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Biology > Biology - Unit 4 > Flashcards

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
What is the process of secondary succession?
``` Bare earth, grass, weeds Grass stage Grass and shrubs Young forest Mature forest ```
26
What is a plagioclimax?
A final community which is partially the result of human intervention
27
What are examples of abiotic factors?
``` Light Temperature Wind and water currents Water availability Oxygen availability Edaphic factors - Soil structure and mineral content ```
28
What are examples of biotic factors?
``` Predation Finding a mate Territory Parasitism and disease Competition ```
29
What is the effect of light on organisms?
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
30
What is the effect of temperature on organisms?
Range of temperature in which an organism can grow and successfully reproduce Extremes not average determine habitat Many animals have adaptations to cope
31
What is the effect of wind and water currents on organisms?
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
32
What is the effect of water availability on organisms?
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
33
What is the effect of oxygen availability on organisms?
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
34
What is the effect of edaphic factors like soil structure and mineral content on organisms?
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
35
What is the predator-prey cycle?
Prey population increases More food so predator numbers increase Therefore, prey numbers decrease Predator numbers decrease
36
What is the effect of finding a mate on organisms?
Abundancy of a type of animal will increase with availability of a mate
37
What is the effect of territory on organisms?
Territories normally used to ensure a breeding pair has sufficient resources Type and size of territory determines species
38
What is the effect of parasitism and disease on organisms?
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
39
What is intraspecific competition and what are possible results of it?
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
40
What is interspecific competition and what are possible results of it?
Different species within a community compete for the same resources Results: -Reduced abundancy of a species -Possible exctinction
41
What is Gross primary productivity (GPP)?
The rate at which energy is incorporated into plants
42
What is net primary productivity (NPP)?
Energy stored in body tissues | GPP - plant respiration
43
Describe the carbon cycle in nature
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
44
What is used as evidence of global warming?
Drilling into ice and taking ice cores Dendrochronology Peat bogs - Looking at pollen grains in it
45
What factors affect the ability for oceans to be efficient carbon sinks?
Water temperature and ocean currents
46
What is proteomics?
The study of proteomes
47
What is a proteome?
All the proteins produced from a genome
48
What is a gene family?
Closely related genes from mutations on the copies of the gene
49
What is habitat isolation?
Where two populations share the same habitat but are active at different times
50
What is temporal isolation?
Where populations may mate or flower at different seasons or times of day
51
What is mechanical isolation?
Where genitalia is incompatible due to shape or size
52
What is behavioural isolation?
Where populations have different courting patterns
53
What is gametic isolation?
Where gametes of different species fail to attract one another
54
What is allopatric speciation?
Where two populations are physically separated
55
What is sympatric speciation?
Where two populations are reproductively isolated in the same environment
56
How is DNA profiling of benefit to the study of speciation?
Can be used to see how closely related organisms are
57
Why does body temperature drop after death?
The metabolic reactions slow and eventually stop
58
What factors affect how quickly body temperature drops?
``` Amount of body fat Mode of death Clothing Body size Surrounding environment ```
59
Why does rigor mortis occur?
Muscle cells run out of ATP so are unable to maintain the relaxed state
60
What factors affect how quickly rigor mortis occurs?
Amount of ATP stored - Genetics, fitness, level of activity | Temperature of person and surroundings
61
What are the stages of succession in a dead body?
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
What factors affect speed of succession in a dead body?
Temperature | Level of exposure
63
What is forensic entomology?
Study of insect life as it relates to crime | Different insects have different life cycles
64
Why is a triplet code used?
Codes for 64 combinations which is more than enough
65
What does non-overlapping mean?
The triplets of bases follow each other
66
Why is a non-overlapping code used?
If overlapping, would be shorter but would mean certain amino acids would have to follow one another
67
What does degenerate mean?
Contains more information than it needs
68
Why is a degenerate code used?
If the final base is changed in a triplet, the same amino acid could still be coded for
69
What is the method of DNA transcription?
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
What is the method of post-transcription modification?
Sections of DNA (Introns) which do not code for protein removed Some exons removed as well causing mutation Spliceosomes join exons together
71
What is the method of translation?
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
What is the method of gel electrophoresis?
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
What is the method of Southern blotting?
Add alkaline buffer solution to gel Place nylon filter on top Add DNA probe
74
What is the method of PCR?
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
What is a capsomere in a virus?
A repeating protein unit which makes up the protein coat
76
What is the capsid in a virus?
The protein coat
77
What is the lysogenic pathway of virus life cycles?
Phage DNA injected into host cell Viral DNA incorporated into host cell DNA Viral DNA replicated when bacterium divides Joins to lytic pathway
78
What is the lytic pathway of virus life cycles?
``` 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
What is the life cycle of a retrovirus?
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
What is a mesosome in a bacterial cell membrane?
Infolding
81
What is the use of a slime layer in a bacterium?
Protects against phagocytosis | Covers cell markers
82
What are the uses and drawbacks to pili (or fimbriae) in bacteria?
Used for attachment to a host Used for sexual reproduction More vulnerable to viral infection
83
What is the genetic material in bacteria?
Circular DNA in cytoplasm | May be plasmids as well
84
What is the cell wall structure and what occurs in Gram staining with Gram-positive bacteria?
Have thick layer of peptidoglycan containing teichoic acid Crystal violet stays stained Shows as purple
85
What is the cell wall structure and what occurs in Gram staining with Gram-negative bacteria?
Thin layer of peptidoglycan with no teichoic acid Outer membrane layer of lipopolysaccharides Crystal violet decolourised Red safranine binds Appear red
86
What are shapes of bacteria?
Spherical - Cocci Rod shaped - Bacilli Twisted - Spirilla Comma shaped - Vibrios
87
What are possible respiratory requirements of bacteria?
Obligate aerobes - Need oxygen Facultative anaerobes - Use oxygen if it's there Obligate anaerobes - Need an absence of oxygen
88
What is a bacteria's generation time?
The time between its cell divisions
89
What are the ways in which genetic material from one bacterium can be given to another one?
Transformation Transduction Conjugation
90
What is bacterial transformation?
Short piece of DNA released by donor and actively taken up by another where it replaces a similar piece of DNA
91
What is bacterial transduction?
Small amount of DNA taken up by bacteriophage in viral coat | Taken into another bacterium where incorporated
92
What is bacterial conjugation?
Genetic information transferred from one bacterium to another by sex pilus
93
What are the methods of pathogen transmission?
``` Vectors - Living organism which transmits the infection Fomites - Inanimate objects Direct contact Inhalation Ingestion Inoculation - Break in skin ```
94
What are the epithelial barriers to entry of the body?
``` 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
What are the body's barriers to entry in the gut?
Stomach acid Natural flora - Competition and anti-microbial compounds Vomiting
96
What are the non-specific responses to infection?
``` Inflammation - Histamines released by mast cells Fever Phagocytosis Lysozymes Interferons - Inhibit viral replication ```
97
What is the process of phagocytosis?
Microbe engulfed Microbe enclosed in phagosome Phagosome fused with lysosome - Phagolysosome Microbe digested
98
What is the method of formation of cloned T helper cells?
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
What is the method of formation of antibodies?
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
What is the process of the cell-mediated response?
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
What are bactericidal antibiotics?
Antibiotics which kill the bacteria
102
What are bacteriostatic antibiotics?
Antibiotics which inhibit growth of the bacterium
103
What is a broad spectrum antibiotic?
Destroys a wide range of bacteria irregardless if they are good or not
104
What is a narrow spectrum antibiotic?
Targets one or two specific pathogens
105
What are the two possible methods of action of antibodies?
Prevent binding to cells | Make the bacteria clump together
106
What is the structure of an antibody?
Y-shaped Two sections with hinge region in middle Antigen binding site is specific Held together by disulphide bonds
107
How does HIV kill T-helper cells?
Infects them so they become APCs | T killer cells kill them
108
What are the four stages of HIV/AIDS infection?
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
What does HIV treatment involve?
Prevention of spread Can't vaccine as rapid mutation Drugs interfering with virus production Combined drug therapies
110
What are the two most common methods of TB infection?
Droplet infection | Infected milk or working close to infected cattle
111
What are the symptoms of TB?
Chest pains Prolonged cough producing sputum Coughing up blood Massive bleeding
112
What are risk factors of TB?
``` HIV Overcrowding Malnutrition Smoking Genetics ```
113
How is TB treated?
BCG vaccine | Course of antibiotics
114
What is natural active immunity?
Antibodies produced by the body in first encounter
115
What is natural passive immunity?
Get antibodies from the mother
116
What is artificial active immunity?
Antibodies produced via injection of pathogen through vaccine
117
What is artificial passive immunity?
Antibodies injected into you
118
What does attenuated mean?
Organisms which are living but modified so they don't cause disease
119
What does adjuvant mean?
Something added to a vaccine which increases effectiveness by causing inflammation

Biology (5 decks)

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