Cell biology worksheet with answers

Proteins are polymers of which monomers?

1. ANucleotides
2. BSimple sugars
3. CGlycerol molecules
4. DAmino acids

What is the main role of the nucleolus?

1. ACopying the whole genome
2. BStoring ATP for the nucleus
3. CBreaking down damaged proteins that are tagged with ubiquitin
4. DMaking ribosomal RNA and assembling ribosome subunits

What happens to a red blood cell placed in pure water?

1. AIt swells and may burst
2. BIt shrinks and shrivels
3. CIt stays the same size
4. DIt divides into two cells

A point mutation changes a codon for an amino acid into a stop codon. What type of mutation is this?

1. ASilent mutation
2. BFrameshift mutation
3. CNonsense mutation
4. DMissense mutation

A codon consists of:

1. AThree amino acids
2. BThree nucleotides on mRNA that code for an amino acid or a stop signal
3. COne nucleotide
4. DA whole gene

Which cell junction anchors intermediate filaments and gives tissues such as skin mechanical strength?

1. ADesmosome
2. BTight junction
3. CGap junction
4. DPlasmodesma

Cholera toxin modifies the alpha subunit of Gs so it cannot hydrolyse GTP. Why does this cause severe watery diarrhoea?

1. AcAMP falls, so gut cells stop absorbing water and sodium from the lumen
2. BThe toxin blocks aquaporins in the colon
3. CcAMP stays high in gut cells, driving chloride and water secretion
4. DThe toxin destroys the villi

What problem does telomerase solve?

1. AThe unwinding of the double helix at each replication fork by helicase
2. BThe joining of Okazaki fragments
3. CThe removal of introns from mRNA
4. DThe shortening of chromosome ends with each round of replication