Basic Genetics

Question 1

1. Which statement best describes the process of mitosis?

a. Cell division by which only one-half of the daughter
cells produced are identical to the parent cell
b. Cell division of germ cells by which two successive
divisions of the nucleus produce cells that contain half
the number of chromosomes of somatic cells
c. Cell division that produces four daughter cells having
the same number of chromosomes as the parent
d. Cell division that produces two daughter cells with the
same number of chromosomes as the parent cell

Answer 1

d. Cell division that produces two daughter cells with the same number of chromosomes as the parent cell

Question 2

2. When a recessive trait is expressed:
   a. One gene carrying the trait was present.
   b. Two genes carrying the trait were present.
   c. No gene carrying the trait was present.
   d. The gene is hemizygous.

Answer 2

b. Two genes carrying the trait were present.

Question 3

3.. In a pedigree analysis, which statement about the symbols
used is true?
a. Deceased family members have a line crossed through the symbol.
b. A consanguineous mating is indicated by a single line
between a male and female.
c. The propositus is always found in the last generation
on the pedigree.
d. A stillbirth is indicated by a triangle.

Answer 3

a. Deceased family members have a line crossed through the symbol.

Question 4

4. Which of the following nitrogenous bases make up DNA?
   a. Adenine, leucine, guanine, thymine
   b. Alanine, cytosine, guanine, thymine
   c. Adenine, lysine, uracil, guanine
   d. Adenine, cytosine, guanine, thymine

Answer 4

d. Adenine, cytosine, guanine, thymine

Question 5

5. Mutations can occur following DNA replication that
   escapes the proofreading and repair systems. Which statement about DNA mutations is true?

a. All mutations result in a phenotypic change.
b. A frameshift mutation at the beginning of the coding
sequence is most likely to result in a phenotypic
change.
c. A transversion always encodes for a stop codon.
d. A missense point mutation never encodes for a stop
codon.

Answer 5

b. A frameshift mutation at the beginning of the coding
sequence is most likely to result in a phenotypic
change.

Question 6

6. Which phenotype would be expected from the mating of
   a Jk(a+b–) female and a Jk(a–b+) male?
   a. Jk(a+b–)
   b. Jk(a+b+)
   c. Jk(a–b+)
   d. All of the above

Answer 6

b. Jk(a+b+)

Question 7

7. Which statement describes an intron?
   a. The part of a gene that contains nonsense mutations
   b. The coding region of a gene
   c. The noncoding region of a gene
   d. The resting stage between cell divisions

Answer 7

c. The noncoding region of a gene

Question 8

8. Which statement about isolation of nucleic acids is true?
   a. All isolation methods involve the use of organic
   solvents.
   b. High protein concentration increases the DNA yield.
   c. mRNA can be effectively isolated with the use of
   poly-A–coated beads.
   d. Silica particles bind DNA under high salt concentrations.

Answer 8

d. Silica particles bind DNA under high salt concentrations.

Question 9

9. The purpose of transcription is to:
   a. Produce a protein.
   b. Read the mRNA by the ribosome.
   c. Synthesize RNA using DNA as a template.
   d. Replicate DNA.

Answer 9

c. Synthesize RNA using DNA as a template.

Question 10

10. When a male possesses a phenotypic trait that he passes
    to all his daughters and none of his sons, the trait is said
    to be:
    a. X-linked dominant.
    b. X-linked recessive.
    c. Autosomal dominant.
    d. Autosomal recessive.

Answer 10

a. X-linked dominant.

Question 11

11. When a female possesses a phenotypic trait that she
    passes to all of her sons and none of her daughters, the
    trait is said to be:
    a. X-linked dominant.
    b. X-linked recessive.
    c. Autosomal dominant.
    d. Autosomal recessive.

Answer 11

b. X-linked recessive.

Question 12

12. Which statement correctly describes DNA replication in
    eukaryotes?
    a. Semiconservative replication from RNA; requires
    DNA polymerase
    b. Bidirectional replication; requires RNA primer
    c. Conservative replication from DNA; requires RNA
    polymerase
    d. Occurs at the replication fork; both strands replicated
    in the same direction

Answer 12

b. Bidirectional replication; requires RNA primer

Question 13

13. How is tRNA different from other types of RNA?
    a. It has a 3′ poly-T tail.
    b. The immature form contains introns.
    c. It has a 3′ methylated cap.
    d. It recognizes amino acids and nucleic acids

Answer 13

d. It recognizes amino acids and nucleic acids

Question 14

14. Which statement about translation of proteins is false?
    a. It occurs on the ribosomes in the cytoplasm of
    the cell.
    b. Post-translation processing can include glycosylation.
    c. mRNA delivers the amino acids to the growing
    peptide chain during elongation.
    d. The codon UAA would terminate translation.

Answer 14

c. mRNA delivers the amino acids to the growing
peptide chain during elongation.

Question 15

15. The purpose of meiosis is to:
    a. Generate two identical daughter cells after division.
    b. Generate four identical daughter cells after division
    with the same number of chromosomes as the parent
    cells.
    c. Generate gametes with a diploid number of
    chromosomes.
    d. Generate daughter cells that contain half the number
    of chromosomes of somatic cells that contain new
    DNA sequences.

Answer 15

d. Generate daughter cells that contain half the number
of chromosomes of somatic cells that contain new
DNA sequences.

Question 16

16. The pattern of inheritance most commonly expressed by
    blood group genes is:
    a. X-linked recessive.
    b. Autosomal recessive.
    c. Autosomal codominant.
    d. X-linked codominant

Answer 16

c. Autosomal codominant.