energy

Question 1

what are the steps in respiration

Answer 1

1. glycolysis
2. link reaction
3. Krebs cycle
4. oxidative phosphorylation

Question 2

where does glycolysis occur

Answer 2

cytoplasm

Question 3

what happens in glycolysis

Answer 3

glucose is phosphorylated making glucose phosphate (requires 2 ATP) which is then hydrolysed to 2 molecules of TP which is then oxidised to 2 molecules of pyruvate This produces 2 reduced NAD and 4ATP

Question 4

what is the net production of ATP in glycolysis

Answer 4

2

Question 5

what happens after glycolysis if no oxygen present

Answer 5

pyruvate converted to lactate or ethanol, reduced NAD is oxidised so that glycolysis can continue

Question 6

where does the link reaction occur

Answer 6

mitochondrial matrix

Question 7

what happens in link reaction

Answer 7

pyruvate decarboxylated and oxidised forming acetate which combines with coenzyme A forming acetyl coenzyme A

Question 8

what are the products per glucose molecule in the link reaction

Answer 8

2 AcetylcoA, 2 CO2, 2 reduced NAD

Question 9

where does the Krebs cycle occur

Answer 9

mitochondrial matrix

Question 10

where does oxidative phosphorylation take place

Answer 10

cristae

Question 11

what happens in oxidative phosphorylation

Answer 11

1. Reduced NAD and FAD oxidised to produce H atoms which are split into protons and electrons
2. electrons passed down electron transport chain by redox reactions
3. energy released by electrons used in production of ATP (chemiosmotic theory)
4. in matrix at end of etc, oxygen is final electron acceptor

Question 12

what are the steps in chemiosmosis (respiration)

Answer 12

1. energy used by electron carriers to actively transport protons from matrix to inner membrane space
2. protons diffuse down electrochemical gradient via ATP synthase back into matrix
3. releasing energy to combine ADP with inorganic phosphate to form ATP

Question 13

why is oxygen needed for production go ATP on Cristae of mitochondrion

Answer 13

The electron transport chain releases energy for most production of ATP so if there’s no oxygen to act as terminal electron acceptor electrons can’t be passed down ETC and the Krebs cycle and link reaction stop in absence of oxygen because NAD and FAD can’t be produced

Question 14

where does the light dependent reaction occur

Answer 14

thylakoid membrane

Question 15

where does the light independent reaction occur

Answer 15

stroma

Question 16

what is photoionisation

Answer 16

chlorophyll absorbs light energy which excites electrons to a higher energy level, releasing them from chlorophyll

Question 17

how is ATP produced in light dependent reaction

Answer 17

1. electrons pass down electron transport chain from PSII to PSI via redox reactions, losing energy at each step
2. this energy used to actively transport protons from stroma into thylakoid
3. creating an electrochemical gradient across thylakoid membrane
4. protons move by facilitated diffusion down electrochemical gradient into stroma via ATP synthase
5. energy from this allows ADP+Pi—>ATP

Question 18

how is reduced NADP produced in light dependent reaction

Answer 18

in PSI electrons are excited and transferred to NADP reducing it

Question 19

what happens in Calvin cycle

Answer 19

CO2 reacts with RUBP catalysed by enzyme RUBISCO
produced 2 molecules of GP
Gp reduced to TP using products from light dependent reaction (energy from hydrolysis ATP and proton from reduced NADP)
some TP converted tp useful organic molecules
5 TP used to regenerate RUBP (using rest of ATP)

Question 20

what is a limiting factor

Answer 20

a factor is limiting if when its made a more favourable value the rate of photosynthesis increases

Question 21

how is temperature a limiting factor of photosynthesis

Answer 21

rate of photosynthesis increases as temp increases then decreases after- limits light independent reaction as its controlled by enzyme rubisco

increase temp us to optimum=more Ek= more E-S complexes

above optimum= H bonds in tertiary structure break= enzyme denatured= fewer E-S complexes

Question 22

how is light intensity a limiting factor of photosynthesis

Answer 22

if light intensity was dramatically reduced
levels of ATP and reduced NADP would fall because light dependent reaction limited due to less photoionisation of chlorophyll therefore light dependent reaction would eventually stop as requires ATP and reduced NADP