lecture 8- mitosis Flashcards

1
Q

what is cell division

A

organisms ability to reproduce
continuity of life through reproduction

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2
Q

roles of cell division

A

reproduction
growth and development
tissue renewal/repair

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3
Q

what is a chromatin

A

dna when the cell is not dividing

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4
Q

what is a chromosome

A

dna during cell division
(chromatin tightly coiled around histones)

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5
Q

what is a genome

A

all the genetic material in a cell

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6
Q

what does each chromosome contain

A

huge molecule of dna and proteins

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7
Q

what is the gene locus

A

the specific place where a gene is located on a specific chromosome

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8
Q

how many chromosomes are there in the human genome

A

46 (number of chromosomes doesn’t mean how advanced a species is)

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9
Q

what is a karyotype

A

organized profile of a person’s chromosomes

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10
Q

how is a karyotype arranged

A

stained
arranged by size (largest to smallest)
photographed

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11
Q

what are the 23 pairs of chromosomes

A

22 autosomes
1 sex chromosomes

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12
Q

what is the use of karyotypes

A

to check irregularities in the number or structure of chromosomes

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13
Q

why do you need an x sex chromosome

A

it has important genes for blood clotting and eyesight

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14
Q

what does having an extra chromosome lead to

A

potentially down syndrome

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15
Q

what is a haploid cell and examples

A

cell that has 23 chromosomes
egg and sperm
N

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16
Q

what are diploid cells and examples

A

23 pairs of chromosomes
all somatic cells
2N

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17
Q

what is a somatic cell

A

cell that isn’t gametic

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18
Q

what happens when the sperm and egg cell unite

A

the nuclei fuse together to form a single nucleus

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19
Q

when does the cell cycle happen

A

between the time a cell is formed and when it divides into two daughter cells

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20
Q

what are the characteristics of mitosis

A

results in two identical cells
occurs during growth and repair
in somatic cells

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21
Q

what are the stages in the cell cycle

A

interphase (G1, S, G2)
mitotic phase (mitosis, cytokinesis)

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22
Q

how long does interphase happen compared to the mitotic phase

A

interphase is most of the cells lifespan (95%)

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23
Q

what are the phases of interphase

A

growth 1
dna synthesis
growth 2

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24
Q

characteristics of growth 1

A

period of active growth (increases in size until it reaches mature size for cell type)
synthesis of new organelles
dna is in chromatin form

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25
Q

what happens during dna synthesis

A

the chromatins are copied

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26
Q

what are the copied chromatins referred to as

A

sister chromatids

27
Q

what are the characteristics of the sister chromatids

A

contain the same genetic information
attached at the centre with a centromere

28
Q

how many chromatins are there after dna replication

A

92 (46 double sister chromatids)

29
Q

what happens during growth 2

A

cell increases slightly
begins preparing for mitotic phase
- duplication of centrosomes
- spindle fibers form
dna is still in chromatin form

30
Q

what are the two parts of the mitotic phase

A

mitosis
cytokinesis

31
Q

what are the steps of mitosis

A

prophase (early)
prometaphase (late)
metaphase
anaphase
telophase

32
Q

what happens in prophase

A

dna condenses (still called sister chromatids)
nuclear envelope breaks
centrosomes separate and move to opposing sides
microtubules fibers extend between the centrosomes to form the mitotic spindle (some attach to chromosomes)

33
Q

what happens during prometaphase

A

nuclear membrane is broken down
centrosomes are at opposing sides
some microtubules attach to centromere region
nucleoli disappears

34
Q

what is the centromere region called

A

kinetochores

35
Q

what happens in metaphase

A

chromosomes align in the middle of the cell (single file)

36
Q

what happens in anaphase

A

centromeres breaks and the sister chromatids separate (now called chromosomes)
chromosomes are pulled to opposite ends of the cell
cell elongates

37
Q

what happens during telophase

A

spindle fibers disappear
nuclear membrane forms around the chromosomes
nucleolus reappears
chromosomes unwind and become less compact

38
Q

what is cytokinesis

A

separation of cells and cytoplasm

39
Q

what happens during cytokinesis

A

cell pinches along the middle and ends with two identical daughter cells

40
Q

how is mitosis different in plant cells

A

they don’t have centrioles but they have microtubule organizing centers
cell can’t pinch in half

41
Q

how do the new cells separate in plant cell mitosis

A

separated by cell plate

42
Q

what are the steps in cytokinesis in plant cells

A

vesicles from the golgi carry cell wall components to the middle
cell plate forms at the center and becomes a cell membrane

43
Q

how do prokaryotic cells divide

A

binary fission (asexual cloning)

44
Q

most bacteria have how many chromosomes

A

one

45
Q

how does binary fission work

A

chromosomes replicate
move to opposite sides
cell elongates to make room
plasma membrane grows inwards
split

46
Q

what happens if the cell doesn’t pass a checkpoint

A

the cell tries to correct it
if it can’t it undergoes apoptosis (cell suicide)

47
Q

what are the checkpoints during mitosis

A

G1 checkpoint
G2 checkpoint (between G2 and M)
M checkpoint (between metaphase and anaphase)

48
Q

what’s does the G1 checkpoint check

A

growth factor proteins
nutrients
cell size
dna damage

49
Q

what does the G2 checkpoint check

A

cell size
dna damage
dna replication

50
Q

what does the M checkpoint check

A

chromosome attachment to spindle

51
Q

what is the purpose of the checkpoints

A

cancer prevention and mutation prevention

52
Q

what is cancer

A

disease of the cell
excessive cell growth and division that is not controlled

53
Q

mutagens can be caused by

A

various agent that changes the dna of an organism (radiation, light, chemicals)

54
Q

when do mutations occur

A

during dna replication

55
Q

what are benign tumours

A

mass of cells that don’t invade neighbouring tissue
not considered cancer
can be removed

56
Q

what are malignant tumours

A

mass of cells that invade neighbouring tissues
can impair functioning of one or more organs
considered cancerous
can spread to the whole body

57
Q

what is it called when a cancer spreads to parts away from original site

A

metastasis

58
Q

how does metastasis work

A

cancer cells get into the bloodstream and move throughout the body

59
Q

what are the treatments for cancer

A

surgery
high energy radiation
chemotherapy

60
Q

what is the process of high energy radiation and what is it used for

A

non specific damage to the dna because cancer cells have lost their ability to repair dna
used for localized tumors

61
Q

what is chemotherapy used to treat and how does it work

A

used for metastatic tumors
damage actively dividing cells
taxol freezes the mitotic spindles by preventing microtubule formation

62
Q

side effects of chemo

A

nausea immune suppression hair loss

63
Q

why doesn’t your immune system attack cancer cells

A

because it’s your own cells so the immune response doesn’t recognize them as dangerous