Topic 2.6: Structure of DNA and RNA

Question 1

What are the three principal components of a nucleotide?

Answer 1

Each nucleotide is comprised of three principal components:

5-carbon pentose sugar (pentagon)
Phosphate group (circle)
Nitrogenous base (rectangle)

Question 2

What is the difference between DNA and RNA in terms of pentose sugar?

Answer 2

DNA: deoxyribose

RNA: ribose

Question 3

What is the difference between DNA and RNA in terms of base composition?

Answer 3

DNA: adenine, guanine, cytosine, thymine

RNA: adenine, guanine, cytosine, uracil

Question 4

What is the difference between DNA and RNA in terms of number of strands?

Answer 4

DNA: double stranded

RNA: single stranded

Question 5

Adenine binds with what?

Answer 5

thymine

Question 6

Thymine binds with what?

Answer 6

adenine

Question 7

Guanine binds with what?

Answer 7

cytosine

Question 8

Cytosine binds with what?

Answer 8

guanine

Question 9

How many bonds form between adenine and thymine?

Answer 9

two hydrogen bonds

Question 10

How many bonds form between guanine and cytosine?

Answer 10

three hydrogen bonds

Question 11

What are the double-ringed purine nitrogenous bases?

Answer 11

guanine and adenine

Question 12

What are the single-ringed pyrimidine nitrogenous bases?

Answer 12

cytosine, thymine, and uracil

Question 13

Define messenger RNA (mRNA)

Answer 13

Messenger RNA (mRNA) – a transcript copy of a gene which encodes a specific polypeptide

Question 14

Define transfer RNA (tRNA)

Answer 14

Transfer RNA (tRNA) – carries the polypeptide subunits (amino acids) to the organelle responsible for synthesis (ribosome)

Question 15

Define ribosomal RNA (rRNA)

Answer 15

Ribosomal RNA (rRNA) – a primary component of the ribosome and is responsible for its catalytic activity