IB Biology Topic 7

Some regions of DNA do not code for the production of proteins. What are these regions of DNA used as?

• A. They have no known function and are recycled to provide nucleotides

• B. Gene regulation and coding for production of enzymes used in translation

• C. Telomeres and coding for production of tRNA

• D. Introns and coding for production of structural proteins

Which types of interactions are found in a part of a protein with secondary but not tertiary structure?

I. Hydrogen bonds

II. Disulphide bridges

III. Ionic bonds

• A. I only

• B. I and II only

• C. II and III only

• D. I, II and III

This image is taken from a visualization of a eukaryotic ribosome. The arrows show the direction of movement of mRNA. Which letter represents a tRNA exiting from the E site?

• A

• B

• C

• D

In which process(es) do nucleosomes play a role in eukaryotes?

I. tRNA activation

II. Transcription regulation

III. DNA supercoiling

• A. I only

• B. II only

• C. II and III only

• D. I, II and III

Scientists have heated a solution containing the protein albumin and measured its relative alpha helix content, shown on the graph.

What does the zone labelled X indicate?

A. Rapid increase in beta pleated sheets

B. Rapid formation of hydrogen bonds

C. Rapid increase in denatured protein molecules

D. Rapid decrease in peptide bonds

• A. Rapid increase in beta pleated sheets

• B. Rapid formation of hydrogen bonds

• C. Rapid increase in denatured protein molecules

• D. Rapid decrease in peptide bonds

Where does a tRNA-activating enzyme attach the appropriate amino acid to the tRNA molecule?

• A

• B

• C

• D

What does post-transcriptional modification of eukaryotic mRNA include?

I. Introns are removed from mRNA.

II. Exons are joined together to form mature mRNA.

III. A 5' cap and 3' poly-A tail are added to mRNA.

• A. I only

• B. I and III only

• C. II and III only

• D. I, II and III

Which of the following is an enzyme associated with the removal of DNA primers and replacing them with DNA nucleotides?

• DNA Polymerase I

• DNA Polymerase III

• DNA Ligase

• DNA Gyrase

Which direction is elongation of mRNA carried out?

• 5' to 3'

• 3' to 5'

• left to right

• antisense to sense strand

Identify the structures shown in the images.

• Nucleosomes

• Double helix structure

• Polysomes

• tRNA transcription factors