DNA and chromosome basics Flashcards Preview

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Flashcards in DNA and chromosome basics Deck (36):
1

diameter of DNA

2nm

2

whats on the outside of dna structure

phosphate- -ve charge which attracts polar water

3

double helix is supported by..

a sugar phosphate back bone which increases the stability of the molecule

4

the two strands run..

parallel but opposite to each other--> due to 5 prime and 3 prime strand

5

why do strands run opposite to each other

due to 5 prime and 3 prime strands

6

intermolecular forces between strands

H bonds- individually weak but together very strong

7

DNA is a ..... handed double helix

DNA is a RIGHT handed double helix

8

A + T

2 bonds

9

C+G

3 bonds

10

the DNA right handed double helix is made up of..

minor and major grooves

11

how is DNA faithfully replicated

Semi-conservative replication- otherwise mutations would be very common and this would lead to many disorders and cancers

12

total DNA in the nucleus

the GENOME - organelles like mitochondria and chloroplasts have their own genomes (circular- majority still found in nucleus

13

which organelles have their own genomes

mitochondria and chloroplasts - circular

14

nucleotides are mad cup of..

sugar (deoxyribose); base; phosphate

15

nucleoside=

sugar and base

16

what gives rise to minor and major grooves

the fact that A+T and C+G have diff number of hydrogen bonds

17

Deoxyribose and adenine

deoxy adenosine

18

Deoxyribose and guanine

deoxy guanosine

19

deoxyribose and cytosine

deoxy cytidine

20

deoxyribose and thymine

deoxy thymidine

21

what does right handed double helix mean

the strand that appear on the top of the molecule will run from right to left

22

how is 5 prime strand different to the 3 prime strand

5 prime is able to connect with a further phosphate group whereas 3 prime is unable to do so

23

enzyme work along DNA from the..

5' to 3'

24

new strand of DNA is formed from the

3' to 5'

25

minor groove

oxygen in deoxyribose points downwards

26

major groove

oxgen in deoxyribose points upwards

27

every human has around

2m worth of DNA- each nucleus has around 10 micrometers diameter

28

what is DNA wrapped around and how many times

DNA wraps twice around 8 core histone proteins to form nucleosomes

29

why will DNA wrap twice around 8 core histones

DNA is negatively charged due to phosphate group and the histones are positively charged

30

nucleosome

a structural unit of a eukaryotic chromosome, consisting of a length of DNA coiled around a core of histones.

31

what does histone H1 do?

brings the nucleosomes together to form chromatin fibres

32

what forms a chromatin fibre

when histone H1 brings nucleosomes together

33

what further condenses chromatin

scaffold proteins

34

net result of DNA folding

each DNA molecule has been packaged into a mitotic chromosome that is 10,000 fold shorter than its fully extended length

35

interphase chromosomes are organised in the..

nucleus

36

chromosome territories

chromosomes organise themselves into discrete patches- located near the chromosomes territory boundary