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AP Biology > Ch 12 and 13 > Flashcards

Ch 12 and 13 Flashcards

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1
Q

a characteristic that best distinguishes living things from non-living matter

A

the ability of organisms to produce more of their kind

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2
Q

Omnis cellula e cellula

A

every cell from a cell

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3
Q

the continuity of life is based on

A

cell division

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4
Q

cell division

A

the reproduction of cells

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5
Q

the division of a prokaryotic cell reproduces

A

an entire organism

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6
Q

dividing cells in your bone marrow

A

continuously make new blood cells

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7
Q

the cell division process is an integral part of

A

the cell cycle

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8
Q

cell cycle

A

the life of a cell from the time it is first formed from a dividing parent until its own division into two daughter cells

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9
Q

a crucial function of cell division

A

passing identical genetic material to cellular offspring

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10
Q

3 functions of cell division

A
  • Reproduction
  • Growth and Development
  • Tissue Renewal
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11
Q

most cell division requires the distribution of

one exception

A

identical genetic material to two daughter cell s (meiosis)

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12
Q

genome

A

a cell’s endowment of DNA, its genetic infromation

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13
Q

prokaryotic genome is often

A

a single DNA molecule

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14
Q

eukaryotic genomes usually consist of

A

a number of DNA molecules

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15
Q

a typical human cell has about (of DNA)

A

2 m of DNA- 250,00 time the length of the diameter of the cell

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16
Q

before the cell can divide to form genetically identical daughter cells

A

all DNA must be copied of replicated

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17
Q

the replication and distribution of so much DNA is manageable because the DNA molecules are packaged into structures called

A

chromosomes

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18
Q

chromosomes

A

the structures DNA is packaged in

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19
Q

chroma

A

color

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20
Q

soma

A

body

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21
Q

eukaryotic chromosomes consist of

A

one very long, linear DNA molecule associated with many proteins

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22
Q

The DNA molecule contains (how many genes)

A

several hundred to a few thousand

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23
Q

genes

A

the units of information that specify an organisms inherited traits

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24
Q

chromatin

A

the entire complex of DNA and proteins that is the building material of chromosomes

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25
Q

every eukaryotic species has (in relation to chromosomes)

A

a characteristic number of chromosomes in each cell nucleus

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26
Q

somatic cells

A

all body cells except the reproductive cells

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27
Q

number of chromosomes in the nuclei of a human somatic cell

A

46, made up of two sets of 23, one from each parent

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28
Q

gametes

A

reproductive cells, sperm and eggs

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29
Q

number of chromosomes in gametes

A

half as many as somatic cells, one set of 23 in humans

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30
Q

number of chromosomes in somatic among species

A

varies wildly

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31
Q

when a cell is not dividing , and even as it replicates its DNA in preparation for cell division each chromosome is in the form of

A

a long thin chromatin fiber

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32
Q

after DNA replication, chromosomes

A

condense as part of cell division. each chromatin fiber becomes densely coiled and folded, making chromosomes much short and so thick they can be viewed with a light microscope

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33
Q

each duplicated chromosome has two

A

sister chromatids

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34
Q

the two sister chromatids are

A

joined copies of the original chromosome

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35
Q

the two sister chromatids each contain

A

an identical DNA molecule

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36
Q

the two sister chromatids are intitially attached all along their lengths by

A

protein complexes called cohesins

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37
Q

cohesins

A

protein complexes that attach the two sister chromatids intially along their lengths

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38
Q

the attachment of the sister chromatids is caleld

A

sister chromatid cohesion

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39
Q

centromere

A

a region containing specific DNA sequences where the chromatid is attached most closely to its sister chromatid

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40
Q

each sister chromatid has

A

a centromere

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41
Q

mediator of the centromere

A

proteins bound to the centromeric DNA sequences and gives the condensed, duplicated chromosome a narrow “waist”

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42
Q

arm of the chromatid

A

what the part of a chromatid on either side of the centromere is referred

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43
Q

an uncondensed, unduplicated chromosome has

A

a single centromere and two arms

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44
Q

Karotype

A

a micrograph of the 46 human chromosomes arranged in pairs starting with the longest chromosome

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45
Q

homologous chromosomes or homologs

A

the two chromosomes composing a pair: they have the same length, centromere position and staining pattern

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46
Q

Both chormosomes of each pair of homologs carry

A

genes controlling the same inheritance patterns

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47
Q

autosomes

A

all non-sex chromosomes

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48
Q

sex chromosomes

A

X and Y chromosome

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49
Q

Both of the sex chromosomes have genes

A

lacking on their opposite

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50
Q

Female Sex chromosomes

A

XX

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51
Q

Male sex chromosome

A

XY

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52
Q

only small parts of X and y chromosomes are

A

homologous

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53
Q

the two sister chromatids of each duplicated

chromosome separate and move into

A

two new nuclei at each end of the cell

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54
Q

once the sister chromatids seperate they are no longer called sister chromatids but are considered

A

individual chromosomes

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55
Q

each new nucleus receives a collection of chromosomes identical to

A

that of the parent cell

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56
Q

mitosis

A

the division of the genetic material in the nucleus

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57
Q

cytokinesis

A

the division of the cytoplasm

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58
Q

mitosis is usually immediately followed by

A

cytokinesis

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59
Q

zygote

A

a fertilized egg

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60
Q

Walther Flemming

A

developed dyes to observe chromosomes during mitosis and cytokinesis; named mitosis and chromatin

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61
Q

Mitotic (M) phase

A
  • mitosis and cytokinesis

- shortest part of cell cycle

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62
Q

interphase

A

90% of the cell cycle

-cell that is about to divide grows and copies its chromosomes in preparation for cell division

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63
Q

3 subphases of interphase

A

G1 phase (first gap), S phase (synthesis), G2 (second gap)

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64
Q

during all 3 subphases of interphase

A

a cell that will eventually divide grows by producing proteins and cytoplasmic organelles

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65
Q

chromosomes are only duplicated during

A

S-phase

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66
Q

most variable subphase in interphase between types of cells in reference to time

A

G1 phase; some cells never divide

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67
Q

5 stages of mitosis

A

prophase,prometaphase,metaphase,anaphase,and telophase

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68
Q

when does the mitotic spindle begin to form

A

in prophase in the cytoplasm

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69
Q

mitotic spindle

A

fibers made of microtubules and associated proteins

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70
Q

when the mitotic spindle assembles

A

microtubules of the cytoskeleton partially disassemble in order to construct it

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71
Q

how does do the spindle microtubules elongate (polymerize) and shorten (depolymerize)

A
  • polymerize by incorporating more subunits of protein tubulin
  • depolymerize by losing subunits
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72
Q

centrosome

A

a subcellular region containing material that functions throughout the cell to organize the cell’s microtubules
also called the microtubule-organizing center

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73
Q

where does the assembly of spindle microtubules start in animal cells

A

centrosome

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74
Q

located at the center of the centrosome

A

a pair of centrioles ; but not necessary for division and plants don’t have them

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75
Q

the single centrosome duplicates when in animal cells

A

interphase

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76
Q

the two centrosomes formed in interphase in animal cells move apart during

A

prophase and prometaphase as spindle microtubules grow from them

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77
Q

by the end of prometaphase the centrosomes, one at each pole of spindle

A

are at opposite ends of the cell an aster extends from each centrosome

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78
Q

an aster

A

a radial array of short microtubules

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79
Q

the mitotic spindle include

A

the centrosomes, the spindle microtubules, and the asters

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80
Q

kinetochore

A
  • each of the two sister chromatids of a duplicated chromosome has one
  • a structure of proteins associated with specific sections of chromosomal DNA at each centromere
  • each of the chromosome’s two face in opposite directions
81
Q

during prometaphase what attach to the kinetochores (they are called kinetochore microtubules) (number varies wildly between species)

A

some of the spindle microtubules

82
Q

at metaphase the centromeres of all the duplicated choromosomes are

A

on a plane midway between the spindle’s two poles called the metaphase plate which is an imaginary rather than real cell structure

83
Q

effect of microtubules on kinetochore of a chromosome

A

pulls on them and counteract each others pulls which ends in a draw (like a game of tug and war)

84
Q

what occurs in G2 phase of interphase

A
  • nuclear envelope encloses nucleus
  • nucleus contains one or more nucleoli
  • two centrosomes formed from one
  • chromosomes duplicated during S phase but not yet condensed
85
Q

what occurs in prophase

A
  • chromatin fibers become more tightly curled
  • nucleoli disappear
  • duplicated chromosome appears as 2 identical sister chromatids
  • mitotic spindle begins to form
  • centrosomes move away from each other
86
Q

what occurs in prometaphase

A
  • nuclear envelope fragments
  • chromosomes more condensed
  • microtubules from each centrosome invade the nuclear area
  • each of the two chromatids of each chromosome now has a kinetochore
  • some microtubules attach to kinetochore
  • nonkinetochore microtubules interact with those from the opposite pole of the spindle
87
Q

what occurs in metaphase

A
  • the centrosomes are now at opposite poles of the cell
  • the chromosomes convene at the metaphase plate
  • for each chromosome, the kinetochores of the sister chromatids are attached to the kinetochore tubules coming from the opposite poles
88
Q

what occurs in anaphase

A
  • shortest stage of mitosis
  • anaphase begins when the cohein proteins are cleaved . this allows the 2 sister chromatids of each pair to part suddenly; each chromatid becomes a chromosome
  • two liberated daughter chromosomes move toward the opposite ends of the cell as their kinetochore microtubules shorten
  • cell elongates as the nonkinetochore microtubules lengthen
  • by end, two ends of cell have equivalent and complete collections of chromosomes
89
Q

what occurs in telophase

A
  • 2 daughter nuclei form, nuclear envelopes arise form the fragments of the parent’s cell’s nuclear envelope and other portions of the endomembrane system
  • nucleoli reappear
  • chromosomes become less condensed
  • any remaining spindle microtubules are depolymerized
  • mitosis is now complete (the division of one nucleus into 2 identical nuclei)
90
Q

what occurs in cytokinesis

A
  • division of cytoplasm well underway by end of telophase, so two daughter cells appear shortly after the end of mitosis
  • in animal cells, cytokinesis involves the formation of a cleavage furrow which pinches the cell in two
91
Q

microtubules that do not attach to kinetochores have been elongating and by metaphase

A

they overlap and interact with other nonkinetochore microtubules from the opposite pole of the spindle (called polar microtubules)

92
Q

by metaphase the microtubules of the asters have

A

grown and are in contact with the plasma membrane; the spindle is now complete

93
Q

anaphase commence when

A

the cohesins holding together the sister chromatids of each chromosome are cleaved by an enzyme called separase

94
Q

separase

A

enzyme which cleaves the cohesins of the sister chromatids

95
Q

once the chromatids become full fledged chromosomes they move

A

towards the opposite ends of the cell

96
Q

how do the chromosomes move

A

they walk along the kinetochores via motor proteins on the kinetochore

97
Q

in animal cells what is responsible for elongating the whole cell

A

the nonkinetochore microtubules; while they may be extensively overlapped, their motor proteins push them apart via ATP; expanding the cell

98
Q

in animal cells, cytokinesis occurs via

A

cleaveage

99
Q

first sign of cleavage

A

the cleavage furrow

100
Q

cleavage furrow

A

shallow groove in the cell surface near old metaphase plate

deepens until cell splits into two

101
Q

on the cytoplasmic side of the cleavage furrow is

A

a contractile ring of actin microfilaments associated with molecules of the protein myosin
actin interacts with myosin causing contraction

102
Q

in plant cells cytokinesis occurs via

A

cell plate

103
Q

cells plate

A

formed via vesicles from the Golgi apparatus which move along microtubules to the middle of the cell

  • fuses with plasma membrane
  • new plasma membrane forms in daughter cells and cell plate begins cell wall
104
Q

binary fission

A

type of reproduction in prokaryotes where cell doubles in size and then divides and asexual reproduction in eukaryotes (but in eukaryotes this includes mitosis)

105
Q

in bacteria most genes are carried on

A

a single bacterial chromosome which consists of a circular DNA molecule and associated proteins

106
Q

in ecoli cell division:

A

-initiated when DNA of bacterial chromosome begin to duplicate at a specific place on the chromosome called the origin of replication producing 2 origins
-the 2 origins move to opposite ends
-cell expands
-plasma membrane pinches
-cell divided into two daughter cells
way of moving is a mystery

107
Q

intermediaries between binary fission and mitosis:3

A

dinoflagellates diatoms and some yeasts

108
Q

yeast and diatom division

A

nuclear envelope in tact
spindle formed inside nucleus
microtubules separate chromosomes and nucleus splits into 2 nuclei

109
Q

dinoflagellates division

A

chromosomes attach to nuclear envelope
nuclear envelope remains intact during division
microtubules pass through nucleus inside cytoplasmic tunnels
then divides in binary fission style process

110
Q

when fused cells from earlier stages

A

jump to the farthest state of the 2

111
Q

cell cycle control system

A

a cyclically operating set of molecules in the cell that both triggers and coordinates the key events in the cell cycle

112
Q

checkpoint

A

a control point where stop and go signals can regulate the system

113
Q

animal cell checkpoints are generally

A

built in, many are internal, but may be from outside the cell

114
Q

three major checkpoints

A

G1, G2, and M phases

115
Q

dubbed the restriction checkpoint in mammalian cells

A

the G1 checkpoint is most important- if given go ahead, division will probably occur

116
Q

if no go ahead given at G1

A

cell goes into G0 phase which is non-dividing

117
Q

regulatory cell cycle molecules

A

mainly two proteins of 2 types: protein kinases and cyclins

118
Q

protein kinases

A

enzymes that activate or inactivate other proteins by phosphorylating them
-particular protein kinases give go ahead signals at the G1 and G2 checkpoints
-many are present at constant concentration, but inactive much of the time
-

119
Q

cyclin

A

activates kinases;attachs to them

cyclically fluctuates concentration in the cell

120
Q

cyclin dependent kinases (Cdks)

A

kinases which need cylcin

121
Q

MPF

A

the cyclin dependent complex that was discovered first in frog eggs
m phase promoting factor-triggers cell’s past G2 checkpoint into M phase
when cyclins that accumulate during G2 associate with Cdk the resulting MPF complex phosphorylates a variety of proteins initiating mitosis; nuclear lamina is phosphorylated fragmenting N envelope
during anaphase cyclin destroyed and Cdk dormant

122
Q

M phase checkpoint

A

will not begin until the kinetochores of all the chromosomes are attached to the spindle

123
Q

growth factor

A

a protein released by certain cell that stimulates other cells to divide

124
Q

density-dependent inhibition

A

a phenomenon where crowded cells stop dividing due to a surface-inhibiting protein which sends a growth inhibiting signal to both cells

125
Q

anchorage dependence

A

in most animal cells, to divide, they must be attached to a substratum like a culture jar

126
Q

cancer cells

A

do not heed normal signals that regulate cell cycle

127
Q

which cells are immortal

A

cancer cells: they divide indefinitely

128
Q

transformation

A

the process that converts a normal cell to a cancer cell, normally destroyed by body, but if not can form a tumor

129
Q

benign tumor

A

a tumor that cannot expand due to too few genetic and cellular challenges to survive at another site

130
Q

malignant tumor

A

can spread to new sites

131
Q

metastasis

A

the spread of cancer from their original site, spread by blood vessels and lymph vessels which may be signaled to grow towards it

132
Q

heres

A

heir

133
Q

heredity or inheritance

A

the transmission of traits from one generation to the next

134
Q

variation

A

the opposite of inherited similarity

135
Q

genetics

A

the scientific study of heredity and hereditary variation

136
Q

genes

A

hereditary units

137
Q

genetics is written in

A

DNA and read via the nucleotides

138
Q

gametes

A

reproductive cells that are the vehicles that transmit genes from one generation to another

139
Q

humans have how many chromosomes in somatic cells

A

46

140
Q

somatic cells

A

all non gamete cells in the body

141
Q

locus

A

from Latin; place- a gene’s specific location along the length of the chromosome

142
Q

asexual reproduction

A

single organism, all DNA passed down

143
Q

offspring of asexual reproduction

A

a clone

144
Q

sexual reproduction

A

2 parents

unique combinations of genes

145
Q

life cycle

A

the generation to generation sequence of stages in the reproductive history of an organism from conception to reproduction of its own offspring

146
Q

diploid cell

A

any cell with two chromosome sets; 2n

147
Q

the number of chromosomes in a single set is represented by

A

n

148
Q

for humans the diploid number is

A

46 (2n=46) the number in our somatic cells

149
Q

haploid cells

A

one set of chromosomes; i.e gametes

150
Q

human haploid number

A

23 (n=23): 22 autosome and 1 sex chromosome (sperm may have X or Y, while an egg must have X

151
Q

each sexually reproducing organism has a characteristic

A

diploid and haploid number

152
Q

fertilization

A

union of gametes culminating in the fusion of their nuclei

153
Q

zygote

A

fertilized egg, is a diploid

154
Q

only cells in the human body not produced by mitosis

A

gametes, develop from specialized cells called germ cells in the gonads and ovaries respectively

155
Q

if gametes were produced by mitosis

A

the number of chromosomes would keep doubling forever each generation

156
Q

meiosis

A

what gametes use- reduces the number of sets of chromosome sets from 2 to 1 occurs in germ cell in reproducing animals

157
Q

alternation of generation

A

life cycle of some algae and plants, both diploid and haploid types and are multicellular

158
Q

in alternation of generation; diploid

A

sporophyte, meiosis of sporophyte produces spores; a type of haploid cell

159
Q

unlike a gamete

A

a haploid spore doesn’t fuse with another cell, but divides mitotically generating a multicellular haploid stage called the gametophyte which if fuse results in the next sporophyte beginning the cycle over

160
Q

life cycle of most fungi and some protists

A
  • gametes fuse and forma diploid zygote
  • meiosis occurs without a multicellular diploid offspring developing
  • meiosis produces not gametes but haploid cells that then divide by mitosis and give rise to either unicellular descendants or a haploid multicellular adult organism
  • haploid completes further mitoses producing cell that develop into gametes
  • only diploid stage is single celled zygote
161
Q

either haploid or diploid cells can divide using what depending on the life cycle

A

mitosis

162
Q

only diploid cells can undergo

A

meiosis

163
Q

two divisions of meiosis

A

meiosis I and Meiosis II; results in 4 daughter cells

164
Q

for a single pair of homologous chromosomes in mitosis

A

both members duplicated and the copies sorted into 4 haploid daughter cells

165
Q

an allele

A

different versions of a gene

166
Q

homologs appear alike but

A

may have different alleles at corresponding loci

167
Q

What happens in Meiosis I

A

separation of homologous chromosomes

168
Q

What happens in Meiosis II

A

separation of sister chromatids

169
Q

What happens in early Phrophase I

A
  • chromosomes begin to condense and homologs loosely pair along their lengths aligned gene by gene
  • paired homologs become physically connected to each other along their lengths by a zipper-like protein structure; the synaptonemal complex; this state is synapsis
  • Crossing over- a genetic rearrangement between non-sister chromatids involving the exchange of corresponding segments of DNA molecules, begins during pairing and synaptonemal complex formation and is completed while homologs are in synapsis
170
Q

What happens in main prophase I

A
  • synapsis has ended with the disassembly of the synaptonemal complex in mid-prophase and the chromosomes in each pair have moved slightly apart
  • each homologous pair has one or more X-shaped regions called chiasmata (chiasma,singular) which exists where a crossover occurred. It appears as a cross because sister chromatid cohesion still holds the original sister chromatids together, even in regions beyond the crossover point, where one chromatid is now part of the other homolog
  • centrosome movement, spindle formation, and nuclear envelope breakdown occur as in mitosis
171
Q

What happens in late prophase I

A

-microtubules from one pole or the other attach to the two kinetochromes, protein structures at the centromeres of the homologs. The homologous pair then move toward the metaphase plate.

172
Q

what happens in metaphase I

A
  • pairs of homologous chromosomes are now arranged at the metaphase plate , with one chromosome in each pair now facing the plate
  • both chromatids of one homolog are attached to kinetochore microtubules from one pole; those of the other homolog are attached to microtubules from the opposite pole
173
Q

what happens in anaphase I

A
  • breakdown of proteins responsible for sister chromatid cohesion along chromatid arms allows homologs to separate
  • the homologs move toward opposite poles,guided by the spindle apparatus
  • sister chromatid cohesion persists at the centromere causing chromatids to move as a unit toward the same pole
174
Q

What happens in telophase I and cytokinesis

A
  • at the beginning, each half of the cell has a complete haploid set of duplicated chromosomes. each chromosome is composed of two sister chromatids; one or both chromatids include regions of nonsister chromatid DNA
  • Cytokinesis usually occurs simultaneously with telophase I forming 2 haploid daughter cells
  • in animal cells a cleavage furrow forms and in plant cells a plate forms
  • in some species chromosomes decondense and N envelope forms
  • no chromosome duplication occurs between Meiosis I and II
175
Q

What happens in Prophase II

A
  • spindle apparatus forms
  • in late prophase II chromosomes each still composed of 2 chromatids associated at their centromere move towards the metaphase II plate
176
Q

What happens in Metaphase II

A
  • chromosomes positioned at metaphase plate
  • because of crossing over in Meiosis I , the sister chromatids of each chromosome are not genetically identical
  • the kinetochore of sister chromatids are attached to microtubules extending from opposite poles
177
Q

What happens in Anaphase II

A

-breakdown of proteins holding the sister chromatids together at the centromere allows the chromatids to separate. the chromatids move toward opposite poles as individual chromosomes

178
Q

What happens in Telophase II and Cytokinesis

A
  • nuclei form, the chromosomes begin condensing and cytokinesis occurs
  • the meiotic division of one parent cell produces four daughter cells, each with a haploid set of (unduplicated) chromosomes
  • the 4 daughter cells are genetically distinct from one another and the parent cell
179
Q

Mitosis vs Meiosis:DNA replication

A

mitosis;occurs during interphase before mitosis begins

Meiosis;occurs during interphase before meiosis I begins

180
Q

Mitosis vs Meiosis:Number of divisions

A

mitosis: one, including the 5 stage
meiosis: two including each of the 4 steps

181
Q

Mitosis vs Meiosis: synapsis of homologous chromosomes

A

mitosis: doesn’t happen
meiosis: occurs during prophase I along with crossing over between non-sister chromatids ,resulting chiasmata hold pairs together due to sister chromatid cohesion

182
Q

Mitosis vs Meiosis: number of daughter cells and genetic composition

A

mitosis: 2 each diploid (2n) and genetically identical to parent cell
meiosis: 4, each haploid (n) containing half as many chromosomes as the parent cell , genetically different from parent cell and each other

183
Q

Mitosis vs Meiosis: role in animal body

A

mitosis: enables multicellular adult to rise from zygote: produces cells for growth, repair, and in some species, asexual reproduction
Meiosis:produces gametes; reduces number of chromosomes sets by half and introduces genetic variability among the gametes

184
Q

3 unique events of meiosis I

A

Synapsis and crossing over, homologous pairs at the metaphase plate, separation of homologs

185
Q

synapsis and crossing over Mitosis vs Meiosis

A

during prophase I, duplicated homologs pair up, and the formation of the synaptonemal complex between them holds them in synapsis. Crossing over also occurs in prophase I. neither occur in the prophase of mitosis

186
Q

homologous pairs at the metaphase plate Mitosis vs Meiosis

A

at metaphase I, chromosome are positioned at the metaphase plate as pairs of homologs, rather that individual chromosomes, as in the metaphase of mitosis

187
Q

Mitosis vs Meiosis: separation of homologs

A

at anaphase I of meiosis, the duplicated chromosome of each homologous pair move toward opposite poles, but the sister chromatids of each duplicated chromosome remain attached. In anaphase of mitosis, by contrast, sister chromatids spate.

188
Q

sister chromatids are attached along their length by protein complexes called

A

cohesins

189
Q

reductional division

A

Meiosis I- it halves the number of chromosome set per cell

190
Q

equational division

A

Meiosis II-sister chromatids separate producing haploid daughter cells

191
Q

in sister chromatids, it is a coin flip whether

A

the maternal or paternal end will face a given pole: it is a 50:50 chance

192
Q

independent assortment

A

each pair of homologous chromosomes is positioned independently of the other pairs at metaphase I

193
Q

number of combination is

A

2 to n (n=haploid cell number) ex. human is 2 to the 23rd or about 8.4 million

194
Q

recombinant chromosomes

A

individual chromosomes that carry genes (DNA) from two different parents; result of crossing over

195
Q

random fertilization

A

random nature of fertilization increases variation

196
Q

asexual reproduction pros

A
  • protects good gens in stable environment

- less energy used

197
Q

successful asexual animal

A

bdelloid rotifier -compensate by absorbing other rotifier DNA and other species DNA while in suspended animation during dry periods called horizontal gene transfer; adds variability

198
Q

crossing over process

A
  • in prophase I
  • homolog genes align with corresponding gene
  • in a single event the DNA of two nonsister chromatids -one maternal and one paternal- is broken by specific proteins at corresponding points and the two segments beyond the crossover point are joined to the other chromatid

AP Biology (13 decks)

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