Nucleic Acids

Question 1

What are the 3 components of nucleic acids

Answer 1

• Phosphate group
• Pentose sugar
• Nitrogenous base

Question 2

What does the backbone of a DNA molecule consist of?

Answer 2

• Phosphate group

- Deoxyribose sugar

Question 3

What bonds are present between bases?

Answer 3

Hydrogen bonds

Question 4

What bonds are present between the sugar and phosphatgroup?

Answer 4

Phosphodiester bonds

Question 5

How are phosphodiester bonds broken?

Answer 5

Hydrolysis

Question 6

How does DNA and RNA differ?

Answer 6

• DNA has the base thymine and RNA has uracil
• Ribose has an oxygen atom and deoxyribose doesn’t
• DNA contains the sugared deoxyribose and RNA contains ribose
• DNA is double stranded and RNA is single stranded

Question 7

What are the 2 groups of nucleotides?

Answer 7

• Purines

- Pyrimidines

Question 8

What are purines?

Answer 8

• Adenine and guanine
• Contain double carbon ring structures (hexagon and pentagon)
• Made up of carbon and nitrogen

Question 9

What are pyrimidines?

Answer 9

• Thymine and cytosine
• Contain a single carbon ring structure (hexagon)
• Made up of carbon and nitrogen

Question 10

How many hydrogen bonds are present between adenine and thymine (purines)?

Answer 10

2

Complementary base pairing

Question 11

How many hydrogen bonds are present between cytosine and guanine (pyrimidines)?

Answer 11

3

Complementary base pairing

Question 12

What’s a nucleoside?

Answer 12

Same as a nucleotide but doesn’t have a phosphate group

Question 13

What is a monomer?

Answer 13

An individual (nearly identical) unit that acts as a building block for large biological molecules

Question 14

What is a polymer?

Answer 14

A large molecule made up many small monomers in a chain

Question 15

Who discovered the double helical structure of DNA?

Answer 15

James Watson and Francis Crick

Question 16

What is Erwin Chargaff’s rule?

Answer 16

The % A = T and the % C= G

Question 17

Describe the order of nucleotides

Answer 17

• 5’ to 3’

- Strands are anti-parallel

Question 18

What is meant by 6’ and 3’ end of a nucleotide?

Answer 18

The 5’ end is the phosphate group and the 3’ end is the hydroxyl group of the sugar

Question 19

Is the helix usually right-handed or left-handed?

Answer 19

Right-handed

Question 20

Does the helix spiral clockwise or anti-clockwise?

Answer 20

Clockwise

Question 21

How many bases are there per twist?

Answer 21

10

Question 22

How big is one big complete turn in the helix?

Answer 22

3.4nm

Question 23

What are the 2 asymmetrical grooves on the outside of the high handed helix called?

Answer 23

• Major groove

- Minor groove

Question 24

What can bind to these grooves to interact with a particular sequence of bases

Answer 24

Proteins

Question 25

What is the predominant form of DNA secondary structures in living cells ?

Answer 25

B-DNA

Question 26

What other double believes can form under certain in vitro conditions?

Answer 26

A-DNA and Z-DNA

Question 27

How long is human nuclear DNA?

Answer 27

2m

Question 28

What are the 4 significant RNA molecules?

Answer 28

• rRNA
• tRNA
• mRNA
• siRNA

Question 29

What is a gene?

Answer 29

A section of DNA that contains the complete sequence of DNA to code for an entire protein