Session 2 - Lecture 2

Question 1

2 - Some Notes

Answer 1

• Replication (and transcription and translation) is very quick
• DNA polymerase acts at about 100 NTs per second
• S phase of cell cycle = synthesis (DNA replication)
• M phase = mitosis or meiosis

Question 2

3 - Chromosome structure

Answer 2

When chromosomes are replicated they become one chromosome with two sister chromatids (See Review Lecture)

Chromosomes visible in cell division (classical X shape) have been replicated – contains two identical DNA molecules

P arm is small (petite), Q arm is long (arbitrary nomenclature by scientists, P and Q can also be the same length)

Centromere in middle of 2 arms, telomere ends of 2 arms

Each sister chromatid is an identical DNA molecule to each other, each one having a p arm, q arm, telomeres either end and a single centromere joining the 4 arms.

Question 3

4 - Telomere

Answer 3

In eukaryotes, telomeres are repeated sequences (TTAGGG) at each end of chromosome (single)/chromatid (replicated) - telomere repeats

Question 4

5 - Centromeres

Answer 4

Centromere is a complex of proteins

Centromeres binds to specific regions within the chromosome, or of the DNA molecule – often repetitive sequences

Humans have meta-, submeta- and acrocentric chromosomes

Question 5

6 - chromosomes and centromeres

Answer 5

Can be represented in either format
RHS – make more simple so shows only one line rather than X shape
However – remember, if the chromosome is visible then it most likely has been replicated

Question 6

7

Answer 6

7

Question 7

8

Answer 7

8

Question 8

9

Answer 8

9

Question 9

10

Answer 9

10

Question 10

11

Answer 10

11

Question 11

12

Answer 11

12

Question 12

13

Answer 12

13

Question 13

14

Answer 13

14

Question 14

15

Answer 14

15

Question 15

16

Answer 15

16

Question 16

17

Answer 16

17

Question 17

18

Answer 17

18

Question 18

19

Answer 18

19

Question 19

20

Answer 19

20

Question 20

21

Answer 20

21

Question 21

22

Answer 21

22

Question 22

23

Answer 22

23

Question 23

24

Answer 23

24

Question 24

25

Answer 24

25

Question 25

26

Answer 25

26

Question 26

27

Answer 26

27

Question 27

28

Answer 27

28

Question 28

29

Answer 28

29

Question 29

30

Answer 29

30

Question 30

31

Answer 30

31

Question 31

32

Answer 31

32

Question 32

33

Answer 32

33

Question 33

34

Answer 33

34

Question 34

35

Answer 34

35

Question 35

36

Answer 35

36

Question 36

37

Answer 36

37

Question 37

38

Answer 37

38

Question 38

39

Answer 38

39

Question 39

40

Answer 39

40

Question 40

41

Answer 40

41

Question 41

42

Answer 41

42

Question 42

43

Answer 42

43

Question 43

44

Answer 43

44