DNA

Question 1

DNA structure

Answer 1

Deoxyribose Sugar, phosphate groups, nitrogenous bases

Question 2

Purines:

Answer 2

Adenine Guanine

Question 3

Pyramidines:

Answer 3

Thymine Cytosine

Question 4

– backbone
- found in the outer structure of the helix.

Answer 4

Sugar and phosphate groups

Question 5

positioned side by side n the inside of the double helix.

Answer 5

Nitrogenous bases

Question 6

breakage of hydrogen bonds mediated by DNA Helicase and single stranded binding protein (SSB)
Result: Y shaped structure aka REPLICATION FORK

Answer 6

Initiation

Question 7

primase generates an RNA primer which initiates replication by binding the DNA Polymerase takes place in both strands but nucleotide can only be added to the 3’ end of an existing strand (leading strand)
- separated strands of DNA serve as templates for production of complementary strand whereas 5’ (lagging strand) is copied by the formation of Okazaki fragments (small fragments of DNA)

Answer 7

Replication

Question 8

the 3’ end which consists of non- coding DNA (telomere) is cut off. Enzymes proof-read the sequence (correct pairing) and enzymes called nuclease remove incorrect DNA.

Answer 8

Termination

Question 9

The nitrogenous bases of DNA are not present in equal proportions and that the proportions of these bases vary from one species to another.

Answer 9

Chargaff’s Rule

Question 10

consist of a single continuous molecule of DNA complexed with histones and non-histone proteins.

Answer 10

Chromatin

Question 11

DNA In a single cell if stretched out would be approximately

Answer 11

2m in length

Question 12

spindle apparatus are responsible for the movement of the two sister chromatids to opposite poles of dividing cell during anaphase.

Answer 12

Kinetochores