3.8 Nucleic Acids

Question 1

What are nucleic acids?

Answer 1

Large polymers formed from monomers called nucleotides.

Question 2

Where are nucleic acids found?

Answer 2

In the nucleus of a cell

Question 3

What are the 3 components of a nucleic acid?

Answer 3

Phosphate group, pentose sugar and a nitrogenous base

Question 4

What are the two types of nucleic acids?

Answer 4

Deoxyribonucleic acid and Ribonucleic acid

Question 5

What are nucleic acids used for?

Answer 5

Storage of genetic information needed to make proteins

Question 6

What elements do nucleic acids contain?

Answer 6

Oxygen, Hydrogen, Nitrogen and Phosphorus

Question 7

How are nucleotides linked together?

Answer 7

The phosphate group at the fifth carbon of the pentose sugar of one nucleotide forms a covalent bond with the hydroxyl group at the 3rd carbon of the pentose sugar of an adjacent nucleotide

Question 8

What type of reaction links nucleotides together?

Answer 8

Condensation reaction

Question 9

What type of bond links nucleotides together?

Answer 9

Phosphodiester bond

Question 10

What does a condensation reaction between nucleotides form?

Answer 10

A polynucleotide connected by phosphodiester bonds, with a long, strong sugar-phosphate backbone.

Question 11

What is the difference between the sugars deoxyribose and ribose?

Answer 11

Deoxyribose has one less oxygen atom than ribose.

Question 12

What are the two groups of nitrogenous bases?

Answer 12

Pyrimidines and Purines

Question 13

What is the difference between a pyrimidine and a purine?

Answer 13

Pyrimidine bases have a single ring, purines have a double ring

Question 14

Which bases are pyrimidines?

Answer 14

T, C and U

Question 15

Which bases are purines?

Answer 15

A and G

Question 16

Which base does Uracil replace?

Answer 16

T

Question 17

Which bases pair with eachother?

Answer 17

A-T, and C-G

Question 18

Where is the U base found?

Answer 18

In RNA

Question 19

What is DNA made up of?

Describe the chains, position, type

Answer 19

Two antiparallel polynucleotide chains (strands)

Question 20

How are the two strands of polynucleotide chains held together?

Answer 20

By hydrogen bonds between the bases.

Question 21

How many hydrogen bonds are there between a C-G?

Answer 21

3

Question 22

How many hydrogen bonds are there between an A-T?

Answer 22

2

Question 23

What do the hydrogen bonds do in DNA?

Answer 23

They hold the bases together, and make the molecule stable.

Question 24

How does the sense strand in DNA run?

Answer 24

From 5’ to 3’ (5 prime to 3 prime, downwards)

Question 25

What does the sense strand contain?

Answer 25

The sequences of bases that codes for the proteins to be synthesised.

Question 26

How does the anti-sense strand run?

Answer 26

From 3' to 5' (3 prime to 5 prime, upwards)

Question 27

What is the anti-sense strand (and what is it a template for)?

Answer 27

A complementary copy of the sense strand. Used as the template for mRNA.

Question 28

What does one mRNA molecule contain?

Answer 28

The transcription of a complementary strand of one gene in DNA (So the same code as a sense strand of one gene of DNA, except T-> U)

Question 29

Why can mRNA molecule only contain a complementary strand of a small amount of DNA?

Answer 29

Because the DNA of each eukaryotic chromosome is very long, and is unable to leave the nucleus for protein synthesis.

Question 30

What are the 2 differences between RNA nucleotides and DNA nucleotides?

Answer 30

-The pentose sugar in RNA is ribose, the pentose sugar in DNA is deoxyribose -The thymine base in DNA is replaced by the Uracil base in RNA

Question 31

What happens to the RNA molecules after protein synthesis?

Answer 31

They are degraded in the cytoplasm. Phosphodiester bonds are hydrolysed, RNA nucleotides are released and re-used.