Nucleic acids 1-2 Flashcards

1
Q

What is a nucleotide?

A

A sugar, phosphate and base bonded together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What kind of bond holds the nucleotides together?

A

Phosphodiester

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What kind of bond is between the base and the sugar?

A

Covalent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What kind of bond is between the two DNA strands?

A

Hydrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many hydrogen bonds between cytosine and guanine?

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How many hydrogen bonds between adenine and thymine?

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why do the sugar and phosphate head point outwards?

A

Because they are negatively charged.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How large is the human genome?

A

6x10^9 base pairs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a karyotype?

A

Organised profile of an individual’s chromosomes, including 22 pairs of autosomes and 1 pair of sex chromosomes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is chromatin?

A

A tightly packed complex of DNA, RNA and protein found in eukaryotes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are nucleosomes?

A

Protein complexes (histone) that are used to condense DNA into chromosomes so that it is able to fit into the nucleus. Provides a 7-fold condensation of DNA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How many histone proteins is a nucleosome made up of?

A

8 ( 2 each of the following: 2A, 2B, 3 and 4)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do histone proteins interact with DNA?

A

Histone proteins are positively charged so interact with the negatively charged sugar-phosphate backbone.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What connects each nucleosome to one another?

A

Histone 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is DNA replication semi-conservative?

A

The daughter cell inherits half of one DNA strand from the parent (template) and a newly synthesised one that is complementary to the template strand.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does DNA helicase work?

A

Unwinds the double helix by breaking the hydrogen bonds holding them together. Energy is taken from the hydrolysis of ATP to ADP.

17
Q

What does the sliding clamp do?

A

Surrounds DNA polymerase to make sure it does not fall off the strand.

18
Q

What are RNA primers?

A

Direct DNA polymerase to where replication is needed. Transient so removed before replication is completed by exonuclease activity.

19
Q

What is proof-reading?

A

A mechanism that reduces the mutation rate during replication of DNA. Before the next nucleotide, the previous nucleotide is checked for correct base pairing. If it is incorrect it is removed and replaced.

20
Q

What is the mutation rate among human DNA replication?

A

1 every 109 base pairs

21
Q

What occurs during prophase?

A

Supercoiling of chromosomes so that they are visible under a microscope.

22
Q

What occurs during metaphase?

A

The condensed chromosomes align along the equator of the nucleus, drawn in by spindle fibres attached to the centromeres of the chromosomes.

23
Q

What occurs during anaphase?

A

Microtubule spindle fibres separate homologous chromosomes in two (forming chromatids) and draw them to opposite poles of the nucleus.

24
Q

What occurs during telophase?

A

Sister chromatids (now chromosomes once again) reach the poles and the nuclear membrane reforms around them.

25
Q

What happens in cytokinesis?

A

Separation into two daughter cells.

26
Q

What happens in G1 phase?

A

DNA is prepared to be replicated and cell growth occurs. (10 hours)

27
Q

What happens in S phase?

A

DNA replication (9 hours)

28
Q

What happens in G2 phase?

A

Checking of DNA replication (4 hours)

29
Q

What is Watson-Crick base pairing?

A

The theory that a purine base must bind with a pyrimidine base but that each purine base binds to a specific pyrimidine base.

30
Q

How many rings does a purine base have?

A

2

31
Q

How many rings does a pyrimidine base have?

A

1

32
Q

Which bases are purine bases?

A

Adenine and guanine

33
Q

Which bases are pyrimidine bases?

A

Cytosine, thymine and uracil

34
Q

What genetic material is present in prokaryotes.

A

Circular ‘chromosome’ called a genophore present in the nucleoid. Plasmids are also present.