Final Exam Flashcards
Which of the following is released by platelets in the vicinity of an injury? A. Cdk B. cyclin C. PDGF D. MPF
C. PDGF
A research team began a study of a cultured cell line. Their preliminary observations showed them that the cell line did not exhibit either density-dependent inhibition or anchorage dependence. What could they conclude right away?
A. The cells are unable to form spindle microtubules.
B. The cells show characteristics of tumors.
C. They have altered the series of cell cycle phases.
D. They were originally derived from an elderly organism.
B. The cells show characteristics of tumors
If there are 20 centromeres in a cell at anaphase, how many chromosomes are there in each daughter cell following cytokinesis? A. 80 B. 10 C. 40 D. 20
B. 10
Movement of the chromosomes during anaphase would be most affected by a drug that prevents \_\_\_\_\_. A. elongation of microtubules B. formation of a cleavage furrow C. nuclear envelope breakdown D. shortening of microtubules
D. shortening of microtubules
The drug cytochalasin B blocks the function of actin. Which of the following aspects of the cell cycle would be most disrupted by cytochalasin B?
A. cleavage furrow formation and cytokinesis
B. spindle attachment to kinetochores
C. cell elongation during anaphase
D. spindle formation
A. cleavage furrow formation and cytokinesis
In a plant’s sexual life cycle _____.
A. gametophytes produce gametes by meiosis
B. gametophytes produce gametes by mitosis
C. sporophytes produce gametes by mitosis
D. sporophytes produce gametes by meiosis
B. gametophytes produce gametes by mitosis
Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do all sexual life cycles have in common?
I. Alternation of generations
II. Meiosis
III. Fertilization
IV. Gametes
V. Spores
A. I, II, and IV
B. II, IV, and V
C. I, II, III, IV, and V
D. II, III, and IV
D. II, III, and IV
Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cells? A. 16 B. 8 C. 32 D. 64
C. 32
Which of the following is a true statement about sexual vs. asexual reproduction?
A. Asexual reproduction, but not sexual reproduction, is characteristic of plants and fungi.
B. In sexual reproduction, individuals transmit half of their nuclear genes to each of their offspring.
C. Asexual reproduction produces only haploid offspring.
D. In asexual reproduction, offspring are produced by fertilization without meiosis.
B. In sexual reproduction, individuals transmit half of their nuclear genes to each of their offspring.
Imagine that there are twenty-five different species of protists living in a tide pool. Some of these species reproduce both sexually and asexually, and some of them can reproduce only asexually. The pool gradually becomes infested with disease-causing viruses and bacteria. Which species are more likely to thrive in the changing environment?
A. the asexually reproducing species
B. Sexually and asexually reproducing species are equally likely to thrive.
C. the sexually reproducing species
D. protists cannot survive in a tide pool
C. the sexually reproducing species
How do cells at the completion of meiosis compare with cells that are in prophase of meiosis I? They have _____.
A. half the number of chromosomes and one-fourth the amount of DNA.
B. half the number of chromosomes and half the amount of DNA.
C. the same number of chromosomes and half the amount of DNA.
D. half the amount of cytoplasm and twice the amount of DNA.
A. half the number of chromosomes and one-fourth the amount of DNA.
Which of the following happens at the conclusion of meiosis I?
A. The chromosome number per cell remains the same.
B. Homologous chromosomes of a pair are separated from each other.
C. Sister chromatids are separated.
D. Sister chromatids are separated.
B. Homologous chromosomes of a pair are separated from each other.
When we first see chiasmata under a microscope, we know that \_\_\_\_\_. A. anaphase II has occurred B. meiosis II has occurred C. prophase I is occurring D. separation of homologs has occurred
C. prophase I is occurring
Homologous pairs of chromosomes align opposite of each other at the equator of a cell during \_\_\_\_\_. A. mitosis metaphase B. meiosis metaphase I C. meiosis telophase II D. meiosis metaphase II
B. meiosis metaphase I
Which of the following occurs in meiosis but not in mitosis?
A. alignment of chromosomes at the equator
B. synapsis of chromosomes
C. condensation of chromosomes
D. chromosome replication
B. synapsis of chromosomes
The bulldog ant has a diploid number of two chromosomes. Therefore, following meiosis, each daughter cell will have a single chromosome. Diversity in this species may be generated by mutations and _____.
A. nothing else
B. independent assortment
C. crossing over
D. crossing over and independent assortment
D. crossing over and independent assortment
A triploid cell contains sets of three homologous chromosomes. If a cell of a usually diploid species with 42 chromosomes per cell is triploid, this cell would be expected to have which of the following?
A. 63 chromosomes in 21 sets of 3
B. 63 chromosomes in 31 half pairs
C. 21 chromosome pairs and 21 unique chromosomes
D. 63 chromosomes, each with three chromatids
A. 63 chromosomes in 21 sets of 3
The somatic cells of a privet shrub each contain 46 chromosomes. How do privet chromosomes differ from the chromosomes of humans, who also have 46?
A. Genes of privet chromosomes are significantly different than those in humans.
B. Privet sex cells have chromosomes that can synapse with human chromosomes in the laboratory.
C. Privet cells cannot reproduce sexually.
D. Privet shrubs must be metabolically more like animals than like other shrubs.
A. Genes of privet chromosomes are significantly different than those in humans.
In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosomes of the pair have in common?
A. length, centromere position, and staining pattern only
B. length, centromere position, staining pattern, and traits coded for by their genes
C. They have nothing in common except that they are X-shaped.
D. length and position of the centromere only
B. length, centromere position, staining pattern, and traits coded for by their genes
For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes? A. about 1000 B. 23 C. 46 D. about 8 million
D. about 8 million
Mendel continued some of his experiments into the F2 or F3 generation to _____.
A. distinguish which alleles were segregating
B. observe whether or not a recessive trait would reappear
C. obtain a larger number of offspring on which to base statistics
D. observe whether or not the dominant trait would reappear
B. observe whether or not a recessive trait would reappear
The individual with genotype AaBbCCDdEE can make many kinds of gametes. Which of the following is the major reason?
A. different possible assortment of chromosomes into gametes
B. the tendency for dominant alleles to segregate together
C. crossing over during prophase I
D. recurrent mutations forming new alleles
A. different possible assortment of chromosomes into gametes
Why did the F1 offspring of Mendel’s classic pea cross always look like one of the two parental varieties?
A. No genes interacted to produce the parental phenotype.
B. Each allele affected phenotypic expression.
C. One allele was dominant.
D. The traits blended together during fertilization.
C. One allele was dominant.
Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division? A. anaphase I of meiosis B. anaphase II of meiosis C. metaphase II of meiosis D. prophase I of meiosis
A. anaphase I of meiosis
In the cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC? A. 1/16 B. 1/64 C. 1/4 D. 1/8
B. 1/64
Which of the following calculations require that you utilize the addition rule?
A. Calculate the probability of children with both cystic fibrosis and polydactyly when parents are each heterozygous for both genes.
B. Calculate the probability of a child having either sickle-cell anemia or cystic fibrosis if parents are each heterozygous for both.
C. Calculate the probability of black offspring from the cross AaBb × AaBb, where B is the symbol for black.
D. Calculate the probability of each of four children having cystic fibrosis if the parents are both heterozygous.
B. Calculate the probability of a child having either sickle-cell anemia or cystic fibrosis if parents are each heterozygous for both.
A man who is an achondroplastic dwarf with normal vision marries a color-blind woman of normal height. The man's father was six feet tall, and both the woman's parents were of average height. Achondroplastic dwarfism is autosomal dominant, and red-green color blindness is X-linked recessive. How many of their daughters might be expected to be color-blind dwarfs? A. half B. three out of four C. none D. one out of four
C. none
Skin color in a certain species of fish is inherited via a single gene with four different alleles. How many different types of gametes would be possible in this system? A. 4 B. 8 C. 16 D. 2
A. 4
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 as follows: 6022 yellow and 2001 green (8023 total). The allele for green seeds has what relationship to the allele for yellow seeds? A. codominant B. recessive C. dominant D. incomplete dominant
B. recessive
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. If true-breeding red long radishes are crossed with true-breeding white oval radishes, the F1 will be expected to be which of the following? A. purple and oval B. white and long C. purple and long D. red and long
C. purple and long
Gray seed color in peas is dominant to white. Assume that Mendel conducted a series of experiments where plants with gray seeds were crossed among themselves, and the following progeny were produced: 302 gray and 98 white.
(a) What is the most probable genotype of each parent?
(b) Based on your answer in (a) above, what genotypic and phenotypic ratios are expected in these progeny? (Assume the following symbols: G = gray and g = white.)
A. (a) Gg × Gg; (b) genotypic = 1:2:1, phenotypic = 3:1
B. (a) gg × Gg; (b) genotypic = 1:2, phenotypic = 3:1
C. (a) GG × Gg; (b) genotypic = 1:2:1, phenotypic = 2:1
D. (a) GG × gg; (b) genotypic = 3:1, phenotypic = 1:2:1
A. (a) Gg × Gg; (b) genotypic = 1:2:1, phenotypic = 3:1
Inheritance patterns cannot always be explained by Mendel’s models of inheritance. If a pair of homologous chromosomes fails to separate during meiosis I, select the choice
that shows the chromosome number of the four resulting gametes with respect to the normal haploid number (n)?
A. n+1; n+1; n-1; n-1
B. n+1; n+1; n; n
C. n+1; n-1; n; n
D. n+1; n-1; n-1; n-1
A. n+1; n+1; n-1; n-1
Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all. A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce_____.
A. It is impossible to determine the phenotypes of the progeny.
B. 25% sharp-spined, 50% dull-spined, 25% spineless progeny
C. all sharp-spined progeny
D. 50% sharp-spined, 50% dull-spined progeny
C. all sharp-spined progeny
One of two major forms of a human condition called neurofibromatosis (NF 1) is inherited as a dominant gene, although it may range from mildly to very severely expressed. Which of the following is the best explanation for why a young, affected child is the first in her family to be diagnosed?
A. The mother carries the gene but does not express it.
B. The child has one more chromosome than either of the parents.
C. The condition skipped a generation in the family.
D. One of the parents has a mild expression of the gene.
D. One of the parents has a mild expression of the gene.
Skin color in a certain species of fish is inherited via a single gene with four different alleles. One fish of this type has alleles 1 and 3 (S1S3) and its mate has alleles 2 and 4 (S2S4). If each allele confers a unit of color darkness such that S1 has one unit, S2 has two units, and so on, then what proportion of their offspring would be expected to have five units of color? A. 0 B. 1/8 C. 1/4 D. 1/2
D. 1/2
Which of the following statements about independent assortment and segregation is correct?
A. The law of segregation requires describing two or more genes relative to one another.
B. The law of independent assortment requires describing two or more genes relative to one another.
C. The law of segregation is accounted for by anaphase of mitosis.
D. The law of independent assortment is accounted for by observations of prophase I.
B. The law of independent assortment requires describing two or more genes relative to one another.
Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following?
A. the allele for blue hydrangea being completely dominant
B. the knowledge that multiple alleles are involved
C. the alleles being codominant
D. environmental factors such as soil pH
D. environmental factors such as soil pH
Mendel's second law of independent assortment has its basis in which of the following events of meiosis I? A. crossing over B. synapsis of homologous chromosomes C. separation of cells at telophase D. alignment of tetrads at the equator
D. alignment of tetrads at the equator
Genomic imprinting is generally due to the addition of methyl (-CH3) groups to C nucleotides and chemical histone changes to silence a given gene. If this depends on the sex of the parent who transmits the gene, which of the following must be true?
A. Methylation must be reversible in ovarian and testicular cells.
B. Methylation of this kind must occur more in males than in females.
C. The imprints are transmitted only to gamete-producing cells.
D. Genes required for early development stages must not be imprinted.
A. Methylation must be reversible in ovarian and testicular cells.
Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their twenties. How likely is it for a woman to have this condition?
A. Only if a woman is XXX could she have this condition.
B. Women can never have this condition.
C. One-half of the daughters of an affected father and a carrier mother could have this condition.
D. One-fourth of the daughters of an affected man would have this condition.
C. One-half of the daughters of an affected father and a carrier mother could have this condition.
The cyclin component of MPF is destroyed toward the end of which phase? A. S B. G2 C. G1 D. M
D. M
The M-phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does not happen, cells would most likely be arrested in \_\_\_\_\_. A. prometaphase B. prophase C. metaphase D. telophase
C. metaphase
Which of the following is a protein maintained at steady levels throughout the cell cycle that requires cyclin to become catalytically active? A. MPF B. Cdk C. cyclin D. PDGF
B. Cdk
Besides the ability of some cancer cells to overproliferate, what else could logically result in a tumor?
A. inability of chromosomes to meet at the metaphase plate
B. inability to form spindles
C. lack of appropriate cell death
D. changes in the order of cell cycle stages
C. lack of appropriate cell death
A research team began a study of a cultured cell line. Their preliminary observations showed them that the cell line did not exhibit either density-dependent inhibition or anchorage dependence. What could they conclude right away?
A. The cells are unable to form spindle microtubules.
B. They were originally derived from an elderly organism.
C. They have altered the series of cell cycle phases.
D. The cells show characteristics of tumors.
D. The cells show characteristics of tumors.
Several organisms, primarily protists, have what are called intermediate mitotic organization.
What is the most probable hypothesis about these intermediate forms of cell division?
A. They rely on totally different proteins for the processes they undergo.
B. They represent a form of cell reproduction, which must have evolved completely separately from those of other organisms.
C. They may be more closely related to plant forms that also have unusual mitosis.
D. They show some but not all of the evolutionary steps toward complete mitosis.
D. They show some but not all of the evolutionary steps toward complete mitosis.
Cells from advanced malignant tumors often have very abnormal chromosomes and an abnormal number of chromosomes. What might explain the association between malignant tumors and chromosomal abnormalities?
A. Cell cycle checkpoints are not in place to stop cells with chromosome abnormalities.
B. Cancer cells are no longer anchorage-dependent.
C. Cancer cells are no longer density-dependent.
D. Transformation introduces new chromosomes into cells.
A. Cell cycle checkpoints are not in place to stop cells with chromosome abnormalities.
Some cells have several nuclei per cell. How could such multinucleated cells be explained?
A. The cell underwent repeated mitosis with simultaneous cytokinesis.
B. The cell had multiple S phases before it entered mitosis.
C. The cell underwent repeated cytokinesis but no mitosis.
D. The cell underwent repeated mitosis, but cytokinesis did not occur.
D. The cell underwent repeated mitosis, but cytokinesis did not occur.
If there are 20 duplicated chromosomes in a cell, how many centromeres are there? A. 40 B. 10 C. 30 D. 20
D. 20
If there are 20 centromeres in a cell at anaphase, how many chromosomes are there in each daughter cell following cytokinesis? A. 40 B. 20 C. 10 D. 80
C. 10
Kinetochore microtubules assist in the process of splitting centromeres by _____.
A. phosphorylating the centromere, thereby changing its conformation
B. using motor proteins to split the centromere at specific arginine residues
C. sliding past each other like actin filaments
D. creating tension by pulling toward opposite poles
D. creating tension by pulling toward opposite poles
The microtubule-organizing center found in animal cells is an identifiable structure present during all phases of the cell cycle. Specifically, it is known as the \_\_\_\_\_. A. microtubulere B. kinetochore C. centromere D. centrosome
D. centrosome
Neurons and some other specialized cells divide infrequently because they \_\_\_\_\_. A. have entered into G0 B. show a drop in MPF concentration C. can no longer bind Cdk to cyclin D. no longer have active nuclei
A. have entered into G0
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 did the nucleus contain 6 picograms of DNA? A. S B. G1 C. G2 D. M
C. G2
At which phase are centrioles beginning to move apart in animal cells? A. prophase B. prometaphase C. metaphase D. anaphase
A. prophase
Scientists isolate cells in various phases of the cell cycle. They find a group of cells that have 1.5 times more DNA than G1 phase cells. The cells of this group are _____.
A. in the M phase of the cell cycle
B. in the G2 phase of the cell cycle
C. between the G1 and S phases in the cell cycle
D. in the S phase of the cell cycle
D. in the S phase of the cell cycle
For a chemotherapeutic drug to be useful for treating cancer cells, which of the following is most desirable?
A. It is safe enough to limit all apoptosis.
B. It interferes with cells entering G0.
C. It interferes with rapidly dividing cells.
D. It does not alter metabolically active cells.
C. It interferes with rapidly dividing cells.
During which phase of mitosis do the chromatids become chromosomes? A. anaphase B. telophase C. prophase D. metaphase
A. anaphase
The drug cytochalasin B blocks the function of actin. Which of the following aspects of the cell cycle would be most disrupted by cytochalasin B?
A. cleavage furrow formation and cytokinesis
B. spindle formation
C. spindle attachment to kinetochores
D. cell elongation during anaphase
A. cleavage furrow formation and cytokinesis
Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol disrupts microtubule formation. Surprisingly, this stops mitosis. Specifically, Taxol must affect _____.
A. the structure of the mitotic spindle
B. anaphase
C. formation of the centrioles
D. chromatid assembly
A. the structure of the mitotic spindle
