dissolves in it
If warmer or still and stagnant, oxygen content drops
In waterlogged soil, there is little oxygen
Some plants have adaptations to cope in waterlogged conditions

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34
Q

What is the effect of edaphic factors like soil structure and mineral content on organisms?

A

Sand has a loose, shifting structure
Can only grow on it if adapted
Soils with lots of sand are light and easily worked and warmed but drain easily
Leaching of minerals occurs when water is easily drained
Ideal soil has particles of varying sizes

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35
Q

What is the predator-prey cycle?

A

Prey population increases
More food so predator numbers increase
Therefore, prey numbers decrease
Predator numbers decrease

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36
Q

What is the effect of finding a mate on organisms?

A

Abundancy of a type of animal will increase with availability of a mate

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37
Q

What is the effect of territory on organisms?

A

Territories normally used to ensure a breeding pair has sufficient resources
Type and size of territory determines species

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38
Q

What is the effect of parasitism and disease on organisms?

A

Diseased animals are weakened and often unable to reproduce successfully
Sick predators less likely to catch prey
Sick prey more likely to get caught
Parasites more likely when population density is higher

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39
Q

What is intraspecific competition and what are possible results of it?

A

Competition for a limited resource between members of the same population or species
Results:
-Some individuals may not survive or reproduce, slowing population growth
-If sufficient resources, there will be little competition so population growth maximises

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40
Q

What is interspecific competition and what are possible results of it?

A

Different species within a community compete for the same resources
Results:
-Reduced abundancy of a species
-Possible exctinction

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41
Q

What is Gross primary productivity (GPP)?

A

The rate at which energy is incorporated into plants

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42
Q

What is net primary productivity (NPP)?

A

Energy stored in body tissues

GPP - plant respiration

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43
Q

Describe the carbon cycle in nature

A

Carbon dioxide removed by photosynthesis
Added in organically by respiration of plants, animals and decomposers
Added in inorganically by fossil fuel combustion and weathering of carbonate rocks

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44
Q

What is used as evidence of global warming?

A

Drilling into ice and taking ice cores
Dendrochronology
Peat bogs - Looking at pollen grains in it

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45
Q

What factors affect the ability for oceans to be efficient carbon sinks?

A

Water temperature and ocean currents

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46
Q

What is proteomics?

A

The study of proteomes

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47
Q

What is a proteome?

A

All the proteins produced from a genome

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48
Q

What is a gene family?

A

Closely related genes from mutations on the copies of the gene

49
Q

What is habitat isolation?

A

Where two populations share the same habitat but are active at different times

50
Q

What is temporal isolation?

A

Where populations may mate or flower at different seasons or times of day

51
Q

What is mechanical isolation?

A

Where genitalia is incompatible due to shape or size

52
Q

What is behavioural isolation?

A

Where populations have different courting patterns

53
Q

What is gametic isolation?

A

Where gametes of different species fail to attract one another

54
Q

What is allopatric speciation?

A

Where two populations are physically separated

55
Q

What is sympatric speciation?

A

Where two populations are reproductively isolated in the same environment

56
Q

How is DNA profiling of benefit to the study of speciation?

A

Can be used to see how closely related organisms are

57
Q

Why does body temperature drop after death?

A

The metabolic reactions slow and eventually stop

58
Q

What factors affect how quickly body temperature drops?

A
Amount of body fat
Mode of death
Clothing
Body size
Surrounding environment
59
Q

Why does rigor mortis occur?

A

Muscle cells run out of ATP so are unable to maintain the relaxed state

60
Q

What factors affect how quickly rigor mortis occurs?

A

Amount of ATP stored - Genetics, fitness, level of activity

Temperature of person and surroundings

61
Q

What are the stages of succession in a dead body?

A

Anaerobic bacteria breed freely
Flies arrive and lay eggs
Maggots hatch and break down tissues
Beetles lay eggs which hatch and eat maggots
Parasitic wasps lay eggs in maggots and beetle larvae
Body starts to dry out
Some species leave and some arrive
Beetles feed on remains of muscle and connective tissue
Mite and moth larvae eat hair

62
Q

What factors affect speed of succession in a dead body?

A

Temperature

Level of exposure

63
Q

What is forensic entomology?

A

Study of insect life as it relates to crime

Different insects have different life cycles

64
Q

Why is a triplet code used?

A

Codes for 64 combinations which is more than enough

65
Q

What does non-overlapping mean?

A

The triplets of bases follow each other

66
Q

Why is a non-overlapping code used?

A

If overlapping, would be shorter but would mean certain amino acids would have to follow one another

67
Q

What does degenerate mean?

A

Contains more information than it needs

68
Q

Why is a degenerate code used?

A

If the final base is changed in a triplet, the same amino acid could still be coded for

69
Q

What is the method of DNA transcription?

A

Strands of DNA split where needed by RNA Polymerase
5’ strand used as template strand and copied
Mononucleotides line up to complementary bases
Nucleotides joined together by RNA Polymerase

70
Q

What is the method of post-transcription modification?

A

Sections of DNA (Introns) which do not code for protein removed
Some exons removed as well causing mutation
Spliceosomes join exons together

71
Q

What is the method of translation?

A

Anticodons of tRNA unit carries particular amino acid to ribosome
Ribosome goes along mRNA, reading it
tRNA line up to complementary codons
Hydrogen bonds form between amino acid and ribosome
Enzymes link amino acids together by peptide bonds

72
Q

What is the method of gel electrophoresis?

A

Cut DNA using restriction endonucleases
Place fragments and known sample in wells in agar plate
Run current through it, fragments move to positive end
When near end, stop
Place under UV light

73
Q

What is the method of Southern blotting?

A

Add alkaline buffer solution to gel
Place nylon filter on top
Add DNA probe

74
Q

What is the method of PCR?

A

Place reactants in PCR machine
Heat to 90C for 30s - Strands separate
Heat at 55C for 20s - Primers bind to strands
Heat at 75C for a minute - DNA polymerase builds up complementary strand
Repeat

75
Q

What is a capsomere in a virus?

A

A repeating protein unit which makes up the protein coat

76
Q

What is the capsid in a virus?

A

The protein coat

77
Q

What is the lysogenic pathway of virus life cycles?

A

Phage DNA injected into host cell
Viral DNA incorporated into host cell DNA
Viral DNA replicated when bacterium divides
Joins to lytic pathway

78
Q

What is the lytic pathway of virus life cycles?

A
Phage DNA injected into host cell
Phage DNA inactivates host DNA
Phage DNA replicated
New phage particles assembled
Lysis occurs due to lysozyme
Phages released
79
Q

What is the life cycle of a retrovirus?

A

Viral RNA enters host cell
Viral RNA translated into viral DNA by reverse transcriptase
Viral DNA incorporated into host cell DNA
Viral genome RNA, mRNA and coat proteins produced
New viral particles assembled and exit cell
Process repeated in cell

80
Q

What is a mesosome in a bacterial cell membrane?

A

Infolding

81
Q

What is the use of a slime layer in a bacterium?

A

Protects against phagocytosis

Covers cell markers

82
Q

What are the uses and drawbacks to pili (or fimbriae) in bacteria?

A

Used for attachment to a host
Used for sexual reproduction
More vulnerable to viral infection

83
Q

What is the genetic material in bacteria?

A

Circular DNA in cytoplasm

May be plasmids as well

84
Q

What is the cell wall structure and what occurs in Gram staining with Gram-positive bacteria?

A

Have thick layer of peptidoglycan containing teichoic acid
Crystal violet stays stained
Shows as purple

85
Q

What is the cell wall structure and what occurs in Gram staining with Gram-negative bacteria?

A

Thin layer of peptidoglycan with no teichoic acid
Outer membrane layer of lipopolysaccharides
Crystal violet decolourised
Red safranine binds
Appear red

86
Q

What are shapes of bacteria?

A

Spherical - Cocci
Rod shaped - Bacilli
Twisted - Spirilla
Comma shaped - Vibrios

87
Q

What are possible respiratory requirements of bacteria?

A

Obligate aerobes - Need oxygen
Facultative anaerobes - Use oxygen if it’s there
Obligate anaerobes - Need an absence of oxygen

88
Q

What is a bacteria’s generation time?

A

The time between its cell divisions

89
Q

What are the ways in which genetic material from one bacterium can be given to another one?

A

Transformation
Transduction
Conjugation

90
Q

What is bacterial transformation?

A

Short piece of DNA released by donor and actively taken up by another where it replaces a similar piece of DNA

91
Q

What is bacterial transduction?

A

Small amount of DNA taken up by bacteriophage in viral coat

Taken into another bacterium where incorporated

92
Q

What is bacterial conjugation?

A

Genetic information transferred from one bacterium to another by sex pilus

93
Q

What are the methods of pathogen transmission?

A
Vectors - Living organism which transmits the infection
Fomites - Inanimate objects
Direct contact
Inhalation
Ingestion
Inoculation - Break in skin
94
Q

What are the epithelial barriers to entry of the body?

A
Skin
Sebum - Inhibits microorganism growth
Natural skin flora - Outcompete and inhibit growth
Mucus - Sticky and contains lysozymes
Lysozymes - Destroy microbial cell walls
Phagocytic white blood cells
Blood clots
Saliva - Bactericidal
95
Q

What are the body’s barriers to entry in the gut?

A

Stomach acid
Natural flora - Competition and anti-microbial compounds
Vomiting

96
Q

What are the non-specific responses to infection?

A
Inflammation - Histamines released by mast cells
Fever
Phagocytosis
Lysozymes
Interferons - Inhibit viral replication
97
Q

What is the process of phagocytosis?

A

Microbe engulfed
Microbe enclosed in phagosome
Phagosome fused with lysosome - Phagolysosome
Microbe digested

98
Q

What is the method of formation of cloned T helper cells?

A

Macrophage engulfs bacterium and displays antigens on MHCs
T helper cells CD4 receptors bind to complementary receptors
Cytokines released and T helper cell activated
T memory cells and active T helper cells formed

99
Q

What is the method of formation of antibodies?

A

Antigen on bacterium binds to B cell with complementary receptor
Activated T helper cell binds and cytokines released
B memory and B effector cells formed
B effector cells differentiate into plasma cells
Plasma cells release antibodies

100
Q

What is the process of the cell-mediated response?

A

Bacterium infects host cell
Host cell becomes APC
Complementary T killer cell binds
Cytokines from T helper cell cause activation
T killer memory and active T killer cells formed
Active T killer cells causes lysis

101
Q

What are bactericidal antibiotics?

A

Antibiotics which kill the bacteria

102
Q

What are bacteriostatic antibiotics?

A

Antibiotics which inhibit growth of the bacterium

103
Q

What is a broad spectrum antibiotic?

A

Destroys a wide range of bacteria irregardless if they are good or not

104
Q

What is a narrow spectrum antibiotic?

A

Targets one or two specific pathogens

105
Q

What are the two possible methods of action of antibodies?

A

Prevent binding to cells

Make the bacteria clump together

106
Q

What is the structure of an antibody?

A

Y-shaped
Two sections with hinge region in middle
Antigen binding site is specific
Held together by disulphide bonds

107
Q

How does HIV kill T-helper cells?

A

Infects them so they become APCs

T killer cells kill them

108
Q

What are the four stages of HIV/AIDS infection?

A

Acute HIV syndrome - Feel unwell
Chronic stage - No symptoms, infection kept in check
Symptomatic disease - Immune system starts to fail, symptoms begin
Advanced AIDS - Severe symptoms and infections occur

109
Q

What does HIV treatment involve?

A

Prevention of spread
Can’t vaccine as rapid mutation
Drugs interfering with virus production
Combined drug therapies

110
Q

What are the two most common methods of TB infection?

A

Droplet infection

Infected milk or working close to infected cattle

111
Q

What are the symptoms of TB?

A

Chest pains
Prolonged cough producing sputum
Coughing up blood
Massive bleeding

112
Q

What are risk factors of TB?

A
HIV
Overcrowding
Malnutrition
Smoking
Genetics
113
Q

How is TB treated?

A

BCG vaccine

Course of antibiotics

114
Q

What is natural active immunity?

A

Antibodies produced by the body in first encounter

115
Q

What is natural passive immunity?

A

Get antibodies from the mother

116
Q

What is artificial active immunity?

A

Antibodies produced via injection of pathogen through vaccine

117
Q

What is artificial passive immunity?

A

Antibodies injected into you

118
Q

What does attenuated mean?

A

Organisms which are living but modified so they don’t cause disease

119
Q

What does adjuvant mean?

A

Something added to a vaccine which increases effectiveness by causing inflammation