Mitosis Flashcards

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1
Q

List the 3 reasons why cells can’t get too large

A
  1. Diffusion
  2. DNA
  3. Surface area-to-volume ratio
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2
Q

Why is diffusion a factor of cell size?

A

If organelles are too far from the cell membrane, they would have to wait a long time to get molecules that are diffusing through

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3
Q

Why is DNA a factor of cell size?

A

The nucleus cannot provide DNA fast enough to act as the blue print for the high amounts of proteins and enzymes that a large cell would need

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4
Q

Why is surface area-to-volume ratio a factor of cell size?

A

The volume of the cell increases a lot faster than the surface area. Therefore if the cell gets too big, the cell membrane will not have enough surface area to diffuse the amount of nutrients the cell needs or get rid of the waste the cell produces

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5
Q

Describe interphase

A

period where the cell is preparing to divide through growth and maintenance

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6
Q

What is the G1 phase?

A

(“first gap”) growth

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7
Q

What is the S phase?

A

(“synthesis”) DNA duplication

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8
Q

What is the G2 phase?

A

(“second gap”) Maintenance

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9
Q

Describe synthesis

A

portion of interphase where cells duplicate their DNA

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10
Q

DNA is packaged into sets of what?

A

chromosomes

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11
Q

Humans have __ chromosomes ( __ from each parent)

A

46; 23

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12
Q

Body cells are considered _______ _____

A

Somatic cells

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13
Q

Are somatic cells diploid or haploid?

A

diploid

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14
Q

Reproductive cells are considered ________

A

Gametes

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15
Q

Are gametes diploid or haploid?

A

haploid

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16
Q

What are sister chromatids

A

identical copies of a chromosome

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17
Q

Describe centromere

A

holds sister chromatids together

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18
Q

How is DNA duplicated in synthesis?

A

each chromosome gets copied and is attached to its copy

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19
Q

Define mitosis

A

Cell division where 1 diploid parent cell makes 2 identical diploid daughter cells

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20
Q

Describe prophase

A

the chromosomes coil up and become visible while the nuclear envelope disappears. Sister chromatids are present

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21
Q

A _______ forms at each pole and ________ ______ made of microtubules grow out

A

centriole; spindle fibers

22
Q

Short microtubules stick out from the centriole in a star shape known as an ____

A

aster

23
Q

Describe prometaphase

A

spindle fibers attach to each of the chromatids at a sight called the kinetochore

24
Q

Describe metaphase

A

the spindle fibers line the chromatids up at the equator of the cell called the metaphase plate

25
Q

Describe anaphase

A

the kinetochores “reel in the spindle fibers to pull the sister chromatids apart by splitting their centromere. The split chromatids are pulled towards opposite poles of the cell

26
Q

Describe telophase

A

Once the chromatids have reached the opposite sides the spindle fibers disappear, the chromosomes unravel, and the nuclear envelope reappears on the two new nuclei.

27
Q

Describe cytokinesis

A

the cytoplasm forms a cleavage furrow at the equator to split the cytoplasm

28
Q

Describe binary fission

A

the chromosome replicates (beginning at the origin of replication), and the two daughter chromosomes actively move apart

29
Q

The cell cycle is controlled by chemical signals in the __________

A

cytoplasm

30
Q

What is the cell cycle control system

A

a set of events that occurs in a sequence to regulate the cell cycle

31
Q

The cell cycle control system has specific _________ where the cell cycle stops until a go-ahead signal is received

A

checkpoints

32
Q

the __ checkpoint is the most important

A

G1

33
Q

If the cell does not receive the go-ahead signal what happens?

A

it will go into a non-dividing state called the G0 phase

34
Q

What is cyclin

A

a regulatory protein that builds up in the G2 phase

35
Q

What are Cyclin dependent kinases (Cdks)

A

a regulatory protein that is always present waiting for the arrival of cyclin

36
Q

What is MPF (maturation-promoting factor)

A

cyclin and Cdks combined to trigger a passage through G2 and Mitosis

37
Q

What are growth factors

A

proteins released by certain cells that stimulate other cells to divide

38
Q

What does the platelet-derived growth factor (PDGF) do

A

stimulates the division of human fibroblast cells (connective tissue). This is released when cut from blood platelets so healing can begin.

39
Q

What is density-dependent inhibition

A

crowded cells stop dividing

40
Q

What is anchorage dependence

A

cells must be attached to something in order to divide

41
Q

Why are cancer cells formed

A

Cancer cells do not respond normally to the cells cycle check points or external signals

42
Q

How do cancer cells’ growth factor work?

A

They may make their own growth factor
They may convey a growth factor’s signal without the presence of the growth factor
They may have an abnormal cell cycle control system

43
Q

Define transformation

A

A normal cell is converted to a cancerous cell

44
Q

What is a benign tumor

A

The lump that is formed if the cancer stays at the original site

45
Q

________ tumors spread to surrounding tissues through _______ through _______ ________

A

Malignant; metastasis; blood vessels

46
Q

Describe the organization eukaryotic genome

A

Eukaryotic genomes are packaged into chromosomes, it is a double helix

47
Q

Compare and contrast cytokinesis in animals and plants

A

Animal cells undergo true cytokinesis- plants do not. In plants a cell plate forms to become the new cell wall separating the two daughter cells. Animal cells form a cleavage furrow. This occurs during telophase of mitosis and ends when the two daughter cells resolve.

48
Q

Describe the S phase checkpoint

A

ensure DNA is fully replicated before mitosis

49
Q

What do the G1 and G2 checkpoints check?

A

if DNA is damaged before moving to the next step

50
Q

What is the checkpoint in mitosis for?

A

to ensure chromosomes are lined up correctly in metaphase before continuing to anaphase