1. Which element is found in both nucleic acids and proteins?

a. nitrogen
b. phosphorus
c. magnesium
d. sulfur
e. iron

2. The sequence of the DNA "backbone is

a. -base-phosphate-sugar-base-
b. -phosphate-base-phosphate-base-
c. -phosphate-sugar-phosphate-sugar-
d. -base-sugar-base-sugar-
e. -base-sugar-phosphate-base-

3. A segment of DNA has one strand with the following sequence of bases:

AGCGCATAGCAA

The complimentary strand of DNA would be

a. UCGCGUAUCGUU
b. TCGCGTATCGTT
c. GAUAUGCGAUGG
d. CTATACGCTACC
e. AGCGCATAGCAA

4. The Dna of a certain organism has guanine as 30 percent of its bases. What percentage of its bases would be adanine?

a. 0 percent
b 10 percent
c. 20 percent
d..30 percent
e. 60 percent

5. Both DNA and RNA

a. are single stranded
b. contain the same four nitrogenous bases
c. are polymers of amino acids
d. have the same five carbon sugars
e. contain phosphate groups

6. A segment of DNA has one strand with the following sequence of bases:

AGCGCATAGCAA

The complimentary strand of RNA would be

a. UCGCGUAUCGUU
b. TCGCGTATCGTT
c. AGCGCAUAGCAA
d. CTATACGCTACC
e. AGCGCATAGCAA

 

 

MOLECULAR GENETICS: PROTEIN SYNTHESIS

7. Which one of the following is TRUE of tRNA?

a. It functions in carrying mRNA from the nucleus to the ribosomes.
b. It disintegrates into nucleotides after leaving the ribosome.
c. It consists of a single strand of RNA.
d. It is necessary for transcription.
e. It carries amino acids to the correct site on the mRNA.

8. All of the following are directly involved in translation EXCEPT

a. mRNA.
b. small part of ribosome
c. tRNA
d. amino acids
e. RNA polymerase

9. Which of the following is NOT found in tRNA?

a. adenine
b. guanine
c. cytosine
d. uracil
e. thymine

10. The direction of transfer of genetic information in most living things is

a. protein --> DNA --> mRNA.
b. DNA --> mRNA --> protein.
c. DNA --> protein --> tRNA.
d. protein --> tRNA --> DNA.
e. RNA --> DNA --> mRNA --> protein.

11. If tRNA specialized for transfer of the amino acid methionine has the anticodon UAC, what codon on the mRNA codes for methionine?

a. UAC
b. TAC
c. AUG
d. ATG
e. ACU

12. According to current ideas about the DNA genetic code, which one of the following statements is FALSE:

a. The codon is three nucleotides long.
b. A triplet may code for more than one amino acid.
c. The code is redundant (i.e. it contains "synonyms").
d. The code is read in a regular sequence.
e. The code is translated into enzymes and other proteins.

13. The process of synthesizing mRNA along a DNA template is called

a. transcription
b. translation
c. transformation
d. replication
e. translocation

14. Which of the following statements best describes the replication of DNA?

a. The double helix is cleaved at the phosphate bonds, and new nucleotides pair with the appropriate sugars.
b. The double helix opens up by disruption of the hydrogen bonds between bases, and new nucleotides pair with the complementary bases in the old strands.
c. The double helix opens up by disruption of the hydrogen bonds between bases; a G nucleotide pairs with an exposed guanine and a C nucleotide pairs with an exposed cytosine, etc.
d. The double helix opens up and RNA forms base pairs with the complimentary strand of DNA
e. The DNA is completely fragmented by restriction enzymes and rebuilt using information provided by the amino-acid sequence of cell proteins.

CELL CYCLE, MITOSIS, MEIOSIS

15. The stage in mitosis when the two sets of single-stranded chromosomes are moving toward the opposite poles of the spindle is called

a. anaphase
b. interphase
c. prophase
d. metaphase
e. telophase

16. Which one of the following statements is FALSE concerning meiosis?

a. DNA is replicated between each cell division.
b. Each chromosome is double-stranded during prophase.
c. Each chromosome pairs with its homolog during meiosis I.
d. Cell division follows chromosome migration.
e. Each chromosome may exchange a part of a chromosome with the equivalent part of a homologous chromosome.

17. If there are 12 single-stranded chromosomes in a cell following mitosis (G1), what is the diploid number of chromosomes for the organism?

a. 6
b. 12
c. 24
d. 36
e. 48

18. Which one of the following occurs in meiosis but NOT in mitosis?

a. Double-stranded chromosomes move to the poles.
b. Chromosomes shorten and thicken and are double-stranded.
c. Single-stranded chromosomes move to the poles.
d. Nuclear membrane and nucleolus disappear.
e. Sister chromatids separate..

19. During the S phase of the cell cycle, the cell

a. undergoes cytokinesis.
b. undergoes meiosis.
c. replicates its DNA.
d. undergoes mitosis.
e. enters interphase.

20. How many chromatids would you expect to find in a cell whose diploid number is 10 at the mitotic stage when the nuclear membrane disappears?

a. 0
b. 5
c. 10
d. 20
e. 40

21. The diploid chromosome number for a certain plant species is 8. You prepare a section of some tissue from this plant and observe it under the microscope. You find a dividing cell and notice that its chromosomes are in two separate clusters. Careful examination reveals that each group contains 4 double-stranded chromosomes. The cell is in

a. prophase of mitosis.
b. prophase of meiosis I.
c. anaphase of mitosis.
d. anaphase of meiosis I.
e. anaphase of meiosis II.

22. Which one of the following does NOT occur during prophase of mitosis in an animal cell?

a. Centrioles move apart.
b. Nucleolus fades.
c. Nuclear membrane disappears.
d. Chromosomes are duplicated.
e. Spindle is organized.

23. If there are 20 independent centromeres in an anaphase cell undergoing mitosis, how many chromosomes are there?

a. 10
b. 20
c. 30
d. 40
e. 80

24. The stage of mitosis in which cytokinesis occurs, the nuclear membrane forms and the nucleolus reappears is called

a. anaphase
b. interphase
c. prophase
d. metaphase
e. telophase

25. Cytokinesis

a. always accompanies mitosis.
b. occurs in animal cells by a pinching-in of the plasma membrane.
c. occurs in higher-plant cells by an internal growth of new wall and membrane.
d. is the division of the nucleus.
e. b and c above.

26. Which one of the following occurs during mitosis?

a. Homologous chromosomes synapse.
b. Double-stranded chromosomes move to the poles.
c. Crossing-over takes place between homologous chromosomes.
d. Chromosome number is reduced from diploid to haploid.
e. Cells genetically identical to the parental cell are produced.

MENDELIAN AND NON-MENDELIAN GENETICS

27. Given a parental cross between blue-flowered and white-flowered plants, what ratio of phenotypic classes would be expected in the F2 generation (obtained by selfing the F1) if these traits show incomplete dominance?

a. 1:0 (only one class)
b. 1:1
c. 3:1
d. 1:2:1
e. 9:3:3:1

28. Being able to curl up your tongue into a U-shape is under the control of a dominant allele at one gene locus. (In the homozygous recessive condition the tongue cannot be rolled.) Suppose a woman who can roll her tongue marries a man who can also roll his tongue. Their first child cannot roll her tongue. What are the phenotypes of the parents?

a. Tt Tt
b. TT TT
c. Tt TT
d. tt tt
e. with only one offspring not enough information is given to make this evaluation.

29. The 9:3:3:1 phenotypic ratio is expected in the F2 generation of

a. a monohybrid cross in which the two alleles exhibita dominance-recessiveness relationship.
b. a dihybrid cross of linked genes (on the same chromosome) in which the alleles of each gene show dominance-recessiveness.
c. a dihybrid cross of linked genes (on the same chromosome) in which the alleles of each gene interact to produce intermediate phenotypes.
d. a dihybrid cross of independent genes in which the alleles of each gene show codominance.
e. a dihybrid cross of independent genes in which the alleles of each gene show dominance-recessiveness.

30. Brown eye color is dominant; blue is recessive. If a brown-eyed man marries a blue-eyed woman and they have a brown-eyed boy and a blue-eyed girl, we can safely conclude that

a. the man is not the true father.
b. the man is heterozygous.
c. eye color is sex-linked.
d. both parents are homozygous.
e. the man has the genotype for blue eyes but the phenotype for brown eyes.

31. In 1944 Charlie Chaplin was involved in a legal battle over the paternity of a child born to Joan Berry, a young starlet. The baby was blood type B, the mother A, and Chaplin O. From what you know about the inheritance of blood types, could Chaplin have been the father of the child? (At the time of the trial, blood group evidence was not admissible in California courts. Charlie Chaplin was declared responsible for the child's support.)

a. Yes, he could have fathered the child.
b. No, he could not possibly have fathered the child.
c. Perhaps, blood tests are inconclusive.
d. In this case, more evidence must be given.
e. If Chaplin's blood was type B, then he MUST be the father.

32. Among white human beings, when individuals with straight hair mate with those with curly hair, wavy-haired children are produced. If two individuals with wavy hair mate, what phenotypic ratios would you predict among their offspring?

a. 3 curly: 1 wavy
b. 1 curly: 1 wavy
c. 1 straight: 2 wavy: 1 curly
d. 3 wavy: 1 straight
e. 1 straight: 2 curly: 1 wavy

33. In a cross between an AABbCcDd individual and an AabbCcDD individual, what will be the expected frequency of AAbbCcDd individuals among their offspring?

P1 = AA Bb Cc Dd x Aa bb Cc DD
F1 = AA bb Cc Dd

a. 1/8
b. 1/16
c. 1/32
d. 1/64
e. 1/128

34. In cattle, a red bull crossed with a white cow yields offspring that are all roan, a shade between red and white. A cross between roans should yield offspring in the ratio of

a. 3 white: 1 red
b. 3 red: 1 white
c. 1 red: 2 roan: 1 white
d. 3 roan: 1 white
e. 3 roan: 1 red

35. If a woman who is red-green color-blind marries a man with normal vision, what phenotypes would you expect their children to have?

a. All their children will be color-blind.
b. All their daughters will be color-blind, but all their sons will have normal vision.
c. All their daughters will be carriers and all their sons will be color-blind.
d. All their daughters will have normal vision and will not be carriers, but all their sons will be color blind.
e. Half their daughters will be carriers and the other half will be fully normal; half their sons will be color-blind and the other half will have normal vision.

36. In cocker spaniels, black color is due to a dominant gene B, and red color to its recessive allele b. Solid color is dependent on a dominant gene S, and white spotting on its recessive allele s. They had five puppies: one black, one red, one black-and-white, and two red-and-white. What were the genotypes of the parents?

B = Black b = Red
S = Solid s = Spotted

a. male bbss and female BBss
b. male bbSs and female BBss
c. male bbss and female BbSs
d. male BbSs and female BBss
e. male BbSS and female Bbss

37. Hemophilia is a genetic disease that has plagued the royal houses of Europe since the time of England's Queen Victoria, who was a carrier. Her granddaughter Alexandra married Nicholas II, the last tsar of Imperial Russia. Alexandra was a carrier of the gene for hemophilia; Nicholas was normal. Their son, Tsarevich Alexis, was afflicted with the disease. Alexis and his four sisters are all thought to have been killed at the outbreak of the Revolution of 1917. It is likely that

a. all four sisters were fully normal with regard to hemophilia.
b. some of the sisters may have been a carrier of hemophilia.
c. all of the sisters were carriers of hemophilia.
d. one or more of the sisters may have had hemophilia.
e. all of the sisters had hemophilia.

38. In chickens, two pairs of genes are involved in comb type. One gene, R, results in rose comb, whereas its recessive allele, r, produces single comb. Gene P produces pea comb, and its recessive allele, p, also produces single comb. When R and P occur together (R_P_), they produce walnut comb. Chickens of the genotype rrpp have single comb. Suppose a walnut-comb chicken is crossed with a rose-comb chicken. They produce 3 rose-comb chickens, 3 walnut-combs, 1 single-comb, and 1 pea comb. The genotypes of the parents are

R = rose r = single
P = pea p = single
R_P_ = walnut

a. RRPp x Rrpp
b. RrPp x Rrpp
c. RRPP x RRpp
d. rrPp x RrPp rrpp = single
e. RrPp x RrPp

39. The normal cloven-footed condition in swine is produced by the recessive allele m, while the mule-footed condition is produced by the dominant allele M. White coat color is governed by the dominant allele of another locus B, and black by its recessive allele b. A white cloven-footed boar is mated with a mule-footed sow and they have several litters. All of the thirty-six offspring are white, but 17 have mule feet and 19 have cloven feet. What are the probable genotypes of the parents?

M = Mule; m = Cloven
B = White; b = Black

a. mmBb x MmBb
b. mmBB x Mmbb
c. mmBb x Mmbb
d. mmBB x MMbb
e. none of the above