FMBG MNTS Lectures 1-2

Question 0

Which is more stable? DNA or RNA helix?

Answer 0

RNA

Question 1

There are ____ base pairs per turn of the DNA helix.
The __ form of DNA is a right handed double helix with 11 base pairs per turn. It is found uncommonly in DNA.
The __ form is the most common form of DNA in humans, and is a right handed double helix with 10.5 base pairs per turn. The ___ form is the most uncommon form of DNA, and is a left handed helix with ___ base pairs per turn.

Answer 1

10.5
A
B
Z
12

Question 2

Which is a higher-energy bond? (A higher proportion of these bonds will increase melting point)
A-T
C-G

Answer 2

C-G (3 H bonds)

Question 3

The composition of our DNA is as follows:

Answer 3

43% transposons
25% misc
30% genes
1.5% exons

Question 4

Biggest difference between eukaryotic and prokaryotic chromosome replication?

Answer 4

eukaryotes have multiple origins of replication

Question 5

The centromere is the ____

Answer 5

center region of chromatid where spindle attaches and sister chromatid separation occurs

Question 6

___ are long repeats of hexameric sequences that are encoded in RNA, found at the ends of DNA

At the end of each cell division, these become ____

Answer 6

telomeres

shortened

Question 7

The linking number is ____

Answer 7

the number of times one strand crosses the other (talking about supercoils)

Question 8

Increasing the linking number by ____ winding gives a ___-handed supercoil (____)

Answer 8

overwinding
right
plectonemic

Question 9

Decreasing the linking number by ___ winding results in a ___ handed supercoil (____)

Answer 9

underwinding
left
solenoidal

Question 10

A type 1 topoisomerase breaks ___ strand(s) and changes Lk by ___
A type 2 topoisomerase breaks ___ strand(s) and changes Lk by ____

Answer 10

1
1

2
2

Question 11

the colloidal structure of DNA is called the ___, which is tightly wrapped in a ___ handed supercoil

state the organization of DNA beyond this level

Answer 11

nucelosome

left-handed (solenoidal)

nucleosomes; 30nm fiber; loops; rosettes; coils ; chromatids ; chromosomes

Question 12

The DNA double helix is wrapped around the ____ core ___(number of times)

There are ___ bp per loop, as well as a ____ bp linker region in between cores, allowing for __-fold compaction

Answer 12

histone
twice

75
50

seven-fold compaction