Cell Cycle Mitosis Flashcards Preview

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Flashcards in Cell Cycle Mitosis Deck (76)
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1
Q

functions of cell division

A

Growth (usually multicellular organism), Asexual reproduction,Repair

2
Q

Chromosome-

A

eukaryotic DNA molecule with proteins attached to it

3
Q

Histones

A

chromosomal proteins that act as a spool for the DNA (DNA wounds twice around each histone)

4
Q

Nucleosome

A

one unit of histone–DNA spool

5
Q

pros and cons of tightly compact

A

benefit of tightly compact–no tangled, organized drawback–sometimes we need enzymes to access the DNA to copy it

6
Q

Genome

A

cell’s total amount of DNA

7
Q

gene

A

section of DNA codes for a protein that governs or controls a specific trait

8
Q

how long is the DNA in a typical human cell?

A

3 meters DNA

9
Q

how many genes do humans have

A

20k

10
Q

Somatic cells amount of chromosomes

A

46

11
Q

Gametes amount of chromosomes

A

23

12
Q

chromatin

A

When not in cell division, chromosomes takes a granular appearance-contains one long linear DNA molecule associated with proteins

13
Q

granular

A

grainy

14
Q

each chromosome after duplication

A

consists of 2 sister chromatids-which are identical copies of one another

15
Q

centromere

A

found in the middle of each chromatid and holds the chromatid together

16
Q

mitosis (technical definition)

A

division of the nucleus

17
Q

during process of mitosis-what happens to sister chromatids?

A

Sister chromatids are pulled apart and function as chromosomes

18
Q

cytokinesis

A

division of the cell

19
Q

what is mitosis followed by?

A

cytokinesis

20
Q

fertilization–chromosomes

A

23 chromosomes from mother’s egg join with23 chromosomes from a father’s sperm to form 46 in a fertilized egg

21
Q

karyotype

A

chromosomal constitution of 46 chromosomes that humans have. 2 copies of 23 (1-22 and xx or xy)

22
Q

xx

A

female

23
Q

xy

A

male

24
Q

down syndrome

A

3 copies of chromosome 21

25
Q

meiosis

A

Gametes in person are produced by meiosis (takes place in germ cells), which halves # of chromosomes and only occurs in gonads

26
Q

M phase

A

Mitosis and cytokinesis. When cell divides. Stages—prophase, prometaphase, metaphase, anaphase, telophase

27
Q

Interphase

A

Rest of cell cycle. Living its life. Phases—G1, S, G2

28
Q

G1 phase

A

First gap/growth. Growth of cell.

29
Q

G0

A

Permanent G1–many cells. Include neurons after certain age.

30
Q

S phase

A

Synthesizing/copying DNA. Only cells destined to divide get here.

31
Q

G2 phase

A

gap growth 2Completes prep for cell division

32
Q

Mitotic spindle

A

Fibers made of microtubules and proteins, forms during prophase, Assembly begins at the microtubule organizing center, or MTOC

33
Q

centrioles number

A

(2 centrioles copy to 4 precell division)

34
Q

microtubule organizing center, orMTOC

A

centrosome

35
Q

Colchicine

A

poison produced by plants that blocks microtubule assembly

36
Q

Animals v plants–centrioles

A

animals have a pair of centrioles at the centrosome + plants lack centrioles

37
Q

Interphase

A

Nucleus is defined; Two centrosomes (centrosome has replicated) are located outside of the nucleus; (4 centrioles) Microtubules extend from centrosomes, in asters- very short–radial shape like wheel spokes; Chromosomes are duplicated, inchromatin form

38
Q

Prophase

A

Chromatin condenses intochromosomes; Nuclear envelope breaks intosmall vesicles; nucleolus disappears; Mitotic spindle starts to form, radiates out from the centrosome; Centrosome moves away from each other, (pair of centrioles ineach centrosome that has earlier duplicated)

39
Q

Prometaphase

A

Microtubules extend toward middle of cell and attach tokinetochores, Chromosome pulls back and forth until itsettles halfway between the poles (opposite ends of the cell), Microtubules that do not attach to kinetochores attach to other microtubules,

40
Q

kinetochores

A

structures of proteins and DNA found on either side of the centromere

41
Q
  • Metaphase
A

Centrosomes are atopposite poles; Chromosomes line up at metaphase plate-the middle of the cell, or the equator of the cell; Kinetochores are attached tomicrotubules; Spindle–entire apparatus of microtubules– is present

42
Q

Anaphase

A

Centromeres of chromosomes separate, thus separating the sister chromatids; Each chromatid is now called a chromosome; Kinetochore microtubules shorten so chromosome move toward the poles; By end of anaphase, duplicate sets of chromosomes areon opposite ends

43
Q

Telophase

A

Daughter nuclei form at two poles, nuclear envelopesstart to reform; Chromosome becomeschromatin; Cytokinesis begins

44
Q

Cytokinesis in animal cells

A

Involves cleavage- appearance of cleavage furrow, which begins as a shallow groove near the metaphase plate–equator of cell. Microfilaments pull like drawstrings until two new cells are formed

45
Q

Cytokinesis in plant cells

A

During telophase, cell plate forms-vesicles join in the middle of the cell. Cell wall materials (cellulose) collect in cell plate as it grows. Cell plate enlarges untilthe membrane fuses with the plasma membrane

46
Q

binary fission

A

reproduction of prokaryotes. Bacteria contain single chromosome consisting of DNA arranged in a double helix circle. Chromosome attaches to plasma membrane and replicates. Plasma membrane grows in between the replicated DNA and splits the cell

47
Q

Molecular control system

A

Regulated at certain checkpoints by internal and external controls

48
Q

Cell-Cycle Checkpoints:

A

internal control. cell cycle in animal cells will stop at certain points, and will only continue if important events in that stage havebeen completed correctly

49
Q

G1–checkpoint

A

system will stop and cell can grow further if necessary before a new round of DNA replication. Cell can check that the environment is favorable for cell division before the S phase

50
Q

G2–checkpoint

A

Another Size checkpoint. also checks that DNA replication iscomplete before mitosis

51
Q

metastasis

A

spread of cancer cells beyond original site

52
Q

third checkpoint in mitosis

A

in metaphase checks that each chromatid has a spindle fiber that’s attached to it before anaphase

53
Q

Cyclins and Cyclin-Dependent Kinases function

A

help at checkpoints; All eukaryotic cells essentially use the same molecules to control the events of their cell cycle

54
Q

Protein kinases

A

enzymes that catalyze the transfer of a phosphate group to a target protein. Since they depend on the activity of the cyclins, they are called cyclin-dependent kinases.

55
Q

Cyclins-

A

Their concentrations vary in a cyclical fashion during mitosis. Must bind to the kinases for the kinases to become active

56
Q

M-Phase promoting factor (MPF)-

A

protein kinase that increases rapidly right before mitosis and falls rapidly toward end of mitosis; Kinase must be bound to a specific cyclin in order to work.

57
Q

What triggers different steps of cell cycle?

A

Different cyclin-Cdk complexes trigger different steps of the cell cycle

58
Q

Cancer cells

A

Divide excessively, invade other tissues, do not respond to internal orexternal control signals, such as density-dependent inhibition oranchorage dependence (perhaps make growth factors themselves)- Either have mutations in proliferation genes or antiproliferation genes.

59
Q

oncogene

A

mutation in proliferation gene causesthe protein produced by the gene to be overexpressed leading to excessive cell multiplication

60
Q

a mutation in a tumor-suppressor gene

A

mutation in anti-proliferation gene can release a cell from the normal restraints on cell multiplication, leading to excess cell division

61
Q

Malignant cells

A

Cancer. can have an abnormal number of chromosomes, an abnormal metabolism. Loses attachments and can spread to other tissues, such as blood, lymph vessels, other organs- can form new tumors.

62
Q

benign tumor

A

If abnormal cells remain at original site –can be easily removed

63
Q

cancer formation

A

Single cell undergoes transformation. If cell does not get destroyed by body, can proliferate to form tumor- mass of abnormal cells within otherwise normal tissue If cells invade one or more other organs–>cancer.

64
Q

transformation of single cell

A

conversion of normal cell into cancer cell

65
Q

Cdk inhibitor proteins

A

block assembly or activity of one or morecyclin-Cdk complexes.

66
Q

p21

A

cdk(inhibits MPF) inhibitor protein. p21 will stop the cell cycle when DNA is damaged, allowing the cell time to repair the damaged DNA.

67
Q

External Signals (cell division)

A

Growth factor, Density-dependent inhibition, Anchorage dependence, Survival factors

68
Q

Growth factor

A

type of protein released by body cells that stimulate other cells to divide

69
Q

platelet derived growth factor

A

released by platelets in a wound that causes the surviving cells to replicate, healing the wound

70
Q

Density-dependent inhibition

A

crowded cells stop dividing at certain population densities.

71
Q

Anchorage dependence

A

cells must be attached to somethingunderneath in order to divide

72
Q

Survival factors

A

are necessary for cells to live- if not, they undergo apoptosis

73
Q

apoptosis

A

programmed cell death. Helps form fingers during development; helps tissues remain the appropriate size.

74
Q

activation of Protein kinases

A

Activated only at certain times throughout the cell cycle, after which they quickly become deactivated. Switched on and off through proteins called cyclins.

75
Q

MPF effects

A

Causes the chromosome to condense, nuclear membrane to break down, and microtubules to form into spindle fibers;

76
Q

p21 production

A

produced when the RNA is stimulated by a protein called p53. Mutations in p53 gene lead to higher rates of cancer.