chapter twelve Flashcards

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1
Q

what does cell division result in?

A

2 daughter cells

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2
Q

what is the purpose of cellular division?

A

reproduction, growth, repair

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3
Q

unicellular cell division

A

clones
- ex. amoeba

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4
Q

multicellular cell division

A
  • reproduction (some organisms that don’t form gametes - asexual/sexual)
  • growing (embryo, new blood cells)
  • differentiating (which genes where expressed when)
  • repair
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5
Q

genome

A

a cell’s DNA/genetic information

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6
Q

chromatin

A

entire complex of DNA and proteins that make up chromosomes

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7
Q

what is the purpose of protein in DNA?

A

combats negative charge of nucleotides

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8
Q

chromosomes

A

structures composed of chromatin
- eukaryotic (long DNA molecule w/ many proteins)
- after S phase, they have sister chromatids

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9
Q

sister chromatids

A

joined copies of the original chromosome
- attached by cohesions

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10
Q

centromere

A

region made up of repetitive sequences in the chromosomal dNA where the chromatid is attached most closely to a sister chromatid
- where kinetochores bind

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11
Q

homologous chromosomes

A

pair of chromosomes that have same order of genes but with some variation

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12
Q

somatic cells

A

diploid
- 2n number of chromosomes

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13
Q

gametes

A

haploid
- n number of chromosomes

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14
Q

mitosis

A

division of genetic material in the nucleus

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15
Q

cytokinesis

A

division of the cytoplasm
- follows mitosis

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16
Q

what do the cell division cycles consist of?

A

alternating M ( mitotic - mitosis/cytokinesis) phase with interphase (90% of cycle)

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17
Q

3 phases of interphase

A
  1. G1 phase
  2. S phase
  3. G2 phase
18
Q

G1 phase

A

first gap, metabolic activity/growth

19
Q

S phase

A

“replication”, synthesis/duplication of chromosomes, metabolic activity

20
Q

G2 phase

A

second gap, metabolic activity/growth, preparation for division

21
Q

stages of mitosis

A
  1. prophase
  2. prometaphase
  3. metaphase
  4. anaphase
  5. telophase
22
Q

spindle

A

fibers made of microtubules and proteins
- elongate by polymerizing and incorporating more tubulin

23
Q

kinetochore

A

structure made up of proteins that have assembled on specific sections of DNA at each centromere
- where spindle attaches during prometaphase

24
Q

centrosomes

A

the of microtubule-organizing center
- aster

25
Q

aster

A

radial array of short microtubules that extend from each centrosomes during division

26
Q

how many centrioles are in centrosomes in animal cells?

A

2

27
Q

prophase

A
  • chromosomes (as chromatin) become condensed
  • spindle appears between centrosomes
  • nucleolus disappears
  • centrosomes pushed away from each other
28
Q

prometaphase

A
  • nuclear envelope fragments
  • microtubules attach to kinetochores
29
Q

metaphase

A
  • chromosomes arrive at metaphase plate (equidistant between spindle’s poles)
  • kinetochore microtubules and nonkinetochore microtubules
30
Q

kinetochore microtubules

A

jerk chromosomes back and forth, attached to kinetochores

31
Q

nonkinetochore microtubules

A

interact w/ those from opposite poles of spindle to lengthen cell

32
Q

anaphase

A
  • sister chromatids separate
  • chromosomes move to opposite ends of cell
33
Q

telophase

A
  • reversal of prophase
  • each cell gets new nuclear envelope
34
Q

cytokinesis

A
  • splitting of cytoplasm through cell plate or cleavage furrow
35
Q

cleavage furrow

A
  • animal cells
  • pinches cell in 2
  • shallow groove near old metaphase plate
  • actin filaments - ring of actin filaments (contractile) on cytoplasmic side, interacts w/ myosin to contract
36
Q

cell plate

A
  • plant cells
  • vesicles move along microtubules to middl elf cell and coalesce
37
Q

binary fission

A

cell grows to double its size then divides
- duplicates of DNA attached to plasma membrane
- used by prokaryotes/bacteria

38
Q

what is another name for mitosis

A

karyokinesis

39
Q

how many chromosomes present in interphase

A

46

40
Q

number of chromosomes in each mitotic phase

A

prophase, prometaphase, metaphase - 46
anaphase - 92
cytokinesis - 46 in each of 2 cells