Practise Paper Topic 2

Question 1

What is a codon?

Answer 1

A sequence of nucleotides that responds to an amino acid

Question 2

What happens to an enzyme when it becomes denatured?

Answer 2

The enzyme works slower

Question 3

Which of these molecules is a disaccharide?:
A. Galactose 
B. Sucrose
C. Cellulose
D. Ribose

Answer 3

B. Sucrose

Question 4

What is the energy absorbed by chlorophyll used directly for in plants?:
A. To produce ATP
B. To split water
C. To fix CO2

Answer 4

A. To produce ATP
AND
B. Split water

Question 5

What does a phosphate look like?

Answer 5

Circle shape on a nucleotide

Question 6

When two nucleotides are linked together to form a dinucleotide, what type of bond is that?

Answer 6

A covalent bond

Question 7

Explain the role of polymerase in DNA replication?

Answer 7

Polymerase is an enzyme that creates two identical DNA strands from one original DNA molecule

Question 8

Explain the properties of water that allow living organisms to use it as a habitat?

Answer 8

Water has a high specific heat capacity which means it takes a relatively large amount of energy to break down so its stable enough for organisms to live in, and water had a high latent heat of vaporisation

Question 9

List two products of aerobic cell respiration

Answer 9

CO2 + H2O

Question 10

State the name of the molecule that is the source of oxygen released by plants during photosynthesis?

Answer 10

Water (H2O)

Question 11

Outline the role of hydrolysis in the relationships between monosaccharides, disaccharides and polysaccharides

Answer 11

Hydrolysis uses an -OH from one molecule and -H from another molecule (monosaccharides) to form a disaccharide (putting them together using H2O)

Question 12

What is the difference between anaerobic and aerobic cell respiration in eukaryotes?

Answer 12

Anaerobic is without the use of oxygen where’s aerobic uses oxygen.
Aerobic respiration takes place in the mitochondria and produces CO2, H2O and ATP. Whereas anaerobic respiration produces less ATP.

Question 13

Outline how different environmental conditions can affect the rate of photosynthesis in plants

Answer 13

• Temperature can affect the rate because the enzyme cellulose causes reactions to occur for the plant to photosynthesis and at its optimum it can be denatured, so the plant can’t make food
• CO2 can affect the rate of photosynthesis in plants as once the plant reached optimum CO2 concentration the cellulose enzyme can denature (too much CO2 not enough energy to break it down) meaning the plant can’t photosynthesise

Question 14

What are the three main ideas of cells

Answer 14

1. Cells are the smallest unit of life
2. Organisms are made up of 1 of more cells
3. All cells must have come from pre-existing cells