Lecture 14

Question 1

Total amount of DNA in a human cell

Answer 1

6.4x10^9 base pairs
(cuz human cell is diploid)

Question 2

Total amount of DNA in human genome

Answer 2

3.2x10^9

Question 3

How many autosomes do we have?

Answer 3

22

Question 4

What DNA types are included in the human genome?

Answer 4

22 +X +Y +mitochondrial

Question 5

Total length of human DNA?

Answer 5

2.176m

Question 6

Length of nucleus in a typical eukaryotic cell

Answer 6

6 to 7micrometers

Question 7

What stage of mitosis does DNA Replication occur?

Answer 7

Interphase

Question 8

Steps of mitosis?

Answer 8

Interphase, M phase, interphase

Question 9

What happens at interphase?

Answer 9

chromosome loosened, gene expression and DNA replication occurs

Question 10

3 parts of chromosome needed for replication and
separation of chromosomes
during cell division

Answer 10

Origin of Replication
* Telomeres (telomere=TIPS)
* Centromeres (center of chromosome)

Question 11

How many genes in 10% of a chromosome arm?

Answer 11

40 genes

Question 12

How many nucleiotide pairs in a gene?

Answer 12

3.4x10^4 nucleiotide pairs

Question 13

What is a mitotic chromosome?
Hint: what stage does it happen?

Answer 13

When mitotic spindle is attached to centromere.

(think mitotic spindle coming to snatch duplicated parts way from each other). During M phase

Question 14

Height of a histone?

Answer 14

11nm

Question 15

How many times does DNA wrap around histone?

Answer 15

1.7 times

Question 16

How many base pairs of DNA on histone core?

Answer 16

147bp

Question 17

What is a nucleosome?

Answer 17

Histone with DNA wrapped around

Question 18

Width of Beads on a string structure of a histone?

Answer 18

11nm

Question 19

Parts of octameric histone core?

Answer 19

H2A, H2B, H3, H4

Question 20

Width of chromatin fibre?

Answer 20

30nm

Question 21

What are the tails on the histone made of?

Answer 21

Proteins (amino acid chains)

Question 22

What does the N terminal in the histone tail allow it to do?

Answer 22

These tails bind to other nucleosomes as well as non-histone proteins

Question 23

Chromatin fibre vs chromatin fibre loops?

Answer 23

Fibre= many nucleoosomes packed together
fibre loops= chromatin fibres folded into loops

Question 24

Size of chromatin fibre loops

Answer 24

700nm

Question 25

size of chromatin fibre

Answer 25

30nm

Question 26

How does the tightness of the loop structure relate to whether its transcribed or not?

Answer 26

Tightly-packed chromosome – RNA polymerases etc. can NOT access easily
Loosely-packed chromosome – RNA polymerases etc. have easy access