𝐫𝐞𝐬𝐩𝐢𝐫𝐚𝐭𝐢𝐨𝐧

Question 1

What is the purpose of respiration?

Answer 1

To release energy from glucose to produce ATP.

Question 2

What do plants need energy for? (5)

Answer 2

-photosynthesis
-active transport of minerals via roots
-DNA replication
-cell division
-proteinsynthesis

Question 3

What are the 3 components of ATP?

Answer 3

1 ribose sugar, 3 phosphate ions and 1 adenine (nitrogenous base)

Question 4

How is ATP formed?

Answer 4

Condensation reaction between ADP and Pi catalysed by ATP synthase.

Question 5

Which enzyme catalyzes the hydrolysis of ATP?

Answer 5

ATP hydrolase

Question 6

What are the 6 properties of ATP?

Answer 6

1. stores and releases small amounts of energy so none is wasted as heat.
   2.small, soluble molecule so easily transported.
   3.easily hydrolysed so energy is released instantly
   4.quickly resynthesised
   5.makes other molecules more reactive (e.g. phosphorylation)
   6.can’t pass out of cell so immediate energy supply.

Question 7

Where does glycolysis take place?

Answer 7

Cell cytoplasm

Question 8

What 3 coenzymes are used in aerobic respiration?

Answer 8

Reduced NAD, FAD and coenzyme A.

Question 9

Which stage of respiration is anaerobic process and why?

Answer 9

Glycolysis because it uses no O2.

Question 10

Describe the 4 main stages of Glycolysis. (hint: P.L.O.D)

Answer 10

𝗣𝗵𝗼𝘀𝗽𝗵𝗼𝗿𝘆𝗹𝗮𝘁𝗶𝗼𝗻 of Glucose (6c) to phosphorylated glucose (e.g. Fructose Biphosphate): Glucose is first made more reactive by the addition of two phosphate molecules. These phosphate molecules come from the hydrolysis of 2 ATP molecules to form 2 ADP. This provides the energy to activate glucose and lowers activation energy for enzyme-controlled reactions that follow.
𝗟𝘆𝘀𝗶𝘀: phosphorylated glucose splits into two triose phosphate molecules (3C).
𝗢𝘅𝗶𝗱𝗮𝘁𝗶𝗼𝗻: 2 hydrogens are removed from each of the TP molecules and transferred to NAD to form 2 molecules of NADH.
𝗗𝗲𝗽𝗵𝗼𝘀𝗽𝗵𝗼𝗿𝘆𝗹𝗮𝘁𝗶𝗼𝗻: 4ADP + 4Pi –> 4ATP.
4ATP molecules are produced through substrate-linked phosphorylation. Net gain of ATP is 2.
𝗣𝘆𝗿𝘂𝘃𝗮𝘁𝗲 𝗶𝘀 𝗽𝗿𝗼𝗱𝘂𝗰𝗲𝗱: Enzyme-controlled reactions convert TP to pyruvate (3c).

Question 11

What is the pyruvate produced in glycolysis used for?

Answer 11

It is actively transported into the matrix then used for the link reaction.

Question 12

Why does glycolysis take place in the cytoplasm?

Answer 12

Glucose can’t cross the mitochondrial membrane because it’s too big.

Question 13

Where does the link reaction occur?

Answer 13

In the mitochondrial matrix.

Question 14

What is the purpose of the link reaction?

Answer 14

to convert pyruvate to acetyle coenzyme A.

Question 15

How does pyruvate move into the mitochondrial matrix?

Answer 15

Pyruvate moves through a transport protein across the double membrane, via active transport, to enter the mitochondrial matrix.

Question 16

Describe what happens during the link reaction.

Answer 16

-Pyruvate undergoes 𝗱𝗲𝗰𝗮𝗿𝗯𝗼𝘅𝘆𝗹𝗮𝘁𝗶𝗼𝗻 so it loses one carbon atom in the form of CO2 and becomes Acetate (2c)
-Pyruvate is then 𝗼𝘅𝗶𝗱𝗶𝘀𝗲𝗱, releasing electrons and H+
-these electrons are then picked up by NAD+ to become NADH (𝗶𝘀 𝗿𝗲𝗱𝘂𝗰𝗲𝗱)
-𝗖𝗼𝗲𝗻𝘇𝘆𝗺𝗲 𝗔 𝗰𝗼𝗺𝗯𝗶𝗻𝗲𝘀 𝘄𝗶𝘁𝗵 𝗔𝗰𝗲𝘁𝗮𝘁𝗲 𝘁𝗼 𝗳𝗼𝗿𝗺 𝗔𝗰𝗲𝘁𝘆𝗹 𝗖𝗼𝗲𝗻𝘇𝘆𝗺𝗲 𝗔.

Question 17

What happens to the CO2 lost in the link reaction?

Answer 17

Lost as a waste product.

Question 18

Where does the Kreb’s cycle take place?

Answer 18

In the mitochondrial matrix.

Question 19

Describe what happens in the Kreb’s cycle.

Answer 19

-Oxolacetate (4c) and Acetyl CoA (2c) combine to make Citrate (6c).
-In the process, CoA is released.
-A series of oxidation/reduction reactions occur:
-the 𝗱𝗲𝗰𝗮𝗿𝗯𝗼𝘅𝘆𝗹𝗮𝘁𝗶𝗼𝗻 of Citrate means 2 carbons are lost in the form of 2CO2.
-3NAD+ is reduced to 3NADH
-FAD+ is reduced to FADH
-ATP is also generated by substrate level phosphorylation.

Question 20

What is substrate-linked phosphorylation in the kreb’s cycle?

Answer 20

𝗔 𝗽𝗵𝗼𝘀𝗽𝗵𝗮𝘁𝗲 𝗶𝘀 𝘁𝗿𝗮𝗻𝘀𝗳𝗲𝗿𝗿𝗲𝗱 𝗳𝗿𝗼𝗺 𝗼𝗻𝗲 𝗼𝗳 𝘁𝗵𝗲 𝗶𝗻𝘁𝗲𝗿𝗺𝗲𝗱𝗶𝗮𝘁𝗲𝘀 𝘁𝗼 𝗔𝗗𝗣, 𝗳𝗼𝗿𝗺𝗶𝗻𝗴 𝟭 𝗔𝗧𝗣. (the formation of one ATP molecule directly from a reaction using energy released within the cycle)

Question 21

What is the CoA produced in the Kreb’s cycle used for?

Answer 21

Link reaction

Question 22

What are the reduced enzymes (NADH and FADH) produced in the Kreb’s cycle used for?

Answer 22

Oxidative phosphorylation.

Question 23

What is a respirometer used for?

Answer 23

Used to measure and investigate the rate of oxygen consumption during aerobic respiration in organisms.

Question 24

Describe the process of ethanal fermentation.

Answer 24

-Pyruvate is decarboxylated to ethanal producing CO2 as a by product.
-Ethanal is reduced to ethanol by the enzyme alcohol dehydrogenase.
-Ethanol is now a waste product as it cannot be further metabolised.

Question 25

Describe the process of lactate fermentation.

Answer 25

-Pyruvate is reduced to lactate by enzyme lactate dehydrogenase. -Final product lactate CAN be further metabolised.