Unit C Scofield Reset Flashcards
(82 cards)
1
Q
C1.1
4 Limiting Factors of Enzymatic Metabolism
A
- Enzyme concentration
- Substrate concentration
- Temperature
- pH
2
Q
C1.1
How enzymes catalyse reactions (11)
A
- Speed up reaction
- Enzyme is chemically unchanged
- Alternate pathway of low Ea
- Ea is min. energy to start a reaction
- (draw a graph to show 4)
- Substrate binds to active site by induced fit
- Formation of enzyme-substrate complex
- Active site is specific to substrate
- Enzymes bring reactants closer to each other
- Active site and substrate undergo induced fit
- Substrate becomes more reactive
3
Q
C1.1
4 Differences between competitive/non-competitive enzyme inhibition
A
- Active/allosteric site
- Effect diminished/unaffected by substrate concentration
- Structurally similar/distinct from substrate
- Does not/Does change shape of enzyme
Eg. malonate competes with succinate dehydrogenase, opioids inhibit nitric oxide synthase
4
Q
C1.1
Examples of anabolism and catabolism (4/2)
A
Anabolism
- Protein synthesis
- Glycogenesis
- Photosynthesis
- Condensation Reactions
Catabolism
- Glycolysis
- Hydrolysis Reactions
5
Q
C1.1
Examples of intracellular and extracellular enzymatic reactions (2/2)
A
Intracellular
- Glycolysis
- Krebs Cycle
Extracellular
- Intestinal chemical digestion
- Saprotrophic nutrition
6
Q
C1.1
Examples of linear and cyclic metabolic reactions (2/2)
A
Linear
- Glycolysis
- Link Reaction
Cyclic
- Krebs Cycle
- Calvin Cycle
7
Q
C1.1
Example of competitive inhibitor (3)
A
- Statins inhibits HMG-CoA reductase
- Statins compete against HMG-CoA for reductase active site
- Statins reduce cholesterol production
8
Q
C1.1
2 Examples of end-product inhibition (3 + 3)
A
Isoleucine
1. Bacteria produces isoleucine from threonine (it is essential in humans)
2. Isoleucine binds to allosteric site of isoleucine deaminase
3. Negative feedback to regulate rate of isoleucine production
Glucose-6-phosphatase
1. Hexokinase phosphorylates glucose to glucose-6-phosphate
2. Glucose-6-phosphate binds to allosteric site of hexokinase
3. Negative feedback to regulate rate of glycolysis
9
Q
C1.1
Example of mechanism-based inhibition
A
- Transpeptidase maintains the rigidity of the bacterial cell wall by cross-linking polysaccharide chains
- Penicillin irreversibly binds to transpeptidase
- Cell wall is weakened, bacterial cell lyses and dies
- Mutations to transpeptidase structure cause resistance to penicillin
Also used in production of AZT, an HIV infection drug
10
Q
C1.2
4 Differences between aerobic and anaerobic respiration
A
- Oxygen/not?
- Much/Little ATP produced
- CO2, H2O/lactate,ethanol
- Mitochondria/Cytoplasm
11
Q
C1.2
4 Steps of Glycolysis
A
- Phosphorylation: Glucose → Fructose-1,6-bisphosphate (2ATP → 2ADP)
- Lysis: Fructose-1,6-bisphosphate → 2 Triose phsophates
- Oxidation: Triose phosphate → Bisphosphotglycerate (NAD → NADH + H+)
- ATP synthesis: Bisphosphoglycerate → Pyruvate (2ADP → 2ATP)
Net per Glucose: 2 ATP produced, 2 NADH + H+ produced
Only the names glucose and pyruvate are required.
12
Q
C1.2
2 Steps of Link Reaction
A
- Pyruvate → Acetate + CO2 (NAD → NADH + H+)
- Acetate + CoA → Acetyl-coA
Net per Glucose: 2NADH + H+ produced, 2 CO2 produced
13
Q
C1.2
5 Steps of Krebs Cycle
A
- Oxaloacetate + Acetyl-coA → Citrate
- Citrate → alpha-Ketoglutarate + CO2 (NAD → NADH + H+)
- alpha-Ketoglutarate → Succinate + CO2 (NAD → NADH + H+) (ADP → ATP)
- Succinate → Fumarate (FAD → FADH2)
- Fumarate → Oxaloacetate (NAD → NADH + H+)
Net per Glucose: 3 NADH + H+ produced, 1 FADH2 produced, 2 CO2 produced
Simplified: 1 Acetylation, 4 Oxidations, 2 Decarboxylations
Only the names oxaloacetate and citrate are required.
14
Q
C1.2
6 Steps of Oxidative Phosphorylation
A
- Charge Separation releases protons and electrons
- Electron Transport Chain releases energy for proton pumping
- Proton Pumping from matrix to intermembrane space generates proton gradient
- Chemiosmosis of protons from intermembrane space to matrix
- ATP synthase couples energy from proton gradient with ATP synthesis
- Oxygen as the terminal electron acceptor
15
Q
C1.3
2 Types of Carbon Dioxide Enrichment Experiments
A
- Enclosed Greenhouse Experiments – strictly controlled laboratory environment
- Free-Air Carbon dioxide Enrichment experiments (FACE) – releasing CO2 into a circular area with controlled pipes, and monitoring with sensors, more natural method of investigation at high financial cost
16
Q
C1.3
Advantage of structure of photosystems (3-step answer)
A
- Photosystems are molecular arrays of chlorophyll and accessory pigments, with a special chlorophyll as the reaction centre, from which an excited electron is emitted
- Photosystems occur in cyanobacteria and chloroplasts
- A single photsynthetic pigment could not provide enough energy for photactivation
17
Q
C1.3
8 Steps of Non-cyclic Photophosphorylation
A
- Photoactivation from PSII
- Electron Transport Chain releases energy for proton pumping
- Electron is transferred to PSI, and is released
- 2 electrons are transferred to NADP reductase, reducing NADP+
- Proton Pumping from stroma to thylakoid lumen
- Chemiosmosis of protons from thylakoid lumen to stroma
- ATP synthase couples energy from proton gradient with ATP synthesis
- Photolysis of water replaces PSII electron
18
Q
C1.3
6 Steps of Cyclic Phosphorylation
A
- Photoactivation from PSI
- Electron Transport Chain releases energy for proton pumping
- Proton Pumping from stroma to thylakoid lumen
- Chemiosmosis of protons from thylakoid lumen to stroma
- ATP synthase couples energy from proton gradient with ATP synthesis
- Electron is returned to PSI
19
Q
C1.3
5 Steps of Calvin Cycle
A
- Ribulose bisphosphate + CO2 → 2 x Glycerate 3-phosphate [Rubisco]
- Glycerate 3-phosphate → Triose phosphate (ATP → ADP) (NADPH → NADP)
- 2 Triose phosphate → 1 Glucose
- 10 Triose Phosphate → 6 Ribulose bisphosphate
- All carbon compounds in plants are made by intermediates in the Calvin Cycle
20
Q
C2.1
6 Steps of Cellular Chemical Signalling
A
- Synthesis
- Diffusion
- Binding
- Signal Transduction
- Cellular Response
- Signal Termination
21
Q
C2.1
4 Steps of Vibrio fischeri Quorum Sensing
A
- N-acyl homoserine lactone binds to regulators to induce lux operon.
- Lux operon encodes regulatory proteins and produces luminescent proteins.
- Luminescent proteins eg. Luciferase produce light when oxidising substrates eg. Luciferin by reversible redox reactions eg. into Oxyluciferin.
- High concentrations of autoinducers in a large population produce protective effect.
22
Q
C2.1
3 Types of Hormones
A
- Amino Acid (tryptophan and tyrosine)
- Peptide
- Lipid-derived
23
Q
C2.1
4 Types of Neurotransmitters
A
- Amino Acid
- Peptide
- Amine
- Nitrous Oxide
24
Q
C2.1
5 Types of Signalling
A
- Autocrine Signalling - same cell
- Paracrine Signalling - cells in the vicinity
- Endocrine Signalling - distant cells
- Juxtacrine Signalling - cells in immediate physical contact
- Gap Junctions - intracellular junctions linking adjacent cells
25
# C2.1
5 Types of Receptors
- Cell-Surface Receptor
bind to extracellular signalling molecules to initiate signalling cascade
- Enzyme-linked
- G-protein-linked
- Ion-channel-linked
- Intracellular Receptor
bind to intracellular, small lipid-derived signalling molecules to form hormone-receptor complex
- Type I, Cytoplasmic Receptor
translocated to nucleus
- Type II, Nuclear Receptor
directly involved in transcription by binding N-terminal
26
# C2.1
5 Steps of Signal Transduction
1. Receptor activation
2. Amplification
3. Second messenger production
4. Activation of protein kinases
5. Changes in gene expression, ion channel function, or enzyme activation
27
# C2.1
5 Pathways of Signal Transduction Termination
- Diffusion
- Degradation
- Reuptake
- Feedback Inhibition
- Receptor Deactivation
28
# C2.1
4 Steps of G-Protein Function
1. Ligand binds to GPCR
1. GDP in GPCR is substituted by GTP
1. a-subunit is separated from b- and g-subunits
1. Subunits detach form GPCR
29
# C2.1
10 Steps of Epinephrine Function
1. Epinephrine binds to GPCR
1. GDP in GPCR is substituted by GTP
1. a-subunit is separated from b- ang g-subunits
1. Subunits detach from GPCR
1. Adenylate cyclase converts ATP to cAMP
1. a-subunit binds to adenylate cyclase
1. cAMP activates PKA
1. PKA activates phosphorylase kinase
1. Phosphorylase kinase activations glycogen phosphorylase
1. Glycogen phosphorylase facilitates glycogenolysis
30
# C2.1
7 Steps of Insulin Function
1. Insulin binds to receptors in hepatocytes
1. Tyrosine kinase in b-receptor autophosphorylates
1. Tyrosine kinase phosphorylates IRS2
1. Cascade stimulates transcription of GLUT-4
1. Golgi apparatus packages GLUT-4 into vesicles
1. GLUT-4 is embedded into the membrane as vesicules fuse with it
1. GLUT-4 increases ability of tissue to intake glucose and conduct glycogenesis
31
# C2.1
4 Steps of Oestradiol Genomic Binding
1. Oestradiol binds to oestradiol receptors
2. Oestradiol detaches Heat Shock Protein 90
3. Dimerised receptor-ligand complex is translocated to nucleus
4. Complex interacts with regulators or transcription factors
32
# C2.1
4 Steps of Oestradiol Non-Genomic Binding
1. Oestradiol binds to GPER
2. Signalling cascade produces cAMP
3. cAMP activates PKA
4. PKA activates transcription factors
33
# C2.1
Oestradiol effect on LH and FSH (2-step)
1. Increased oestradiol increases GnRH
2. Increased GnRH increases anterior pituitary gland secretion of LH and FSH
34
# C2.1
3 Functions of Progesterone
- Induces differentiation in endometrium
- Induces proliferation of endometrial cells
- Produces mucus to help sperm reach ovum
35
# C2.1
6 Steps of Positive Feedback in Blood Clotting
1. Intrinsic/extrinsic pathway activates Factor X
2. Factor X converts Prothrombin to Thrombin
3. Thrombin activates Factor X
4. Thrombin combines Fibrinogen to Fibrin
5. Thrombin activates Factor XIII
6. Factor XIII stabilises Fibrin
36
# C2.1
3 Steps of Negative Feedback in Homeostasis of Blood Glucose
1. Blood glucose rises
2. Pancreas secretes insulin
3. Blood glucose falls to 90 mg/dL
37
# C2.2
4 Steps of Nerve Impulse Generation
1. Depolarisation
2. Repolarisation
3. Hyperpolarisation
4. Resting Potential
38
# C2.2
3 Factors Affecting Nerve Impulse Propagation Speed
- Diameter
- Temperature
- Myelination
39
# C2.2
6 Steps of Synaptic Transmission
1. Action potential arrives presynaptic neuron
2. Calcium influx through voltage-gated channels
3. Vesicles fuse with presynaptic membrane
4. Neurotransmitters diffuse across synaptic cleft
5. Neurotransmitters bind to postsynaptic receptors
6. Summation of excitatory and inhibitory neurotransmitters
40
# C2.2
6 Steps of Neonicotinoid Effects
1. Neonicotinoids are similar in chemical structure to acetylcholine
2. Inhibits cholinergic receptors
3. Not broken down by acetylcholinesterase
4. Permanent binding
5. Prevent action of acetylcholine
6. Paralysis
41
# C2.2
7 Steps of Cocaine Effects
1. Cocaine is similar in chemical structure to dopamine
2. Inhibits dopamine reuptake proteins
3. Dopamine accumulates in synaptic cleft
4. Psychoactive effects due to amplified signals
5. Continuous consumption creates more dopamine receptors
6. More dopamine needed to achieve similar level of excitation
7. Addiction
42
# C2.2
6 Types of Receptors in Skin
* Nociceptors - pain
* Thermoreceptors - temperature
* Meissner's Corpuscles - light pressure, slow vibration
* Pacinian Corpuscles - heavy pressure, fast vibration
* Ruffini Endings - skin stretch, continuous pressure
* Free Nerve Endings - pain EPSPs
43
# C2.2
3 Layers of Skin
* Epidermis - protective barrier, strength, waterproofness
* Dermis - blood vessels, hair follicles, sweat glands, sensory receptors, strength, elasticity
* Hypodermis - fat storage, shock absorption, thermal insulation
44
# C1.3
3 Advantages of Having Multiple Pigments
* Combination of pigment molecules increases the photon absorbance frequency
* Greater proportion of sunlight can be used for photosynthesis
* Reduction of light energy loss by fluorescence
45
# C3.1
2 Functions of Auxin
- Cell elongation in tropic movements
- Apical dominance for vertical growth
46
# C3.1
3 Functions of cytokinin
- Promote cell division
- Stimulate meristem differentiation
- Delay senescence
47
# C3.1
4 Functions of Gibberellin
- Shoot elongation
- Seed germination
- Flower/fruit maturation
- Delay senescence
48
# C3.1
3 Functions of Abscisic acid
- Reduce water loss by abscission of leaves
- Inhibit stem elongation
- Induce dormancy in seeds
49
# C3.1
Polar auxin transport (5-step)
1. IAA influx by influx carriers
1. IAA dissociates and the anion cannot exit the cell
1. Efflux carriers pump IAA ions out of the cell using ATP
1. Efflux carriers are localised on one side of the cell, creating a high IAA level in the apoplast
1. Coordination between cells causes IAA to accumulate on one side of the plant
50
# C3.1
6 Steps of Acid Growth Theory
1. Auxin binds to receptors on shaded side of cell
1. Auxin binding activates ATPases to pump H+ into the cell wall
1. Hydrogen bonds between cellulose fibres are weakened, and the cell walls weaken
1. K+ influx by facilitated diffusion
1. Water enters cell by osmosis
1. Internal turgor pressure increases and the cell elongates
51
# C3.1
Interactions of auxin and cytokinins (3-step)
1. Root tips produce cytokinin and transports them to shoots
1. Shoot tips produce auxin and transports them to roots
1. Interactions between auxin and cytokinin ensure the integrated growth of the plumule and radicle
52
# C3.1
6 Functions of Ethylene
- Soften fruit by breaking down cell walls
- Sweeten fruits by breaking down starch into simple sugars
- Sweeten fruits by reducing bitter phenolic compounds
- Changes colour of fruits by converting chlorphyll to other coloured pigments
- Creates aroma of ripening fruit by releasing volatile compounds
- Stimulates ethylene production by positive feedback
53
# C3.2
4 Steps of blood clotting
1. Platelets release clotting factors
1. Thromboplastin converts prothrombin to thrombin
1. Thrombin converts soluble fibrinogen to insoluble fibrin
1. Fibrin mesh traps erythrocytes to form a clot
54
# C3.2
6 Steps of phagocytosis
1. Ameboid movement of professional phagocytes
1. Phagocyte cell membrane receptors bind to pathogen antigens
1. Pseudopodia encircle the pathogen and fuse to a phagosome
1. Phagosome maturation occurs
1. Phagosome fuses with lysosomes to form phagolysososmes
1. Hydrolytic enzymes digest microbial components
55
# C3.2
Clonal selection theory (4-step)
1. Pathogen antigen activates B-cell and helper T-cell by receptor binding
1. Helper T-cell activates B-cell
1. B-cell undergoes mitotic clonal selection and differentiates into plasma cells and memory cells
1. Plasma cells produce complementary antibodies
56
# C3.2
3 Stages of HIV
1. Acute: HIV level is high
1. Chronic: HIV level is low
1. AIDS: Body cannot fight opportunistic infections
57
# C3.2
4 Steps of antibiotic resistance development
1. Patient has a bacterial infection
2. Patient takes antibiotic infections which kills some bacteria, but stop before all bacteria are killed
3. Surviving bacteria reproduce, mutation makes bacteria resistant to antibiotics
4. Antibiotic-resistant bacteria survives and reproduces, creating a population of antibiotic-resistant bacteria (or by Lateral Gene Transfer)
58
# C3.2
4 Examples of zoonotic disease
Zoonosis occurs by spillover of pathogens
- Tuberculosis -- cows
- Rabies -- dogs, bats, racoons, foxes
- Japanese encephalitis virus -- pigs, aquatic wading birds
- SARS-CoV-2 -- bats
59
# C4.1
5 Steps of Speciation
1. Different environmental biotic and abiotic factors
2. Different selective pressures
3. Divergent evolution
4. Reproductive isolation
5. Repeated breeding results in speciation
60
# C4.1
5 Density-dependent factors
* Resource competition
* Predation
* Disease
* Parasitism
* Waste accumulation (/disease lmao)
61
# C4.1
3 Density-independent Factors
* Natural disasters
* Anthropogenic events
* Climate change
62
# C4.1
Example of ecological cooperation (as opposed to competition) (3)
1. Social amoeba
2. When starved of nutrients, amoeba aggregate to form a multicellular structure
3. Multicellular structure is altruistic as individual amoeba sacrifice themselves to aid spore disperal
63
# C4.1
Example of herbivory, predation, interspecific competition, mutualism, parasitism and pathogenicity
- Pandas and giant bamboo
- Grizzly bears and salmon
- Eastern grey squirrel and American red squirrel
- Bees and flowers
- Tapeworms in digestive system
- Mycobacterium tuberculosis in humans
64
# C4.1
3 Examples of mutualism
Root Nodules of Fabacae
- Nitrogen-fixing bacteria provide plant with nitrogen
- Plants provides bacteria with carbohydrates
Mycorrhizae in Orchidaceae
- Fungal hyphae extends range of nutrient absorption
- Orchids provide glucose by photosynthesis
Zooxanthellae in hard corals
- Algae protect corals from UV
- Corals offer algae a shelter environment
65
# C4.1
Example of invasive species (3)
1. Killer algae from Indian Sea transferred to Mediterranean
2. Toxin deters molluscs, fish and sea urchins, and has few predators
3. Competes with Neptune grass and takes over large areas
66
# C4.1
Example of allelopathy and antibiotic secretion
* Black walnut tree secretes juglone
* Streptomyces bacteria synthesises a wide range of antibiotics
67
# C4.2
Example of chemoautotroph
Iron-oxidising bacteria in acidic mine drainage or iron-rich soil
68
# C4.2
Primary Production
v
Secondary Production
Primary
Accumulation of carbon compounds in biomass by autotrophs
Secondary
Accumulation of carbon compounds in biomass by heterotrophs
69
# C4.1
4 Properties of K-Strategists
Small population
Each offspring receives more parental care
Long life span
Large body size
| eg. oak trees, elephants
70
# C4.1
4 Properties of r-Strategists
Large population
Each offspring receives less parental care
Short life span
Small body size
| eg. jellyfish, dandelions
71
# C4.1
5 Steps of Counting Motile Organisms
1. Capture a sample of motile organisms.
2. Mark the organisms using a small amount of non-toxic waterproof paint in an area which does not affect the survival of the organism.
3. Released the first sample.
4. After 24 hours, capture a second sample in the same area. Count the number of marked organisms in the sample.
5. Using the Lincoln Index formula P = MN/R, estimate the total population.
72
# C4.1
4 Assumptions of Capture-Mark-Release-Recapture
* Marking technique does not affect chances of survival.
* Marked sample fully reintegrates into the population and has an equal chance of being in the second sample.
* No births, deaths, or migrations.
* The ratio of marked to unmarked individuals in the second sample is equal to that of the general population.
73
# C4.1
4 Types of Mutualistic Relationships
* Mutualism - both organisms benefit
* Commensalism - one organism benefits without significant effect to the other
* Parasitism - parasite benefits at expense of host
* Pathogenicity - pathogen harms host
74
# C4.1
4 Models of Speciation
* Allopatric - Geographic isolation due to physical barrier
* Peripatric - Geographic isolation by breaking off from majority
* Parapatric - Behavioural isolation
* Sympatric - Reproductive isolation due to genetic polymorphism
75
# C4.1
2 Biochemical Processes in Interspecific Competition
- Allelopathy - Juglans nigra releases juglone as growth inhibitor
- Antibiotic Secretion - Streptomyces bacteria releases streptomycin
76
# C4.1
Autotrophs vs Heterotrophs
- Autotrophs synthesise own unorganic molecules for nutrition
- Heterotrophs obtain nutrition by consuming organic matter of other organisms
77
# C4.2
4 Reasons for Energy Loss in Food Webs
- Energy lost from respiration as heat
- Energy used for metabolism
- Egestion
- Not all of prey is eaten/digested
78
# C4.2
Difference between Nutrient and Energy Flow
- Nutrients are recycled within an ecosystem by decomposers
- Energy enters ecosystem and is dispersed as heat. Ecosystems require a constant source of energy from sunlight
79
# C4.2
5 Steps of Nitrogen Cycle
1. Nitrogen-fixing bacteria in legume root modules absorb atmospheric nitrogen
2. Decomposers and nitrogen-fixing bacteria in soil synthesis ammonia
3. Nitrifying bacteria converts ammonia into nitrites then nitrates
4. Plants assimilate nitrates
5. Denitrifying bacteria converts nitrates into nitrogen
80
# C4.2
4 Consequences of Enhanced Greenhouse Gas Effect/Global Warming
- Increased detritus decomposition rate in permafrost.
- Changes in distribution of temperate/arctic predators/prey.
- Increased success of pathogens/pests (esp. zoonotic transmission).
- Rising sea levels and loss of ice habitat due to melting glaciers.
81
# C4.2
7 Components of Carbon Cycle
- plant respiration
- plant photosynthesis
- animal respiration
- animals consume plants
- decomposer respiration
- fossil fuel combustion
- ocean absorption
82
# C4.2
6 Consequences of CO2 Increase
- rising sea levels causes flooding
- global warming + enhanced greenhouse effect
- extreme weather patterns
- melting glactiers
- mass extinction events
- changes in ocean currents
