BIOLOGY CH 5 Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

The place where helicase begins to unwind is a specific sequence of nucleotides on the chromosome called the __________ .

A

Origin of replication (ORI)

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

A chromosome would get tangled and eventually break, except that enzymes called ___________ cut one or both strands and unwrap the helix, releasing the excess tension created by the helicases.

A

Topoisomerase

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

An ______ primer must be synthesized for each template strand because DNA polymerase cannot start a new DNA chain from scratch.

A

RNA

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

RNA primer is synthesized by a set of proteins called the ____________, of which the central component is an ____________ called ____________.

A

RNA primer is synthesized by a set of proteins called the primase, of which the central component is an RNA polymerase called primase.

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

DNA polymerase reads the template strand in which direction?

A

From 3’ to 5’

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

DNA polymerase elongates a daughter strand by adding dNTPs to its _____ end.

A

3’

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

DNA pol is part of a large complex of proteins called the ________________ .

A

Replisome

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

The prokaryotic replisome contains __ components and the eukaryotic replisome contains __ components. Additional complexity in the eukaryotic system is required because replication machinery must also ___________ .

A

13 components prokaryotes; 27 components eukaryotes; unwind DNA from histone proteins

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

T/F: DNA pol checks each new nucleotide to make sure it forms a correct base-pair

A

True

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

The driving force for the polymerization reaction of DNA synthesis is?

A

The removal and hydrolysis of pyrophosphate (P2O7) from each new dNTP added to the chain

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

Eventually all RNA primers are replaced by DNA, and the fragments are joined by an enzyme called ____________ .

A

DNA ligase

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

T/F: Eukaryotes have several different DNA polymerase enzymes?

A

True

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

T/F: In eukaryotic replication, each chromosome has one ORI?

A

False, each chromosome has several

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

T/F: In prokaryotic replication, the one chromosome only has one origin?

A

True

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

_____________ are disposable repeats at the end of chromosomes. They are consumed and shorten during cell division.

A

Telomeres

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

When ________ becomes too short, they reach a critical length where the chromosome can no longer replicate.

A

Telomeres

17
Q

What is the Hayflick limit?

A

The number of times a normal human cell type can divide until telomere length stops cell division

18
Q

__________ is an enzyme that adds repetitive nucleotide sequences to the ends of chromsomes and therefore lengthens _________ .

A

Telomerase; telomeres

19
Q

______________ can express telomerase, which can help the cells immortalize.

A

Cancer cells

20
Q

What does it mean when a cell enters a ‘senescent state?’

A

Where they are alive but not dividing

21
Q

What are 3 things a cell can do when their telomeres become too short?

A
  1. Active DNA repair pathways
  2. Enter a senescent state
  3. Apoptosis
22
Q

What are germline mutations?

A

Mutations that can be passed onto offspring, since they occur in the germ cells (which give rise to gametes).

23
Q

What do germ cells give rise to?

A

Gametes

24
Q

T/F: Somatic mutations cannot pass onto offspring?

A

True

25
Q

What is a mutagen?

A

Any compound that can cause mutations

26
Q

Name things that chemical can do to DNA structure

A
  1. covalently alter bases
  2. cross-linking
  3. strand breaks
27
Q

What does intercalating mean?

A

When compounds that look like purines and pyrimidines cause mutations by inserting themselves between base pairs

28
Q

What is a transition point mutation?

A

Purine for another purine/Pyrimidine for another pyrimidine

29
Q

What is a transversion point mutation?

A

Purine for a pyrimidine and vice-versa

30
Q

Define missense mutation.

A

A point mutation that results in one amino acid being replaced with a different amino acid

31
Q

Define nonsense mutation.

A

A stop codon replaces a regular codon and prematurely shortens the protein

32
Q

Define silent mutation.

A

A codon is changed into a new codon for the same amino acid, so there is no change in the protein’s amino acid sequence

33
Q

An ________ is when a segment of chromosome is reversed end to end.

A

Inversion

34
Q

What is chromosome amplification?

A

When a segment of a chromsome is duplicated, similar ot copy number variation

35
Q

What is translocation?

A

When recombination occurs between nonhomologous chromosomes. This can create a gene fusion, where a new gene product is made from parts of two genes that were not previously connected.

36
Q

When ________ are mobilized, they can insert in any part of the genome and this can affect gene expression or cause mutations.

A

Transposons

37
Q

What is hemizygous?

A

When there is only one gene copy (allele) in a diploid organism.

38
Q

Oncogene defined.

A

A gene that can cause cancer when it is mutated or expressed at high levels