Biochemistry

Question 1

Where does fatty acid synthesis and activation occur?

Answer 1

Cytoplasm

Question 2

What is the only substrate that can be synthesised to fatty acyl-CoA?

Answer 2

Malonyl Co-A

Question 3

Where does B-oxidation occur?

Answer 3

Mitochondrion

Question 4

What is the only form that fatty acids can cross the mitochondrial membrane for metabolism as?

Answer 4

Fatty acyl-carnitine

Question 5

What is the breakdown pathway of fatty acids called?

Answer 5

B-oxidation

Question 6

What is the first step of fat catabolism?

Answer 6

Lipolysis

Question 7

What is the main storage form of lipids?

Answer 7

Triglycerides

Question 8

What are the products of each B-ocidation cycle?

Answer 8

1 fatty acyl-CoA (shortened by 2C), 1 acetyl Co-A, 1 FADH2, 1 NADH + H

Question 9

What is the calculation for the number of oxidation cycles for a fatty acyl-CoA chain?

Answer 9

For Cn, (n/2-1)

Question 10

What would be the product of the breakdown of a 14C fatty acid?

Answer 10

7 acetyl-CoA, 6NADH + H, 6 FADH2

as one less oxidation cycle than no of acetyl-CoA produced

Question 11

Is gluconeogenesis the reverse of glycolysis?

Answer 11

No

Question 12

Where are ketone bodies formed?

Answer 12

Liver mitochondria

Question 13

Under what conditions are ketone bodies formed?

Answer 13

Fasting

Question 14

What smell do ketone bodies cause?

Answer 14

Pear drop breath

Question 15

How do ketone bodies travel around the body?

Answer 15

In the bloodstream

Question 16

Where does fatty acid synthesis mainly occur?

Answer 16

The liver (cytoplasm)

Question 17

What enzyme converts acetyl-CoA to malonyl CoA?

Answer 17

Acetyl CoA carboxylase

Question 18

Does insulin increase or decrease the activity of acetyl CoA carboxylase?

Answer 18

Increase

Signals fed state so increases fatty acid synthesis

Question 19

Does glucagon increase or decrease the activity of acetyl CoA carboxylase?

Answer 19

Decrease

Signals fasting state so fatty acid degradation is required

Question 20

What is the purpose of urea?

Answer 20

To deal with excess nitrogen in either the urine or sweat

Question 21

Where does the urea cycle occur?

Answer 21

In the liver mitochondria

Question 22

Where does the nitrogen for the urea cycle come from?

Answer 22

1 from aspartic acid (amino acid)

1 from free ammonium

Question 23

What is the catalyst for the start of glycogen polymer and how many glucose molecules does it require?

Answer 23

Glycogenin protein

4

Question 24

How does glycogen synthase work?

Answer 24

Adds on single glucose molecules to an existing glycogen polymer

Question 25

Do fatty acids act directly as precursors to the TCA cycle?

Answer 25

No

Question 26

Can amino acids provide carbons to the TCA cycle?

Answer 26

Yes

Question 27

Where can muscle cell glycogen supply energy to?

Answer 27

Only the muscle cell

Question 28

What is glyconeogenesis?

Answer 28

A pathway for the synthesis of new glucose from non-carbohydrate precursors

Question 29

What is the type of protein contained within plasma?

Answer 29

Globulins

Question 30

What form of globulin is utilised in the immune system?

Answer 30

Gamma globulin (forms the backbone of immunoglobulins)

Question 31

Where are plasma proteins secreted from and what is their importance in maintaining BP?

Answer 31

Secreted from and produced in the liver | Maintain balance of fluid across the walls of vessels

Question 32

What is the most abundant plasma protein?

Answer 32

Albumin

Question 33

What is the importance of iron in the body and what is its transporter + storage protein?

Answer 33

Used to form haemoglobin Transporter: transferrin Storage: ferritin

Question 34

What disease is due to copper deficiency?

Answer 34

Wilsons disease

Question 35

What is used for fat transport between organs and tissues?

Answer 35

Lipoproteins

Question 36

What is contained within the core of lipoproteins?

Answer 36

Cholesterol esters | Triglycerides

Question 37

What is the only organ that can esterify and excrete cholesterol?

Answer 37

Liver

Question 38

What is the importance of cholesterol in the body?

Answer 38

Rigidity of cell membranes | Precursor to bile acids, steroid hormones and vit D

Question 39

How is cholesterol transported in the body?

Answer 39

Mostly esterified to insoluble long chain fatty acids

Question 40

Where is cholesterol synthesised?

Answer 40

Cytoplasm of liver cells (very energy heavy process)

Question 41

What compound is unique to cholesterol synthesis?

Answer 41

Mevalonic acid

Question 42

What is the key rate limiting enzyme in cholesterol synthesis?

Answer 42

HMG-CoA reductase (generates mevalonic acid)

Question 43

Which hormones are produced from cholesterol?

Answer 43

Steroid hormones: corticosteroids + sex hormones (androgens + estrogen's)