Chromosome structure and function

Question 1

How many pairs of chromosomes in humans?

Answer 1

23 pairs of chromosomes (22 autosomal/1 sex)

Question 2

How many pairs of chromosomes in haploid cells?

Answer 2

1

Question 3

How many pairs of chromosomes in diploid cells?

Answer 3

2

Question 4

Function of Centromeres?

Answer 4

• Megabases of repetitive DNA
• Alpha satellite DNA
• Locks Sister chromatids together
• Atatchment site for chromosomes to mitotic spindle via kinetochore

Question 5

Function of Telomeres?

Answer 5

• Tandem repeat
• TTAGGG
• End of telomere lost at each replication

Question 6

What is Hayflick limit?

Answer 6

Number of times a cell can divide before it dies

Question 7

What is telomerase?

Answer 7

RNA dependent DNA polymerase which adds telomeric DNA to telomeres

Question 8

Origin of replication

Answer 8

(multiple origins of replication fire because eukaryotic chromosomes are large/replication is slow)

Question 9

Explain how the DNA in a human cell is folded and packed into the nucleus.

Answer 9

• DNA wraps around histone octamer
• Forms a nucleosome
• Multiple octamers form nucleosome array
• Assembled into chromatin
• condensation
• chromosome