Metabolism

Question 1

Define metabolism

Answer 1

A series of activities that provide cells with the molecules and energy they need to function and grow/divide

Question 2

What are the molecules from metabolism used for?

Answer 2

Structure and reactions

Question 3

What is the energy from metabolism used for?

Answer 3

Cell function

Question 4

What is a multi-enzyme complex?

Answer 4

A stable assembly of enzymes usually involved in sequential catalytic reactions

Question 5

What does rate of amino acid synthesis depend on?

Answer 5

Amount of amino acids and their individual biochemical activities

Question 6

What is allosteric inhibition?

Answer 6

When molecules are binding to different sites which are not the active site

Question 7

What is the role of enzyme multiplicity?

Answer 7

Prevents one product from shutting down the pathway completely

Question 8

Which 3 precursors is histidine derived from?

Answer 8

PRPP, ATP, and glutamine

Question 9

What does PRPP contribute to histidine?

Answer 9

5 carbons

Question 10

What does ATP contribute histidine?

Answer 10

A nitrogen and a carbon

Question 11

What does glutamine contribute to histidine?

Answer 11

A carbon

Question 12

How many amino acids are there?

Answer 12

20

Question 13

How many amino acids can mammals synthesise?

Answer 13

11

Question 14

How many amino acids can plants synthesise?

Answer 14

20

Question 15

How many amino acids can bacteria synthesise?

Answer 15

20

Question 16

Where are the other 9 amino acids obtained from for mammals?

Answer 16

The diet

Question 17

Why can’t mammals synthesise the other 9 amino acids?

Answer 17

More complex so require more energy to synthesise

Question 18

Which are the 9 amino acids that mammals can’t synthesise?

Answer 18

1. Tryptophan
2. Isoleucine
3. Histidine
4. Phenylalanine
5. Valine
6. Threonine
7. Methionine
8. Leucine
9. Lysine

Question 19

What are the 7 important intermediary pathways in humans?

Answer 19

1. glycolysis
2. gluconeogenesis
3. TCA cycle
4. pentose phosphate pathways
5. fatty acid catabolism
6. urea cycle
7. oxidative phosphorylation

Question 20

What are nucleosides?

Answer 20

Bases covalently joined to sugars

Question 21

How are deoxy-nucleotides formed?

Answer 21

By the reduction of ribonucleotides

Question 22

Which enzyme catalyses deoxy-nucleotide synthesis?

Answer 22

Ribonucleotide reductase

Question 23

How many subunits does ribonucleotide reductase have?

Answer 23

2

Question 24

What is the function of the first subunit (R1) in ribonucleotide reductase?

Answer 24

Site of reduction

Question 25

What is the function of the second subunit (R2) of ribonucleotide reductase?

Answer 25

Contains a stable free radical on a Tyr

Question 26

What do cancer cells need as precursors for RNA and DNA?

Answer 26

Nucleotides

Question 27

What is the role of chemotherapeutic agents?

Answer 27

Inhibit growth of tumours

Question 28

How do chemotherapeutic agents inhibit growth of tumours?

Answer 28

Reducing the amount of precursors available for RNA and DNA

Question 29

How can chemotherapeutic agents act to inhibit metabolism?

Answer 29

By targeting enzymes in nucleotide biosynthetic pathways

Question 30

How do the synthesis of the purine ring system and pyrimidine bases differ?

Answer 30

Purine ring system is built step by step, attached to sugar and phosphate whereas pyrimidine bases are synthesised separately to sugar and phosphate and then attached post-synthesis

Question 31

What does synthesis of AMP require?

Answer 31

GTP

Question 32

What does synthesis of GMP require?

Answer 32

ATP