midterm revision Flashcards
1
Q
- The centromere is a region in which
A) chromatids are attached to one another.
B) metaphase chromosomes become aligned.
C) chromosomes are grouped during telophase.
D) new spindle microtubules form.
A
A) chromatids are attached to one another.
2
Q
- Which of the following statements is not true?
A) Mitosis produces new nuclei with exactly the same chromosomal endowment as the
parent nucleus entering mitosis.
B) Mitosis may occur without cytokinesis.
C) Mitosis and cytokinesis are required for asexual reproduction.
D) The mitotic spindles in prokaryotic cells are composed of microtubules.
A
D) The mitotic spindles in prokaryotic cells are composed of microtubules.
3
Q
- Cytokinesis usually, but not always, follows mitosis. If a cell completed mitosis but not
cytokinesis, the result would be a cell with
A) a single large nucleus.
B) high concentrations of actin and myosin.
C) two abnormally small nuclei.
D) two nuclei.
A
D) two nuclei.
4
Q
5. The formation of a cell plate is beginning across the middle of a cell and nuclei are reforming at opposite ends of the cell. What kind of cell is this? A) a plant cell undergoing cytokinesis B) an animal cell in telophase C) an animal cell undergoing cytokinesis D) a plant cell in metaphase
A
A) a plant cell undergoing cytokinesis
5
Q
- The correct sequence of steps in the M phase of the cell cycle is
A) prophase, prometaphase, metaphase, anaphase, telophase.
B) prophase, metaphase, prometaphase, anaphase, telophase.
C) prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis.
D) prometaphase, prophase, metaphase, anaphase, telophase, cytokinesis.
A
C) prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis.
6
Q
- Measurements of the amount of DNA per nucleus were taken on a large number of cells
from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus.
In which stage of the cell cycle was the nucleus with 6 picograms of DNA?
A) G0
B) G1
C) S
D) G2
A
D) G2
7
Q
- If mammalian cells receive a go-ahead signal at the G1 checkpoint, they will usually
A) move directly into telophase.
B) complete the cycle and divide.
C) exit the cycle and switch to a nondividing state.
D) show a drop in MPF concentration
A
B) complete the cycle and divide.
8
Q
9. Cells that are in a non-dividing state are in which phase? A) G0 B) G2 C) G1 D) S
A
A) G0
9
Q
10. a protein maintained at constant levels throughout the cell cycle that requires cyclin to become catalytically active A. Cdk B. MPF C. protein kinase D. cyclin
A
- a protein maintained at constant levels throughout the cell cycle that requires cyclin to
become catalytically active A
10
Q
11. a protein synthesized at specific times during the cell cycle that associates with a kinase to form a catalytically active complex A. Cdk B. MPF C. protein kinase D. cyclin
A
- a protein synthesized at specific times during the cell cycle that associates with a kinase
to form a catalytically active complex D
11
Q
12. a protein complex that acts at the G2 checkpoint to trigger mitosis A. Cdk B. MPF C. protein kinase D. cyclin
A
- a protein complex that acts at the G2 checkpoint to trigger mitosis B
12
Q
- Which of the following is true concerning cancer cells?
A) They do not exhibit density-dependent inhibition when growing in culture.
B) The may be considered immortal.
C) They are generally not subject to cell cycle controls.
D) All of the above
A
D) All of the above
13
Q
14. During prophase a homologous pair of chromosomes consists of A) four chromosomes and two chromatids. B) two chromosomes and two chromatids. C) two chromosomes and four chromatids. D) one chromosome and two chromatids.
A
C) two chromosomes and four chromatids.
14
Q
- Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes
with the assembly of microtubules, its effectiveness must be related to
A) disruption of mitotic spindle formation.
B) inhibition of regulatory protein phosphorylation.
C) suppression of cyclin production.
D) myosin denaturation and inhibition of cleavage furrow formation.
A
A) disruption of mitotic spindle formation.
15
Q
- Which of the following differentiates between independent assortment and segregation?
A) The law of segregation requires describing two or more genes relative to one another.
B) The law of segregation requires having two or more generations to describe.
C) The law of independent assortment is accounted for by observations of prophase I.
D) The law of independent assortment requires describing two or more genes relative to one
another.
A
D) The law of independent assortment requires describing two or more genes relative to one
another.
16
Q
- Which of the following statements about genes is incorrect?
A) Genes correspond to segments of DNA.
B) Many genes contain the information needed for cells to synthesize enzymes and other
proteins.
C) During fertilization, both the sperm and the ovum contribute genes to the resulting
fertilized egg.
D) Under normal circumstances, each chromosome contains precisely one gene.
A
D) Under normal circumstances, each chromosome contains precisely one gene.
17
Q
- Mendel crossed yellow seeded and green seeded pea plants and then allowed the
offspring to self-pollinate to produce an F2 generation. The results were 6022 yellow and
2001 green seeds. The allele for green seeds had what relationship over the allele for yellow
seeds?
A) dominant
B) incomplete dominant
C) codominant
D) recessive
A
D) recessive
18
Q
19. At which stage of mitosis are chromosomes photographed in the preparation of a karyotype? A) prophase B) metaphase C) anaphase D) telophase
A
B) metaphase
19
Q
- There is good evidence for linkage when
A) two genes occur together in the same gamete.
B) a gene is associated with a specific phenotype.
C) two genes work together to control a specific characteristic.
D) genes do not segregate independently during meiosis.
A
D) genes do not segregate independently during meiosis.
20
Q
- In the cells of many eukaryotic species, the nuclear envelope has to disappear to permit
which of the following events in the cell cycle?
A) DNA synthesis
B) attachment of microtubules to kinetochores
C) separation of the centrosomes
D) condensation of the chromosomes
A
B) attachment of microtubules to kinetochores
21
Q
- After telophase I of meiosis, the chromosomal makeup of each daughter cell is
A) diploid, and the chromosomes are composed of a single chromatid.
B) diploid, and the chromosomes are composed of two chromatids.
C) haploid, and the chromosomes are composed of a single chromatid.
D) haploid, and the chromosomes are composed of two chromatids.
A
D) haploid, and the chromosomes are composed of two chromatids.
22
Q
I. prophase I II. metaphase I III. anaphase I IV. telophase I V. prophase II VI. metaphase II VII. anaphase II VIII. telophase II 24. Synapsis of homologous pairs occurs; crossing over may occur. A) I B) II C) IV D) VI
A
A) I
23
Q
I. prophase I II. metaphase I III. anaphase I IV. telophase I V. prophase II VI. metaphase II VII. anaphase II VIII. telophase II 23. Tetrads of chromosomes are aligned at the centre of the cell; independent assortment soon follows. A) I B) II C) IV D) VII
A
B) II
24
Q
25. Centromeres of sister chromatids uncouple and chromatids separate. A) II B) III C) IV D) VII
A
D) VII
25
Q
26. Which of the following happens at the conclusion of meiosis I? A) Homologous chromosomes are separated. B) The chromosome number is conserved. C) Sister chromatids are separated. D) Four daughter cells are formed.
A
A) Homologous chromosomes are separated.
26
Q
27. In the cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC? A) 1/32 B) 1/4 C) 1/64 D) 1/8
A
C) 1/64 (1/4 x ¼ x ¼)
27
Q
- A plant with purple flowers is allowed to self-pollinate. Generation after generation, it
produces purple flowers. This is an example of
A) hybridization.
B) incomplete dominance.
C) pure breeding.
D) the law of segregation.
A
C) pure breeding.
28
Q
- A cross between homozygous purple-flowered and homozygous white-flowered pea
plants results in offspring with purple flowers. This demonstrates
A) the blending model of genetics.
B) true-breeding.
C) dominance.
D) a dihybrid cross.
A
C) dominance.
29
Q
- The F1 offspring of Mendel’s classic pea cross always looked like one of the two parental
varieties because
A) one allele was completely dominant over another.
B) each allele affected phenotypic expression.
C) the traits blended together during fertilization.
D) no genes interacted to produce the parental phenotype.
A
A) one allele was completely dominant over another.
30
Q
31. A 9:3:3:1 phenotypic ratio is characteristic of which of the following? A) a monohybrid cross B) a dihybrid cross C) a trihybrid cross D) linked genes
A
B) a dihybrid cross
31
Q
- P = purple, pp = white. The offspring of a cross between two heterozygous purpleflowering plants (Pp × Pp) results in
A) all purple-flowered plants.
B) purple-flowered plants and white-flowered plants.
C) two types of white-flowered plants: PP and Pp.
D) all white-flowered plants.
A
B) purple-flowered plants and white-flowered plants.
32
Q
- Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long
tails (t). What fraction of the progeny of the cross BbTt × BBtt will have black fur and long
tails?
A) 1/16
B) 3/16
C) 3/8
D) 1/2
A
D) 1/2
33
Q
- In snapdragons, heterozygotes have pink flowers, whereas homozygotes have red or
white flowers. When plants with red flowers are crossed with plants with white flowers, what
proportion of the offspring will have pink flowers?
A) 0%
B) 25%
C) 50%
D) 100%
A
D) 100%
34
Q
- Sally has just given birth to a baby girl. The medical professional involved in her care has
advised Sally that mosaic Down Syndrome is suspected in her baby. Sally had received
prenatal screening which had suggested a low likelihood of a Down syndrome baby, so the
diagnosis came as quite a shock. A sample of the baby’s blood has been taken for karyotype
analysis. If the suspected mosaicism is confirmed, the karyotype analysis is most likely to
show the following:
A) Three of chromosome 21 in all 20 cells analysed
B) Three of chromosome 21 in some of the 20 cells analysed
C) Three of chromosome 18 in all 20 cells analysed
D) Three of chromosome 18 in some of the 20 cells analysed
A
B) Three of chromosome 21 in some of the 20 cells analysed
35
Q
- Further to the situation described in question 35. above, the baby’s karyotype has indeed
revealed mosaic Down Syndrome. It is more likely that the molecular event leading to the
mosaicism was
A) a non-disjunction during meiosis I in oogenesis
B) a non-disjunction during meiosis II in oogenesis
C) a non-disjunction during cell division in the early embryo
D) a chromosomal duplication during meiosis in oogenesis
A
C) a non-disjunction during cell division in the early embryo
36
Q
- In a cell in which n = 3, the independent assortment of chromosomes during meiosis can
by itself give rise to how many genetically different gametes.
A) 8
B) 16
C) 4
D) 10
A
A) 8
37
Q
38. In the following list, which term is least related to the others? A) hemophilia B) autosome C) sex-linked genes D) color blindness
A
B) autosome
38
Q
39. A man who carries an X-linked allele will pass it on to A) all of his daughters. B) half of his daughters. C) all of his sons. D) half of his sons.
A
A) all of his daughters.
39
Q
40. Which of these syndromes afflicts mostly males? A) Turner syndrome B) Down syndrome C) colour blindness D) cri du chat syndrome
A
C) colour blindness
40
Q
41. A man who carries a Y linked allele will pass it on to A) 50% of his sons B) 25% of his sons C) all of his sons D) 75% of his sons
A
C) all of his sons
41
Q
- Punnett squares are used for
A) determining the DNA sequence of a given gene
B) predicting the outcome of gene crosses
C) determining the degree of gene mutation
D) predicting the sex of offspring
A
B) predicting the outcome of gene crosses
42
Q
43. The mode of inheritance of cystic fibrosis is A) Autosomal dominant B) Autosomal recessive C) X-linked dominant D) X-linked recessive
A
B) Autosomal recessive
43
Q
44. The AB blood group in humans is an example of A) polygenic inheritance B) co-dominance C) epistasis D) lethal alleles
A
B) co-dominance
44
Q
45. Patau Syndrome is characterised by A) Trisomy 18 B) Translocation between chr13 and chr21 C) Trisomy 13 D) Trisomy 21
A
C) Trisomy 13
