Nucleic Acids and Chromosomes

Question 1

Which bases are purines?

Answer 1

A and G

Question 2

Which bases are pyrimidines?

Answer 2

C, T and U

Question 3

Are purines or pyrimidines bigger?

Answer 3

purines

Question 4

In deoxyribose and ribose, which C is 1’C and 5’C?

Answer 4

1’C = attached to base, 5’C = attached to phosphate

Question 5

What is a nucleoside?

Answer 5

base + sugar

Question 6

What is a nucleotide?

Answer 6

base + sugar + phosphate

Question 7

How many hydrogen bonds between bases?

Answer 7

A - T = 2 H bonds

G - C = 3 H bonds

Question 8

Methods for denaturing

Answer 8

high heat/low salt

Question 9

Methods for re-annealing

Answer 9

low heat/high salt

Question 10

When are chromosome visible?

Answer 10

during mitosis

Question 11

Define karyotype

Answer 11

organised profile of an organism’s chromosome

Question 12

How is eukaryotic DNA packaged?

Answer 12

tightly, complex with histones called chromatin, more condense in mitosis

Question 13

Define nucleosome

Answer 13

DNA wrapped around a core of histones

Question 14

Define histone

Answer 14

positively charged proteins that interact with negatively charged sugar-phosphate backbone

Question 15

What is a nucleosome structure made up of?

Answer 15

8 histones, 150 base pairs wrapped around histone octomer (core DNA), linker DNA between core DNA, histone 1 between nucleosomes