Understanding the structure of DNA

Question 1

What is DNA?

Answer 1

Deoxyribonucleic acid (DNA) is the molecule that carries genetic information for the development and functioning of an organism

Question 2

Where is DNA found?

Answer 2

Found in all prokaryotic and eukaryotic cells. In eukaryotic cells, the DNA is in the nucleus.

Question 3

What is the shape of DNA?

Answer 3

Double helix

Question 4

What are the sides of the DNA chains made of?

Answer 4

The sides of the ladder are made of chains of alternating sugar and phosphate units

Question 5

What are the steps of the ladder made of?

Answer 5

Nitrogenous bases

Question 6

What is DNA made of?

Answer 6

Nucleotides:
- 5 carbon sugar- deoxyribose sugar
- phosphate group
- one of four nitrogenous bases

Question 7

What are the 4 main nitrogenous bases?

Answer 7

Adenine, thymine, guanine, cytosine

Question 8

What nitrogenous base pairs with what?

Answer 8

Adenine& thymine
Guanine& cytosine

AT
GC

Question 9

What is the process of DNA replication?

Answer 9

1) DNA untwists
2) DNA polymerase attaches to DNA
3) DNA polymerase brings together nucleotides to form a new strand
4) After the chromosome is copied, polymerase falls off and two sets of chromosomes exist in the cell
5) The two DNA helixes re-twists
6) The cell divides again

Question 10

What is the function of enzymes in DNA?
- helicase
- primase
- polymerase

Answer 10

Helicase: unzips DNA
Primase: places primers
Polymerase: builds new strands

Question 11

Why is DNA considered semi-conservative?

Answer 11

Each new strand is part of the old strand, so it is not entirely new material