Biological Molecules - DNA

Question 1

What does DNA and RNA stand for? What do they do?

Answer 1

Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) are important information-carrying molecules.

Question 2

Bond between phosphate and sugar

Answer 2

Ester bond

Question 3

What are the 2 types of base pairings in DNA and RNA?

Answer 3

Pyrimidines:

Cytosine C

Thymine T

Purines:

Adenine A

Guanine G

Question 4

What are the components of the DNA nucleotide?

Answer 4

The components of a DNA nucleotide are deoxyribose, a phosphate group and one of the organic bases adenine,
cytosine, guanine or thymine.

Question 5

What are the components of an RNA nucleotide?

Answer 5

The components of an RNA nucleotide are ribose, a phosphate group and one of the organic bases adenine, cytosine, guanine or uracil.

Question 6

What is an RNA molecule?

Answer 6

An RNA molecule is a relatively short polynucleotide chain.

Single stranded

Ribose sugar

3 types:

mRNA

tRNA

rRNA

Question 7

Bond between sugar and base

Answer 7

Glycosidic bond

Question 8

Nucleotide structure

Answer 8

Phosphate group

Pentose sugar

Organic base

Penrose sugar is 5 carbon atoms

Question 9

How are ribosomes formed?

Answer 9

Ribosomes are formed from RNA and proteins.

Question 10

Gene

Answer 10

Sequence of bases on a DNA molecule coding for a sequence of amino acids in a polypeptide chain.

All the genes are called the genome.

Question 11

What does DNA and RNA do with genetic information?

Answer 11

DNA holds genetic information

and

RNA transfers genetic information

Question 12

What does the semi-conservative replication of DNA ensure? What is the process? Explain in detail.

Answer 12

The semi-conservative replication of DNA ensures genetic continuity between generations of cells.

The process of semi-conservative replication of DNA in terms of:

• unwinding of the double helix
• breakage of hydrogen bonds between complementary bases in the polynucleotide strands
• the role of DNA helicase in unwinding DNA and breaking its hydrogen bonds
• attraction of new DNA nucleotides to exposed bases on template strands and base pairing
• the role of DNA polymerase in the condensation reaction that joins adjacent nucleotides.

Question 13

What is the role of DNA helicase?

Answer 13

(unwinding DNA and)
breaking hydrogen bonds / bonds between
chains / bases / strands;

Question 14

What is the role of DNA polymerase?

Answer 14

joins (adjacent) nucleotides OR forms phosphodiester bond / sugar-phosphate backbone;