Lecture 1

Question 1

What is metabolism?

Answer 1

A collection of coupled and interlinked series of chemical reactions which starts with a particular molecule and converts it to some other molecule(s).

Question 2

2 main functions of metabolism?

Answer 2

Extract biologically useful energy from cell’s environment.

Synthesise building blocks of cell (simple molecules to complex macromolecules).

Question 3

2 types of metabolic reactions, and description?

Answer 3

Catabolic - extraction of biologically useful energy.

Anabolic - Synthesise complex structures/molecules from simple ones. Requires input of energy from catabolism.

Question 4

Six types of chemical reactions in metabolism?

Answer 4

Redox,
Ligation requiring ATP cleavage,
Isomerisation,
Group transfer,
Hydrolytic,
Addition/removal of function groups.

Question 5

Example of oxidation reaction?

Answer 5

Succinate + FAD -> Fumarate + FADH2.

Question 6

Are ligation reactions energy dependent?

Answer 6

Yes.

Question 7

An example of a ligation reaction?

Answer 7

Pyruvate + CO2 + ATP + H2O Oxoloacetate +ADP + Pi + H+.

Question 8

Example of isomerisation reaction?

Answer 8

Citrate Isocitrate.

Question 9

Example of group transfer (involving high energy phosphate)?

Answer 9

Glucose + ATP -> ADP + G-6P

Question 10

Example of condensation reaction?

Answer 10

Oxaloacetate + Acetyl CoA -> Citryl CoA.

Question 11

How do condensation reactions work?

Answer 11

Functional groups added to double bonds to form single bonds or removed from single bonds to form double bonds.

Question 12

3 main components of ATP?

Answer 12

Triphosphate, Ribose, Adenine.

Question 13

What type of molecule is ATP?

Answer 13

Activated carrier (been conserved through evolution).

Question 14

What is the reduced form of FAD (oxidised)?

Answer 14

FADH2.

Question 15

Does oxidation require or release electrons?

Answer 15

Releases.

Question 16

Is Acetyl CoA an activated carrier?

Answer 16

Yes, of acetyl unit.

Question 17

3 main parts of coenzyme A?

Answer 17

β-mercapto-ethylamine unit.
Pantothenate unit.
ADP + Extra phosphate.

Question 18

What are the reactive group for Acetyl CoA?

Answer 18

Sulphur on CoA.

Question 19

Why are activated carriers typically biologically stable?

Why is this important?

Answer 19

Because they require specific catalysts.

Enables enzymes to control flow of electrons and free energy.

Question 20

In the absence of a catalyst, what to NADH and FADH2 resist?

Answer 20

Oxidation and release of electrons.

Question 21

Are ATP and Acetyl CoA hydrolysed in absence of catalyst?

Answer 21

Yes, but slowly.

Question 22

Is generation of ATP one of the primary roles of catabolism?

Answer 22

Yes.

Question 23

4 uses of ATP?

Answer 23

Motion,
Active transport,
Biosynthesis,
Signal amplification.

Question 24

2 uses of ADP?

Answer 24

Oxidation of fuel,

Photosynthesis.

Question 25

Which has a lower ΔGºOxidation, methane or carbon dioxide?

Answer 25

Methane, as more possibility to release energy through oxidation.

Question 26

Is glucose or fatty acids a more efficient fuel? Why?

Answer 26

Fatty acids are a more efficient fuel, as they are reduced more and can be oxidised much further than glucose.

Question 27

Where do electrons lost in metabolism go?

Answer 27

To NAD and FAD carriers.

Question 28

When are NAD and FAD oxidised? What happens?

Answer 28

At electron transport chain.

Causes H+ to be pumped out of mitochondria.

Question 29

What forms ATP in final stage of fuel catabolism with influx of H+? Where?

Answer 29

Oxidative phosphorylation. Mitochondria (eukaryotes).

Question 30

What happens after final stage of ETC?

Answer 30

Electrons fed to O2, combining with H+ to form H20.

Question 31

Broadly speaking, what happens in the first stage of catabolism?

Answer 31

Complex C fuels (fats, polysaccharides, proteins) degraded into smaller units.

Question 32

Broadly speaking, what happens in the second stage of catabolism?

Answer 32

Convergence of small units into a few simple units. Acetyl CoA.

Question 33

Broadly speaking, what happens in the third stage of catabolism?

Answer 33

Acetyl oxidised to CO2,
Reduction of NAD+ and FAD,
Generation of H+ gradient and synthesis of ATP.