Genetics Exam 1
A biologist examines a series of cells and counts 160 cells in interphase, 20 cells in prophase, 6 cells in prometaphase, 2 cells in metaphase, 7 cells in anaphase, and 5 cells in telophase. If the complete cell cycle requires 24 hours, what is the average duration of the M Phase in these cells? A) 4.8 hours B) 6.2 hours C) 9.6 hours D) 48 hours E) Unable to determine from the data provided
A
A cell has eight chromosomes in G1 of interphase. Indicate how many chromosomes and DNA molecules are present at anaphase II of meiosis. A) 8 chromosomes and 8 DNA molecules B) 8 chromosomes and 16 DNA molecules C) 16 chromosomes and 16 DNA molecules D) 16 chromosomes and 32 DNA molecules E) 4 chromosomes and 8 DNA molecules
A
A cell in G1 of interphase has 12 chromosomes. How many chromosomes and DNA molecules will be found per cell when this original cell progresses through cytokinesis following meiosis II? A) 6 chromosomes and 6 DNA molecules per cell B) 6 chromosomes and 12 DNA molecules per cell C) 12 chromosomes and 12 DNA molecules per cell D) 12 chromosomes and 24 DNA molecules per cell E) 24 chromosomes and 24 DNA molecules per cell
A
A primary oocyte divides to give rise to a secondary oocyte and a first polar body. The secondary oocyte then divides to give rise to an ovum and a second polar body. Is the genetic information found in the second polar body identical with that in the ovum and why? A) No, it is not because genetic recombination in prophase I will have generated new and different arrangements of genetic material for the sister chromatids that separated during anaphase II. B) Yes, it is because of the two sister chromatids separated from the same chromosome and separated during anaphase II of meiosis. C) Yes, it is because they are both products of meiosis I, which results in the separation of sister chromatids from the same chromosome. D) Answers B and C are both correct. E) None of the above is correct.
A
Meiosis generally produces all of the following EXCEPT: A) diploid cells B) four cells instead of two C) variability due to crossing over D) variability due to random assortment
A
Name the stage in mitosis where the nuclear envelope disintegrates and the sister chromatids become attached to microtubules from opposite centrosomes. A) Prophase B) Metaphase C) Anaphase D) Telophase
A
Name the stage of mitosis where the chromosomes initially condense and centrosomes move apart. A) Prophase B) Prometaphase C) Metaphase D) Anaphase E) Telophase
A
Of the following, which is a difference between prokaryotic and eukaryotic cells? A) Eukaryotic cells have a nuclear envelope surrounding the genetic material, whereas prokaryotes have no nucleus. B) Prokaryotic cells have multiple paired chromosomes, but eukaryotic cells have only one. C) Prokaryotic cells have linear DNA, whereas eukaryotes have circular DNA. D) Plasmids contain some genes for eukaryotes, whereas organelles contain some genes for prokaryotes. E) Eukaryotes have histone proteins, whereas prokaryotes do not.
A
On average, what proportion of the genome in an uncle and niece would be exactly the same if no crossing over occurred? (For the purposes of this question only, we will ignore the special case of the X and Y sex chromosomes and assume that all genes are located on non-sex chromosomes.) A) One-fourth of their genomes B) One-third of their genomes C) One-half of their genomes D) Three-fourths of their genomes E) It cannot be determined from the information given.
A
On average, what proportion of the genome in two half siblings would be exactly the same if no crossing over occurred? (For the purposes of this question only, we will ignore the special case of the X and Y sex chromosomes and assume that all genes are located on non-sex chromosomes.) A) One-fourth of their genomes B) One-third of their genomes C) One-half of their genomes D) Three-fourths of their genomes E) It cannot be determined from the information given.
A
The natural ends of eukaryotic chromosomes that serve to stabilize the ends of the chromosomes are the ______________________. A) telomeres B) origins of replication C) centromeres D) kinetochore proteins E) histone proteins
A
What are the major results of meiosis? A) Production of haploid daughter cells from a diploid original cell that are genetically different from each other and from the original cell B) Production of diploid daughter cells from a haploid original cell C) Production of haploid daughter cells from a diploid original cell that are genetically identical to each other and to the original cell D) Production of diploid daughter cells from a diploid original cell that are genetically different from each other and from the original cell E) None of the above is correct.
A
What is the difference between genotype and phenotype? A) Phenotype refers to the physical manifestation of a trait, whereas genotype refers to the genes or sets of alleles found within an individual. B) Phenotype refers to the sets of alleles found within an individual, whereas genotype refers to the physical expression of a trait. C) Genotype refers to the physical expression of the genes or sets of alleles found within an individual, whereas phenotype refers to the physical manifestation of a trait. D) Genotype refers to the physical location of a gene on a chromosome, whereas phenotype refers to the total number of alleles found within an individual. E) Genotype and phenotype are essentially two terms for the same thing.
A
What would be the consequences to the outcome of meiosis if shugoshin fails to break down after anaphase I of meiosis? A) Sister chromatids could fail to separate during anaphase II. B) Homologous pairs could separate prior to anaphase I. C) Sister chromatids could separate along with homologous pairs during anaphase I. D) Homologous pairs could fail to separate during anaphase I. E) The absence of shugoshin during meiosis is likely to have no impact on mitosis.
A
What would be the consequences to the outcome of mitosis if mitotic cohesin fails to form early during mitosis? A) Sister chromatids could separate prior to anaphase. B) Homologous pairs could separate prior to anaphase. C) Sister chromatids could fail to separate during anaphase. D) Homologous pairs could fail to separate during anaphase. E) Failure of cohesin to form is likely to have no impact on mitosis
A
Which of the following crosses would likely produce a genotypic ratio of 1:2:1? A) Aa × Aa B) Aa × aa C) AA × Aa D) aa × aa
A
Which of the following organisms does NOT have the characteristics that would make it suitable for studies of the principles of inheritance? A) Loxodonta africana, an elephant B) Saccharomyces cerevisiae, a yeast C) Arabidopsis thaliana, a plant D) Caenorhabditis elegans, a nematode E) Drosophila melanogaster, a fruit fly
A
White (w) coat color in guinea pigs is recessive to black (W). In 1909, W. E. Castle and J. C. Phillips transplanted an ovary from a black guinea pig into a white female whose ovaries had been removed. They then mated this white female with a white male. All the offspring from the mating were black in color (W. E. Castle and J. C. Phillips, 1909, Science 30:312-313). Which of the following statements BEST explains the results of this cross? A) The color of the offspring was determined by genes in the transplanted ovary, not the genes of the female who gave birth. B) The black coats likely arose from mutations that occurred from the transplanting of the ovaries. C) The eggs from the ovary of the black coat guinea pig were likely fertilized by a black-coated male guinea pig before the transfer. D) The researchers failed to remove the original ovaries of the white female before adding the ovaries from the black guinea pig. E) The white female was heterozygous for the black trait, which explains how the offspring inherited the trait for black coats.
A
Why do sister chromatids remain together in anaphase I of meiosis but separate in anaphase of mitosis and anaphase II of meiosis? A) Shugoshin protects cohesin at the centromeres in anaphase I, protecting it from the action of separase. B) Separase is active only in anaphase II of meiosis and in anaphase of mitosis. C) Cohesin protects shugoshin at the centromeres in anaphase I, protecting it from the action of separase. D) The enzyme separase becomes active at the end of metaphase in both mitosis and meiosis II cleaves the securin protein complex holding the sister chromatids together. E) None of the above is correct.
A
Why was the chromosome theory of heredity important? A) It explained the biological basis for Mendel's principles of heredity. B) It determined whether DNA or protein was the genetic material. C) It described the difference between genotype and phenotype. D) It helped Mendel to understand the results of his crosses. E) It aided in the discovery of the concept of dominance.
A
_______________ is the part of interphase within the cell cycle where the cell growth and protein synthesis necessary for cell division and DNA replication take place. A) G1 B) S C) G2 D) M E) Telophase
A
A cell has eight chromosomes in G1 of interphase. Indicate how many chromosomes and DNA molecules are present at diplotene of meiosis I. A) 8 chromosomes and 8 DNA molecules B) 8 chromosomes and 16 DNA molecules C) 16 chromosomes and 16 DNA molecules D) 16 chromosomes and 32 DNA molecules E) 4 chromosomes and 8 DNA molecules
B
A cell has eight chromosomes in G1 of interphase. Indicate how many chromosomes and DNA molecules are present at metaphase of mitosis. A) 8 chromosomes and 8 DNA molecules B) 8 chromosomes and 16 DNA molecules C) 16 chromosomes and 16 DNA molecules D) 16 chromosomes and 32 DNA molecules E) 4 chromosomes and 8 DNA molecules
B
A cell in G1 of interphase has 12 chromosomes. How many chromosomes and DNA molecules will be found per cell when this original cell progresses to prophase II of meiosis? A) 6 chromosomes and 6 DNA molecules per cell B) 6 chromosomes and 12 DNA molecules per cell C) 12 chromosomes and 12 DNA molecules per cell D) 12 chromosomes and 24 DNA molecules per cell E) 24 chromosomes and 24 DNA molecules per cell
B
A horse has 64 chromosomes and a donkey has 62 chromosomes. A cross between a female horse and a male donkey produces a mule. How many chromosomes does a mule have? A) 62 B) 63 C) 64 D) 32 E) 31
B
Chromosomes move toward the spindle poles during anaphase due to A) growth of the plasma membrane to which the chromosomes are attached. B) the activity of the microtubule subunits attached to the kinetochores at the centromeres of the chromosome along with the action of motor proteins associated with the microtubules. C) cytoplasmic streaming of material within the cytoplasm. D) the activity of the microtubule subunits attached to the kinetochores at the telomeres of the chromosome along with the action of motor proteins associated with the microtubules. E) the interaction of actin and myosin.
B
Differences between prokaryotes and eukaryotes include all of the following EXCEPT: A) presence or absence of the nucleus B) use of circular chromosomes by eukaryotes C) small size of prokaryotes D) absence of organelles in prokaryotes E) All of the above are differences
B
For the stages of meiosis II below, which is INCORRECTLY matched to the major event that takes place during that stage? A) Prophase II—spindle fibers form B) Metaphase II—homologous pairs of chromosomes line up along the equatorial plane of the metaphase II plate C) Anaphase II—sister chromatids separate D) Telophase II—spindle fibers breakdown E) Prophase II—nuclear envelope breaks down
B
Hairlessness in American rat terriers is recessive to the presence of hair. Suppose that you have a rat terrier with hair. How can you determine whether this dog is homozygous or heterozygous for the hairy trait? A) Cross your rat terrier with a rat terrier with hair from the same litter as your rat terrier. B) Cross your rat terrier with a hairless rat terrier. C) Cross your rat terrier with a rat terrier with hair from a different litter than your rat terrier. D) All of the above are crosses that would allow you determine if your rat terrier is heterozygous or homozygous. E) It cannot be determined with the information provided.
B
In a family of seven children, what is the probability of obtaining all boys? A) 1/64 B) 1/128 C) 3/128 D) 7/128 E) 35/128
B
In humans, alkaptonuria is a metabolic disorder in which affected persons produce black urine. Alkaptonuria results from an allele (a) that is recessive to the allele for normal metabolism (A). Sally has normal metabolism, but her brother has alkaptonuria. Sally's father has alkaptonuria, and her mother has normal metabolism. What is the genotype of Sally's brother and Sally's father? A) AA B) aa C) Aa D) Answers A and C are both correct. E) Answers B and C are both correct.
B
Joe has a white cat named Sam. When Joe crosses Sam with a black cat, he obtains 1/2 white kittens and 1/2 black kittens. When the black kittens are interbred, they produce all black kittens. On the basis of these results, would you conclude that white or black coat color in cats is a recessive trait and why? A) White is the likely the recessive trait because it did not appear when the black kittens were interbred. B) Black is the recessive trait because the black kitten offspring only produced black offspring when interbred, suggesting they are all homozygous for black coat color. C) White and black are likely both recessive traits because when Sam was crossed with a black cat, both white and black kitten offspring were produced. D) White is likely the recessive trait because when Sam was crossed with a white cat, one-half the offspring were white, and one-half the offspring were black. E) None of the above is correct.
B
Sister chromatids have the following features EXCEPT that: A) both parts have telomeres B) they are homologs to each other C) they remain attached to each other at their centromere D) they will separate during anaphase E) Actually, they have all of these features
B
The inheritance of red hair was discussed in the introduction to this chapter. At times in the past, red hair in humans was thought to be a recessive trait and at other times, it was thought to be a dominant trait. What features of heritance would red hair be expected to exhibit as a dominant trait? A) Red hair would often appear in children whose parents lacked red hair. B) Red hair would appear only in children who had at least one parent with red hair. C) A cross between two non-red-hair parents would produce some red-hair offspring. D) A mating between two red-haired parents would never produce children with non-red hair. E) None of the above is correct.
B
The purpose of cell checkpoints is to: A) verify that the chromosomes have been packaged properly B) prevent division of cells that have damaged DNA C) allow the body to block division D) make sure the cell has shrank enough for division E) All of the above
B
What are checkpoints? A) Key transition points in the cell cycle that lead to cancer B) Periods during the cell cycle that ensure all cellular components are in good working order C) Transition points during the process of replication that allow DNA repair D) The last process that occurs before a cell divides E) Critical points that ensure correct and complete cytokinesis
B
What are the genetically important results of the cell cycle and mitosis? A) The resulting daughter cells have genomes identical to each other but not to the original cell. B) The resulting daughter cells have genomes identical to each other and to the original cell. C) The resulting daughter cells have genomes identical to each other and have half the genetic complement of the original cell. D) The resulting daughter cells are no longer identical to each other and have half the genetic complement of the original cell. E) No correct answer listed.
B
What is the principle of segregation? Why is it important? A) The principle of segregation proposes that offspring are the result of blended genetic material from the parent and the genetic factors are not discrete units. It explains how the genotypic ratios in the diploid gametes are produced. B) The principle of segregation states that a diploid organism possesses two alleles for any one particular trait and that these alleles separate during the formation of gametes. It explains how the genotypic ratios in the haploid gametes are produced. C) The principle of segregation states that genes for different characteristics that are at different loci segregate independently of one another. It explains the phenotypic ratios seen in the diploid parents. D) The principle of segregation states that genes are located on chromosomes. It explains how genes are passed on from parent to offspring. E) The principle of segregation proposes that once genetic material is blended, it cannot be separated. It explains how the genotypic ratios of offspring are produced.
B
Which of the following crosses would likely produce a genotypic ratio of 1:1? A) Aa × Aa B) Aa × aa C) AA × aa D) aa × aa
B
Which of the following statements is INCORRECT about spermatogenesis and oogenesis? A) In spermatogenesis cytokinesis is equal, resulting in haploid cells of similar sizes. B) Spermatogenesis undergoes just one round of meiosis, whereas oogenesis undergoes two rounds of meiosis. C) Spermatogonia and oogonia may undergo many rounds of mitosis to produce more primordial cells. D) Spermatogenesis results in four haploid spermatids that mature into sperm, whereas oogenesis results in a single haploid ovum. E) In oogenesis each round of meiosis produces a small haploid cell called a polar body, which usually disintegrates.
B
White (w) coat color in guinea pigs is recessive to black (W). In 1909, W. E. Castle and J. C. Phillips transplanted an ovary from a black guinea pig into a white female whose ovaries had been removed. They then mated this white female with a white male. All the offspring from the mating were black in color (W. E. Castle and J. C. Phillips. 1909, Science 30:312-313). Give the genotype of the offspring from this cross. A) WW B) Ww C) ww D) Both answers A and B are likely genotypes. E) Both answers A and C are likely genotypes.
B
__________________ is the part of interphase within the cell cycle where DNA replication takes place. A) G1 B) S C) G2 D) M E) Telophase
B
_______________________ are the start points for DNA synthesis on chromosomes. A) telomeres B) origins of replication C) centromeres D) kinetochore proteins E) histone proteins
B
A cell has eight chromosomes in G1 of interphase. Indicate how many chromosomes and DNA molecules are present at anaphase of mitosis. A) 8 chromosomes and 8 DNA molecules B) 8 chromosomes and 16 DNA molecules C) 16 chromosomes and 16 DNA molecules D) 16 chromosomes and 32 DNA molecules E) 4 chromosomes and 8 DNA molecules
C
A cell in G1 of interphase has 12 chromosomes. How many chromosomes and DNA molecules will be found per cell when this original cell progresses through cytokinesis following mitosis? A) 6 chromosomes and 6 DNA molecules per cell B) 6 chromosomes and 12 DNA molecules per cell C) 12 chromosomes and 12 DNA molecules per cell D) 12 chromosomes and 24 DNA molecules per cell E) 24 chromosomes and 24 DNA molecules per cell
C
A cell in G1 of interphase has 12 chromosomes. How many chromosomes and DNA molecules will be found per cell when this original cell progresses to anaphase II of meiosis? A) 6 chromosomes and 6 DNA molecules per cell B) 6 chromosomes and 12 DNA molecules per cell C) 12 chromosomes and 12 DNA molecules per cell D) 12 chromosomes and 24 DNA molecules per cell E) 24 chromosomes and 24 DNA molecules per cell
C
A cell in prophase II of meiosis contains 12 chromosomes. How many chromosomes would be present in a cell from the same organism if it were in prophase I of meiosis? A) 6 B) 12 C) 24 D) 48
C
A cell in prophase II of meiosis contains 12 chromosomes. How many chromosomes would be present in a cell from the same organism if it were in prophase of mitosis? A) 6 B) 12 C) 24 D) 48
C
Alkaptonuria is a metabolic disorder in which affected persons produce black urine. Alkaptonuria results from an allele (a) that is recessive to the allele for normal metabolism (A). Sally has normal metabolism, but her brother has alkaptonuria. Sally's father has alkaptonuria, and her mother has normal metabolism. What is Sally's genotype? A) AA B) aa C) Aa D) Answers A and C are both correct. E) None of the above is correct.
C
For the stages of meiosis I below, which is INCORRECTLY matched to a major event that takes place during that stage? A) Prophase - synapsis B) Metaphase -- homologous pairs of chromosomes line up on the equatorial plane of the metaphase plate C) Anaphase -- separation of sister chromatids D) Telophase -- separated chromosomes reach spindle poles at opposite ends of the cell E) Prophase -- genetic recombination through crossing over
C
Name the stage of mitosis where the chromosomes are arranged on the equatorial plane of the cell. A) prophase B) prometaphase C) metaphase D) anaphase E) telophase
C
On average, what proportion of the genome in two full siblings (offspring who have the same two biological parents) would be exactly the same if no crossing over occurred? (For the purposes of this question only, we will ignore the special case of the X and Y sex chromosomes and assume that all genes are located on non-sex chromosomes.) A) One-fourth of their genomes B) One-third of their genomes C) One-half of their genomes D) Three-fourths of their genomes E) It cannot be determined from the information given.
C
Phenylketonuria (PKU) is a disease that results from a recessive gene. Two normal parents produce a child with PKU. What is the probability that a sperm from the father will contain the PKU allele? A) 1/4 B) 1/3 C) 1/2 D) 2/3 E) 3/4
C
Phenylketonuria (PKU) is a disease that results from a recessive gene. Two normal parents produce a child with PKU. What is the probability that an egg from the mother will contain the PKU allele? A) 1/4 B) 1/3 C) 1/2 D) 2/3 E) 3/4
C
The fruit fly Drosophila melanogaster has four pairs of chromosomes. How many different combinations of chromosomes are possible in the gametes? A) 4 B) 8 C) 16 D) 64
C
What are three essential structural elements of a functional eukaryotic chromosome? A) Histone proteins, spindle fibers, and a pair of telomeres B) Origins of replication, chromatids, and kinetochores C) A centromere, a pair of telomeres, and origins of replication D) A centromere, chromatids, and kinetochores E) Spindle fibers, kinetochores, and chromatids
C
What is the concept of dominance? A) The concept of dominance states that when two different alleles are present in a genotype, both alleles can be observed equally in the phenotype. B) The concept of dominance states that recessive alleles are only visible in the heterozygous condition. C) The concept of dominance states that when two different alleles are present in a genotype, only the dominant allele is observed in the phenotype. D) The concept of dominance states that an organism can only exhibit two alleles at a time. E) None of the above is correct.
C
What is the probability of rolling one six-sided die and obtaining a 2? A) 1/3 B) 2/3 C) 1/6 D) 5/6 E) 1/2
C
What would be the consequences to the outcome of meiosis if shugoshin is absent during meiosis? A) Sister chromatids could fail to separate during anaphase II. B) Homologous pairs could separate prior to anaphase I. C) Sister chromatids could separate along with homologous pairs during anaphase I. D) Homologous pairs could fail to separate during anaphase I E) The absence of shugoshin during meiosis is likely to have no impact on meiosis.
C
Which checkpoint is incorrectly matched with its function? A) G1/S checkpoint—maintains cell in G1 until necessary enzymes for replication are synthesized. B) G2/M checkpoint—detection of DNA damage after replication. C) The spindle-assembly checkpoint—correct orientation of spindle fibers in prophase. D) All of the above checkpoint functions are correctly matched. E) None of the above checkpoint functions are correctly matched
C
__________________ is the part of interphase within the cell cycle where additional biochemical reactions take place preparing the cell for mitosis, such as the synthesis of spindle proteins. A) G1 B) S C) G2 D) M E) Telophase
C
A biologist examines a series of cells and counts 160 cells in interphase, 20 cells in prophase, 6 cells in prometaphase, 2 cells in metaphase, 7 cells in anaphase, and 5 cells in telophase. If the complete cell cycle requires 24 hours, what is the average duration of metaphase in these cells? A)19.2 hours B) 2.4 hours C) 43.2 minutes D) 14.4 minutes E) 36 minutes
D
A cell in G1 of interphase has 12 chromosomes. How many chromosomes and DNA molecules will be found per cell when this original cell progresses to G2? A) 6 chromosomes and 6 DNA molecules per cell B) 6 chromosomes and 12 DNA molecules per cell C) 12 chromosomes and 12 DNA molecules per cell D) 12 chromosomes and 24 DNA molecules per cell E) 24 chromosomes and 24 DNA molecules per cell
D
A cell in G1 of interphase has 12 chromosomes. How many chromosomes and DNA molecules will be found per cell when this original cell progresses to anaphase I of meiosis? A) 6 chromosomes and 6 DNA molecules per cell B) 6 chromosomes and 12 DNA molecules per cell C) 12 chromosomes and 12 DNA molecules per cell D) 12 chromosomes and 24 DNA molecules per cell E) 24 chromosomes and 24 DNA molecules per cell
D
A cell in G1 of interphase has 12 chromosomes. How many chromosomes and DNA molecules will be found per cell when this original cell progresses to metaphase I of meiosis? A) 6 chromosomes and 6 DNA molecules per cell B) 6 chromosomes and 12 DNA molecules per cell C) 12 chromosomes and 12 DNA molecules per cell D) 12 chromosomes and 24 DNA molecules per cell E) 24 chromosomes and 24 DNA molecules per cell
D
A cell in G1 of interphase has 12 chromosomes. How many chromosomes and DNA molecules will be found per cell when this original cell progresses to prophase of mitosis? A) 6 chromosomes and 6 DNA molecules per cell B) 6 chromosomes and 12 DNA molecules per cell C) 12 chromosomes and 12 DNA molecules per cell D) 12 chromosomes and 24 DNA molecules per cell E) 24 chromosomes and 24 DNA molecules per cell
D
A primary oocyte divides to give rise to a secondary oocyte and a first polar body. The secondary oocyte then divides to give rise to an ovum and a second polar body. Is the genetic information of the first polar body identical to that of the secondary oocyte and why? A) No, it is not because genetic recombination in prophase I will have generated new and different arrangements of genetic material for each member of the pair. B) No, it is not because they are both products of meiosis I, and each will contain only one member of the original homologous pair. C) Yes, it is because they are both products of meiosis I and will receive the same genetic material. D) Answers A and B are both correct. E) None of the above is correct.
D
From 80% to 90% of the most common human chromosome abnormalities arise because the chromosomes fail to divide properly in oogenesis. Which of the following could be a reason why failure of chromosome division might be more common in female gametogenesis than male gametogenesis? A) Spermatogenesis in males occurs regularly and throughout the lifetime of the male and the sperm cells are not suspended in the cell cycle for long periods of time. B) In female oogenesis, egg cells arrest in prophase I, generating a primary oocyte, and the length of time in prophase I, which may last for over 35 years, may allow opportunities for meiotic machinery to be damaged. C) In males, the spermatogonium divides by meiosis to produce four haploid sperm cells, while in females, the primary oocyte produces only a single functional egg cell at the completion of meiosis. D) Answers A and B are both correct. E) Answers A and C are both correct.
D
In cucumbers, orange fruit color (R) is dominant over cream fruit color (r). A cucumber plant homozygous for orange fruit is crossed with a plant homozygous for cream fruit. Give the genotypes and phenotypes of the offspring of a backcross between the F1and the orange parent. A) Orange (RR) B) Orange (Rr) C) Cream (rr) D) Answers A and B are both correct. E) Answers B and C are both correct.
D
In cucumbers, orange fruit color (R) is dominant over cream fruit color (r). A cucumber plant homozygous for orange fruit is crossed with a plant homozygous for cream fruit. The F1 are intercrossed to produce the F2. What are genotypes of the parents, the F1, and the F2? A) Parents (Rr × Rr); F1 (Rr); F2 (RR, Rr, and rr) B) Parents (RR × RR); F1 (RR); F2 (RR) C) Parents (RR × Rr); F1 (Rr); F2 (RR, Rr, and rr) D) Parents (RR × rr); F1 (Rr); F2 (RR, Rr, and rr) E) Parents (RR × rr); F1 (Rr); F2 (RR and Rr)
D
In humans, alkaptonuria is a metabolic disorder in which affected persons produce black urine. Alkaptonuria results from an allele (a) that is recessive to the allele for normal metabolism (A). Sally has normal metabolism, but her brother has alkaptonuria. Sally's father has alkaptonuria, and her mother has normal metabolism. If Sally marries a man with alkaptonuria, what is the probability that their first child will have alkaptonuria? A) 100% B) 25% C) 75% D) 50% E) 0%
D
In humans, alkaptonuria is a metabolic disorder in which affected persons produce black urine. Alkaptonuria results from an allele (a) that is recessive to the allele for normal metabolism (A). Sally has normal metabolism, but her brother has alkaptonuria. Sally's father has alkaptonuria, and her mother has normal metabolism. If Sally's parents have another child, what is the probability that this child will have alkaptonuria? A) 100% B) 25% C) 75% D) 50% E) 0%
D
In sheep, lustrous fleece results from an allele (L) that is dominant over an allele (l) for normal fleece. A ewe (adult female) with lustrous fleece is mated with a ram (adult male) with normal fleece. The ewe then gives birth to a single lamb with normal fleece. What are the likely genotypes of the two parents? A) ewe (LL); ram (ll) B) ewe (ll); ram (LL) C) ewe (Ll); ram (Ll) D) ewe (Ll); ram (ll) E) The genotypes of the parents cannot be determined from the information provided.
D
In the reproduction of prokaryotic cells, A) replicated chromosomes are often attached to the plasma membrane. B) the replicated chromosomes separate as the plasma membrane grows with the cell. C) spindle fibers separate the replicated chromosomes. D) Both A and B are correct. E) Both A and C are correct.
D
Mitosis and meiosis are similar in that A) chromosomes line up on the metaphase plate during metaphase of mitosis and metaphase II of meiosis. B) sister chromatids separate in both anaphase of mitosis and anaphase II of meiosis. C) genetically identical daughter cells are produced at the end of both mitosis and meiosis. D) Answers A and B are both correct. E) Answers A and C are both correct.
D
Name the stage in mitosis when sister chromatids separate at the centromere and move to opposite poles of the cell. A) Prophase B) Prometaphase C) Metaphase D) Anaphase E) Telophase
D
Reproduction by prokaryotic cells requires all of the following EXCEPT: A) replication of the chromosomes B) division of the cell C) separation of the chromosomes D) dissolution of the nucleus E) Actually, all of these are required
D
Suppose that you are raising Mongolian gerbils. You notice that some of your gerbils have white spots, whereas others have solid coats. What type of cross could you carry out to determine whether white spots are due to a recessive allele? A) Cross a gerbil with white spots to another gerbil with white spots. If this cross produces only gerbils with solid coats, then white spots are due to a recessive allele. B) Cross a gerbil with white spots to another gerbil with white spots. If this cross produces one-half gerbils with solid coats and one-half with white spots, then white spots are due to a recessive allele. C) Cross a gerbil with white spots to another gerbil with white spots. If this cross produces three-fourths gerbils with solid coats and one-fourth with white spots, then white spots are due to a recessive allele. D) Cross a gerbil with white spots to another gerbil with a solid coat. If this cross produces either all solid or one-half gerbils with solid coats and one-half with white spots, then white spots are due to a recessive allele. E) Cross a gerbil with white spots to another gerbil with a solid coat. If this cross produces only gerbils with white spots, then white spots are due to a recessive allele.
D
The additive rule of probability A) allows for predicting the probability of a single event that can occur in two or more ways. B) indicates that the probability of a single mutually exclusive event can be determined by adding the probabilities of the two or more different ways in which this single event could take place. C) indicates that the probability of two events occurring together is the product of their probabilities of occurring independently. D) Answers A and B are both correct. E) Answers A and C are both correct.
D
The chromosomal structures that serve as the attachment point for spindle fibers are the _____________________. A) telomeres B) origins of replication C) centrosomes D) kinetochore proteins at the centromere E) histone proteins
D
The chromosome theory of heredity states that A) DNA is the genetic material. B) genes are inherited from a common ancestor. C) chromosomes segregate during mitosis. D) genes are located on chromosomes. E) chromosomes are made of DNA and protein.
D
The housefly Musca domestica has six pairs of chromosomes. How many different combinations of chromosomes are possible in the gametes? A) 4 B) 8 C) 16 D) 64
D
The inheritance of red hair was discussed in the introduction to this chapter. At times in the past, red hair in humans was thought to be a recessive trait and, at other times it was thought to be a dominant trait. What features of heritance would red hair be expected to exhibit as a recessive trait? A) Non-red hair would often appear in children whose parents had red hair. B) Red hair would appear only in children who had at least one parent with red hair. C) Two red hair parents could have some offspring with non-red hair. D) In matings between two red hair parents, all of the offspring would be expected to have red hair. E) None of the above is correct.
D
What process(es) unique to meiosis is/are responsible for genetic variation and at what point in meiosis do(es) each occur? A) Independent assortment of chromosomes that takes place during anaphase I B) Crossing over of chromosomes that takes place during prophase I C) Independent assortment of chromosomes that takes place during anaphase II D) Answers A and B are both correct. E) Answers A and C are both correct.
D
What would be the consequences to the outcome of mitosis or meiosis if separase is defective? A) Sister chromatids could separate prior to anaphase II of meiosis and anaphase of mitosis. B) Homologous pairs could separate prior to anaphase I. C) Sister chromatids could separate along with homologous pairs during anaphase I. D) Homologous pairs and sister chromatids would fail to separate during both meiosis and mitosis. E) A defective separase would likely have no impact on mitosis or meiosis.
D
Which of the following are fundamental events that must take place in cell reproduction? A) A cell's genetic information must be copied. B) The copies of the genetic information must be separated from one another. C) The cell must divide. D) All of the above are fundamental events that must take place in cell reproduction.
D
Cohesin is a protein that: A) holds sister chromatids together B) holds sister chromatids of homologous chromosomes together in metaphase I C) is broken down where is it not protected by shugoshin during anaphase I of meiosis D) B and C E) all are correct
E
How are Mendel's principles different from the concept of blending inheritance discussed in Chapter 1? A) According to Mendel's principles, alleles (or genetic factors) are discrete units that remain separated within an individual organism. B) According to the concept of blending inheritance, offspring result from a blending of their parents' genetic material. C) According to the concept of blending inheritance, once blended, the genetic material from each parent is no longer discrete units that remain separated within an individual organism. D) According to the concept of blending inheritance, genetic material once blended cannot be separated in future generations. E) All of the above are correct.
E
How are the events that take place in spermatogenesis and oogenesis similar? A) Cytokinesis is equal in both processes, resulting in haploid cells of similar size. B) Polar bodies are produced in each process. C) Spermatogonia and oogonia undergo just one round of mitosis to produce primordial cells. D) Each process results in four mature, haploid cells that can take part in fertilization. E) Spermatogonia and oogonia can undergo multiple rounds of mitosis to produce more primordial cells, or both types of cells can enter into meiotic division.
E
In cucumbers, orange fruit color (R) is dominant over cream fruit color (r). A cucumber plant homozygous for orange fruit is crossed with a plant homozygous for cream fruit. Give the genotypes and phenotypes of a backcross between the F1 and the cream parent. A) Orange (RR) B) Orange (Rr) C) Cream (rr) D) Answers A and B are both correct. E) Answers B and C are both correct.
E
Meiosis differs from mitosis in that A) homologous chromosomal pairs separate in anaphase I, but chromatids separate in anaphase of mitosis. B) the cells produced at the end of meiosis are genetically different, whereas the cells produced at the end of mitosis are genetically identical. C) the chromosome number within the daughter cells produced by meiosis is half that of the original cell, whereas chromosome number within daughter cells produced by mitosis is the same as that of the original cell. D) recombination between nonsister chromatids of the homologous pairs takes place in meiosis but not in mitosis. E) All of the above are correct.
E
Meiosis differs from mitosis in that: A) meiosis II includes crossing over B) meiosis I includes separation of sister chromatids C) meiosis II includes separation of homologs D) mitosis includes crossing over E) None of the above
E
Name the stage of mitosis where the nuclear envelope re-forms around each set of daughter chromosomes, the nucleoli reappear, and the spindle microtubules disintegrate. A) Prophase B) Prometaphase C) Metaphase D) Anaphase E) Telophase
E
Question 30 Genetic differences between prokaryotes and eukaryotes include: A) the presence of a nucleus in eukaryotes B) the use of histones by eukaryotes to condense DNA C) the presence of chromosomes in pairs in eukaryotes D) A and C E) All of the above
E
The multiplication rule of probability A) allows for predicting the probability of two or more independent events occurring together. B) indicates that the probability of a single mutually exclusive event can be determined by adding the probabilities of the two or more different ways in which this single event could take place C) indicates that the probability of two events occurring together is the product of their probabilities of occurring independently. D) Answers A and B are both correct. E) Answers A and C are both correct.
E
The purpose of meiosis is to: A) produce haploid cells B) produce sex cells C) reduce the number of chromosomes D) B and C E) All of the above
E
What is the probability of rolling one six-sided die and obtaining a 1 or a 2? A) 1/2 B) 2/3 C) 1/6 D) 5/6 E) 1/3
E
Which of the following is a characteristic of an organism that would make it suitable for studies of the principles of inheritance? A) Easy to grow and maintain B) Grows rapidly, producing many generations in a short period of time C) Produces large numbers of offspring D) Has distinctive phenotypes that are easy to recognize E) All of the above are correct.
E
Why are the two cells produced by the cell cycle genetically identical? A) An exact copy of each DNA molecule was created in S phase giving rise to the two identical sister chromatids. B) Chromosomal replication in prophase ensures two identical copies of each chromosome for the two cells. C) Mitosis ensures that each cell receives one copy of the two identical sister chromatids created during S phase. D) Both A and B are reasons that the two cells produced by the cell cycle are identical. E) Both A and C are reasons that the two cells produced by the cell cycle are identical.
E
Why was Mendel's approach to the study of heredity so successful? A) He chose to work with a plant that was easy to cultivate, grew relatively rapidly, and produced many offspring whose phenotype was easy to determine. B) The seven characteristics he chose to study were important because they exhibited only a few distinct phenotypes and did not show a range of variation. C) By looking at each trait separately and counting the numbers of the different phenotypes, he was able to detect mathematical ratios of progeny phenotypes. D) He adopted an experimental approach and applied the scientific method. From his observations, he proposed hypotheses that he was then able to test empirically. E) All of the above are correct.
E
