Energy (Krebs etc ) please finnish

Question 1

How do cells obtain energy?

Answer 1

Cells can get energy from carbohydrates, Proteins and lipids

Nutrients undergo biochemical reactions, known collectively as metabolism

These processes are:
Anabolic processes- create larger molecules. Require energy. Example: bonding of amino acids to make proteins,
Catabolic processes- larger molecules are broken down to smaller ones. Release energy . Example: glucose breakdown

Cells conserve some of the energy to generate a metabolic currency (ATP)

Question 2

How do cells generate energy from nutrients?

Answer 2

Glycolysis- anaerobic break down of glucose to pyruvate. Small amount of ATP generated by substrate level phosphorylation

Krebs’ Cycle- oxidation of Acetyl CoA to CO. generates coenzymes: NADH and FADH2

Oxidative phosphorylation- transduction of energy derived from fuel oxidation to high energy phosphate. Generates large amounts of ATP.

Question 3

where does glycolysis occur

Answer 3

in cytosol

Question 4

is glycolysis anaerobic or aerobic

Answer 4

Aerobic

Question 5

what are the products of glycolysis

Answer 5

2 ATP, 2 NADH, 2 Pyruvate

Question 6

What is the rate limiting enzyme in glycolysis?

Answer 6

Phosphofructokinase-1

Question 7

Draw a glycolysis diagram with the words or each product + enzymes involved

Answer 7

Compare to diagram from ppt

Question 8

In glycolysis ATP: is an inhibitor of _______

Answer 8

phosphofructokinase-1

Question 9

in glycolysis what are the regulators of Phosphofructokinase-1

Answer 9

ATP, AMP, Citrate, fructose,2,6,bisphasphate

Question 10

In glycolysis how does AMP regulate PFK1

Answer 10

Increasing levels of AMP from used up ATP relieves the inhibition of PFK-1 by ATP. i.e activates PFK1

Question 11

In glycolysis how does citrate regulate PFK1

Answer 11

first product of kreb’s also allosterically inhibits PFK-1.

Increase citrate levels is a signal that the cycle does not need more fuel.

Question 12

Which 2 cellular conditions may the fate of pyruvate fall under

Answer 12

Aerobic and anaerobic respiration

Question 13

what is the fate of pyruvate under aerobic conditions

Answer 13

Pyruvate enters mitochondria converted to Acetyl CoA and CO2 by Pyruvate Dehydrogenase.

Acetyl CoA can enter Krebs for more energy production

Question 14

what is the fate of pyruvate under anaerobic conditions

Answer 14

Lactate formation, catalysed by lactate dehydrogenase
Regeneration on NAD+

Question 15

Draw anaerobic and aerobic fates of pyruvate

Answer 15

compare to ppt

Question 16

is aerobic conversion of pyruvate
a)reversible
b)irreversable

Answer 16

b

Question 17

Where does Krebs occur and under which conditions

Answer 17

mitochondrial matrix

aerobic conditions

Question 18

what is the first stage of krebs

Answer 18

Acetyl CoA combines with oxaloacetate

forms Citrate using citrate synthase

Question 19

What is the second stage of Krebs

Answer 19

Citrate is converted to Isocitrate by aconitase

Question 20

What is the third stage of krebs

Answer 20

Isocitrate is oxidized and decarboxylated by isocitrate dehydrogenase to form alpha-ketoglutarate

Question 21

What is the 4th stage of Krebs

Answer 21

alpha-ketoglutarate converted to succinyl CoA by alpha-ketoglutarate dehydrogenase

Question 22

What is the 5th stage of Krebs

Answer 22

Succinyl CoA converted to Succinate as CoA is subtracted and GDP is phosphorylated by succinyl CoA synthetase

Generates ATP through substrate level phosphorylation

Question 23

What is the 6th stage of krebs

Answer 23

Succinate oxidized to Fumarate by succinate dehydrogenase ( complex II part of the ETC), reducing FAD in process

Question 24

What is the 7th stage in Krebs

Answer 24

Fumarate converted to Malate by fumarase, adding H20 in the process

Question 25

What is the 8th(final) stage of Krebs

Answer 25

Malate converted back to oxaloacetate by malate dehydrogenase

further oxidized, and NAD+ is reduced.

Question 26

What is the total energy gain from 1 cycle of krebs

Answer 26

2 ATP
2 FADH
6NADH

Question 27

Where does oxidative phosphorylation occur and under which conditions

Answer 27

mitochondrial membrane
Aerobic conditions