Molecular Biology

Question 1

Define molecular biology.

Answer 1

The study of living processes in terms of chemical substances.

Question 2

Define anabolism.

Answer 2

The synthesis of complex molecules from simpler molecules, including the formation of macromolecules from monomers by condensation reactions.

Question 3

Define catabolism.

Answer 3

The breakdown of complex molecules into simpler molecules, including the hydrolysis of macromolecules into monomers.

Question 4

State the theory of vitalism.

Answer 4

The theory that organic compounds can only be produced in living organisms because a vital force was needed for their synthesis. Falsified by the artificial synthesis of urea.

Question 5

Define solvent properties.

Answer 5

The ability to dissolve substances.

Question 6

Define cohesion.

Answer 6

The force by which individual molecules stick together.

Question 7

Define adhesion.

Answer 7

The force by which individual molecules stick to surrounding material and surfaces.

Question 8

Define specific heat capacity.

Answer 8

The amount of energy required to increase the temperature of 1kg of a particular substance by 1°C.

Question 9

Define latent heat of vapourisation.

Answer 9

The amount of energy required to turn a substance from a liquid to a gas.

Question 10

What are thermal properties ?

Answer 10

Refers to a substance’s responses to change in heat energy.

Question 11

Why is water known as the medium of life ?

Answer 11

Because most of the metabolic reactions in cells occur in water and it is used as a transport medium and a coolant.

Question 12

Define monomers.

Answer 12

Molecules that consist of a single sub-unit.

Question 13

Define monosaccharides.

Answer 13

Simplest carbohydrates.

Question 14

Define disaccharides.

Answer 14

2 simple sugars joined together.

Question 15

Define polysaccharides.

Answer 15

Many monosaccharides joined together (polymers).

Question 16

Équation to form maltose.

Answer 16

Glucose + glucose —> maltose + water

Question 17

Equation to form lactose.

Answer 17

Glucose + galactose —> lactose + water

Question 18

Equation to form sucrose.

Answer 18

Glucose + fructose —> sucrose + water

Question 19

Define condensation reaction.

Answer 19

A reaction where 2 molecules join to form a larger one and water is formed.

Question 20

Define hydrolysis.

Answer 20

A reaction where large molecules are split into smaller molecules with the addition of water.

Question 21

Define appetite.

Answer 21

The feeling of hunger leading to the desire to eat.

Question 22

Define proteins.

Answer 22

Macromolecules composed of C, H, O, N and sometimes S. Used for growth and repair

Question 23

Define proteome.

Answer 23

The entire set of proteins expressed by a cell or organism.

Question 24

What is the primary structure of a protein?

Answer 24

The sequence and number of amino acids in a polypeptide.

Question 25

What is the secondary structure of a protein ?

Answer 25

Regular folding or spiralling of the polypeptide.

Question 26

What is the tertiary structure of a polypeptide ?

Answer 26

Further folding resulting in its 3D conformation, it results in the precise, compact structure that is unique to proteins.

Question 27

What is the quaternary structure of a protein?

Answer 27

Linking together of polypeptides to form a single protein.

Question 28

Define enzyme.

Answer 28

Globular proteins that act as catalysts, hence speeding up a reaction without being used up in the process.

Question 29

Define metabolic pathways.

Answer 29

A series of reactions which consist of chains and cycles of enzyme-catalysed reactions.

Question 30

Define substrate.

Answer 30

The substance that enzymes convert into product.

Question 31

Define denaturation.

Answer 31

A structural change in the 3D conformation of a protein that results in the loss of its biological properties.

Question 32

What is enzyme substrate specificity ?

Answer 32

The enzyme’s active site and substrate have a specific 3D shape and chemical properties which must match.

Question 33

How does pH affect enzyme activity ?

Answer 33

Gain or loss of hydrogen ion distorts tertiary structure of enzyme by disrupting hydrogen bonds.

Question 34

How does temperature affect enzyme activity?

Answer 34

As temp increases, K.E of particles increases, there are more chances of a substrate colliding with an enzyme with enough force to bind to it.

Question 35

Define immobilised enzyme.

Answer 35

An enzyme that is trapped in place and unable to move by attaching it to an insoluble surface.

Question 36

Define coding region.

Answer 36

Region of eukaryotic DNA that codes for synthesis of DNA.

Question 37

Define exons.

Answer 37

Protein-coding genes.

Question 38

Define non-coding regions.

Answer 38

Regions that do not code for proteins.

Question 39

Define enhancers & silencers.

Answer 39

DNA sequences that promote expression of a gene.
DNA sequences that inhibit expression of a gene.

Question 40

Define introns.

Answer 40

DNA sequences that are interspersed with exons and process mRNA.

Question 41

Define highly repetitive sequences.

Answer 41

Form telomeres at the end of chromosomes which prevent loss of genes.

Question 42

Define variable number tandem repeats.

Answer 42

Specific unique regions that show significant variation (in terms of the number of times a sequence is repeated) between individuals. Used in DNA profiling.

Question 43

Define structural DNA.

Answer 43

Occurs around the centromere and near the ends of chromosomes to provide structural support.

Question 44

What is NADP ?

Answer 44

An electron carrier.

Question 45

What is photophosphorylation ?

Answer 45

Production of ATP using light energy.

Question 46

Define polysomes.

Answer 46

Groups of 2 or more ribosomes translating the same mRNA transcript.

Question 47

Define transcription factors.

Answer 47

Proteins that bind to specific base sequences in DNA and regulate transcription

Question 48

Define cell respiration

Answer 48

The controlled release of energy from organic compounds to form ATP