Unit C 死记烂背 Flashcards
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
Example of end-product inhibition (3)
A
- Bacteria produces isoleucine from threonine (it is essential in humans)
- Isoleucine is produced
- Isoleucine binds to allosteric site of isoleucine deamine
- Hexokinase phosphorylates glucose to glucose-6-phosphate
- Glucose-6-phosphate binds to allosteric site of hexokinase
- 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)
- Malate → 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 olecular 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 → 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 Derived - derived from tryptophan and tyrosine
- water soluble
melatonin (pineal gland)
thyroxin (thyroid gland)
epinephrine, norepinephrine (adrenal gland)
Peptide - polypeptides/glycoproteins
- water soluble
insulin (pancreas)
oxytocin
HGH
FSH
Lipid Derived / Steroid - derived from cholesterol
- lipid-soluble
oestradiol
testosterone
cortisol
aldosterone
23
Q
C2.1
3 Types of Neurotransmitters
A
Amino Acid fast synaptic transmission Glycine
Glutamate
GABA
Peptide regulates metabolic processes Neuropeptide Y
Amine
Serotonin
Dopamine
Norepinephrine
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. binding of a ligand to GPCR:
2. phosphorylates GDP to GTP
3. separates a and bg subunits
4. separates subunits from GPCR
29
# C2.1
9 Steps of Epinephrine Function
1. binding of a ligand to GPCR:
2. phosphorylates GDP to GTP
3. separates a and bg subunits
4. separates subunits from GPCR
5. alpha-subunit binds to adenylate cyclase
6. Adenylate cyclase converts ATP to cAMP
7. cAMP activates protein kinase A
8. PKA activates phosphorylase kinase
9. Phosphorylase kinase activates glycogen phosphate
30
# C2.1
5 Steps of Insulin Function
1. Insulin binds to beta receptor
2. Tyrosine kinase in beta receptor autophosphorylates
3. Tyrosine kinase phosphorylates Insulin Receptor Substrate 2
4. Cascade attracts vesicles of GLUT-4
5. GLUT-4 increases ability of cells in adipose and muscle tissue to intake glucose
31
# C2.1
3 Functions of Insulin
- peripheral insulin sensitivity
- beta-cell development
- central leptin sensitivity
32
# C2.1
4 Steps of Oestradiol Genomic Binding
1. Oestradiol binds to oestradiol receptors
2. Oestradiol detaches Heat Shock Protein 90
3. HSP90 is translocated to nucleus
4. HSP90 interacts with regulators or transcription factors
or cAMP → PKA which activates some transcription factors {non-genomic binding)
33
# C2.1
4 Steps of Oestradiol Non-Genomic Binding
1. Oestradiol binds to oestradiol receptors
2. Oestradiol detaches Heat Shock Protein 90
3. HSP90 is translocated to nucleus
4. cAMP → PKA activates transcription factors
34
# C2.1
2 Steps of Oestradiol effect on LH and FSH
1. Increased oestradiol increases GnRH Gonadotropin Regulating Hormones
2. Increased GnRH increases anterior pituitary gland secretion of LH and FSH
35
# C2.1
3 Functions of Progesterone
- Induces differentiation in endometrial
- Induces proliferation of endometrial cells
- Produces mucus to help sperm reach ovum
36
# 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
37
# 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
38
# C2.2
4 Steps of Nerve Impulse Generation
1. Depolarisation
2. Repolarisation
3. Hyperpolarisation
4. Resting Potential
39
# C2.2
3 Factors Affecting Nerve Impulse Propagation Speed
- Diameter
- Temperature
- Myelination
40
# 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
41
# 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
42
# 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
43
# 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
44
# 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
45
# C1.2
6 Steps of Glycolysis
1. Glucose → glucose-6-phosphate (ATP → ADP)
2. Glucose-6-phosphate → Fructose-6-phosphate
3. Fructose-6-phosphate → Fructose-1,6-phosphate (ATP → ADP)
4. Fructose-1,6-bisphosphate → 2 Triose phosphate
5. 2 Triose phosphate → 2 Bisphosphoglycerate (NAD → NADH)
6. 2 Bisphosphoglycerate → 2 Pyruvate (2ADP → 2ATP)
46
# C1.2
2 Steps of Link Reaction
1. Pyruvate → Acetate + CO2 (NAD → NADH)
2. Acetate + CoA → Acetyl-coA
47
# C1.2
7 Steps of Krebs Cycle
1. Oxaloacetate + Acetyl-coA → Citrate
2. Citrate → Isocitrate
3. Isocitrate → alpha-Ketoglutarate + CO2 (NAD → NADH)
4. alpha-Ketoglutarate → Succinate + CO2 (NAD → NADH) (ADP → ATP)
5. Succinate → Fumarate (FAD → FADH2)
6. Fumarate → Malate
7. Malate → Oxaloacetate (NAD → NADH)
48
# C1.2
6 Steps of Oxidative Phosphorylation
1. Charge Separation - NADH → NAD + H+ + e-
2. Electron Transport Chain - electrons travel releasing energy through series of redox reactions
3. Proton Pumping - energy used to pump H+ into intermembrane space by active transport
4. Chemiosmosis - diffusion of H+ from intermembrane space into matrix
5. ATP Synthesis - H+ binding to ATP synthase causes conformation change, causing ADP + Pi → ATP
6. Oxygen - O2 + 4H+ + 4e- → 2H2O. Cycle repeats.
49
# c1.3
7 Steps of Non-Cyclic Phosphorylation
1. Excitation - PSII electrons absorb energy, moving to higher energy level
2. Electron Transport Chain - electrons travel releasing energy through series of redox reactions
3. NADP Reduction - emits electron to NADP reductase
4. Proton Pumping - ETC energy used to pump H+ into thylakoid membrane space by active transport
5. Chemiosmosis - diffusion of H+ from thylakoid membrane space into stroma
6. ATP Synthesis
7. Photolysis - 2H2O → 4H+ + 2O + 4e- to replace PSII electron
50
# C1.3
5 Steps of Cyclic Phosphorylation
1. Excitation - PSI electrons absorb energy, moving to higher energy level
2. Electron Transport Chain - electrons travel releasing energy through series of redox reactions
3. Proton Pumping - ETC energy used to pump H+ into thylakoid membrane space by active transport
4. Chemiosmosis - diffusion of H+ from thylakoid membrane space into stroma
5. ATP Synthesis
51
# C1.3
5 Steps of Calvin Cycle
1. RuBisCO fixes 6 CO2 to RuBP
2. 6-carbon compound splits into 2 G3P
3. G3P reduced to triose phosphate by ATP hydrolysis and NADPH oxidation
4. 2 triose phosphates form 1 glucose
5. 10 triose phosphates regenerate 6 RuBP
52
# C1.3
3 Pigments in Plants
* Chlorophyll a - 440 nm
* Chlorophyll b - 590 nm
* Carotenoids - 470, 510 nm
53
# 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
54
# C1.3
3 Limiting Factors of Photosynthesis
* Temperature
* Light Intensity
* CO2 Concentration
55
# 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
56
# C4.1
3 Types of Isolation
* Geographic Isolation
* Behavioural Isolation
* Temporal Isolation
57
# 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
58
# C4.1
4 Properties of r-Strategists
Large population
Each offspring receives less parental care
Short life span
Small body size
| eg. jellyfish, dandelions
59
# 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.
60
# 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.
61
# 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
62
# 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
63
# C4.1
2 Biochemical Processes in Interspecific Competition
- Allelopathy - Juglans nigra releases juglone as growth inhibitor
- Antibiotic Secretion - Streptomyces bacteria releases streptomycin
64
# C4.1
Autotrophs vs Heterotrophs
- Autotrophs synthesise own unorganic molecules for nutrition
- Heterotrophs obtain nutrition by consuming organic matter of other organisms
65
# 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
66
# 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
67
# 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
68
# 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.
69
# C4.2
7 Components of Carbon Cycle
- plant respiration
- plant photosynthesis
- animal respiration
- animals consume plants
- decomposer respiration
- fossil fuel combustion
- ocean absorption
70
# 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
