Cell metabolism

Question 1

Metabolism

Answer 1

The sum of all biochemical reactions that occur in

the body.

Question 2

2 types of metabolism

Answer 2

Catabolism (decomposition reaction)

Anabolism (synthesis)

Question 3

Catabolism or catabolic reactions

Answer 3

break down larger/complex organic molecules into smaller ones. Release energy i.e. exergonic (produce more energy
than they use). e.g. used in glycolysis, Krebs cycle, electron transport chain, and digestion of food etc.

Question 4

Anabolism or anabolic reactions.

Answer 4

They use simple molecules/monomers to make larger organic molecules. They consume energy i.e. endergonic (use more energy than they produce). e.g. make proteins from amino acids and phospholipids from fatty acids.

Question 5

What does ATP stand for?

Answer 5

Adenosine triphosphate

Question 6

What is ATP

Answer 6

The cell’s “energy currency”; around 1 billion molecules per cell. Transfers energy released from exergonic (catabolic)
reactions to power endergonic (energy requiring) reactions.
Powers activities e.g. muscle contraction, chromosome
movement during cell division, membrane pumps and
anabolic reactions. Three phosphate groups attached to adenosine (adenine plus ribose sugar). Energy stored in the phosphate bond.

Question 7

ATPase hydrolyses ATP into…

Answer 7

ADP + phosphate group, releasing energy stored in the phosphate bond. ATP synthase catalyzes the addition of a phosphate group to ADP.

Question 8

Glucose metabolism

Answer 8

Glucose is the preferred energy molecule for a cell. Complex polysaccharides digested/hydrolyzed into
monosaccharides (simple 6 carbon sugars). 80% glucose, also fructose and galactose.

Question 9

What does Hepatocytes (liver cells) do for glucose?

Answer 9

convert most fructose and almost all galactose into glucose?

Question 10

What is considered normal blood glucose levels?

Answer 10

between 4 and 8 mmol/L

Question 11

What 3 things happen when glucose is put into a cells (via Glucose Transporter)?

Answer 11

It is firstly used for ATP production, it is then stored as glycogen which is then used to make amino acids and triglycerides.

Question 12

What type of glucose transporters does insulin increases the number of inserted into cell membrane?

Answer 12

Type 4 glucose transporters

Question 13

Glucose catabolism (cellular respiration) and the 4 sets of reactions

Answer 13

Cellular respiration: oxidation of glucose (removal of
electrons and H atoms) to produce ATP.
Four sets of reactions:
1. Glycolysis in the cytosol
2. Formation of acetyl coenzyme A
3. Krebs cycle (citric acid cycle)
4. Electron transport chain
(last 3 happen inside the mitochondria)

Question 14

Glycolysis

Answer 14

Occurs in the cytosol. It turns glucose into two 3 carbon molecules (pyruvic acid). It Uses two ATP, produces four ATP (net gain 2 ATP)

Question 15

What happens when oxygen is and isn’t available during glycolysis?

Answer 15

When oxygen is available, it turns pyruvic acid into acetyl coenzyme A (acetyl CoA) inside mitochondria (aerobic respiration).
When oxygen is not available, pyruvic acid turns into lactic
acid/lactate (anaerobic respiration).

Question 16

Krebs cycle (cytric acid cycle)

Answer 16

Acetyl CoA (product of glycolysis with oxygen) enters Krebs cycle within the matrix of mitochondria. It releases carbon dioxide (CO 2).Energy (electrons) are then transferred to two energy carrying coenzymes, NAD+ and FAD.
For each turn of the cycle (citric acid turns into oxaloacetic acid):
3 NADH
3 H+
1 FADH
1 ATP
Two turns of the cycle per glucose molecule ( because 1 molecule of glucose produces two pyruvic acid molecules).

Question 17

Electron transport chain

Answer 17

On inner mitochondrial membrane; cristae increase surface area. Integral membrane proteins that are electron carriers. those electrons passed along the chain generating ATP by
pumping hydrogen ions (H ++); known as chemiosmosis. With the final electron acceptor being oxygen.

Question 18

Aerobic respiration equation?

Answer 18

C6 H12 O6 + 6 O2 → 6 H2O + 6 CO2 + 30-32 ATP + heat

Glucose + oxygen into water + carbon dioxide + ATP +
heat

Question 19

How much ATP does Aerobic respiration in mitochondria form

Answer 19

Krebs cycle (2), chemiosmosis and electron transport chain (26-28).

Question 20

How much ATP does anaerobic respiration (glycolysis) gives up

Answer 20

2 net ATP.

Question 21

What is glycogen?

Answer 21

Many molecules of glucose joined together.

Question 22

What is glycogenesis?

Answer 22

Glucose storage and release

Question 23

Glucose storage

Answer 23

Glucose storage in liver and skeletal muscle cells. Formed when not needed to produce ATP