Exam 1 Flashcards

(80 cards)

1
Q

Prokaryotic cells divide by…

A

Binary Fission

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2
Q

Prokaryotic cells contain…

A

One circular chromosome

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3
Q

Cell division requires what 3 things?

A

Replication, segregation, and division of cytoplasm

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4
Q

Cell division is important for…

A

Reproduction, growth, wound healing, and replacing cells that die or are lost

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5
Q

How are bacterial chromosomes compacted?

A

DNA is compacted around SMC proteins to form loop domains

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6
Q

How are bacterial cells partitioned?

A

FtsZ proteins from a septum; septation

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7
Q

What genes regulate FtsZ proteins?

A

Kai A, B, C

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8
Q

During cell division in eukaryotes, what proteins are associated with the sister chromatids?

A

Kinetochore and cohesion proteins

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9
Q

What does a cohesion protein do?

A

Hold the sister chromatids together after DNA replication

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10
Q

What does a kinetochore protein do?

A

They are where microtubules attach during cell division

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11
Q

What is a centromere?

A

An area of repetitive DNA sequences; visible constriction on the chromosome

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12
Q

What is a telomere?

A

Repetitive sequences of DNA that protect the ends of chromosomes

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13
Q

What is associated with the shortening of telomeres?

A

Aging and disease

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14
Q

What enzyme maintains telomeres?

A

Telomerase

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15
Q

What charge does DNA have?

A

Negative

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16
Q

What charge do histone proteins have?

A

Positive

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17
Q

What do DNA and histone proteins come together to form?

A

Nucleosome

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18
Q

A nucleosome contains…

A

146 bp of DNA and 8 histone proteins

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19
Q

What do nucleosomes form?

A

Selenoids

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20
Q

When a cell is not actively dividing, DNA has a…

A

Lower level of compaction; the chromosomes are not visible under a microscope

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21
Q

When a cell is actively dividing, DNA is…

A

So compact it is visible under a microscope

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22
Q

What are the 5 main phases of the cell cycle?

A

G1, S, G2, M, and Cytokinesis

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23
Q

What is interphase?

A

G1, S, and G2 phases when the cell is metabolically active between nuclear divisions

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24
Q

The cell cycle is …. between …..

A

an oscillation

interphase, mitosis, and cytokinesis

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25
Mitosis is when...
DNA is segregated
26
Cytokinesis is when...
Cytoplasm is divided
27
What phase is a non-dividing state?
G0
28
What protein controls the cell cycle?
Cyclins
29
What is a kinase?
A protein enzyme that phosphorylates other molecules
30
What is a phosphatase?
An enzyme that dephosphorylates other molecules
31
What does CDK stand for?
Cyclin Dependent Kinase
32
What is a CDK?
A kinase that is inactive unless they are joined with a cyclin protein
33
What do activated CDK's do?
Phosphorylate other proteins that are necessary to advance the cell cylce
34
How are different phases of the cell cycle regulated?
By different cyclin/CDK complexes
35
What do cell cycle checkpoints do?
Halt the progression of the cell cycle if something is wrong
36
When is the first cell cycle checkpoint?
The start, whether or not to commit to divide at all
37
When is the second cell cycle checkpoint?
G2/M transition, commit to proceed to mitosis
38
When is the third cell cycle checkpoint?
The spindle checkpoint, commit to proceed into anaphase
39
The first 2 cell cycle checkpoints are regulated by what?
Cyclins/ CDKs
40
The third cell checkpoint is regulated by what?
APC (anaphase promoting complex)
41
What happens if a cell fails a checkpoint?
Cell division is halted for repairs or induced cell death
42
How does cancer arise from cell cycle regulation?
Cells divide when they shouldn't or cells don't die when they should because genes that control the cell cycle are the most frequently mutated
43
What holds the sides of the helix in DNA?
Covalent (phosphodiester) bonds
44
What holds the middle of the helix together in DNA?
Hydrogen bonds
45
What is the structure of a nucleotide?
5-carbon sugar (ribose or deoxyribose), phosphate group, nitrogenous base (A,T,C,G), and free hydroxyl group
46
Where is the phosphate group attached in DNA?
The 5' end of the sugar
47
Where is the hydroxyl group attached in DNA?
The 3' end of the sugar
48
How many hydrogen bonds are in the T/A pairing?
2
49
How many hydrogen bonds are in the C/G pairing?
3
50
Which direction is DNA synthesized in?
5' to 3'
51
What are the 3 phases of DNA replication?
Initiation, elongation, and termination
52
What are the DNA sequences where replication begins?
Origins of Replication
53
How does DNA replication proceed?
Bidirectionally
54
What is helicase?
An enzyme that separates the DNA strands
55
What strand of DNA is replicated continously as the replication fork opens?
Leading strand
56
What strand is replicated in discontinous fragments away from the replication fork?
Lagging strand
57
What enzyme adds the new DNA bases?
DNA polymerase III
58
What enzyme provides an RNA 'primer sequence'?
Primase
59
DNA Polymerase III needs what to begin elongation?
DNA primase and a free 3'-OH from the RNA added by primase
60
What are the lagging strand fragments called?
Okazaki fragments
61
What enzyme replaces the RNA nucleotides in both DNA strands?
DNA Polymerase I
62
What protein helps DNA polymerases stay attached to the DNA strand?
Sliding clamp protein
63
What happens when there is a mistake in DNA replication?
DNA polymerase can back up and fix mistakes
64
What enzyme detects and repairs mismatches and DNA damage?
Excision repair enzyme
65
What are the phases of mitosis?
S, prophase, metaphase, anaphase, and telophase
66
What happens during prophase?
Chromosomes condense, nuclear membrane breaks down, two spindle poles (centrosomes) form and migrate to opposite ends of the cell, and microtubules grow from the spindle poles
67
What does DNA polymerase I leave behind?
"nicks" in the phosphate backbone
68
What enzyme repairs nicks in the phosphate backbone?
Ligase
69
What happens during metaphase?
Kinetochore microtubules grow from the spindle poles and attach to the centromeres and the chromosomes get moved to the metaphase plate
70
What are microtubules made of?
Tubulin protein
71
Where do microtubules grow and shrink from?
The positive end
72
What is polymerization?
The addition of tubulin proteins
73
What is depolymerization?
The removal of tubulin proteins
74
What happens during anaphase?
Chromosomes are aligned at the metaphase plate, APC is activated, APC dissolves the cohesion proteins, chromatids separate, chromosomes are pulled to opposite poles
75
What happens during telophase?
Spindle apparatus disassembles, nuclear envelope forms and each set of chromosomes, and chromosomes begin to decondense
76
What type of microtubules extend from spindle pole to spindle pole?
Polar
77
What type of microtubules connect spindles poles to cell membrane?
Aster
78
What type of microtubules connect the chromosomes to the spindle poles and segregate DNA
Kinetochore
79
What is movement A of anaphase?
Chromosomes move to poles
80
What is movement B of anaphase?
Poles move apart