遗传学（英文）(西北农林科技大学) 中国大学mooc答案满分完整版章节测试

枷拼伟广哦抠感疗捕渺尉匣禄

Chapter 1 Introduction to Genetics Chapter 1 测验

1、 The first complete DNA sequence of a non-viral, free-living organism was obtained for:

答案: a bacterium in 1995.

2、 Genetic information can be carried in which of the following biomolecules?

答案: Either DNA or RNA

3、 Which of the following species is considered a genetic model organism?

答案: the worm, Caenorhabditis elegans

4、 Which of the following would serve least well as a model for understanding basic mechanisms of inheritance?

答案: humans

5、 Which of the following scientists contributed significantly to the foundations of transmission genetics?

答案: Thomas Hunt Morgan 

6、 The contribution Charles Darwin made to genetics was to:

答案: propose that evolution occurs by natural selection.

7、 The contribution of Gilbert and Sanger to modern genetics was to: 

答案: develop a method for sequencing DNA.

8、 Humans first applied genetics to the domestication of plants and animals between approximately 10,000 and 12,000 years ago. 

答案: 正确

9、  The theory of pangenesis states that all living organisms are composed of cells. 

答案: 错误

10、 Many human traits, such as skin and hair color, exhibit blending inheritance, in which genetic information is mixed and is not separated in future generations.  

答案: 错误

11、 Bacteria and viruses can be used to study genes and inheritance, even though they are structurally and metabolically different from animal and plant cells.

答案: 正确

12、 Some viruses have RNA as their genetic information. 

答案: 正确

13、 Charles Darwin accurately described the laws of inheritance in his landmark book, On the Origin of Species.

答案: 正确

14、 Some phenotypes or traits, such as hair color, are determined by the information provided by more than a single gene. 

答案: 正确

15、 Evolution cannot occur without genetic changes in populations. 

答案: 正确

Chapter 2 Chromosomes and Cellular Reproduction Chapter 2 测验

1、 A dividing eukaryotic cell is treated with a drug that inhibits the molecular motors associated with kinetochores.  At which cell cycle stage would it stop?

答案: M (anaphase)

2、 In eukaryotes, chromosomes do not contain:

答案: ribosomes.

3、 In order to be functional, a eukaryotic chromosome requires all of the following except:

答案: a nucleoid.

4、 What process is unique to plants?

答案: double fertilization

5、 Suppose that a diploid cell contains 8 chromosomes (2n = 8).  How many different combinations in the gametes are possible?

答案: 16

6、 Which of the following statements is FALSE?

答案: Errors in chromosome separation are rarely a problem for an organism.

7、 Which of the following are NOT prokaryotes?

答案: viruses

8、 Which of the following statements is FALSE?

答案: Generally, chromosomes of eukaryotes are circular.

9、 The attachment point on the chromosome for spindle microtubules is the:

答案: centromere

10、 The process of splitting the cytoplasm, which separates one cell into two, is termed:

答案: cytokinesis

11、 Diploid cells are cells with ______ chromosomes.

答案: two sets of

12、 If a healthy cell passes the G1/S checkpoint:

答案: DNA will be replicated.

13、 Errors in chromosome separation are rarely a problem for an organism.

答案: 错误

14、 The prokaryotes include both the eubacteria and the archaea.

答案: 正确

15、 Archaea are more closely related to eukaryotes than they are to eubacteria.

答案: 正确

16、 Generally, chromosomes of eukaryotes are circular.

答案: 错误

17、 Cells with a single set of chromosomes are called diploid.

答案: 错误

Chapter 3 Basic Principles of Heredity Chapter 3 测验

1、 Genes come in different versions called:

答案: alleles

2、 In Mendel’s peas, purple flower color is dominant to white.  From which of the following descriptions can you not infer the genotype for the locus completely?

答案: purple

3、 Which of the following was not one of Mendel’s conclusions based on his monohybrid crosses?

答案: Genes are carried on chromosomes.

4、 In Mendel’s peas, yellow seeds are dominant to green.  A pure-breeding yellow plant is crossed with a pure-breeding green plant.  All of the offspring are yellow.  If one of these yellow offspring is crossed with a green plant, what will be the expected proportion of plants with green seeds in the next generation?

答案: 50%

5、 In a cross between pure-breeding tall plants with pure-breeding short plants, all of the F1 are tall.  When these plants are allowed to fertilize themselves, the F2 plants occur in a ratio of 3 tall:1 short.  Which of the following is not a valid conclusion from these results?

答案: The tall and short traits assort independently of each other in this cross.

6、 In poodles, black is dominant to white.  A black poodle is crossed with a white poodle.  In a litter of four, all of the puppies are black.  What is the best conclusion?

答案: The black poodle is probably homozygous

7、 Which of the following statements is TRUE?

答案: A testcross can be used to determine whether an individual is homozygous or heterozygous for a dominant allele.

8、 Alleles, genes, and loci are different names for the same thing. 

答案: 错误

9、 The probability of two or more independent events occurring together is calculated by multiplying their independent probabilities.

答案: 正确

10、 The phenotype of a dominant allele is never seen in the F1 progeny of a monohybrid cross.

答案: 错误

11、 A Mendelian dihybrid cross involves one gene and two different alleles.

答案: 错误

12、 The principle of independent assortment can be demonstrated using a monohybrid cross.

答案: 错误

13、 Branched diagrams are used for determining probabilities of various genotypes for genetic crosses involving more than one gene pair.

答案: 正确

14、 Mendel’s experiments involved both discrete and continuous genetic traits.

答案: 错误

15、 The genotype is the physical appearance of a trait.

答案: 错误

16、 A testcross can be used to determine whether an individual is homozygous or heterozygous. 

答案: 正确

17、 The probability of a woman giving birth to three girls in a row is 1/8.

答案: 正确

18、 The chi-square test is used to determine if observed outcomes are consistent with expected outcomes. 

答案: 正确

Chapter 4 Sex Determination and Sex-linked Characteristics Chapter 4 测验

1、 What is the role of the SRY gene in humans?

答案: It is located on the Y chromosome and initiates the developmental pathway toward the male phenotype.

2、 Which of the following chromosome constitutions would never lead to a viable human baby being born?

答案: YY

3、 In which of the following organisms is gender/sex determined by the temperature during embryonic development?

答案: many turtles and alligators

4、 In species of birds, males are the homogametic sex and females the heterogametic sex. Which of the following statements is TRUE in this system of sex determination?

答案: The gender of the offspring is determined by the female parent.

5、 The sex determination system used by Drosophila is called:

答案: the X:A sex determination system.

6、 In Drosophila, flies that are XXY but have a normal diploid set of autosomes have been found. Such XXY chromosome constitutions have also been found in humans. The sex of such individuals is expected to be:

答案: female in Drosophila but male in humans.

7、 Red–green color blindness is X-linked recessive. A woman with normal color vision has a father who is color blind. The woman has a child with a man with normal color vision. Which phenotype is NOT expected?

答案: a color-blind female;
a color-blind female

8、 If a female Drosophila that is heterozygous for a recessive X-linked mutation is crossed to a wild-type male, what proportion of female progeny will have the mutant phenotype?

答案: 0%

9、 A Barr body is a(n):

答案:  inactivated X chromosome, visible in the nucleus of a cell that is from a female mammal.

10、 In humans SRY is the male determining gene.

答案: 正确

11、 Female mammals that are heterozygous for an X-linked gene have patches of cells that express one allele and patches of cells that express the other.

答案: 正确

12、 The cellular reason for X-inactivation is to reduce the amount of nondisjunction during meiosis.

答案: 错误

13、 The condition XXXY is always lethal in humans. 

答案: 错误

14、 The condition of having no X chromosomes, for example YO, is lethal in humans.

答案: 正确

15、 Temperature during embryonic development determines sex in reptiles like turtles and alligators. 

答案: 正确

16、 In species in which females are the homogametic sex, gender of offspring is determined by the male. 

答案: 正确

17、 A female with androgen insensitivity may have XY sex chromosomes rather than XX.

答案: 正确

18、 Species in which individuals have only male or only female reproductive structures are called dioecious. 

答案: 正确

19、 The X and Y chromosomes are named after their characteristic shape.

答案: 错误

Chapter 5 Extensions and Modifications of Basic Principles Chapter 5 测验

1、 The R locus determines flower color in a new plant species. Plants that are genotype RR have red flowers, and plants that are rr have white flowers. However, Rr plants have pink flowers. What type of inheritance does this demonstrate for flower color in these plants?

答案: incomplete dominance

2、 Interactions among the human ABO blood group alleles involve _ and ___.

答案: codominance; complete dominance

3、 Polydactyly is the condition of having extra fingers or toes. Some polydactylous persons possess extra fingers or toes that are fully functional, whereas others possess only a small tag of extra skin. This is an example of:

答案: variable expressivity.

4、 Achondroplasia is a common cause of dwarfism in humans. All individuals with achondroplasia are thought to be heterozygous at the locus that controls this trait. When two individuals with achondroplasia mate, the offspring occur in a ratio of 2 achondroplasia : 1 normal. What is the MOST likely explanation for these observations?

答案: The allele that causes achondroplasia is a recessive lethal allele.

5、 In humans, blood types A and B are codominant to each other and each is dominant to O. What blood types are possible among the offspring of a couple of blood types AB and A?

答案: A, B, and AB only

6、 Hair color is determined in Labrador retrievers by alleles at the B and E loci. A dominant allele B encodes black pigment, whereas a recessive allele b encodes brown pigment. Alleles at a second locus affect the deposition of the pigment in the shaft of the hair; dominant allele E allows dark pigment (black or brown) to be deposited, whereas recessive allele e prevents the deposition of dark pigment, causing the hair to be yellow. A black female Labrador retriever was mated with a yellow male. Half of the puppies were black and half were yellow. If the genotype of the black female parent was Bb Ee, then what was the genotype of the other parent?

答案: BB ee

7、 Which organelle in an animal cell, in addition to the nucleus, contains genes?

答案: mitochondrion

8、 Leber hereditary optic neuropathy (LHON) is a human disease that exhibits cytoplasmic inheritance. It is characterized by rapid loss of vision in both eyes, resulting from the death of cells in the optic nerve. A teenager loses vision in both eyes and is later diagnosed with LHON. How did this individual MOST likely inherit the mutant DNA responsible for this condition?

答案: a mitochondrial gene from the mother

9、 The bicoid mutation (bcd) in fruit flies is inherited as a maternal effect recessive allele. What is the expected ratio of phenotypes in the offspring of a cross between a heterozygous +/bcd female and a heterozygous +/bcd male?

答案: all normal

10、 The phenomenon in which a gene’s expression is determined by its parental origin is called:

答案: genomic imprinting.

11、 What phenomenon describes a genetic trait that is expressed more strongly or earlier in development with each generation?

答案: anticipation

12、 The himalayan allele in rabbits produces dark fur at the extremities of the body—on the nose, ears, and feet. The dark pigment develops, however, only when a rabbit is reared at a temperature of 25°C or lower; if a Himalayan rabbit is reared at 30°C, no dark patches develop. What does this exemplify?

答案: temperature-sensitive allele

13、 Multifactorial traits are influenced by _ and ___.

答案: multiple genes; environment

14、 In order to determine if mutations from different organisms that exhibit the same phenotype are allelic, which test would you perform?

答案: complementation test

15、       At a single genetic locus, a diploid individual may have more than two different alleles.

答案: 错误

16、       Skin color in humans is an example of a discontinuous trait. 

答案: 错误

17、       For a given species, sex-influenced traits are expressed in only one sex and have zero penetrance in the other sex.

答案: 错误

18、        All human ABO blood group alleles are co-dominant.

答案: 错误

19、       Epistatic genes must be dominant.

答案: 错误

20、       Recessive alleles form no gene products, and thus are not expressed.

答案: 错误

21、  Genomic imprinting and genetic anticipation both involve the inhibition of specific genes, or chromosomes, based on parental origin.  

答案: 错误

22、       A temperature-sensitive allele is an example of a phenocopy.

答案: 错误

23、        Epistasis involves interaction between alleles at a single genetic locus.

答案: 错误

24、       Sex-influenced traits are, by definition, on the X or Y chromosome.

答案: 错误

25、       All the genetic material in a eukaryotic cell is found in the nucleus.

答案: 错误

Chapter 6 Linkage, Recombination, and Eukaryotic Gene Mapping Chapter 6 测验

1、 Crossing over occurs during:

答案: prophase

2、 FISH stands for

答案: fluorescent in situ hybridization

3、 Linked genes

答案: co-segregate

4、 Linked genes always exhibit

答案: recombination frequencies of less than 50%

5、 Recombination occurs through

答案: crossing over and independent assortment

6、 A genetic map shows which of the following?

答案: the linear order of genes on a chromosome

7、 A testcross includes

答案: one parent who shows the dominant phenotype for one or more genes and a second parent who is homozygous recessive for these genes.

8、 Recombination frequencies can be calculated by

答案: counting the number of recombinant and parental offspring when an individual who is heterozygous for two genes is involved in a testcross.

9、 Is it possible for two different genes located on the same chromosome to assort independently?

答案: Yes, if the genes are far enough apart on the same chromosome, a crossover will occur between them in just about every meiotic event.

10、 What major contribution did Barbara McClintock and Harriet Creighton make to the study of recombination?

答案: Genetic recombination of alleles is associated with physical exchange between chromosomes.

11、 Two linked genes, (A) and (B), are separated by 18 m.u. A man with genotype Aa Bb marries a woman who is aa bb. The man’s father was AA BB. What is the probability that their first child will be Aa bb?

答案: 0.09

12、 Assume that A and B are two linked genes on an autosome in Drosophila. A testcross is made where AB/ab flies are crossed to ab/ab flies and the progeny are counted and shown below. However, it is known that the Aa/bb genotype is lethal before the flies hatch and does not appear among the testcross progeny counted. What is the most precise map distance between the two genes that can be calculated from these data?Aa Bb = 235aa bb = 225aa Bb = 20

答案: 8.0 m.u.

13、 If the recombination frequency between genes (A) and (B) is 5.3%, what is the distance between the genes in map units on the linkage map?

答案: 5.3 m.u.

14、 Assume that you are able to examine a total of 100 separate meiotic events in an animal species. You note that within 10 of these meiotic events, there was a crossover event occurring between genes A and B. In the remaining 90 events there was no crossover event between these two genes. What would be the expected map distance between genes A and B?

答案: 5 m.u.

15、 A low coefficient of coincidence indicates that:

答案: far fewer double-crossover recombinant progeny were recovered from a testcross than would be expected from the map distances of the genes involved.

16、 The map distances for genes that are close to each other are more accurate than map distances for genes that are quite far apart because:

答案: with genes that are far apart, double crossovers and other multiple-crossover events often lead to nonrecombinant or parental offspring and thus reduce the true map distance.

17、 Linkage disequilibrium is defined by which of the following?

答案: the nonrandom association between alleles in a haplotype

18、 Interference occurs when:

答案: one crossover inhibits another

19、 Linked genes always exhibit recombination frequencies of less than 50%. 

答案: 正确

20、 A chromosome map shows the linear order of gene loci present on a chromosome and the relative distances between them. 

答案: 正确

21、 Recombination frequencies can be predicted by a chi-square test.  

答案: 错误

22、 The higher the coefficient of coincidence, the higher the degree of crossover interference. 

答案: 错误

23、 Mapping experiments become more accurate as the distance between genes increases. 

答案: 错误

24、 Interference occurs when one crossover inhibits another.  

答案: 正确

25、 Recombination can only occur through crossing over. 

答案: 错误