BGM1002/L20 Metabolism

Question 1

Where does all energy on Earth originate?

Answer 1

The Sun

Question 2

What 4 groups can all living organisms be classified into? (Considering energy sources)

Answer 2

Phototrophs
Autotrophs
Chemotrophs
Heterotrophs

Question 3

Salivary amylase hydrolyses polysaccharides into what 3 products?

Answer 3

Oligosaccharides
Disaccharides
Monosaccharides

Question 4

Pancreatic amylase hydrolyses oligosaccharides into what 2 products?

Answer 4

Disaccharides
Monosaccharides

Question 5

Intestinal amylase hydrolyses disaccharides into what product?

Answer 5

Monosaccharides

Question 6

Define metabolism.

Answer 6

Biochemical modification of chemical compounds in living cells and organisms

Question 7

What is a catabolic reaction?

Answer 7

Breaking down of larger molecules

Question 8

What is an anabolic reaction?

Answer 8

Reactions which build larger molecules from smaller ones

Question 9

Give 3 features of catabolic reactions.

Answer 9

Degradative
Energy producing
Oxidative

Question 10

Give 3 features of anabolic reactions.

Answer 10

Biosynthetic
Energy consuming
Reductive

Question 11

Give 3 potential uses of energy in the body.

Answer 11

Mechanical work
Active transport
Heat production

Question 12

Give 3 classes of macromolecules.

Answer 12

Storage
Structural
Functional

Question 13

What are metabolic reactions which release free energy called?

Answer 13

Exergonic

Question 14

What are metabolic reactions which use up free energy called?

Answer 14

Endergonic

Question 15

How can endergonic reactions be induced in cells? (3)

Answer 15

Increased temperature
Increased [S]
Reaction linkage (coupled reactions)

Question 16

How energetic is the gamma phosphoanhydride bond in ATP?

Answer 16

-30.7 kJ/mol

Question 17

How energetic is the beta phosphoanhydride bond in ADP?

Answer 17

-27.3 kJ/mol

Question 18

Why can’t AMP be hydrolysed?

Answer 18

Phosphoester bond is not very energetic and not easily hydrolysed due to lack of repulsion

Question 19

What is the main role of GTP?

Answer 19

Protein metabolism

Question 20

What is the main role of CTP?

Answer 20

Lipid biosynthesis

Question 21

What is the main role of UTP?

Answer 21

Carbohydrate metabolism

Question 22

Name 3 thioesters.

Answer 22

Acetyl CoA
Succinyl CoA
Fatty acid CoA

Question 23

Why are thioesters easily hydrolysed?

Answer 23

High delta(G)

Question 24

What does NAD+ stand for?

Answer 24

Nicotinamide adenosine dinucleotide

Question 25

What is the purpose of NAD+?

Answer 25

Transport of hydrogen/electrons

Question 26

Describe the general movement of electrons.

Answer 26

From one atom with lower affinity (reductant) to one with greater affinity (oxidant)

Question 27

Where do hydrogens bind in FAD?

Answer 27

Across isoalloxazine group

Question 28

How is hydrogen broken up in FADH2? (2)

Answer 28

Two free radicals
No ionisation

Question 29

How are metabolic pathways controlled? (3)

Answer 29

Negative feedback
Feed forward
Isoenzymes
Multi-enzyme compelxes
Compartmentalised
Reciprocal regulation

Question 30

Summarise stage 1 of carbohydrate metabolism.

Answer 30

Breakdown of complex molecules into simple units

Question 31

Summarise stage 2 of carbohydrate metabolism.

Answer 31

Conversion of simple units into acetyl CoA (or citric acid cycle intermediates)

Question 32

Summarise stage 3 of carbohydrate metabolism.

Answer 32

Production of ATP by complete oxidation of acetyl CoA

Question 33

How is metabolism altered by starvation?

Answer 33

Structural proteins broken down and used to drive energy generation

Question 34

How is metabolism affected by obesity?

Answer 34

Anabolic reactions turn more ingested molecules into storage molecules