energy transfer in & between organisms

anaerobic repiration word equation in plants

glucose → ethanol + carbon dioxide + 2ATP

anaerobic repiration word equation in animals

Glucose → lactate + 2 ATP

when does anaerobic repiration occur ?

• in plant roots when soil is water logged

• in animals when oxygen suply is low, oxegen supply is temporarily restricted, oxygen is used quicker than it can be supplied

• in yeast when oxygen supply runs out

why does reduced NAD formed in glycolysis have to become oxised again ? 

so NAD doesnt run out

• if it did glycolysis would stop so no ATP reproduction 

what are the similarities of anaerobic respiration in plants & yeast than animals?

• glycolysis occurs to produce ATP

• reduced NAD reoxidised to NAD (so it can be reused)

what are the differences of anaerobic respiration in plants & yeast than animals?

• ethanol & carbon dioxide produced rather than lactic acid

What is the only stage of aerobic respiration occuring anaerobic repiration ?

glycolysis

where in the cell does anaerobic repiration occur ?

cytoplasm

what is the role of NAD in anaerobic respiration ?

to accept hydrogen during glycolysis

what happens to pyruvate to form lactate in animals in anaerobic respiration ?

pyruvate accepts the hydrogen from the reduced NAD forming lactate

what happens to pyruvate to form ethanol in plants & yeast in anaerobic respiration?

pyruvate accepts the hydrogen from the reduced NAD forming ethanol

what happens to reduced NAD in anaerobic respiration & why is it important ?

reduced NAD regenated to NAD so it can continue to accept hydrogen

how many ATP are generated by anaerobic respiration ?

only 2 ATP (net) produced

oxygen debt in anaerobic repiration ?

• lactate causes cramp & muscle fatigue

• needs to be oxidised back into pyruvate in liver

• transport to liver in the bloodstream

• pyruvate can then be used in link reaction & krebs cycle

what other respiratory substrates (except glucose) ?

(not anaerobic respiration)

• lipid → fatty acids + glycerol

glycerol → triose phosphate → pyruvate → moves into link reaction

lipids release more H atoms than carbs so more energy quantity

• protein → amino acids → (deamination - amino group removed) molecules with different number of C atoms → enter respiratory pathway at different points 

what is oxidisation ?

loss of electrons, loss of hydrogen ion or gain of oxygen

• energy given out

what is reduction ?

gain of electrons, gain of hydrogen or loss of oxygen

• energy taken in

what is photophosphorylation?

add inorganic phosphate molecules to ADP making ATP

what is photolysis ?

splitting water into H+ ions (protons), electrons & oxygen

where does photophosphorylation & photolysis take place ?

on the thylakoids

what are the products of light dependent reaction that passes to light independent reaction ?

• reduced NAPD (NADPH)

• ATP

waste molecule of light dependent reactions that leave the plant ?

oxygen leaves the plant

molecules from light dependent reaction that is reused ?

• H+ ions

• electrons

Why can't plants only rely on APT & also need to respire ?

• ATP not made in the dark

• not alot of ATP made

• cells without chlorophyll can't make ATP

• can't be transported around organism but glucose can

what are the steps of chemiosmotic theory ?

1. H+ ions produced by phospholysis of H2O, move into thylakoid from stroma using active transport using energy released from the electron released from chlorphyll

2. H+ ions can only pass from thylakoid space to stroma through ATP sythase channel proteins (rest of membrane is impermeable)

3. as H+ ions pass through the channels, they cause enzymes to change shape. This enzyme catalyses ADP + Pi → ATP

how are H+ ions moved in to thylakoid during chemiosmotic theory ?

H+ ions moved by active transport

how are H+ ions moved out of thylakoid during chemiosmotic theory ?

H+ ions moved by facilitated diffusion

how are protons transported into the thylakoid during chemiosmotic theory?

using a proton pump which actively transports inot the thylakoid using energy from electrons from chlorophyll

where is the low concentration of proteins in chemiosmotic theory ?

in the stroma (outside the thylakoid)

where is the high concentration of protons in the chemiosmotic theory ?

inside the thylakoid

what is the equation for photolysis ?

2H2O → 4H+ +4e- + O2

How are chloroplasts adapted for light dependent reactions ?

• thylakoid membrane has large surface area to allow chlorplasts to attach to

• network for proteins in grana mean chloroplast held in precise place for maximum absorption of light

• granal membranes contain ATP synthase channels to catalyse production of ATP

• chloroplasts contain DNA & ribsomoses to manufacture some of the proteins for light dependent reactions

steps of phosphorylation?

• photon of light hits chlorophyll molecule

• 2 high energy e- picked up by e- carriers

• e- pass through e- carriers on thylakoid molecule

• e- released to form ATP

• low energy e- left over

afterward phosphorylation

• e- passed through thylakoid combined with H+ ions from photolysis & attach to NADP

• NADPH

steps of photolysis ?

• photon of light hits a chlorphyll molecule

• chlorphyll short of e- & must be reproduced

• light splits water into H+, e- & O2

what happens to the oxygen after photolysis ?

used in repiration or diffusion

what happens to the e- after photolysis ?

combine with chlorphyll

what are the steps after photophosphorylation & photolysis?

• e- passes through thylakoid & combined with H+ ions from photolysis & attach to NADP

• NADPH (reduced NADP) formed & enters light independent reaction

where does the light independent reactions occur ?

occurs in the stroma of the chloroplast

why do light dependent reactions occur in the stroma and not the thylakoid ?

because specific enzymes that catalyse the reaction are present in the stroma and not the thylakoid

what do light dependent reactions provide light independent reactions with ?

provide it with NADPH and ATP

what is the CO2 acceptor in the calvin cycle ?

ribulose biphosphate (RuBP)

what catalyses the reaction between RuBP and carbon in the calvin cycle ?

rubisco catalyses this reaction

How is glycerate 3 phosphate oxidised to form triose phosphate ?

because it is gaining a H+

what is the product of the light independent reaction ?

glusose is the product

what are other organic molecules formed as a result in the calvin cycle ?

• sucrose

• amino acids

• starch

• cellulose

• lipids

• nucleic acids

can you do light independent reactions at night any why/ why not ?

no as light is needed to make ATP and NADPH

how many times does the calvin cycle need to take place to made a molecule of glucose ?

6x as one cycle releases 1x C atom and we need 6 for a molecule of glucose

what are the steps of the calvin cycle ?

1. Fixation of CO2

• CO2 combineds with RuBP (ribulose bisphosphate, a 5 carbon sugar) in reaction catalysed by enzyme rubisco

• resulting in instable 6 carbon compound & splits into 2 molecules of glycerate 3-phosphate (GP), 3 carbon molecules

2. reduction of glycerate 3-phosphate to triose phosphate-

• ATP and reduced NADP are used to reduce GP to triose phosphate

3. regeneration of ribulose biphosphate

• ATP used to convert 5 of the 6 carbons present into the 2 triose phosphate molecules back into RuBP

4. the production of useful organic substances

• remaining triose phosphate molecules used to produce useful organic molecules needed by plant e.g. starch, cellulose ,lipids, proteins

how are the chloroplasts adapted for light independent reactions ?

• fluid in stroma contain all enzymes needed

• products from light dependent reaction can easily diffuse into the stroma

• contains DNA & ribsomoses to easily manufacture proteins for light independent reaction

what are the limiting factors in photosynthesis?

• light intensity

• CO2 concentration

• temperature

what is the compensation point ?

the point at which the organic compounds made by photosynthesis will exactly match the amount of organic compounds being used in respiration

why does more light increase the rate of photosynthesis?

more light means electrons are more excited on chlorophyll and are emitted so more electrons pass down the elcetron transport chain so more ATP is produced and more NADPH is formed

why are glasshouses used ?

heating them prevents night temperatures falling to low & allows the growers to provide optimum temp for growth

what type of respiration is oxidative phosphorylation?

aerobic repiration

where does oxidative phosphorylation occur ?

in cristae (folded mitochondria membrane)

how is the cristae adapted ?

folded which increases surface area & means oxidative phosphorylation can occur more rapidly as more carrier proteins so more e- transport chain

how many reduced NADs and reduced FADs are carried into electron transport chain ?

• 10 reduced NADs

• 2 reduced FADs

what happens to the low energy e- & hydrogen ions at the end of oxidative phosphorylation?

low energy e- & H+ ions combine with oxygen to form water

how many ATP does 1 NAD form ?

3 ATP

how many ATP does 1 FAD form ?

2 ATP

how many ATP is formed from oxidative phosphorylation?

34 ATP

How many ATP is produced from one of glucose in aerobic repiration ?

38 ATP

what are the steps of oxidation phosphorylation?

1. hydrogen ions produced during glycolysis & krebscombine with the coenzymes NAD & FAD

2. reduced NAD and reduced FAD donate the e- from the hydrogen ions to the first molecule in the electron transport chain

3. the e- move down the e- transport via a series of oxidation-reduction reactions losing energy as they go

4. this energy used to pump protons from hydrogen ions across the inner membrane space of the mitochondria

5. this builds up a concentration gradient of hydrogen ions & they diffuse back into the matrix via ATP synthase

6. for every H+ion that passses across ATP synthase and ADP & phosphate are joined to make ATP = oxidative phosphorylation

7. oxygen is final e- acceptor & combines with H+ ions to make water

where does the link reaction take place ?

mitochondrial matrix

how do you get pyruvate into the mitochondrial matrix ?

active transport

how and where is pyruvate produced ?

• glycolysis

• cytoplasm

steps of the link reactions?

1. pyruvate oxidised to acetate

• 3 carbon pyruvate loses a carbon dioxide and 2 hydrogen molecules

• hydrogens accepted in NAD to make reduced NAD

2. 2 carbon acetate combines with coenzyme A (COA) to form acetylcoenzyme A

overall reaction for the link reaction

pyruvate + NAD + CoA → acetyl CoA + reduced NAD + CO2

why is the link reaction important ?

to oxidise the pyruvate molecules so it can then be turned into acetylcoenzyme to be used in the krebs cycle

what is oxidised in the link reaction ?

the pyruvate is oxidised as it loses a hydrogen

what is reduced in the link reaction ?

the NAD is reduced as it gains a hydrogen

what forms acetylcoenzyme A and where is it deposited ?

• coenzyme A + acetate

• deposited in the krebs cycle

what are the products of the link reaction ?

• acetylcoenzyme

• CO2

• 1x reduced NAD

steps to the krebs cycle ? ????????????????

1. 2 carbon acetylcoenzyme combines with 4 carbon moleule to form 6 carbon molecule

2. series of reactions 6 carbon molecules loses carbon dioxide & hydrogen to form a 4 carbon molecule & one ATP

products of krebs cycle ?

• reduce coenzyme (NAD & FAD)

• 3 CO2

• 1 ATP

what is respiration ?

the process by which organisms extract the energy stored in complex molecules & us it to generate ATP

why is ATP used as energy source instead of glucose ?

• ATP releases energy instantantly in a single reaction

• hydrolysis of ATP releases a small amount of energy, ideal for fuelling reactions in the body

2 types of photophosphorylation during respiration ?

1. substrate level : glycolysis & krebs cycle

• single reaction involving direct transfer of a phosphate group from minor molecule to ADP

2. oxidative : electron transfer chain

• series of oxidation reactions that produce sufficient energy to form ATP from ADP & phosphate

where does glycolysis take place ?

cytoplasm

steps of glycolysis?

1. phosphorylation of glucose to glucose phosphate

• make more reactive by adding 2 phosphate molecule

• phosphate molecules from hydrolysis of 2 molucules of ATP

2. splitting phosphorylated gllucose

• each glucose molecule split into 2 3 carbon molecules (triose phosphate)

3. oxidation of triose phosphate

• hydrogen removed from 2 triose phosphate molecules

• transfer hydrogen to NAD to form reduced NAD

4. production of ATP

• enzyme controlled reactions convert each triose phosphate inot another 3 carbon molecule pyruvate

• 2 ATP regenerated from ADP

where does glycolysis take place ?

cytoplasm

what is the products of glycolysis ?

• 2 molecules ATP

• 2 molecules of reduced NAD

• 2 molecules of pyruvate

what is phosphorylated in glycolysis ?

glucose as phosphate is added to it

what is oxidised in glycolysis?

triose phosphate as it loses a hydrogen

what is reduced in glycolysis and what does it form?

NAD is reduced to make NADH as it gain a hydrogen

how is ATP made in mitochondria ?

• ATP produced in Krebs cycle

• link reaction produces reduced coenzyme

• e- released from coenzyme

• e- pass along carriers

• energy released

• ADP

• protons move into intermembrane space

• ATP synthase