Topic 7_Nucleic Acids

What contribution did the X-ray diffraction conducted by Rosalind Franklin make to our understanding of DNA?

• It identified DNA as the genetic material

• It indicated the helical shape of the molecule

• It showed that the DNA of eukaryotes was associated with histone proteins

• It showed that replication was a semi-conservative process

The diagram shows the arrangement of introns and exons in a segment of pre-mRNA. Pre-mRNA is immature mRNA containing introns and exons. Which is a mature mRNA molecule derived from the pre-mRNA by splicing?

• 
• A

• B

• C

• D

The image shows a polysome in a bacterial cell. How many genes have been transcribed?

• 1

• 2

• 3

• 4

What are the functions of DNA primase and DNA polymerase I in DNA replication?

• A

• B

• C

• D

A nucleotide containing dideoxyribose is shown. What is the reason for the use of dideoxyribonucleotides to terminate sequences in base sequencing?

• Nucleotides cannot form 5′ to 3′ linkages with dideoxyribonucleotides

• Nucleotides cannot form base pairs with dideoxyribonucleotides.

• Dideoxyribonucleotides cannot form hydrogen bonds with deoxyribose

• Dideoxyribonucleotides do not have all four nitrogenous bases

In which image are polysomes visible? (The images do not have the same magnification)

• A

• B

• C

• D

The diagram shows how pre-mRNA is processed into mature mRNA. Which structures are indicated by the letters W and X?

• 
• A

• B

• C

• D

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

• I only

• I and II only

• II and III only

• 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

What is a feature of transcription?

• Both strands of a DNA molecule act as a template for mRNA.

• Nucleoside triphosphates become nucleotides by losing three phosphates.

• RNA polymerase binds to the promoter region.

• The sense strand acts as a template for mRNA.