Week 1 - Basic Concepts

Question 1

What reaction cleaves a bond within a molecule and

adds water elements?

Answer 1

Hydrolysis

Question 2

What reaction forms a bond between hydroxyl

groups of 2 molecules and expels water?

Answer 2

Condensation

Question 3

Why is carbon well-suited to life?

Answer 3

Small, provides 4 covalent bonds, binds various functional groups. Can form linear and branched chains, and rings.

Question 4

List (in order most to least) the 4 main elements in the

human body.

Answer 4

Hydrogen, Oxygen, Carbon, Nitrogen

Question 5

What term is used to describe molecules that have

both polar and nonpolar regions?

Answer 5

Amphipathic

Question 6

Allosteric Control

Answer 6

The regulation of an enzyme by a regulatory molecule that interacts at a site (allosteric site) other than the active site (at which catalytic activity occurs).

Question 7

Allosteric Modulator

Answer 7

A substance which indirectly influences (modulates) the effects of a primary ligand that directly activates or deactivates the function of a target protein (can be positive or negative influence).

Question 8

Isoenzymes

Answer 8

Each of two or more enzymes with identical function but different structure. Both catalyse the same reaction, and multiple final products feed back to both enzymes.

Question 9

How does phosphorylation / dephosphorylation affect the activity of enzymes?

Answer 9

It regulates them. Phosphorylation may switch an enzyme on, whilst dephosphorylation may switch an enzyme off.. Alternatively, it may switch them off and on, respectively.

Question 10

Zymogens

Answer 10

Inactive precursors that become

active following cleavage, eg trypsinogen to trypsin.

Question 11

Name the 3 general factors affecting the activity of

enzymes.

Answer 11

Amount
Catalytic Activity
Accessibility of substrates

Question 12

State the concept used for regulation of an enzyme by
a regulatory molecule that interacts at a site other
than the active site?

Answer 12

Allosteric Control

Question 13

What is the underlying principle of metabolic pathways

Answer 13

Fuels are degraded and large molecules are constructed in a series of reactions.

Question 14

What does oxidation do in regards to ATP?

Answer 14

Fuels its formation.

Question 15

What is a metabolic pathway?

Answer 15

A linked series of chemical reactions occurring within a cell. The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence of chemical reactions catalyzed by enzymes.

Question 16

The three forms of energy in biology?

Answer 16

• Energy carriers
• Macromolecules (highly reduced molecules eg food)
• Electrochemical gradients, ie electrical force (membrane potential) and chemical force (ion concentrations).

Question 17

The three parts of an ATP molecule?

Answer 17

An adenine molecule (a purine structure - double ring), a ribose sugar, and three phosphate groups linked together (triphosphate). Note that adenine together with the ribose are called adenosine.

Question 18

What do NADH, NADPH, and FADH2 stand for?

Answer 18

Nicotinamide adenine dinucleotide.
Nicotinamide adenine dinucleotide phosphate.
Flavin adenine dinucleotide.

Question 19

What do the electron carriers do?

Answer 19

Act to shuttle electrons and H+ between anabolic and

catabolic processes. Also act as cofactors for many enzymes.

Question 20

What is the difference between NADH and NADPH?

Answer 20

No effect on the electron-carrying properties, but allows NADPH to bind different substrates compared to NADH. NADPH is mainly used in the synthesis of organic molecules, whereas NADH is mainly used in ATP generation.

Question 21

Which vitamin are NADH and NADPH derived from?

Answer 21

Vitamin B3 (Niacin).

Question 22

What is Coenzyme A?

Answer 22

An activated carrier of acyl groups, its main function is to deliver the acetyl group to the citric acid cycle (Krebs cycle) to be oxidized for energy production.

Question 23

Oxidation of organic molecules is important for

energy production. True or false?

Answer 23

True.

Question 24

A loss of a C-H bond from an organic molecule is

indicative of what process?

Answer 24

Oxidation.

Question 25

State the concept used to describe metabolic
reactions that occur in separate compartments
of the cell (or organism).

Answer 25

Compartmentation or compartmentalisation.

Question 26

What do NADH and FADH2 do vs NADPH?

Answer 26

NADH and FADH2 give rise to ATP production, whereas NADPH gives rise to macromolecules.