A-Level A-Level Biology

Question 1

What is the role of ATP in cellular processes?

Accepted Answer

The universal energy currency that transfers energy between exergonic and endergonic reactions in cells

Answer

Long-term energy storage only

Answer

The structural component of cell membranes

Answer

The enzyme that catalyses glycolysis

Question 2

What is the difference between a gene and an allele?

Accepted Answer

A gene is a section of DNA coding for a polypeptide; an allele is a variant form of that gene at the same locus

Answer

They are the same thing

Answer

An allele is a chromosome; a gene is a protein

Answer

Genes are only found in plants; alleles are in animals

Question 3

What is the fluid mosaic model of the cell membrane?

Accepted Answer

A model describing the membrane as a phospholipid bilayer with mobile proteins embedded in it

Answer

A model showing a rigid, impermeable barrier

Answer

A model for the nuclear envelope only

Answer

A model describing the cytoskeleton

Question 4

What is the process of transcription in protein synthesis?

Accepted Answer

Copying a section of DNA into mRNA in the nucleus

Answer

Building a polypeptide from tRNA at a ribosome

Answer

Replicating DNA before cell division

Answer

Activating amino acids for translation

Question 5

What is codominance in genetics?

Accepted Answer

When both alleles in a heterozygote are fully expressed, producing a phenotype distinct from either homozygote

Answer

When one allele completely masks another

Answer

When recessive alleles skip a generation

Answer

When genes are on the X chromosome

Question 6

What is the role of the mitochondrion in aerobic respiration?

Accepted Answer

The site of the Krebs cycle and oxidative phosphorylation, producing the majority of ATP per glucose molecule

Answer

Producing ATP by photosynthesis

Answer

Storing glucose as glycogen

Answer

Synthesising proteins from mRNA