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Flashcards in Cell Cycle Deck (72):
1

meiosis

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

mitosis

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

phases of cell cycle

(1) M phase

(2) Interphase

4

interphase

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

M phase

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

G1 phase

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

S phase

2nd step of interphase in cell cycle
- DNA synthesis (break down)
- chromosome replicated

"synthetic phase"

8

G2 phase

3rd step of interphase in cell cycle
- 4 unreplicated chromosomes
- sister chromatids

growth phase

9

gamate

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

(ie) eggs & sperm & precursor cells

10

gene

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

deoxyribonucleic acid (DNA)

nucleic acid composed of deoxyribonucleotides
- double helix structure
- encodes cells' hereditary info or genetic material

12

chromatid

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

13

number of chromosomes in human somatic cell

46 chromosomes
(23 chromosome pairs)

2n

14

cell cycle checkpoints

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

G2 checkpoint

(1) chromosomes must have replicated successfully

(2) no DNA damage

(3) MPF activated & present

16

G1 checkpoint

(1) adequate cell size

(2) sufficient supply of nutrients

(3) social signals present

(4) no DNA damage

17

M phase checkpoint

(1) chromosomes attached to spindles

(2) chromosomes properly segregated

(3) MPF absent

18

cytokinesis

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

cell divides
actin-myosin pinch plasma membrane

19

cytoskeleton roles during mitosis

(1) architectural framework cells can organize subcell organelles & metabolic machinery

(2) cell shape

(3) cell movement

(4) cell division

20

cyotoskeleton - cell shape

cytoskeleton determines cell shape (intermediate filaments)

21

cytoskelton - cell movement

microfilaments + microtubules assemble & dissemble to move cell

22

cytoskeleton - cell division

microtubules move chromosomes to daughter nucleus

23

kinase

enzyme that catalyzes transfer of phosphate group from ATP to a target protein
- subunit of MPF
- always present

24

cyclin-dependent kinase (Cdk)

protein related to kinase
- fcnal when bound to cyclin
- activated by other modifications
- regulates other proteins & cell cycle

25

benign tumor

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

cancer

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

27

malignant tumor

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

invasive

28

metastasis

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

29

social control over cell division

cells divide in response to signals from other cells
- social control of cell cycle based on growth factors

30

unreplicated chromosome

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

31

replicated chromosome

2 copies of double helices (DNA)
- same chromosomes

32

ploidy

number of copies of each chromosome

33

types of ploidy

(1) haploid

(2) diploid

34

haploid (n)

gamates
- one copy of DNA

35

diploid (2n)

somatic cells
- 2 copies of DNA

36

discovery of interphase

(1) subphases via autoradiography

(2) gap phases - pulse chase experiments

37

M phase components

(1) prophase

(2) prometaphase

(3) metaphse

(4) telophase

38

prophase

(1st stage of M phase)

chromosomes condense
spindle apparatus form
rearrange to reduce erros

"before phase"

39

prometaphase

(2nd stage of M phase)

nuclear envelope breaks down
microtubules contact chromosome @ kinetochore

rearrange to reduce errors

40

metapahse

(3rd stage of M phase)

chromosomes line up in the middle

rearrange to reduce errors

41

anaphase

(4th stage of M phase)

chromatids separate & pulled to opposite poles

accurately divide replicates

42

telopahse

(5th stage of M phase)

nuclear envelope reforms
chromosomes recondense

rearrange for normal fcn

43

binary fission

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

oncogenes

genes for proteins that causes cell to divide

"Go!"

45

tumor suppressor genes

genes that causes cell to stop dividing

"Stop!"

46

embryo

newly developing organism

47

histone

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

48

chromosome

single long DNA double helix wrapped around histones in a highly organized matter
- colored body
- threadlike structures
- made up of: DNA & genes

49

gene

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

50

sister chromatid

chromatid copies that remain attached @ their centromere

51

cell cycle

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

spindle apparatus

structure that provides mechanical forces
- consists of microtubules

53

function of spindle apparatus

(1) move replicated chromosomes during early mitosis

(2) pull chromatids apart in late mitosis

54

microtubule properties

(1) composed of alpha & beta tubulin dimers

(2) asymmetric structure
- plus & minus ends

55

plus end of mictrotubules

where growth occurs

56

minus end of microtubules

where disassembly occurs

57

cell plaste

flattened sac-like structure formed in middle of dividing plant cell
- originates from golgi-vesicles
- divides cytoplasm into 2 separate cells

58

cleavage furrow

pinching in of plasma membrane that occurs as cytokinesis begins
- deepens into cytoplasm until forms 2 daughter cells
- animals & otro eukaryotes only

59

oocyte

egg phase stuck in phase similar to G2 phase
- about to enter M phase

60

M phase promoting factor (MPF)

cyclin & Cdk complex that phosphorylates specific proteins needed to initiate mitosis
- found in eukaryotic cells
- MPF induces M phase

"start M phase please"

61

subunits of MPF

(1) kinase

(2) cyclin

62

cyclin

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

63

how MPF is turned on?

(1) interphase - cyclin builds up

(2) Cdk regulated by two phosphorylation events

64

how MPF is turned off?

(1) anaphase - cyclin degradation [leads to destruction]

(2) negative feedback

(3) activated enzyme complex causes ubiquitin attaches to cyclin

65

types of tumors

(1) benign

(2) malignant

66

p53

tumor suppressor protein that responds to DNA damage
- stops cell cycle
- turns on DNA repair machinery
- (perhaps) triggers apoptosis or self-destruction

67

apoptosis

self-destruction

68

growth factors

a large number of signaling molecules
- secreted by certain cells
- stimulate other cells to grow, divide or differentiate

social control of cell cycle

69

serum

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

70

components of serum

(1) water

(2) dissolved gases

(3) growth factors

(4) nutrients

(5) otro soluble substances

71

negative feedback

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

E2F

transcription factor - initiates transcription

"Go!"