Week 2

Question 1

Define metabolic pathways?

Answer 1

Biochemical reactions that occur in progression from the substrate to product, usually involving enzymes and cofactors

Question 2

What is the difference between anabolic and catabolic pathways?

Answer 2

anabolic: builds molecules, use energy
catabolic: breaks down molecules, produce energy

Question 3

What are the three steps of catabolism?

Answer 3

1. digestion: break down of complex molecules to their component building blocks
2. conversion of building blocks to acetyl CoA (or other simple intermediates)
3. metabolism of acetyl CoA to Co2 and formation of ATP

Question 4

What is an oxidation-reduction reaction?

Answer 4

The movement of electrons

Oxidised organic compounds
– Increased oxidation state or loss of electrons
Reduced organic compounds
– Decreased oxidation state or gain of electrons

Question 5

How do enzymes control oxidation/reduction reactions

Answer 5

dehydrogenases remove hydrogen ions from energy-containing nutrients and donate them to oxygen to form water (and ATP is produced)

Question 6

What do Niacin and riboflavin do?

Answer 6

help transport hydrogens from energy-yielding compounds to oxygen in metabolic pathways

Question 7

What is the difference between anaerobic and aerobic respiration?

Answer 7

Anaerobic:

• no oxygen
• respiration of one glucose molecule= 2 ATP

Aerobic

• oxygen
• respiration of one glucose molecule= 32 ATP

Question 8

What are the 4 steps of aerobic metabolism of glucose?

Answer 8

1. Glycolysis (anaerobic step): Glucose is oxidized to pyruvate
2. Pyruvate is metabolized to acetyl coenzyme A (CoA) by pyruvate dehydrogenase.
3. Acetyl CoA enters citric acid cycle (CAC) producing NADH+ H+, FADH2, and CO2
4. Electron Transport Chain: oxidative phosphorylation. ATP is derived from NADH + H+ and FADH2 as H+ travel down the concentration gradient from the intermembrane space via ATP synthase.

Question 9

What is lipolysis?

Answer 9

Triglycerides broken down into free fatty acids and

glycerol

Question 10

What is Beta-oxidation?

Answer 10

fatty acid oxidation

Question 11

1 fatty acid made of 16 carbons makes how many ATPs?

Answer 11

106

Question 12

how are fatty acid molecules turned into acetyl molecules?

Answer 12

beta-oxidation

Question 13

Carbohydrates aid in fat metabolism to some extent. true or false?

Answer 13

true

Question 14

What are the 5 stages of formation of ketone bodies?

Answer 14

1. blood insulin drops
2. lipolysis promoted and FA’s stores in adipose tissues are released
3. FA’s taken up by the liver
4. liver oxidized the FA’s to acetyl-CoA then to ATP
5. when there is enough ATP, the liver cells combine 2 acetyl-CoA molecules together to form a 4 carbon molecule. this is further metabolized into ketone bodies

Question 15

Define Ketogenesis

Answer 15

formation of ketones

Question 16

define ketosis

Answer 16

elevated levels of ketones in the blood

Question 17

Define ketoacidosis

Answer 17

high levels of ketones making the blood more acidic

Question 18

Where are ketone bodies formed?

Answer 18

in the liver from the break down of fatty acids

Question 19

Define deamination

Answer 19

removal of the amine group from the carbon skeleton

Question 20

what is gluconeogenesis

Answer 20

forming new glucose from glucogenic amino acids

- from non-glucose sources)

Question 21

Which is the first organ to receive the most nutrients from GIT via portal vein?

Answer 21

Liver

Question 22

What happens when there is a high level of ATP?

Answer 22

Anabolic reactions are activated

Question 23

What happens when there is a high ADP or AMP to ATP ratio

Answer 23

Catabolic reactions are activated

Question 24

What does the post prandial (fed) state promote?

Answer 24

Up-regulation of relevant enzymes of:

• Glucose synthesis glycogenesis
• Fat synthesis (lipogenesis)
• Protein synthesis
• Urea synthesis

Question 25

What is the primary hormones that is involved in the post prandial state?

Answer 25

Insulin

Question 26

Does the post prandial state promote catabolism or anabolism

Answer 26

Anabolism

Question 27

What does the fasting state promote?

Answer 27

``` Hepatic glycogen breakdown glycogen turning to energy for muscles Protein breakdown fat breakdown ketogenesis ```

Question 28

Where does the conversion of glucose to glycogen occur

Answer 28

Liver

Question 29

Describe what happens due to uncontrolled diabetes mellitus type 1?

Answer 29

- Insufficient insulin production due to damage pancreas - glucose cannot get into the cells which rely on insulin for glucose transport - large amounts of FA’s released from adipose cells - FA’s flood the liver and are broken down into acetyl CoA - slows CAC - High production of ketone bodies - ketoacidosis??

Question 30

What is Glycolysis? Where does it occur

Answer 30

Glucose to pyruvate | Cytosol

Question 31

What is the transition reaction? Where does it occur?

Answer 31

Pyruvate to acetyl CoA | Mitochondria

Question 32

What is fatty acid oxidization? Where does it occur?

Answer 32

Fatty acids to acetyl CoA | Mitochondria

Question 33

What is glycogenic amino acid oxidation? Where does it occur?

Answer 33

Amino acid to acetyl CoA | cytosol

Question 34

What is non-glucogenic amino acid oxidation

Answer 34

amino acid to acetyl CoA | Mitochondria

Question 35

what happens in the Citric Acid Cycle? where does it occur?

Answer 35

acetyl CoA to Co2 | mitochondria