Chapter 8 Flashcards

Cell Division & Reproduction

1
Q

cell division

A

cell reproduction;
- genome duplication / cytoplasm division
- makes 2 genetically identical daughter cells

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2
Q

chromosomes

A

gene structure in nucleus
- long DNA molecule and proteins

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3
Q

asexual reproduction

A

genetically identical offspring w/ only 1 parent
- no gametes

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4
Q

clone

A

group of genetically identical individuals

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5
Q

sexual reproduction

A

genetically unique offspring w/ 2 parents
- fusion of two gametes (fertilization)
- forms diploid zygote

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6
Q

cell division in protists are used for what ?

A

reproduction only

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7
Q

cell division in the human body is used for what ?

A
  • development
  • growth
  • repair
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8
Q

binary fission

A

parent organism duplicates itself into two genetically identical individuals
- asexual reproduction

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9
Q

do eukaryotes or prokaryotes hold more genes ?

A

eukaryotes; 7x more than prokaryotes
- 21000 vs 3000

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10
Q

how many chromosomes are in a cell of an organism ?

A

depends on organism

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11
Q

how many chromosomes are in humans, dogs, hedgehogs ?

A

46; 78; 90

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12
Q

chromatin

A

DNA / protein that make up chromosomes
- long form of chromosomes
- coils up / distinct chromosomes when dividing

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13
Q

sister chromatids

A

two identical chromatids on a duplicated chromosome

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14
Q

centromere

A

spot where two sister chromatids of duplicated chromosome attach to each other

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15
Q

when does chromosome consist of two identical sister chromatids ?

A

when cell is prepping to divide / before dividing

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16
Q

cell cycle

A

ordered sequence of events from cell formation to duplication
- interphase
- mitotic phase

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17
Q

interphase

A

growing stage of cell’ 90% of total cell cycle
- G1
- S phase
- G2

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18
Q

G1

A

first gap; prep for duplication (cell growth)
- synthesize mRNA / proteins in prep for mitosis

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19
Q

S phase

A

chromosome duplication (sister chromatids are formed)
- 50% of interphase

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20
Q

G2

A

second gap; finish prep for cell division
- ensure all parts of cell are ready to divide

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21
Q

mitotic (M) phase

A

cell division; 10% of total cell cycle
- mitosis
- cytokinesis

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22
Q

mitosis

A

nucleus, contents, duplicated chromosomes divide
- form 2 identical daughter nuclei

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23
Q

cytokinesis ?

A

begins at end of mitosis, cytoplasm splits into two separate daughter cells

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24
Q

how often does an error occur in mitosis ?

A

~ 1/100,000; extremely accurate

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25
Q

1) prophase

A
  • nuclear envelope disappears
  • chromatin condenses
  • mitotic spindles begin to form
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26
Q

2) metaphase

A

duplicated chromosomes line up in middle

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27
Q

3) anaphase

A

sister chromatids separate
- mitotic spindles pull sis. chromatids to opposite ends of cell

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28
Q

4) telophase / cytokinesis

A

daughter nuclei form and cell divides into two daughter cells

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29
Q

mitotic spindles

A

spindle microtubules for chromosome movement
- found in centrosomes

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30
Q

centrosomes

A

structure in animal cells where microtubules form / organize
- contain 2 centrioles

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31
Q

cytokinesis in animal cells vs plant cells

A

animal cells = cleavage furrow
plant cell = cell plate

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32
Q

how does cleavage furrow work ?

A

actin microfilaments contract toward each other, cleaving cell in two

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33
Q

how does cell plate work ?

A

vesicles collect along middle of cell and form new cell wall

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34
Q

what type of environment would constitute more cell division ?

A

a more abrasive environment

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35
Q

anchorage dependence

A

cell division requires cells to be attached to a surface

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36
Q

density dependent inhibition

A

cell division stops when cell is in-contact w/ another cell

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37
Q

what happens to density dependent inhibition when the cell is cancerous ?

A

cancer cells ignore this inhibition, they keep dividing forming clumps if overlapping cells

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38
Q

growth factors

A

protein secreted by body cells
- stimulates cells to divide
- different cells respond to different / combinations of growth factors

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39
Q

what is the biggest thing growth factors do ?

A

signals cell cycle to continue / stop

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40
Q

cell cycle control system

A

set of proteins tat trigger / coordinate events in cell cycle
- triggers mitosis
- checks if key components of cell are completed
- checkpoints

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41
Q

G1 checkpoint

A

signal allowing start of S phase
- checks cell size, nutrients, growth factors, DNA damage

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42
Q

what happens if G1 checkpoint never gets signaled ?

A

cell goes into G0 phase
- permanent non-dividing state

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43
Q

G0 cell examples

A

mature nerve / muscle cells

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44
Q

G2 checkpoint

A

after G2 is done, before mitotic (M) phase
- checks for DNA damage after chromosome replication

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45
Q

M checkpoint

A

(spindle checkpoint) after cell replication, before cytokinesis
-checks if all sister chromatids are correctly attached to microtubules

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46
Q

at which checkpoints are chromosomes duplicated ?

A

G2 / M

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47
Q

what is cancer

A

a disease of the cell cycle
- cells divide uncontrollably

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48
Q

what do cancer cells have altered that allow them to divide uncontrollably ?

A

cells w/ altered proteins that fail to be killed by immune system

49
Q

tumor

A

abnormal mass of rapid growing tissue within normal tissue
- ignores cell cycle control system
- proceed past checkpoints w/o growth factors / can make own growth factors

50
Q

benign tumor

A

abnormal mass of cells that remains in its original site
- removal by surgery
- no immediate threat unless left alone

51
Q

malignant tumor

A

abnormal mass that can spread to neighboring tissue / other body parts
- cancerous
- spread via blood / lymph system and start forming new sites

52
Q

cancer

A

disease due to malignant tumors within the bodt

53
Q

metastasis

A

process of spreading cancer within the body beyond its original site

54
Q

somatic cells

A

body cells
- have 46 chromosomes
- in mitosis; 23 sets of duplicated chromosomes

55
Q

homologous chromsomes

A

homologs; two chromosomes that make a matched pair within diploid cell
- same centromere position, length, gene loci, staining, etc
- one from mom, one from dad

56
Q

locus (loci)

A

site where specific gene is found on chromosome
- same gene is found in same loci on different chromosomes

57
Q

sex chromosomes

A

X/Y chromsome; determines sex
- XX = female
- XY = male

58
Q

autosomes

A

any chromosome other than X/Y
- doesnt affect sex

59
Q

are all chromosomes for male and female homologous ?

A

no
- female = 23 homologs (22 autosomes + XX)
- male = 22 homologs (22 autosomes + XY)

60
Q

life cycle

A

sequence of stages in life
- one adult to next generation adult

61
Q

diploid (2n)

A

somatic cells
- set of homologous chromosomes (46)
- in organisms that reproduce sexually (one set from each parent)

62
Q

human 2n = ?

A

46 (23 sets)

63
Q

haploid (n)

A

sex cell
- single set of chromosomes (23)
- in organisms that reproduce sexually

64
Q

human n = ?

65
Q

gametes

A

sex (reproductive) cells (egg/sperm) formed by meiosis
- single set of chromosomes (23)
- fusing of two gametes forms zygote

66
Q

fertilization

A

nucleus of sperm / egg combine

67
Q

zygote

A

diploid fertilized egg
- one set of chromosomes from each parent
- mitosis of zygote makes all somatic cells

68
Q

how many autosomes and which sex cells are in human sperm ?

A

22 autosomes and XY

69
Q

meiosis is also known as what ?

A

reduction division

70
Q

meiosis

A

divide single diploid cell into 4 genetically unique haploid daughter cells
- only sexual reproduction
- fertilization restores diploid state
- duplication of chromosomes followed by two cell divisions

71
Q

meiosis I

A

crossing over of chromosomes from parents occurs and homologs split
- homologs separate

72
Q

prophase I

A
  • chromosomes condense
  • homologs pair
  • non-sister chromatids of homologs cross over
73
Q

metaphase I

A
  • microtubules attach to individual chromosomes
  • homologs line up in middle next to each other
74
Q

anaphase I

A

homologs separate to opposite ends

75
Q

meiosis II

A

sister chromatids separate
- like mitosis but x2 (2 cells into 4 haploid cells)

76
Q

tetrad orientation equation

A

2^n
- n = haploid # of organism

77
Q

total # of possible tetrad orientations in humans ?

A

human n = 23
2^23 ~ 8mil

78
Q

organisms w/ a diploid # of 10 have how many possible tetrad orientations ?

A

32;
2n = 10 —> n = 5
2^5 = 32

79
Q

crossing over

A

homolog non-sister chromatid synapsis during prophase I
- where loci swap genes

80
Q

chiasma

A

site where crossing over between non-sister chromatids occur

81
Q

recombinant chromosomes

A

chromosome name after crossing over

82
Q

how many crossing overs occur in a human chromosome on average ?

83
Q

are chromosomes in gametes going to look like chromosomes in skin cells ?

A

no; gametes have half the # of chromosomes compared to autosomes and more varied (cut/paste) segments from a homolog pair

84
Q

nondisjunction

A

anaphase in mitosis / meiosis homologs / sister chromatids fail to separate

85
Q

how does nondisjunction affect a fertilized zygote ?

A

that zygote will transmit abnormal # of chromosomes to all of its cells
- 10-30% of all human conceptions
- main reason for miscarriages

86
Q

nondisjunction in meiosis I will affect the chromosomes of the 4 haploid daughter cells how ?

A

2 cells = n +1
2 cells = n - 1

87
Q

nondisjunction in meiosis II will affect the chromosomes of the 4 haploid daughter cells how

A

2 cells = n
1 cell = n - 1
1 cell = n + 1

88
Q

how could nondisjunction turn a gamete diploid ?

A

if in meiosis I and II all chromosomes are affected
- all chromosomes in meiosis I pulled into 1 daughter cell
- all chromosomes in meiosis II pulled into 1 daughter cell

89
Q

karyotype

A

display of metaphase chromosomes by descending shape / size
- 46 chromosomes total (22 homologs / 1 pair sex chromosomes)

90
Q

male sex chromosomes

91
Q

female sex chromosomes

92
Q

normal female karyotype will display how many homologs ?

A

23 homologs (22 homologs and XX)

93
Q

normal male karyotype will display how many homologs ?

A

22 homologs (22 homologs and XY)

94
Q

trisomy 21

A

disorder w/ extra chromosome 21 (3 total)
- heart / respiratory defects
- varying lvls of mental retardation
- majority cases of abnormal chromosomes

95
Q

what can abnormal chromosome #s lead to ?

A

spontaneous embryo abortion (miscarriage)

96
Q

down syndrome

A

condition of having trisomy 21
- 1/850 kids
- all / half of all affected sexually underdeveloped / sterile
- 50% all female eggs have extra chromosome
- risk of birthing child w/ disorder starts to increase at 40+

97
Q

will abnormal amounts of X/Y sex chromosomes compared to abnormal amounts of autosome chromosomes have more of an affect on the child ?

A

no, abnormal autosome chromosome # affects child more

98
Q

characteristic of the Y sex chromosome

A

small and few genes

99
Q

can people afford to live with only one X sex chromosome ?

A

yes;
- males already only have 1 X chromosome - females can survive w/ only 1 because they have a set

100
Q

klinefelter syndrome

A

extra X chromosome in men (XXY, XXXY, XXXXY)
- more X chromosomes = more likely for harmful disorders

101
Q

extra X in females are shown in person how ?

A
  • slightly taller
  • higher risk of learning disabilities
  • really cannot distinguish from normal XX
102
Q

extra Y in males are shown in person how ?

A

normal male
- no symptoms

103
Q

turner syndrome

A

Xo female
- lacks 1 X sex chromosome
- sterile / lesser development of secondary sex characteristics
- only case where 45 chromosomes in a human is NOT fatal

104
Q

total # of autosomes in female w/ turner syndrome ?

A

44 + 1 X sex chromosome

105
Q

how can new species arrive due to chromosomal errors ?

A

polyploidy; 2n = 4
meiosis fails —> gametes form by mitosis
2n gamete + 2n gamete = 4n zygote
new species (diff. chromosome #) w/ only ONE generation

106
Q

polyploidy

A

more than 2 sets of homolog chromosomes

107
Q

colchicine

A

disrupt microtubule formation —> no separation of chromosomes
- new species due to new chromosome #

108
Q

chromosome breakage caused by ?

A
  • errors in meiosis
  • damaging agents (radiation); mutagens / mutagenesis
109
Q

chromosome fragment

A

at least 1 nucleotide

110
Q

deletion

A

fragment becomes detached from chromosome

111
Q

duplication

A

repeated part of chromosome due to re-entry of a chromosome fragment from homolog

112
Q

inversion

A

re-attaching fragment to same chromosome but in reverse orientation

113
Q

which forms of chromosome breakages are more severe ?

A

deletion / duplication
- complete loss / double fragment in one chromosome

114
Q

why are inversions and translocation not as severe as deletion / duplication ?

A

still have the gene, just not correct

115
Q

“cry of the cat” syndrome

A

deletion in chromosome 5;
- developmental disabilities
- smaller head / unusual facial features
- shrill cat-like cry

116
Q

myelogenous leukemia (CML)

A

translocation of chromosome 22 w/ tip of chromosome 9;

117
Q

is cancer caused by chromosomal mutations heritable ?

A

no not usually;
- chromosomal mutations are usually in somatic cellsho

118
Q

how is reciprocal translocation different than crossing over

A

reciprocal translocation is swapping of fragments between NON homologs
- crossing over is in a pair of homologs