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Biology > 5- Energy Transfers > Flashcards

5- Energy Transfers Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Where does the light dependent reaction occur

A

Thylakoid membranes and thylakoid spaces

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2
Q

What is the first stage of the light dependent reaction

A

Light absorption

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3
Q

Where is light energy absorbed by chlorophylls

A

Photosystems

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4
Q

What are photosystems made from

A

Accessory Pigments

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5
Q

What happens to the electrons when light energy is absorbed

A

The enter a more excited state and are released from the chlorophyll

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6
Q

What is the term used to describe chlorophyll, after the electrons have been released

A

Photoionized

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7
Q

What 3 reactions in photosyntheis are driven by the energy released from the photoionisation of chlorophylls

A

Photophosphorylation
Reduction
Photolysis

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8
Q

What is produced in photophosphorylation

A

ATP (from ADP and Pi)
Using Light energy and ETC
using proton gradient to drive ATP synthase

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9
Q

Where does photolysis occur

A

Thylakoid Lumen

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10
Q

What is the purpose of photolysis

A

to form a proton gradient between thylakoid lumen and stroma, as creates high conc of H+ in thylakoid lumen

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11
Q

In plants, where are the Electron carriers located?

A

Thylakoid Membranes

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12
Q

Where are the High energy electrons transferred to

A

Electron transport chain

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13
Q

How are electrons replaced in photosynthesis

A

the hydrolysis of water

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14
Q

How are H+ ions transported out of the thylakoid lumen

A

ATP synthase

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15
Q

what reaction does NADPH / reduced NADP get passed to

A

Light independent reaction

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16
Q

When electrons move down the ETC, they lose energy. What is this energy used for

A

To actively transport H+ from stroma into thylakoids through a proton pump, against their conc grad

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17
Q

What is the process of converting ADP –> ATP called, when using energy from protons diffusing through ATP synthase enzyme

A

Chemiosmosis

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18
Q

Some HEE are not passed along the ETC. Where do they get directly transferred to?

A

NADP

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19
Q

How do electrons transferred directly to NADP produce reduced NADP?

A

react with proton in stroma

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20
Q

What is produced in Non-cyclic phosphorylation

A

Reduced NADP and ATP

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21
Q

In non cyclic phosphorylation, which photosystem absorbes light to produce reduced NADP

A

PS1

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22
Q

What does not happen in non-cyclic phosphorylation

A

Electrons not recycled- , transferred from PSII to PSI

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23
Q

Which type of photophosphorylation only involves one photosystem, and which one is it?

A

Cyclic, photosystem 1

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24
Q

What happens to electrons in cyclic phosphorylation

A

cycle continously through electron carriers in PSI

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25
Q

What is chemiosmosis

A

Protons diffuse down conc grad across thylakoid mebrane through ATP synthase, releasing energy, which converts ADP + Pi –> ATP

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26
Q

What are the similarities and differences between Cyclic and Non-cyclic phosphorylation

A

Both produce ATP
Cyclic doesn’t produced NADP, Photlyisis doesn’t occur (as electrons continously recycled) so electrons in PSII aren’t replaced

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27
Q

Where does the light independent reaction (Calvin Cycle) occur

A

Stroma of chloroplasts

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28
Q

What does the calvin cycle use

A

ATP, reduced NADP, (from LDR)
CO2 and RuBP

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29
Q

What does the calvin cycle produce

A

Triose phosphates

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30
Q

Describe the first stage of the calvin cycle, giving its name

A

Carbon Fixation
CO2 diffuses into leaves, through stomata, and combines with RuBP -5C- producing an unstable 6C compound
Catalysed by rubisco
UNstable 6C splits into 2 molecules of GP- glycerate 3-phosphate, 3C

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31
Q

Describe the second stage of the calvin Cycle

A

Reduction of glycerate 3-phosphate
2 molecules of GP reduced to TP
reaction driven by Energy from 2 ATP, protons from 2 reduced NADP, both from LDR, recyled after use
1/6 TP molecules condense to hexose sugars (starch, sucrose, cellulose) converted to glycerol and GP (fatty acids, lipids (for cell membranes) ) used in production of some amino acids for protein synthesis

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32
Q

In the third stage of the calvin cycle, RuBP is regenerated. How does this occur

A

5/6 TP not converted, used to regenrate.
Driven by 1ATP

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33
Q

What are the three biomolecule products of the calvin cycle

A

Carbohydrates
Lipids
Amino Acids

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34
Q

Describe Cristae

A

Folded extensions of the inner membrane of the mitochondria,
less permeable than the outer mebrane
site of the ETC
location of ATP synthase

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35
Q

Give two conditions of the intermembrane space of the mitochondira

A

Low pH, due to a high conc of protons
Conc grad across inner membrane, formed during oxidative phosphorylation, essential for ATP synthase

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36
Q

What does the matrix of the mitochondria contain

A

Ribosomes, enzymes, circular mitochondrial DNA

37
Q

What is meant by the term “Autotrophs” and what is the opposite of this

A

Organisms that can synthesise their own usable carbon compounds from CO2 in air through photosyntheis
Heterotrophs- can’t, rely on supply of premade carbon compounds from food

38
Q

What is the first stage in respiration, and where does it occur

A

Glycolysis
cell cytoplasm

39
Q

What molecules does glycolysis produce, and what is the net gain

A

2 pyruvate 3C molecules
Net gain: 2 ATP and 2 reduced NAD

40
Q

Name and desrcibe the 5 stages of Glycolysis

A
  1. Phosphorylation
    Glucose phosphorylated by 2ATP to form fructose Bisphosphate
  2. Lysis
    fructose bisphosphate splits into 2 molecules of triose phosphate
  3. Oxidation
    Hydrogen removed, transfered to NAD to form 2 reduced NAD
  4. Dephosphorylation
    Phosphates transferred from intermediated substrate molecules. Forms 4 ATP, through substrate-linked phosphorylation
  5. Pyruvate formed
    end product, contains substantial amount of chem E. 2 produced per glucose
41
Q

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

A

Link Reaction
Matrix of mitochondria

42
Q

Describe the Link reaction

A

when there’s O2 available, pyruvate enters mitochondria matrix, through active transport, requiring transport protein and small amount of ATP
pyruvate is then oxidised by enzymes –> acetate and 2
requires reduction of NAD to NADH
dehydrogenation and decarboxylation
combined with coenzyme A, forming acetyl CoA

43
Q

What si the overall equation for the link reaction

A

Pyruvate+ NAD + CoA –> acetyl CoA + CO2 + reduced NAD (NADH)

44
Q

What is a coenzyme

A

Molecule that helps an enzyme carry out a function, but not used in reaction itself

45
Q

What is the structure of Coenzyme A

A

Nucleoside (ribose and adenine)
A vitamin

46
Q

What is the function of CoA

A

in the link reaction, binds to acetyl group
Supplies acetyle group to krebs cycle

47
Q

Where does the Krebs cycle occur

A

Matrix of Mitochondria

48
Q

Describe the Krebs cycle, 3 stages

A
  1. 2C acetyl CoA enters circular parthway from links reaction
  2. 4C oxaloacetate accepts 2C acetyl fragment from acetyl CoA to form 6C citrate. CoA released
  3. Citrate converted back to oxaloacetate through series of redox reactions
    Citrate Decarboxylated, 2 CO2 waste gas
    Citrate oxidised (dehydrogentaion), releases H atoms, reduce coenzymes NAD and FAD
    Substrate linked phosphorylation, phosphate transferred from intermediate to ADP, forming ATP
49
Q

Where does oxidative phosphorylation occyr during respiration

A

Inner membrane of mitochondria

50
Q

Describe the chemiosmotic theory (the current model for oxidative phosphorylation during respiration)

A

H donated by reduced NAd and reduced FAD from krebs cycle
H –> H+ & e-
HEE enter ETC, releasing energy as they move through ETC
released energy transports H+ across inner mitochondrial membrane, from matrix -> intermembrane space, estabilishing a conc grad
H+ return to matrix via facilliated diffusion, through channel protein: ATP synthase, providing energy for ATP synthesis
Oxygen is the final electron acceptor, combines H+ with e– to form water

51
Q

How do coenzymes work in the electron transport chain

A

when coenzymes gain H atom - reduced
When coenzymes lose H atom- oxidised

52
Q

Where is NAD produced in respiration, giving the sum total from 1 glucose

A

Glycolysis : 2 x 1 = 2
Links: 2 x 1= 2
Krebs: 2 x 3 = 6

Total: 10

53
Q

Where is FAD produced in respiration, giving the sum total from 1 glucose

A

Krebs: 2 x 1 = 2

Total: 2

54
Q

What effect does aerobic respiration have

A

No final acceptor of electrons from ETC
ETC stops functioning
No more ATP produced via oxidative phosphorylation
Reduced NAD and FAD aren’t oxidised, therfore not available for dehydrogenation in krebs cycle
Krebs cycle stops

55
Q

WHat stage can continue during anaerobic respiration

A

Glycolysis,
producing small amounts of ATP

56
Q

Describe ethanol fermentation

A

Pyruvate is decarboxylated to ethanal,
produces CO2
Reduced NAD transfers H to ethanal, Ethanal reduced to ethanol
by enzyme alcohol dehydrogenase
Ethanal acts as hydrogen acceptor
Ethanol can’t be metabolised, so is waste product

57
Q

Describe Lactate Fermentation

A

Reduced NAD transfers H to pyruvate
Pyruvate is reduced to lactate
by enzyme pyruvate dehydrogenase
pyruvate is hydrogen acceptor
lactate can’t be further metabolised,

58
Q

What 2 things can be done with lactate

A

1.Oxidise back to pyruvate, then channelled to krebs cycle for ATP production
Needs extra oxygen - “oxygen debt”

  1. Convert to glycogen for storage in liver
59
Q

Give the definition of an ecosystem

A

All the living (biotic) and non living (abiotic) components/ factors in a particular area

60
Q

Give the definition of biomass

A

the chemical energy stor of an organism/ mass of living material

61
Q

What is a trophic level

A

Posiiton of an organism in a food chain/web/pyramid
Represented by a number, trophic level 1= producers

62
Q

Give 2 ways to measure biomass

A
  1. dry mass of tissue per unit area
    mass of organism after removing water
    dry in oven for several days to dehydrate
  2. Mass of carbon in an organism
    water content not taken into account
    normall 1/2 dry mass
63
Q

WHat is the name for the peice of appartus that measures energy contained within dry mass, and how does it work

A

Calorimeter
Burns biomass, calculates energy released per gram
Measure change in temp of known volume of water that happens as result of sample being burnt

64
Q

What are the units for biomass

A

kg per m squared
per time
can change over time, trees loose leaves

65
Q

What do food chains show

A

How energy flows within a biological community

66
Q

Give the definition of Gross Primary Production- GPP

A

Chemical energy stored in carbohydrates within a plant, in given area or volume

67
Q

Give the definition of Net Primary Production - NPP

A

Chemical energy stored in plant biomass after respiratory losses (R) to environment have been considered

NPP = GPP- R

\represents energy available to organisms in higher trophic levels

68
Q

Give the definition of Net Production of Consumers

A

Production of new biomass by consumer

N= I(F+R)

69
Q

Where is energy primarily lost in the food chain

A

Respiration (R)
Excretion (F)
faeces and urine

70
Q

How do you calculate efficiency of energy transfer

A

Net productivity/ total energy consumed x100

71
Q

whats the definition of productivity in food chains

A

Rate of production of new biomass
Biomass in given area in given time

72
Q

WHy do herbivores have lower secondary productivity than carnivores

A

Eat plant material, higher in cellulose, hard to digest, more energy lost in excretion

73
Q

How does agriculture increase the efficiency of energy transfer

A

Simplify food webs
Reduce respiratory losses

74
Q

What is percentage yeild

A

Actual/ theoretical x 100

75
Q

How to increase primary productivity (4 ways)

A
  1. overcome limiting factors (to photosynthesis)
    max exposure to light, warmer temos, irrigation maximises water supply
  2. Fertlisers
    maintain nutrient levels, high levels, convert energy to biomass efficiently
  3. Pesticides
    Remove pests that spoil crops, prevents loss of biomass,
    kill weeds, reduce comp for light and nutrients
    Fungicides - prevent fungal diseases
  4. Biological Agents
    toads consume caterpillars, etc
76
Q

How to increase secondary productivity

A
  1. Reduce energy lost through heat from respiration
    Limit movement, heating in barns, antibiotics
  2. Increase growth rate
    Selective breeding - breeds with higher growth rates
    Steroids - accumulation of biomass
    Harvest when young - biomass maximise
77
Q

Where is nitrogen used

A

Proteins
Nucleic acids- DNA & RNA

78
Q

What is the name for microorganism feeds on dead/decaying organic matter, and how do they work

A

Saprobionts
e.g. bacteria, fungi
secrete enzymes onto dead organic matter: “extracellular digestion” so they can be absorbed

79
Q

What are the 4 stages of the nitrogen cycle

A
  1. Nitrogen fixation
    nitrogen fixing bacteria in soil turn atmospheric nitrogen -> ammonia/nitrogen containing compounds
  2. Ammonification
    Organism dies/ produces waste, decomposed by saprobionts, releasing nutrients inside through waste/excess thats not absorbed
    3.Nitrifcation
    Ammonium ions converted to nitrates by bacteria in soil
    Nitrifying bacteria NH4+ –> Nitrites
    Another nitrifying bacteria Nitrites->Nitrates
  3. Denitrification
    denitrifying bacteria:nitrates in soil->nitrogen gas, use nitrates in respiration
    need anaerobic conditions - waterlogged soil
80
Q

Where is phosphorus found

A

Phospholipids for cell membranes
Nucleic acids - DNA, RNA
ATP

81
Q

What is Mycorrhizae

A

Fungi that form symbiotic relationship with roots of plants
Help plants absorb inorganic ion and water from soil
Associate with roots using hyphae, increase SA

82
Q

How doe Bacteria, e.g. Rhizobium, help leguminous plants, e.g. alfalfa, peas, beans, clover

A

Form mutualistic relationship
Bacteria provide source of ammonium ions for plants
Plants provide sugars

83
Q

Describe the Phosphorus Cycle

A
  1. Released from rocks slowly intol soil by weathering
  2. Uptake
    PO4 3- assimilated by plants
    symbiotic relation between roots and mycorrhizaae
    or from water by algae
  3. Breakdwon phosphate ions
    ion transported through food chain, lost as waste/through death
    saprobionts decompose
    released into soil, reused
84
Q

How do agricultural ecosystems interupt natural processes

A

Livestock/crop removed instead of dying and decomposing
Mineral ions not returned
Lack of minerals leads to lower yeilds
fertilisers used to replace minerals

85
Q

What are natural fertilisers, and what are their pros and cons

A

MAde of organic matter, e.g. manure, compost, sewage, crop residue

Improve soil structure, reducing soil erosion, increasing water holding ability

Nutrients released over long time, not v concentrated, large amounts needed

86
Q

What are artificial fertilisers, and what are their pros

A

Inorganic matter, powders/pellets
contain pure chemical compounds

Exact chem comp know, so easier to knwo how much to apply, and the effects
Conc- less needed, transport costs lower
Easy to apply evenly, clean, easy to handle

87
Q

What are the cons of artificial fertilisers

A

Applied in excess, crops can’t use all, remain in soil water
Transported by rain water/ water from irrigation systems, into nearby water/waterways - “leeching
more likely to occur if just before rainfall

Inorgnic ions readily soluble, if not quickly absorbed, leach

88
Q

Why is phosphate leaching lesser extnet than nitrate

A

Phosphates less soluble in water

89
Q

Describe and name the process that leaching of mineral can lead to

A

Eutrophication
mineral ions from farmlands leach to water ways
Cause rapid growth of algae on water surface - “algae bloom”
Blocks sunlight, aquatic plants can’t photosyntheise so die
Algae dies, when comp is too much
High levels of death, decomposing bacteria feed on matter, numbers increase
Respire aerobically, use dissolved O2
O2 levels decrease, aquatic organisms die

Biology (5 decks)

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