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Flashcards in Chapter 11 Deck (182):
1

Which statement about cytokinesis is true?

A. In animals, a cell plate forms.
B. In plants, it is initiated by furrowing of the membrane.
C. It follows mitosis.
D. In plant cells, actin and myosin play an important part.
E. It is the division of the nucleus.

C

2

Which statement about the cell cycle is not true?

A. It consists of interphase, mitosis, and cytokinesis.
B. The cell’s DNA replicates during G1.
C. A cell can remain in G1 for weeks or much longer.
D. DNA is not replicated during G2.
E. Cells enter the cell cycle as a result of internal or external signals.

B

3

Which statement about eukaryotic chromosomes is not true?

A. They sometimes consist of two chromatids.
B. They sometimes consist only of a single chromatid.
C. They normally possess a single centromere.
D. They consist only of proteins.
E. During metaphase they are visible under the light microscope.

D

4

Nucleosomes

A. are made of chromosomes.
B. consist entirely of DNA.
C. consist of DNA wound around a histone core.
D. are present only during mitosis.
E. are present only during prophase.

C

5

Which statement about mitosis is not true?

A. A single nucleus gives rise to two identical daughter nuclei.
B. The daughter nuclei are genetically identical to the parent nucleus.
C. The centromeres separate at the onset of anaphase.
D. Homologous chromosomes synapse in prophase.
E. The centrosomes organize the microtubules of the spindle fibers.

D

6

In meiosis,

A. meiosis II reduces the chromosome number from diploid to haploid.
B. DNA replicates between meiosis I and meiosis II.
C. the chromatids that make up a chromosome in meiosis II are identical.
D. each chromosome in prophase I consists of four chromatids.
E. homologous chromosomes separate from one another in anaphase I.

E

7

In meiosis,

A. a single nucleus gives rise to two daughter nuclei.
B. the daughter nuclei are genetically identical to the parent nucleus.
C. the centromeres separate at the onset of anaphase I.
D. homologous chromosomes synapse in prophase I.
E. no spindle forms.

D

8

An animal has a diploid chromosome number of 12. An egg cell of that animal has 5 chromosomes. The most probable explanation is

A. normal mitosis.
B. normal meiosis.
C. nondisjunction in meiosis I.
D. nondisjunction in meiosis I or II.
E. nondisjunction in mitosis.

D

9

The number of daughter chromosomes in a human cell (diploid number 46) in anaphase II of meiosis is

A. 2.
B. 23.
C. 46.
D. 69.
E. 92.

C

10

Apoptosis

A. occurs in all cells.
B. involves the formation of the plasma membrane.
C. does not occur in an embryo.
D. is a series of programmed events resulting in cell death.
E. is the same as necrosis.

D

11

Which of the following statements regarding cell division in prokaryotes (shown) is false?

A. The bacterial chromosome is circular.
B. Prokaryotic cells undergo mitosis, but not meiosis.
C. The initial step in prokaryotic cell division involves replication of the single chromosome.
D. Cytokinesis starts immediately after DNA replication in rapidly growing cells.
E. Cell division in some prokaryotes can occur in as little as 20 minutes.

Q image thumb

B

12

Which of the following pairings regarding the eukaryotic cell cycle (shown) is false?

A. M phase: Mitosis and Cell Division.
B. G1 phase: Gap 1; cell begins preparation for DNA replication.
C. S phase: Synthesis stage; DNA is replicated.
D. G2 phase: Gap 2; cell begins preparation for mitosis.
E. G0 phase: Gap 0; separation of sister chromatids occurs.

Q image thumb

E

13

Which of the following statements about protein signals involved in the control of the cell cycle (shown) is false?

A. Transition from G1 to S and G2 to M depends on the phosphorylation of certain key proteins by cyclin-dependent kinase or Cdk.
B. Cdk's must be bound with a specific cyclin to be active as kinases.
C. In humans, cyclin D-cdk4 triggers the G1-to-S transition, whereas cyclin B-cdk1 triggers the G2-to-M transition.
D. External control mechanisms involving growth factors and hormones can activate cells that are arrested or are cycling slowly.
E. The phosphorylation of retinoblastoma protein effectively inhibits cell division.

Q image thumb

E

14

During formation of the mitotic spindle, there is (are) _______ centriole(s) while each chromosome consists of _______ chromatid(s), _______ centromere(s), and _______ kinetochore(s).

A. 1; 1; 1; 2
B. 1; 2; 1; 2
C. 2; 2; 1; 2
D. 2; 2; 2; 2
E. 2; 2; 1; 4

Q image thumb

C

15

Complete the following sentence for the cell shown. This cell is in _______ of mitosis and has _______ copies of each chromosome.

A. prometaphase; two
B. prometaphase; four
C. prometaphase; eight
D. anaphase; two
E. anaphase; four

Q image thumb

A

16

Which of the following statements regarding the stage of mitosis shown here is false?

A. All chromosomes have aligned at the equatorial plate.
B. Chromosomes are maximally condensed in this stage.
C. At the end of this stage, the chromatid pairs separate simultaneously.
D. The molecule cohesin holds the sister chromatids together in this stage.
E. The separation of sister chromatids requires the digestion of cohesin by the enzyme securin.

Q image thumb

E

17

Which of the following statements regarding mitosis is true?

A. Only diploid cells can divide mitotically.
B. Crossing over can occur during prophase of mitosis.
C. Cells produced by mitosis are almost always genetically identical.
D. Each mitotically produced cell has one-fourth the mass of DNA present in the parent cell.
E. At metaphase, each chromosome has a single kinetochore attached at the centromere.

Q image thumb

C

18

Complete the following sentence about the photomicrograph shown. This is _______ cell, undergoing _______, with the formation of a _______.

A. an animal; apoptosis; division furrow
B. an animal; cytokinesis; division furrow
C. an animal; interkinesis; division furrow
D. a plant; cytokinesis; cell plate
E. a plant; cytokinesis; division furrow

Q image thumb

D

19

In the diplontic life cycle diagram (shown) depicting stages of sexual reproduction, which stage (1–4) represents an adult elephant?

A. 1
B. 2
C. 3
D. 4
E. None of the above

Q image thumb

D

20

This photomicrograph shows a human somatic cell containing 23 pairs of homologous chromosomes. Which of the following statements regarding homologous chromosomes is false?

A. Haploid cells have only one homolog from each of the pairs of homologous chromosomes.
B. Each of the homologs of a pair of chromosomes comes from a different parent.
C. There is a simple relationship between the number of pairs of homologous and the complexity of organisms.
D. Homologs of a pair of homologous chromosomes contain the same types of genetic information.
E. The size and appearance of a condensed homologous pair of chromosomes is generally the same.

Q image thumb

C

21

Which of the following statements regarding meiosis I (shown here) is false?

A. Pairing of homologous chromosomes occurs along their entire length.
B. Meiosis I involves the separation of chromosomes into daughter cells.
C. Synapsis occurs during meiosis I.
D. The alignment of homologous chromosomes at the equatorial plate is random.
E. Paired homologous chromosomes are called tetrads.

Q image thumb

B

22

Which of the following statements regarding crossing over (shown) is false?

A. Chiasmata are formed at areas of attachment between homologous chromosomes.
B. Crossing over occurs at areas where chiasmata appear between homologous chromosomes.
C. Crossing over increases genetic variation.
D. Recombinant chromatids result from crossing over.
E. Crossing over occurs during anaphase I of meiosis.

Q image thumb

E

23

Which of the following statements about cell death is false?

A. Cell death by necrosis is highly specific.
B. Signal transduction pathways for apoptosis are similar in plants and animals.
C. Enzymes called “caspases” are made by cells entering apoptosis.
D. Apoptosis occurs during development.
E. Exposure of epithelial cells to radiation can induce apoptosis.

A

24

Treatments for cancer include radiation that damages _______, causing apoptosis, and 5-fluorouracil that blocks _______. Some agents, such as taxol, interfere with the formation of the _______.

A. proteins; DNA replication; mitotic spindle
B. DNA; protein synthesis; mitotic spindle
C. DNA; DNA replication; microfilaments
D. DNA; DNA replication; mitotic spindle
E. proteins; protein synthesis; microfilaments

Q image thumb

D

25

A bacterial cell gives rise to two genetically identical daughter cells by a process known as

A. nondisjunction.
B. mitosis.
C. meiosis.
D. binary fission.
E. fertilization

D

26

The microtubules of the mitotic spindle attach to a specialized structure int he centromere region of each chromosome called the

A. kinetochore.
B. nucleosome.
C. equatorial plate.
D. aster.
E. centrosome.

A

27

In sexually reproducing organisms, the diploid phase of the life cycle begins at

A. mitosis.
B. meiosis.
C. fertilization.
D. gamete formation.
E. spore formation.

C

28

Anaphase

A. is the phase when sister chromatids separate and move to opposite poles.
B. involves chromosomes lining up at the equatorial plate.
C. occurs before the nuclear envelope breaks down.
D. takes place just before cytokinesis.
E. both a and c

A

29

During mitosis and meiosis the chromatin compacts. Which of the following processes takes place more easily because of this compatction?

A. The orderly distribution of genetic material to two new nuclei
B. The replication of the DNA
C. Exposing the genetic information on the DNA
D. The unwinding of DNA from around the histones
E. The disappearance of the nuclear membrane

A

30

The members of a homologous pair of chromosomes

A. are identical in size and appearance.
B. always contain identical genetic information.
C. separate to opposite poles of the cell during mitosis.
D. are found only in haploid cells.
E. are present only after the S phase.

A

31

In contrast to mitosis, in meiosis

A. genetically identical daughter cells are produced.
B. pairing of homologous chromosomes occurs.
C. crossing over can take place.
D. there is no cytokinesis.
E. Btoh b and c

E

32

DNA replication occurs

A. before both mitosis and meiosis.
B. during G2.
C. only before mitosis.
D. only before meiosis.
E. during chromosome condensation.

A

33

How does a nucleus in G2 differ from a nucleus in G1?

A. The G2 nucleus has double the amount of DNA as the G1 nucleus.
B. DNA synthesis occurs only in the G1 phase.
C. Inactive cells are arrested only in the G2 phase.
D. During G2, the cell prepares for S phase.
E. All of the above

A

34

Which of the following phases of the cell cycle is not part of interphase?

A. M
B. S
C. G1
D. G2
E. G0

A

35

Chromatin consists of

A. DNA and histones.
B. NA, histones, and many other nonhistone proteins.
C. mostly RNA and DNA.
D. RNA, DNA, and nonhistone proteins.
E. DNA only.

B

36

Homologous chromosomes undergo crossing over during

A. prophase I of meiosis.
B. prophase I and II of meiosis.
C. anaphase II of meiosis.
D. prophase I of mitosis.
E. prophase II of meiosis.

A

37

tumor suppressor

gene that codes for a protein that inhibits cell proliferation

inactive in cancer cells

38

centriole

paired organelle

helps to organize microtubule in animal & protict cells during nuclear division

39

growth factor

chemical signal that stimulates cell division

40

prometaphase

begins with the disintegration of the nuclear envelope

41

chromatin

nucleic acid-protein complex that makes up eukaryotic chromosomes

42

cohesin

protein invovled in chromatid binding

43

aneuploidy

condition in which one or more chromosomes is either lacking or present in excess

due to "incorrect" cell division

44

zygote

cell created by union of two gametes

earliest stage of diploid generation

45

mitosis

nuclear division in eukaryotes leading to 2 identital daughter nuclei

46

interphase

period between cell divisions

consists of G1, S, and G2 

47

synapsis

parallel alignment/pairing of homologous chromosomes during meiosis

48

metaphase

cellular division stage in which chromosomal centromeres all lie on equatorial division plane 

49

G1

gap stage between end of mitosis and onset of S phase

50

haploid

containing one copy of chromosomal set

1n or n

51

monosomic

description of organism that has one less than normal diploid number of chromosomes

e.g. only one X chromosome (Turner's syndrome)

52

anaphase

division stage in which separation of sister chromatids (mitosis) or paired homologs (meiosis I) begins/occurs

53

centrosome

major microtubule organizing center of animal cell

54

independent assortment

random separation of genes into gametes such that inheritance of genes is random

55

gamete

mature sexual reproductive cell

e.g. egg or sperm

56

chiasma

X-shaped connection between paired homologous chromosomes during prophase I or meiosis

required for cross-over

57

sexual reproduction

reproduction via union of gametes

58

crossing over

mechanism by which linked genes undergo recombination

exchange of corresponding segments between two homologous chromatids

59

diploid

having chromosome complement consisting of two homologs of each chromosome

2n

60

cyclin-dependent kinase
(abbreviation)

Cdk
(long form)

61

cyclin-dependent kinase (Cdk)

protein kinase with target proteins involved in transitions within cell cycle

active with cyclins bound to protein kinase

62

cyclin

protein required for activation of Cdk and as a result, causes transition in cell cycle

63

prophase

division stage during which chromosomes condence from blobby chromatin to discrete, compact chromosomes

64

necrosis

premature cell death caused by external agents, e.g. a toxin

65

alternation of generations

succession of multicellular haploid & diploid phases in some seuxally reproducing organisms (PLANTS!)

66

malignant

characteristic of tumor that can grow indefinitely and/or spread from original growth site to other locations in the body

67

segregation

separation of alleles/homologous chromosomes from each other during meiosis

68

fertilization

union of gametes

AKA syngamy

69

daughter chromosomes

separated chromatids from the beginning of anaphase onward

(mitosis)

70

histone

one of the group of proteins froming the core of a nucleosome

71

nucleosome

structural unit of eukaryotic chromosome

consists of DNA and histones

72

somatic cell

cells within body that are not specialized for reproduction

73

asexual reproduction

reproduction without sex

74

benign

characteristic of a tumor that grows to a certain size then stops

usually with a gibrous capsule surrounding mass of cells

75

homology

similarity between two or more features dur to inheritance from a common ancestor

76

retinoblastoma protein

protein that inhibits animal cell from passing through restriction point

inactivation of this protein is necessary for the cell cycle to proceed

77

disorganized mass of cells

tumor

78

haplontic

type of life cycle

zygote is the only diploid cell; mitosis occurs only in haploid cells

79

diplontic

type of life cycle

gametes are the only haploid cells; mitosis occurs only in diploid cells

80

metastasis

spread of cancer cells from their original site to other parts of the body

81

sister chromatid

each pair of newly replicated chromatids

82

S phase

stage within interphase when DNA replication occurs

83

tetrad

pair of homologous chromosomes containing 4 chromatids

(prophase I of meiosis)

84

oncogene

gene that codes for protein that stimulates cell division

85

oncogene mutations lead to ____

excessive cell proliferation that can give rise to cancer

86

cell cycle

stages through which cell passes between one division and the next

includes all stages of interphase and mitosis

87

telophase

final stage of mitosis/meiosis during which 
chromosome become diffuse
nuclear envolopes reform
nucleoli begin to reappear in daughter nuclei

88

M phase

cell cycle stage in which mitosis takes place

89

chromosome (bacteria and viruses)

DNA molecule that containes most or all of genetic information of the cell or virus

90

chromosome (eukaryotes)

structure composes of DNA and proteins that bears part of genetic information of the cell

counted based on number of centromeres; can contain one or two chromatids

91

caspase

group of proteases that catalyze cleavage of targe proteins

active in apoptosis

92

binary fission

manner in which prokaryotes reproduce/divide

progeny identical to parent cell

93

kinetochore

structure on a centromere to which microtubules attach

94

polyploid

cell or organism containing more than 2 complete sets of chromosomes

95

cytokinesis

division of cytoplasm of a dividing cell

96

replication

duplication of genetic material

97

translocation

rare mutational event that moves a portion of a chromosome to a new location, generally on a nonhomologous chromosome

98

apoptosis

series of genetically programmed events leading to cell death

99

karyotype

number, forms, and types of chromosomes within a cell

100

clone

genetically identical cells or organisms produced from common ancestor or by asexual means

 

101

meiosis

division of a diploid nucleus to produce 4 haploid daughter cells

102

centromere

region where sister chromatids join

103

nondisjunction

failure of sister chromatids to separate during meiosis II or mitosis

OR failure of homologous chromos to separate in meiosis I

104

nondisjunction results in ____

aneuploidy

105

trisomic

containing 3 members of a chromosome pair (instead of the usual 2)

106

restriction point (R)

specific time during G1 at which cell becomes committed to undergo the rest of the cell cycle

107

G2

gap between S phase and onset of mitosis (M phase)

108

array of microtubules emanating from both poles of a dividing cell

spindle

109

recombinant

description of when genetic materials originally present in two individuals end up in the same haploid complement of genes.

110

homolog

one of a pair of chromosomes that have the same overall genetic composition and sequence

111

gene that codes for a protein that inhibits cell proliferation

inactive in cancer cells

tumor suppressor

112

paired organelle

helps to organize microtubule in animal & protict cells during nuclear division

centriole

113

chemical signal that stimulates cell division

growth factor

114

begins with the disintegration of the nuclear envelope

prometaphase

115

nucleic acid-protein complex that makes up eukaryotic chromosomes

chromatin

116

protein invovled in chromatid binding

cohesin

117

condition in which one or more chromosomes is either lacking or present in excess

due to "incorrect" cell division

aneuploidy

118

cell created by union of two gametes

earliest stage of diploid generation

zygote

119

nuclear division in eukaryotes leading to 2 identital daughter nuclei

mitosis

120

period between cell divisions

consists of G1, S, and G2 

interphase

121

parallel alignment/pairing of homologous chromosomes during meiosis

synapsis

122

cellular division stage in which chromosomal centromeres all lie on equatorial division plane 

metaphase

123

gap stage between end of mitosis and onset of S phase

G1

124

containing one copy of chromosomal set

1n or n

haploid

125

description of organism that has one less than normal diploid number of chromosomes

e.g. only one X chromosome (Turner's syndrome)

monosomic

126

division stage in which separation of sister chromatids (mitosis) or paired homologs (meiosis I) begins/occurs

anaphase

127

major microtubule organizing center of animal cell

centrosome

128

random separation of genes into gametes such that inheritance of genes is random

independent assortment

129

mature sexual reproductive cell

e.g. egg or sperm

gamete

130

X-shaped connection between paired homologous chromosomes during prophase I or meiosis

required for cross-over

chiasma

131

reproduction via union of gametes

sexual reproduction

132

mechanism by which linked genes undergo recombination

exchange of corresponding segments between two homologous chromatids

crossing over

133

having chromosome complement consisting of two homologs of each chromosome

2n

diploid

134

Cdk
(long form)

cyclin-dependent kinase
(abbreviation)

135

protein kinase with target proteins involved in transitions within cell cycle

active with cyclins bound to protein kinase

cyclin-dependent kinase (Cdk)

136

protein required for activation of Cdk and as a result, causes transition in cell cycle

cyclin

137

division stage during which chromosomes condence from blobby chromatin to discrete, compact chromosomes

prophase

138

premature cell death caused by external agents, e.g. a toxin

necrosis

139

succession of multicellular haploid & diploid phases in some seuxally reproducing organisms (PLANTS!)

alternation of generations

140

characteristic of tumor that can grow indefinitely and/or spread from original growth site to other locations in the body

malignant

141

separation of alleles/homologous chromosomes from each other during meiosis

segregation

142

union of gametes

AKA syngamy

fertilization

143

separated chromatids from the beginning of anaphase onward

(mitosis)

daughter chromosomes

144

one of the group of proteins froming the core of a nucleosome

histone

145

structural unit of eukaryotic chromosome

consists of DNA and histones

nucleosome

146

cells within body that are not specialized for reproduction

somatic cell

147

reproduction without sex

asexual reproduction

148

characteristic of a tumor that grows to a certain size then stops

usually with a gibrous capsule surrounding mass of cells

benign

149

similarity between two or more features dur to inheritance from a common ancestor

homology

150

protein that inhibits animal cell from passing through restriction point

inactivation of this protein is necessary for the cell cycle to proceed

retinoblastoma protein

151

tumor

disorganized mass of cells

152

type of life cycle

zygote is the only diploid cell; mitosis occurs only in haploid cells

haplontic

153

type of life cycle

gametes are the only haploid cells; mitosis occurs only in diploid cells

diplontic

154

spread of cancer cells from their original site to other parts of the body

metastasis

155

each pair of newly replicated chromatids

sister chromatid

156

stage within interphase when DNA replication occurs

S phase

157

pair of homologous chromosomes containing 4 chromatids

(prophase I of meiosis)

tetrad

158

gene that codes for protein that stimulates cell division

oncogene

159

stages through which cell passes between one division and the next

includes all stages of interphase and mitosis

cell cycle

160

final stage of mitosis/meiosis during which 
chromosome become diffuse
nuclear envolopes reform
nucleoli begin to reappear in daughter nuclei

telophase

161

cell cycle stage in which mitosis takes place

M phase

162

DNA molecule that containes most or all of genetic information of the cell or virus

chromosome (bacteria and viruses)

163

structure composes of DNA and proteins that bears part of genetic information of the cell

counted based on number of centromeres; can contain one or two chromatids

chromosome (eukaryotes)

164

group of proteases that catalyze cleavage of targe proteins

active in apoptosis

caspase

165

manner in which prokaryotes reproduce/divide

progeny identical to parent cell

binary fission

166

structure on a centromere to which microtubules attach

kinetochore

167

cell or organism containing more than 2 complete sets of chromosomes

polyploid

168

division of cytoplasm of a dividing cell

cytokinesis

169

duplication of genetic material

replication

170

rare mutational event that moves a portion of a chromosome to a new location, generally on a nonhomologous chromosome

translocation

171

series of genetically programmed events leading to cell death

apoptosis

172

number, forms, and types of chromosomes within a cell

karyotype

173

genetically identical cells or organisms produced from common ancestor or by asexual means

 

clone

174

division of a diploid nucleus to produce 4 haploid daughter cells

meiosis

175

region where sister chromatids join

centromere

176

failure of sister chromatids to separate during meiosis II or mitosis

OR failure of homologous chromos to separate in meiosis I

nondisjunction

177

containing 3 members of a chromosome pair (instead of the usual 2)

trisomic

178

specific time during G1 at which cell becomes committed to undergo the rest of the cell cycle

restriction point (R)

179

gap between S phase and onset of mitosis (M phase)

G2

180

spindle

array of microtubules emanating from both poles of a dividing cell

181

description of when genetic materials originally present in two individuals end up in the same haploid complement of genes.

recombinant

182

one of a pair of chromosomes that have the same overall genetic composition and sequence

homolog