MCBG - Intro To DNA Flashcards Preview

CJ: UoL Medicine Semester One (ESA1) > MCBG - Intro To DNA > Flashcards

Flashcards in MCBG - Intro To DNA Deck (16)
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1
Q

What is the width of a strand of DNA?

A

2 nanometres

2
Q

What are the circular cores of nucleosomes called?

A

Histones

3
Q

What is the name given to tightly ravelled nucleosomes?

A

Solenoids

4
Q

What do genes carry?

A

The code for proteins. They have a chromosomal location.

5
Q

How many chromosomes does a human have?

A

22 pairs plus two sex chromosomes, XX or XY

6
Q

What is the difference between a nucleotide and a nucleoside?

A

Base + sugar + phosphate = nucleotide

Base + sugar = nucleoside

7
Q

What are polynucleotides?

A

Linear polymers of nucleotides

8
Q

What is the difference between the sugar on DNA and RNA?

A

On DNA is termed “deoxyribose” and has H on 2’ carbon. On RNA has OH group and is termed “ribose”.

9
Q

What is the difference between a purine and a pyrimidine?

A

Purines have two rings, pyrimidines have one ring.

10
Q

Which bases are purines?

A

Adenine and guanine

11
Q

Which bases are pyrimidines?

A

Cytosine, uracil, thymine.

12
Q

Which pair of bases has three hydrogen bonds rather than the usual two?

A

G-C

13
Q

What catalyses DNA replication?

A

DNA polymerase

14
Q

In which direction does DNA replication occur?

A

5’ to 3’

15
Q

What are Okazaki fragments?

A

Short sections of replicated DNA that form in the 5’ to 3’ direction on the lagging (top) strand during DNA replication.

16
Q

What is used to join Okazaki fragments?

A

DNA ligase

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