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Flashcards in Cell Cycle Deck (72)
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1
Q

meiosis

A

special 2-stage type of cell division in which 1 diploid (2n) parent cell produces haploid (n) cells (gamates)

  • result: halving chromosome #
  • sexually reproduction
  • leads to production of gamates (sperm & eggs)
  • daughter cells have half the amount of hereditary material as parent cell

Mei -> gamates

2
Q

mitosis

A

process of nuclear division in which 2 daughter nuclei are genetically identical to the parent nucleus

  • cytokinesis leads to 2 identical daughter cells
  • lead to production of all other types of cells (somatic cells)
  • cellular replication

mit -> somatic/other cells

3
Q

phases of cell cycle

A

(1) M phase

(2) Interphase

4
Q

interphase

A

portion of cell cycle btwn one M phase and the next

  • DNA replication occurs here
  • uncondensed chromatin

(1) G1 phase
(2) S phase
(3) G2 phase

*most cells spend their time here (not dividing stage - G1 phase)

5
Q

M phase

A

2nd step of cell cycle

  • cell division occurs here
  • replicated chromosome condense
  • sister chromatids separate
  • 2 daughter cells formed by cytokinesis

division of nucleus & cytoplasm

M phase = PPMAT

6
Q

G1 phase

A

1st step of interphase in cell cycle

  • 4 unreplicated chromosomes
  • non-dividing cells stuck here
  • allow parent cell to grow large enough to divide into 2 cells that will fcn normally

growth phase

7
Q

S phase

A

2nd step of interphase in cell cycle

  • DNA synthesis (break down)
  • chromosome replicated

“synthetic phase”

8
Q

G2 phase

A

3rd step of interphase in cell cycle

  • 4 unreplicated chromosomes
  • sister chromatids

growth phase

9
Q

gamate

A

haploid (n) reproductive cell
- can fuse w/ another haploid cell to form a zygote

(ie) eggs & sperm & precursor cells

10
Q

gene

A

a section of DNA (RNA for some viruses)
- encodes info for building related polypeptides or fcnal RNA molecules along w/ regulatory sequences required for its transcription

11
Q

deoxyribonucleic acid (DNA)

A

nucleic acid composed of deoxyribonucleotides

  • double helix structure
  • encodes cells’ hereditary info or genetic material
12
Q

chromatid

A

1 of 2 identical double-stranded DNA composing a replicated chromosome
- sister chromatids connected @ centromere

13
Q

number of chromosomes in human somatic cell

A

46 chromosomes
(23 chromosome pairs)

2n

14
Q

cell cycle checkpoints

A

critical point in cell cycle in which cell progression is regulated

  • G1 checkpoint
  • G2 checkpoint
  • M phase checkpoint

no pass checkpoint, cannot proceed onward

“is this ready?”

15
Q

G2 checkpoint

A

(1) chromosomes must have replicated successfully
(2) no DNA damage
(3) MPF activated & present

16
Q

G1 checkpoint

A

(1) adequate cell size
(2) sufficient supply of nutrients
(3) social signals present
(4) no DNA damage

17
Q

M phase checkpoint

A

(1) chromosomes attached to spindles
(2) chromosomes properly segregated
(3) MPF absent

18
Q

cytokinesis

A

cytoplasm divides to form 2 daughter cells
- occurs after M phase

cell divides
actin-myosin pinch plasma membrane

19
Q

cytoskeleton roles during mitosis

A

(1) architectural framework cells can organize subcell organelles & metabolic machinery
(2) cell shape
(3) cell movement
(4) cell division

20
Q

cyotoskeleton - cell shape

A

cytoskeleton determines cell shape (intermediate filaments)

21
Q

cytoskelton - cell movement

A

microfilaments + microtubules assemble & dissemble to move cell

22
Q

cytoskeleton - cell division

A

microtubules move chromosomes to daughter nucleus

23
Q

kinase

A

enzyme that catalyzes transfer of phosphate group from ATP to a target protein

  • subunit of MPF
  • always present
24
Q

cyclin-dependent kinase (Cdk)

A

protein related to kinase

  • fcnal when bound to cyclin
  • activated by other modifications
  • regulates other proteins & cell cycle
25
Q

benign tumor

A

mass of abnormal tissue due to unregulated growth

  • does not spread to other organs
  • not cancerous

could be caused by social control does not work properly

noninvasive

26
Q

cancer

A

general term for any tumor whose cells grow in an uncontrolled fashion, invade nearby tissues, and spread to other sites in the body

27
Q

malignant tumor

A

tumor that is actively growing & disrupting local tissues or spreading to other organs

invasive

28
Q

metastasis

A

spread of cancerous cells from original site to distant sites in body
- may create additional tumors

29
Q

social control over cell division

A

cells divide in response to signals from other cells

- social control of cell cycle based on growth factors

30
Q

unreplicated chromosome

A

a single strand of double helix (DNA) wrapped around proteins

31
Q

replicated chromosome

A

2 copies of double helices (DNA)

- same chromosomes

32
Q

ploidy

A

number of copies of each chromosome

33
Q

types of ploidy

A

(1) haploid

(2) diploid

34
Q

haploid (n)

A

gamates

- one copy of DNA

35
Q

diploid (2n)

A

somatic cells

- 2 copies of DNA

36
Q

discovery of interphase

A

(1) subphases via autoradiography

(2) gap phases - pulse chase experiments

37
Q

M phase components

A

(1) prophase
(2) prometaphase
(3) metaphse
(4) telophase

38
Q

prophase

A

(1st stage of M phase)

chromosomes condense
spindle apparatus form
rearrange to reduce erros

“before phase”

39
Q

prometaphase

A

(2nd stage of M phase)

nuclear envelope breaks down
microtubules contact chromosome @ kinetochore

rearrange to reduce errors

40
Q

metapahse

A

(3rd stage of M phase)

chromosomes line up in the middle

rearrange to reduce errors

41
Q

anaphase

A

(4th stage of M phase)

chromatids separate & pulled to opposite poles

accurately divide replicates

42
Q

telopahse

A

(5th stage of M phase)

nuclear envelope reforms
chromosomes recondense

rearrange for normal fcn

43
Q

binary fission

A

process of cell division

  • similar to mitosis
  • proteins different
  • bacteria divide via fission
  • used for asexual reproduction of many prokaryotic cells

creates 2 genetically identical cells

44
Q

oncogenes

A

genes for proteins that causes cell to divide

“Go!”

45
Q

tumor suppressor genes

A

genes that causes cell to stop dividing

“Stop!”

46
Q

embryo

A

newly developing organism

47
Q

histone

A

positively charged (basic) proteins associated w/ DNA in chromatin of eukaryotic cells

48
Q

chromosome

A

single long DNA double helix wrapped around histones in a highly organized matter

  • colored body
  • threadlike structures
  • made up of: DNA & genes
49
Q

gene

A

a length of DNA that codes for a particular protein or ribonucleic acid (RNA) found in cell

50
Q

sister chromatid

A

chromatid copies that remain attached @ their centromere

51
Q

cell cycle

A

orderly sequence of events that lead to a eukaryotic cell through duplication of its chromosome to the time it divides
- made up of: M phase + interphase

timing depends on cell type & growth conditions

52
Q

spindle apparatus

A

structure that provides mechanical forces

- consists of microtubules

53
Q

function of spindle apparatus

A

(1) move replicated chromosomes during early mitosis

(2) pull chromatids apart in late mitosis

54
Q

microtubule properties

A

(1) composed of alpha & beta tubulin dimers

(2) asymmetric structure
- plus & minus ends

55
Q

plus end of mictrotubules

A

where growth occurs

56
Q

minus end of microtubules

A

where disassembly occurs

57
Q

cell plaste

A

flattened sac-like structure formed in middle of dividing plant cell

  • originates from golgi-vesicles
  • divides cytoplasm into 2 separate cells
58
Q

cleavage furrow

A

pinching in of plasma membrane that occurs as cytokinesis begins

  • deepens into cytoplasm until forms 2 daughter cells
  • animals & otro eukaryotes only
59
Q

oocyte

A

egg phase stuck in phase similar to G2 phase

- about to enter M phase

60
Q

M phase promoting factor (MPF)

A

cyclin & Cdk complex that phosphorylates specific proteins needed to initiate mitosis

  • found in eukaryotic cells
  • MPF induces M phase

“start M phase please”

61
Q

subunits of MPF

A

(1) kinase

(2) cyclin

62
Q

cyclin

A

regulatory protein whose concentration fluctuates cyclically throughout cell cycle
- MPF subunit

63
Q

how MPF is turned on?

A

(1) interphase - cyclin builds up

(2) Cdk regulated by two phosphorylation events

64
Q

how MPF is turned off?

A

(1) anaphase - cyclin degradation [leads to destruction]
(2) negative feedback
(3) activated enzyme complex causes ubiquitin attaches to cyclin

65
Q

types of tumors

A

(1) benign

(2) malignant

66
Q

p53

A

tumor suppressor protein that responds to DNA damage

  • stops cell cycle
  • turns on DNA repair machinery
  • (perhaps) triggers apoptosis or self-destruction
67
Q

apoptosis

A

self-destruction

68
Q

growth factors

A

a large number of signaling molecules

  • secreted by certain cells
  • stimulate other cells to grow, divide or differentiate

social control of cell cycle

69
Q

serum

A

liquid portion of blood that remains after blood cells & cell fragments have been removed

70
Q

components of serum

A

(1) water
(2) dissolved gases
(3) growth factors
(4) nutrients
(5) otro soluble substances

71
Q

negative feedback

A

corrective response

change triggers responses aimed to return variable back to normal

  • means of maintaining homeostais
  • occurs when process is slowed or shut down by one of its products
72
Q

E2F

A

transcription factor - initiates transcription

“Go!”