Chapter 16-molecukar Basis Of Inheritance

Question 1

What are Chargaff’s rules

Answer 1

1. The base composition of DNA varies between species
2. For each species, the percentage of A and T bases are roughly equal and the percentage of G and C bases are roughly equal

Question 2

Transformation

Answer 2

Change in geneotyoe due to assimilation of foreign DNA

Question 3

Mismatch repair

Answer 3

When enzymes remove and replace incorrectly paired nucleotides that have resulted from replication errors

Question 4

What is nucleotide excision repair?

Answer 4

A damaged strand will be excised by nuclease(DNA CUTTING ENZYME); new nucleotides will be filled in the gap using the I damaged strand as a template. DNA polymerase and DNA ligaments are involved

Question 5

What are telomeres

Answer 5

Special nucleotide sequences on the ends of DNA molecules that do not contain genes but rather multiple repetitions of a short nucleotide sequence.

Question 6

What are the functions of telomeres?

Answer 6

1. Specific proteins associated with telomeric DNA prevent the staggered ends of the daughter molecule being detected as DNA damage
2. Acts as a sort of buffer zone that protects the organisms genes shortening

Question 7

Telomerase

Answer 7

Catalyses the lengthening of telomeres in eukaryotic germ cells, thus restoring their original length and compensating for the shortening that occurs during DNA replication. The activity of this enzyme results in telomeres of maximum length in the zygote