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Nucleic Acid and Gene Expression > Nucleic Acids and Chromosomes > Flashcards

Flashcards in Nucleic Acids and Chromosomes Deck (23):
1

What is a nucleoside?

Sugar and base with no phosphate

2

What are names of the natural nucleosides?

Adenosine, guanosine, cytidine, uridine, thymidine

3

Which are the purines?

Adenine and guanine

4

Which are the pyrimidines?

Cytosine, thymine and uracil

5

Whats the difference between a pyrimidine and purine?

1 ring in a pyrimidine vs 2 rings in a purine

6

Which prime carbon attaches to the base?

1

7

Which prime carbon attaches to the phosphate?

5

8

What is the bind formed between the phosphate and hydroxyl group?

Phosphodiester

9

How are sugars and phosphates linked in nucleotides (not bond wise)?

The 3’-OH of sugar of one nucleotide is linked to phosphate group, which in turn is joined to 5’-OH of adjacent sugar

10

The first nucleotide in a sequence has a free....

..5' phosphate

11

The last nucleotide in a sequence has a free...

....3' hydroxyl group

12

How are DNA sequences read directionally?

5' to 3'

13

Which grooves are the major interactions with DNA madE?

Major

14

How many bp per helical turn?

10

15

How wide is DNA?

2nm

16

What conditions melt/denature DNA?

Low salt/high heat

17

What conditions anneal/hybridise DNA?

High salt/low heat

18

What is a karyotype?

Organised profile of someone's chromosomes

19

What is DNA wrapped around? What does this form?

Proteins known as histones, forms chromatin.

20

What is the lowest level of DNA packaging called?

The nucleosome

21

How many bp per nucleosome?

200

22

Why do histones interact well with DNA?

Histones are positive and the negative phosphate backbone gives an attraction between the two

23

What're the 5 levels of nuclear packaging?

DNA, chromatin, 30nm chromatin fibre, fibre folded into loops, chromosomes