Nucleotides And Nucleic Acid

Question 1

What are nucleotides made up of?

Answer 1

• Pentose sugar (in the centre)

• Nitrogenous base

• Phosphate group (negatively charged)

Question 2

Which elements do nucleotides contain?

Answer 2

CHONP

Question 3

What is the difference between pentose sugars in DNA and RNA?

Answer 3

In DNA, it’s deoxyribose. In RNA, it’s ribose.

Question 4

What are the four bases found in DNA?

Answer 4

• Adenine (A)

• Thymine (T)

• Guanine (G)

• Cytosine (C)

Question 5

Which bases have a double-ring structure (purines)?

Answer 5

Adenine and guanine (think ADD a ring)

Question 6

Which bases have a single-ring structure (pyrimidines)?

Answer 6

Thymine and cytosine

Question 7

Which base found in DNA is not found in RNA?

Answer 7

Thymine

Question 8

What are the four bases found in RNA?

Answer 8

Adenine, uracil, guanine and cytosine

Question 9

How are polynucleotides formed?

Answer 9

The phosphate group and the hydroxyl group (on carbon 3 of the pentose sugar) of another nucleotide join together to form a phosphodiester bond.

Question 10

What is the bond between two nucleotides called?

Answer 10

Phosphodiester bond

Question 11

What makes up the backbone of DNA?

Answer 11

Sugar-phosphate (pentose sugar joined to phosphate group)

Question 12

What bonds occur between opposite strands of bases?

Answer 12

Hydrogen bonds

Question 13

What does guanine always pair with?

Answer 13

Cytosine

Question 14

What does adenine always pair with?

Answer 14

Thymine

Question 15

What are the complementary base pairs?

Answer 15

• AT

• GC

Question 16

Why is the distance between bases constant the whole length of the DNA molecule?

Answer 16

Because pyrimidines always pair with purines

Question 17

How many hydrogen bonds do guanine and cytosine form?

Answer 17

Three

Question 18

How many bonds do adenine and thymine form?

Answer 18

Two

Question 19

What are the differences between DNA and RNA?

Answer 19

• DNA found in nucleus - RNA found in cytoplasm

• DNA is extremely long - RNA is relatively short

• DNA is double-stranded - RNA is single-stranded

Question 20

What does DNA helicase do?

Answer 20

It causes the hydrogen bonds between complementary bases to break

Question 21

What is the difference between normal nucleotides and activated nucleotides?

Answer 21

Activated nucleotides have three phosphate groups

Question 22

What does DNA polymerase do?

Answer 22

Catalyses the formation of phosphodiester bonds between activated nucleotides

Question 23

When do the activated nucleotides lose their extra two phosphate groups?

Answer 23

When the phosphodiester bonds reform

Question 24

What is semi-conservative replication?

Answer 24

When the original DNA splits into two strands, and then each strand is then replicated into a complementary new strand