8.2 - DNA And Chromosomes

Question 1

What are the differences in DNA between prokaryotic and eukaryotic cells

Answer 1

1. Prokaryotic cells have shorter DNA molecules which form a circle, Eukaryotic cells have longer DNA molecules which form a line
2. Prokaryotic cells do not associate with protein molecules, eukaryotic cells associate with proteins called histones to form structures called chromosomes
3. Prokaryotic cells don’t have chromosomes, eukaryotic cells do

Question 2

Chromosomes are only visible when?

Answer 2

The cell is dividing

Question 3

When the chromosomes divide and have two threads what is a single thread called?

Answer 3

Chromatid

Question 4

How id the DNA in chromosomes held?

Answer 4

By histones

Question 5

What shape is DNA

Answer 5

Double helix

Question 6

A chromosome contains just a single molecule of what?

Answer 6

DNA

Question 7

Each gene occupies a specific position along what?

Answer 7

The DNA molecule

Question 8

What is another work for the specific position along the DNA molecule where a gene occupies

Answer 8

Locus

Question 9

How many chromosomes do humans have?

Answer 9

46

Question 10

How many pairs of chromosomes do humans have?

Answer 10

23

Question 11

What are homogenous pairs?

Answer 11

• is always two chromosomes that carry the same genes but not necessarily the same alleles of the genes
• Pairs of chromosomes derived from parents (maternal - mother, paternal - father)

Question 12

What is the total number of homologous pairs called?

Answer 12

Diploid

Question 14

What is a allele?

Answer 14

Is one of a number of alternative forms of a gene

Question 15

Any changes in the base sequence of a gene produces what?

Answer 15

A new allele of that gene

Question 16

A new allele of a gene that is produced is known as what?

Answer 16

A mutation