Chromosome function & genomics (L11)

Question 1

What is the distance in Angstroms and the number of nucleotides that DNA will repeat itself each time?

Answer 1

34 Angstroms,

~10 nucleotides

Question 2

What is a nucleoside?

Answer 2

Base w/ sugar (no phosphates)

Question 3

Give the names of the pyrimidine and purine bases and their respective nucleoside names

Answer 3

Base name, nucleoside name

Pyrimidines:

Cytosine, Cytidine

Uracil, Uridine

Thymine, Thymidine

Purines:

Adenine, Adenosine

Guanine, Guanosine

Question 4

A pairs w/ __

G pairs w/ __

How many H bonds in each?

Answer 4

A-T (2 H bonds)

G-C (3 H bonds)

Question 5

What does annealing DNA mean? What is a synonymn and 2 antonyms?

Answer 5

The act of 2 DNA strands coming together; AKA hybridization;

Melting/Denaturation

Question 6

Does single or double strand DNA absorb more light?

What is the hyperchromatic shift?

Answer 6

Single stranded DNA;

The absorbance of DNA solution at 260nm increases when double helix is melted into 2 strands.

Question 7

What is the effect of alkali on DNA and RNA?

Why are the effects different?

Answer 7

DNA strands stay intact, but separate;

RNA strands are degraded to nucleotides b/c of the 2’ OH group.

This can be used to eliminate RNA from nucleic acid preparations.

Question 8

What is a nucelosome composed of?

Answer 8

H2A, H2B, H3, H4 (140bp around this core)

60bp spacer b/w nucleosomes, and H1 associates w/ this space

Question 9

How many autosomal chromosomes and sex chromosomes are in a haploid and diploid cell?

Answer 9

Haploid: contains chromosomes 1-22 and X or Y

Diploid: contains 2 copies of chromosomes 1-22 and XX or XY