V. Genetics questions
Genetics questions
There are a total of 44 genetics questions, which are important content-oriented in the summary part of this chapter. Click the ‘Answer’ button to see the corresponding answers and explanations, and click the ‘Go back’ button to slove the next questions.
1. A cell contains 32 sister chromatids at metaphase I. How many chromosomes can be shown in one daughter cell after finishing meiosis II completely?
A. 64 chromosomes
B. 32 chromosomes
C. 16 chromosomes
D. 8 chromosomes
E. 4 chromosomes
2. Which of the following is NOT a condition of Hardy-Weinberg Equilibrium?
A. No large population
B. No gene flow
C. No mutation
D. No natural selection
E. Random mating
3. In a Hardy-Weinberg population there are two alleles, the dominant allele and the recessive allele. If the frequency of the dominant allele is 0.6, what percentage of dominant phenotype is present in this population?
A. 40%
B. 36%
C. 16%
D. 48%
E. 84%
4. A woman has normal vision but her father has color blindness. If she has her children with a normal man, what is the percentage likelihood that a male child would have color blindness?
A. 100%
B. 75%
C. 50%
D. 25%
E. 0%
5. In Griffith’s experiment, when he inducted living S cells into a mouse, the mouse died, and when he injected living R cells into a mouse, the mouse survived. However, when he injected a mixture of heat-killed S cells and living R cells into a mouse, the mouse died. What did he find?
A. Unknown materials transformed the living R bacteria into the pathogenic S bacteria.
B. DNA is the transforming factor.
C. DNA is an agent for reproduction of phage T2.
D. Protein is one component of bacteria.
E. A and D
6. Which of the following statements is a FALSE statement?
A. DNA is packed by histone composed of proteins to become a nucleosome.
B. Humans have 46 chromosomes: 2 sex chromosomes and 44 autosomes.
C. Location of the centromere at end of the chromosome is called telocentric.
D. The probability of crossing over is increased the closer the gap between two linked genes.
E. The distance between two linked genes is measured by the probability of crossing over.
7. Which of the following does NOT apply to Okazaki fragments during DNA replication?
A. New nucleotides are elongated in the same direction as the movement of the replication fork.
B. The direction of growth of new strands of DNA is from 5′ to 3′.
C. Short segments are added during synthesis.
D. The overall direction of new strands is from 3′ to 5′.
E. They are elongated by DNA Pol III.
8. All of the following factors are transcribed from DNA strands EXCEPT _____________.
A. Exon
B. Codons
C. Amino acid
D. 5′ Cap
E. r-RNA
9. If one protein in an eukaryotic cell contains 120 amino acids, overall how many numbers of DNA nucleotides are needed for codes of these amino acids?
A. 720
B. 360
C. 240
D. 120
E. 40
10. Which of the following mutations is INCORRECTLY matched?
A. Nonsense: becoming a different amino acid by altering a codon
B. Missense: becoming a stop codon by substitution of one nucleotide
C. Silent: not resulting in mutated amino acid
D. Frame shift: missing or insertion of a single nucleotide
E. A and B
11. Which of the following gene technology is useful for amplifying an original double strand of DNA?
A. Dideoxy Chain-Termination
B. Polymerase chain reaction (PCR)
C. X-ray diffraction
D. DNA finger print
E. Gel electrophoresis
12. Which of the following statements about cell cycle is (are) true?
I. One chromosome consists of two sister chromatids from G2 of interphase to metaphase of mitosis. II. Daughter cells have half the number of chromosomes after the completion of meiosis. III. The longest phage of cell life is G1 phase. |
A. I only
B. I and II
C. I, II, and III
D. II, III, and IV
E. All of the above
13. One organism has a chromosome number of 2n = 8. Which of the following about this organism is FALSE?
A. 8 diploid numbers
B. 8 chromosomes
C. 4 homologous pairs
D. 4 chromosomes in a formed gamete from this organism
E. Forming 16 chromosomes during S phage
14. In a hypothetical population of 100 people, dominant homozygotes are 64 and heterozygotes are 32. What is the frequency of the recessive allele?
A .8
B. 4
C. 32
D. 2
E. 16
15. How many different types of gametes can be formed from the genotype, AaBBCcDdEE?
A. 2
B. 4
C. 8
D. 16
E. 32
16. Choose all possibilities that the children would be normal from their parents.
I. A male child from a Hemophiliac mother and normal father II. A female child from a homozygous normal mother and color blind father III. A male child from a mother who has sickle cell anemia disease and homozygous normal father IV. A female child whose mother and father both have sickle cell anemia disease |
A. II only
B. I and II
C. II and III
D. I, II, and III
E. All of the above
17. Alleles for black fur on the X chromosome are not active after cell division. All of the following are true about this organism EXCEPT _______________.
A. This occurrence is related to the Barr body.
B. This organism is male.
C. The black fur does not show up at the spot.
D. The X chromosome of the black fur alleles is condensed.
E. All are correct.
18. Chromosomes do not separate during meiosis II. Which can be expected?
A. Presence of monosomic chromosomes
B. Presence of trisomic chromosomes
C. Turner syndrome
D. A and C
E. All of the above
19. An organism contains 26% of guanine in DNA. What percentage of the nucleotides will be thymine?
A. 24%
B. 48%
C. 26%
D. 52%
E. 13%
20. Which of the following is true of spliceosomes?
A. They remove exons from pre-mRNA.
B. snRNPs and other proteins combine to become spliceosomes.
C. They are needed for DNA replication.
D. Spliced introns are used for codons.
E. A and D
21. Which of the following mutations causes the most serious genetic disease?
A. Missense
B. Silent
C. Frame shift
D. Nonsense
E. Point mutation
22. During which phases are sister chromatids separated?
A. Metaphase of mitosis
B. Anaphase of mitosis
C. Anaphase I of meiosis
D. Anaphase II of meiosis
E. B and D
23. When do the greatest genetic exchange and combination happen between gametes?
A. S phase
B. Prophase of mitosis
C. Prophase I of meiosis
D. Prophase II of meiosis
E. C and D
24. A small group was isolated from the large population and lost genetic variation. Finally this small group became a different population from the origin population. This is called _____________.
A. Bottleneck effect
B. Found effect
C. Gene flow
D. Hybridization
E. Cline
25. A roan horse has a black and white coat from its black mother horse and white father horse. This is an example of _______________.
A. Complete dominance
B. Incomplete dominance
C. Codominance
D. Epistasis
E. Pleiotrophy
26. Which of the following is an IMPOSSIBLE blood type of a child from a B blood typed mother and A blood typed father?
A. B
B. O
C. A
D. AB
E. All are possible blood types
27. Which of the following about changing chromosomal structures is correctly matched?
A. Translocation: reverse attachment of chromosomal segment
B. Deletion: breakage and rearrangement of chromosome
C. Duplication: repeating chromosomal segment
D. Inversion: lost chromosomal segment
E. A and C
28. Which of the following is an INCORRECT statement about mitotic cell division?
A. Duplicated chromatins occur during S phase.
B. Chromatins are condensed into chromosomes during prophase.
C. Chromosomes are lined up along the metaphase plate during metaphase.
D. The nuclear envelope disappears during telophase.
E. During cytokinesis cell plates are formed in plant cells.
29. Assessment of DNA synthesis occurs at _____________ checkpoint.
A. Go
B. G1
C. G2
D. M
E. S
30. Which of the following is an INCORRECTLY matched pair?
A. Complete dominance: purple flower × white flower → purple flower
B. Incomplete dominance: white flower × red flower → pink flower
C. Polygenic inheritance: quantitative variation of gene → phenotypic expression of blood type
D. Epistasis: alternation of one gene to the second gene → phenotypic expression of color of mice
E. Pleiotrophy: single gene → multiple phenotypic traits
31. Which of the following statements is FALSE?
A. Allele can be dominant or recessive as an alternative form of a gene.
B. The phenotype of an organism is determined by the dominant allele.
C. Recessive homozygotes do not affect the phenotype of an organism.
D. Dominant homozygotes and heterozygotes affect the phenotype of an organism.
E. Male chromosomes such as XY are heterozygous.
32. Klinefelter Syndrome is _______________.
A. Nondisjunction of chromosome number of 21
B. Sterile male with XXY chromosomes
C. Male body characteristics
D. Monosomic
E. B and C
33. Which of the following about enzymes is an INCORRECTLY matched pair?
A. DNA ligase: joining the ends of DNA strand
B. Telomerase: prevent eroding DNA strand
C. Topoisomerase: relieving the strain of tighter twisting DNA
D. Primase: synthesizing pre-mRNA
E. Helicase: separating the double strands of DNA
34. Which of the following is the correct order?
A. Translation → transcription → protein → phenotype
B. RNA → transcription → protein → phenotype
C. DNA → translation → RNA → transcription
D. DNA → RNA → transcription → translation
E. DNA → RNA → protein → phenotype
35. If the sequence of t-RNA anticodons has been determined to be ‘AUA GAU GUA’, what is the corresponding base sequence of DNA from this strand? (DNA sequence is the same direction as the sequence of t-RNA anticodons.)
A. AUA GAU GUA
B. UAU CUA CAU
C. ATA GAT GTA
D. TAC CTA CAT
E. None of the above
36. Which of the following is INCORECTLY matched?
A. Go checkpoint: nondividing state
B. G1 checkpoint: cell growth checkpoint
C. G2 checkpoint: checkpoint before M phase
D. M checkpoint: spindle checkpoint
E. All are correct.
37. Which of the following is an INCORRECT statement?
A. If an organism contains 23 pairs of chromosomes in gametes, the genetic diversity of this organism is 223.
B. After combining two gametes a zygote is formed.
C. Somatic cells are produced by mitotic and meiotic cell division.
D. Germ-line cells are produced by meiotic cell division.
E. Sperm and eggs cells are haploid cells and somatic cells are diploid cells.
38. Which of the following is INCORRECT?
A. If a male inherits blue eyes but does not inherit curly hair from his father, it is called Mendel’s law of independent assortment.
B. F1 generation produced all pink flowers from mating purple and white flowers.
C. F1 generation was all heterozygotes.
D. F2 generation showed that the ratio of purple and white flowers was 3:1.
E. F2 generation showed that the ratio of genotype (PP: Pp: pp) was 1:2:1.
39. Which of the following statements about testcross is (are) true?
I. This method is used for determining the phenotype of a parent organism. II. Recessive homozygotes cross with the dominant phenotype of a parent organism. III. The result of all dominant phenotypes can say that the parents have homozygous type. IV. The result of half dominant and half recessive phenotypes can say that that parents have heterozygous type. |
A. I only
B. II and III
C. III and IV
D. II, III, and IV
E. All of the above
40. A semiconservative model showed that a daughter strand has 12.5 % of conservative molecules from the parent strand. How many times has the daughter strand been duplicated?
A. 1
B. 2
C. 3
D. 4
E. 5
41. Which of the following statements about DNA structure is (are) true?
I. Pyrimidine has one nitrogenous ring and purine has two nitrogenous rings. II. There are hydrogen bonds between adenine and cytosine. III. Carbon sugars and nitrogen bases form the DNA backbone. IV. Molecules containing A and T have a higher melting point than those containing G and C. |
A. I only
B. I and II
C. I, II, and III
D. II, III, and IV
E. All of the above
42. All statements are about ribosome EXCEPT _______________.
A. Polyribosomes read a single mRNA simultaneously at cytoplasm.
B. Translocation of peptide bonds and departing tRNA happen at E site.
C. GTP energy is needed for synthesizing polypeptide.
D. Peptide bonds form at P site.
E. Aminoacyl-tRNA is bound at A site.
43. What is the trait of inheritance in the following pedigree?
A. Autosomal dominant
B. Autosomal recessive
C. X-linked dominant
D. X-linked recessive
E. Hemizygous recessive
44. Reducing three codons to two codons when tRNA matches with mRNA strands is called _______________.
A. Anticodon
B. Stop codon
C. Start codon
D. Wobble
E. Methyliosine
Answers
1. D
One cell of prophase II would contain 16 sister chromatids after telophase I and then a nucleus in telophase II would contain 8 sister chromatids. Finally, the 8 sister chromatids in one cell would be 8 chromosomes in one daughter cell.
2. A
Hardy-Weinberg Equilibrium conditions are large population, no gene flow (isolation), no mutation, random mating, and no natural selection.
3. E
In the Hardy-Weinberg equation, the allele equation is p+q=1. If the frequency of the dominant allele p is 0.6, then the frequency of the recessive allele q is 0.4. In the population equation, p2+2pq+q2=1, the dominant phenotype is p2+2pq or 1-q2. Thus, 1-(0.4)2=0.84. The percentage of dominant phenotype is 84%.
4. D
Color blindness is an X-linked recessive trait.The woman has normal vision and her father has color blindness. She will be XXa as below.
Also, when she has children with a man who has normal vision, the genotypes of the children are as below.
Only a male son would have color blindness. Thus, the percentage likelihood of male child colorblindness: 1/4 = 25%.
5. A
B is the conclusion of the Avery, Macleod, McCarty experiment. C is the conclusion of the Hersh-Chase experiment.
6. D
The greater the gap between two linked genes, the greater the probability of crossing over.
7. A
The statement of A is for the leading strand. Okazaki fragments on the lagging strand are the opposite direction of elongating new nucleotides against the movement of the replication fork.
8. C
Pre-mRNA transcribed from DNA consists of 5′ Cap, exon, intron, and poly-A tail. Pre-mRNA becomes mRNA for codons of amino acids after cutting out introns and splicing exons together. r-RNA is transcribed from DNA.
9. B
To produce one amino acid there must be one codon and three nucleotides of DNA. Thus, 360 DNA nucleotides and 12o codons are needed to make 12o amino acids.
10. E
Nonsense of mutation is a result of a stop codon by substitution of one nucleotide. Missense is becoming a different amino acid by altering a codon.
11. B
The Dideoxy Chain-Termination method is useful for determining the long sequencing DNA rapidly. X-ray diffraction is used for knowing the arrangement of molecular structure. DNA fingerprint is used to identify an individual’s DNA. Gel electrophoresis is used for separating nucleic aids or proteins.
12. C
During mitosis chromosomes line up along the metaphase plate. During meiosis I the pairs of homologous chromosomes line up along the metaphase plate.
14. D
In the Hardy-Weinberg equation, the population equation is p2+2pq+q2=1. Recessive homozygotes population is 100-64-32= 4 and the frequency of recessive homozygotes q2 is 4/100 = 0.04.
16. C
I. Because Hemophilia disease is a sex-linked trait, all male children from a diseased mother and normal father would be abnormal.
II. Color blindness is also a sex-linked trait. The female children from a homozygous normal mother and color blind father will be normal.
III. Sickle cell anemia is an autosomal recessive trait. All male and female children from a diseased mother and homozygous normal father would be normal.
IV. All children from both mother and father who have sickle cell anemia disease are abnormal.
17. B
An inactivated X-chromosome called the Barr body is condensed after cell division. The alleles on the inactivated X-chromosome do not show up. The Barr body occurs only in females.
18. E
Nondisjunction of homologous chromosomes or chromosomes occurs during each meiosis I and meiosis II. An abnormal number of chromosomes from the nondisjunction is called aneuploidy, monosomic and trisomic. The presence of one chromosome is monosomic (n-1) and the presence of three chromosomes is trisomic (n+1). Monosomic chromosomes cause Turner syndrome (only X chromosome) and trisomic chromosomes cause Klinefelter Syndrome (XXY chromosomes).
19. A
In the DNA structure the ratios of A, G, C, and T are A=T and G=C. In Chargaff’s rule the amount between purine and pyrimidine has to be equal: A+G = C+T = 50%.
G=C=26%
C+T=50%, T=50%-26%=24%
Therefore, thymine would be 24%.
20. B
snRNP and other proteins combined are called spliceosomes. They remove introns from pre-mRNA and splice exons for codons of mRNA during RNA processing.
21. C
Frameshift mutation, missing or insertion of a single nucleotide, changes all codons for the amino acids and causes serious genetic diseases.
22. E
During anaphase of mitosis and anaphase II of meiosis the sister chromatids are separated. Pairs of chromosomes are separated during anaphase I of meiosis. Chromosomes are lined up during metaphase of mitosis and metaphase II of meiosis.
23. C
During prophase I of meiosis, homologous chromosome pairs are formed and then synapsis and crossing over occur between the homologous chromosomes. These events are the genetic exchange and combination between gametes.
24. B
Found effect means that the isolated group from large population loses genetic variation and establishes new population. Bottleneck effect is a drastic reduction in size of population by a sudden disaster. Gene flow means changing alleles of population by movements of individual alleles. Hybridization is breeding different related animals to increase variation. Cline is geographic variation along geographic height.
25. C
Having both phenotypes of F1 generation from both parental traits is called codominance. Complete dominance means having one phenotype of F1 generation from both parental traits. Incomplete dominance means having an intermediated phenotype of F1 generation from both parental traits. Epistasis is phenotypic expression by alternation one gene to the second gene. Pleiotrophy means that a single gene affects symptoms of the multiple phenotypic traits.
26. E
When a IBIO genotyped mother has children with a IAIO genotyped father, the genotypes of the children would be IAIB, IAIO, IBIO, and IOIO. Therefore, the possible blood types of the children would be AB, A, B, and O.
27. C
Translocation: breakage and rearrangement of chromosome. Deletion: lost chromosomal segment. Inversion: reverse attachment of chromosomal segment.
30. C
Polygenic inheritance means phenotypic expression by quantitative variation of a trait such as skin color. Phenotypic expression of blood type is an example of codominance.
31. E
Sex-linked genes such as XY of male chromosomes are called hemizygous. A pair of different and alternative alleles such as Aa or Bb is called heterozygous.
32. B
Klinefelter syndrome is the result of nondisjunction of X chromosome and is sterile male with XXY trisomic chromosomes. These people have female body characteristics. Nondisjunction of chromosomes number of 21 is down syndrome.
33. D
Primase synthesizes the RNA primer for starting point of DNA synthesis. RNA polymerase synthesizes pre-mRNA.
35. C
When the sequence of t-RNA anticodons is ‘AUA GAU GUA’, the sequence of m-RNA codons is ‘UAC CUA CAU’, and then the sequence of DNA is ‘ATA GAT GTA’.
39. C
Recessive homozygotes cross with the dominant phenotype of a daughter organism to determine the genotype of the parent organism.
40. C
One time duplication: 50% conservation of molecules from parent strands
Two times duplication: 25% conservation of molecules from parent strands
Three times duplication: 12.5 % conservation of molecules from parent strands
41. A
Hydrogen bonds are formed between adenine (A) and thymine (T) or G (guanine) and C (cytosine). DNA backbone is composed of carbon sugars and phosphate groups. Molecules containing A and T have a lower melting point than those containing G and C because the two hydrogen bonds between A and T are less than the three hydrogen bonds between G and C.
43. B
At the first generation, both parents have no disease but one of children has a disease. This is a recessive trait. At the second generation, the father has no disease but one daughter has the disease. This is an autosomal trait. Thus this pedigree illustrates an autosomal recessive trait.
44. D
Wobble is only necessary at the first two codons when tRNA meet with mRNA. Anticodons are triplet nucleotides at the end of tRNA. Stop codons, such as UAA, UAG, and UGA inhibit the synthesis of polypeptide. Start codons, AUG, begin the synthesis of polypeptide. Methyliosine is one of the tRNA bases.