DNA structure

Question 1

What are nucleic acids?

Answer 1

Contain 5-carbon sugar, a phosphate group, and a nitrogenous base.
DNA (deoxyribose) and RNA (ribonucleic acid)

Question 2

What is the structure of DNA?

Answer 2

•2 polynucleotide strands joined together by hydrogen bonding to from an alpha double helix. Contain:
⇾Deoxyribose
⇾A phosphoric acid molecule
⇾Nitrogenous base
•Nucleotides join together by condensation reaction between pentose and phosphate groups, forming a phosphodiester bond
•Sugar and phosphate groups form backbone
•Organic bases oriented towards centre of helix to prevent reactions with chemicals, joined by hydrogen bonding, stable due to amount

Question 3

What is the sugar backbone for ?

Answer 3

Gives stability

Question 4

Why is DNA coiled?

Answer 4

Gives compact shape

Question 5

What do the hydrogen bonds do?

Answer 5

Gives stability, allows chain to unzip for easy replication

Question 6

What does the sequence of bases do?

Answer 6

Codes for synthesis of specific proteins

Question 7

Why are the bases complementary?

Answer 7

Enables information to be replicated accurately

Question 8

Why is it a double helix?

Answer 8

Strands are templates in replication, protects sequence, makes molecules more stable

Question 9

What are the functions of DNA?

Answer 9

-Genes are sections of DNA, which code for polypeptides
It can self replicate, which is essential for cell division
Provides genetic variation via natural selection- the basis of evolution- if mutations occur

Question 10

What are genes?

Answer 10

Sections of DNA, code for polypeptides that determine the nature and development of organisms