GENETICS

Question 1

1. What is the term for a chromosomal abnormality where a segment of a chromosome breaks off and attaches to another organism?
   A. Inversion
   B. Duplication
   C. Translocation
   D. Deletion

Answer 1

C. Translocation

Question 2

2. Which syndrome is caused by a trisomy of chromosome 18?
   A. Turner syndrome
   B. Edwards syndrome
   C. Down syndrome
   D. Patau syndrome

Answer 2

B. Edwards syndrome

Question 3

3. Which chromosomal disorder is characterized by a single X chromosome in females?
   A. Turner syndrome
   B. Klinefelter syndrome
   C. Down syndrome
   D. Patau syndrome

Answer 3

A. Turner syndrome

Question 4

4. What is the primary function of the spindle fibers during mitosis?
   A. To replicate DNA
   B. To condense chromatin into chromosomes
   C. To attach to kinetochores and pull sister chromatids apart
   D. D. To reform the nuclear envelope

Answer 4

C. To attach to kinetochores and pull sister chromatids apart

Question 5

5. What is the role of the enzyme helicase in DNA replication?
   A. Adds nucleotide to the growing DNA strand
   B. Unwinds the DNA double helix
   C. Seals nick between Okazaki fragments
   D. Synthesizes RNA primers

Answer 5

B. Unwinds the DNA double helix

Question 6

6. Which amino acid is specified by the start codon in mRNA translation?
   A. Glycine
   B. Methionine
   C. Leusine
   D. Serine

Answer 6

B. Methionine

Question 7

7. Which enzyme is responsible for synthesizing the RNA primer during DNA replication?
   A. DNA polymerase I
   B. DNA polymerase III
   C. Primase
   D. Ligase

Answer 7

C. Primase

Question 8

8. Which molecular technique allows amplification of specific DNA sequences?
   A. Gel electrophoresis
   B. PCR (Polymerase Chain Reaction)
   C. Southern blotting
   D. Northern blotting

Answer 8

B. PCR (Polymerase Chain Reaction)

Question 9

9. What is the role of restriction enzymes in molecular biology?
   A. Unwinding DNA
   B. Synthesizing RNA primers
   C. Cutting DNA at specific sequences
   D. Sealing nicks in the DNA backbone

Answer 9

C. Cutting DNA at specific sequences

Question 10

10. Which technique is used to separate DNA fragments based on size?
    A. PCR
    B. Gel electrophoresis
    C. Western blotting
    D. DNA sequencing

Answer 10

B. Gel electrophoresis

Question 11

11. What does the term “epigenetics” refer to?
    A. Changes in the DNA sequence
    B. Changes in gene expression without altering the DNA sequence
    C. Inheritance of traits through RNA
    D. Mutations in mitochondrial DNA

Answer 11

B. Changes in gene expression without altering the DNA sequence

Question 12

12. Which RNA molecule is involved in the initiation of translation by binding to the ribosome and mRNA?
    A. mRNA
    B. tRNA
    C. rRNA
    D. miRNA

Answer 12

B. tRNA

Question 13

13. In Mendelian genetics, what does the term “segregation” refer to?
    A. The separation of alleles during gamete formation
    B. The combination of alleles during fertilization
    C. The inheritance of traits in pairs
    D. The dominance of one allele over another

Answer 13

A. The separation of alleles during gamete formation

Question 14

14. Which of the following best describes a dihybrid cross?
    A. A cross between two individuals that are homozygous for a single trait
    B. A cross between two individuals that are heterozygous for a single trait
    C. A cross between two individuals that are heterozygous for two traits
    D. A cross between two individuals that are heterozygous for two traits

Answer 14

C. A cross between two individuals that are heterozygous for two traits

Question 15

15. In Mendelian genetics, what is expected phenotypic ratio for a monohybrid cross of two heterozygous individuals?
    A. 1:1
    B. 3:1
    C. 9:3:3:1
    D. 1:2:1

Answer 15

B. 3:1

Question 16

16. What is the principle of independent assortment?
    A. Genes for different traits assort independently of each other during gamete formation
    B. Alleles segregate during the formation of gametes
    C. Each organism has two alleles for each trait
    D. One allele is dominant over the other

Answer 16

A. Genes for different traits assort independently of each other during gamete formation

Question 17

17. In a dihybrid cross, what is the expected phenotypic ratio of the offspring?
    A. 3:1
    B. 1:2:1
    C. 9:3:3:1
    D. 1:1

Answer 17

C. 9:3:3:1

Question 18

18. Which of the following represents a test cross?
    A. Crossing two homozygous individuals
    B. Crossing an individual of unknown genotype with a homozygous recessive individual
    C. Crossing two heterozygous individuals
    D. Crossing an individual of unknown genotype with a homozygous dominant individual

Answer 18

B. Crossing an individual of unknown genotype with a homozygous recessive individual

Question 19

19. What does it mean if an allele is dominant?
    A. It is more common in the population
    B. It masks the expression of a recessive allele in a heterozygous individual
    C. It is expressed only in homozygous individuals
    D. It is located on the X chromosome

Answer 19

B. It masks the expression of a recessive allele in a heterozygous individual

Question 20

20. In a cross between two individuals heterozygous for a single trait, what proportion of the offspring is expected to be homozygous recessive?
    A. 1/4
    B. 1/2
    C. 3/4
    D. 1/3

Answer 20

A. 1/4

Question 21

21. What is the expected genotypic ratio of the F2 generation in a monohybrid cross of two heterozygous individuals?
    A. 1:1
    B. 3:1
    C. 9:3:3:1
    D. 1:2:1

Answer 21

D. 1:2:1

Question 22

22. In incomplete dominance, the phenotype of the heterozygote:
    A. resembles the dominant homozygote
    B. resembles the recessive homozygote
    C. is intermediate between the two homozygotes
    D. is a blend of the two homozygotes

Answer 22

C. is intermediate between the two homozygotes

Question 23

23. What is the term when both alleles in a heterozygous organism are fully expressed, as in human blood type AB?
    A. Codominance
    B. Incomplete dominance
    C. Epistasis
    D. Polygenic inheritance

Answer 23

A. Codominance

Question 24

24. In which type of genetic interaction does the expression of one gene mask the effect of another gene at different locus?
    A. Codominance
    B. Incomplete dominance
    C. Epistasis
    D. Polygenic inheritance

Answer 24

C. Epistasis

Question 25

25. Which pattern of inheritance is characterized by a continuous range of phenotypes such as skin color? A. Codominance B. Incomplete dominance C. Polygenic inheritance D. Epistasis

Answer 25

C. Polygenic inheritance

Question 26

26. What term describes the inheritance pattern of traits controlled by genes on the sex chromosome? A. Autosomal dominant B. Autosomal recessive C. Sex-linked D. Polygenic

Answer 26

C. Sex-linked

Question 27

27. In rabbits, the gene coat color has four alleles: C (full color), cch (chinchilla), ch (Himalayan), and c (albino). The dominance hierarchy is C > cch > ch > c. If a rabbit with genotype Ccch is crossed with a rabbit with genotype cchch, what is the expected phenotypic ratio of the offspring? A. 4 Full colors B. 2 Full colors: 2 Chinchilla C. 2 Chinchilla: 1 Himalayan: 1 Albino D. 4 Chinchilla

Answer 27

B. 2 Full colors: 2 Chinchilla

Question 28

28. In a population of birds, feather color is controlled by three alleles: B (blue), bw (white), and b (black). The dominance hierarchy is B > b > bw. If two birds with genotype Bbw are crossed, what is the expected phenotypic ratio of the offspring? A. 1 Blue: 2 Black: 1 White B. 2 Blue: 1 Black: 1 White C. 3 Blue: 1 White D. 1 Blue: 1 Black: 2 White

Answer 28

C. 3 Blue: 1 White

Question 29

29. In mice, coat color is determined by two genes: Gene A and Gene B. The A allele produces black fur, while the a allele produces brown fur. Gene B, when present in the homozygous recessive form (bb), causes albinism regardless of the alleles at gene A. If two heterozygous mice (AaBb) are crossed, what is the expected phenotypic ratio of the offspring? A. 9 Black: 3 Brown: 4 Albino B. 9 Black: 4 Brown: 3 Albino C. 9 Albino: 3 Black: 4 Brown D. 9 Brown: 3 Black: 4 Albino

Answer 29

A. 9 Black: 3 Brown: 4 Albino

Question 30

30. In a population genetics context, what does inbreeding generally lead to: A. Increased genetic diversity B. Reduced genetic diversity C. Increased frequency of heterozygotes D. Increased mutation rate

Answer 30

B. Reduced genetic diversity

Question 31

31. Which of the following equations represents the Hardy-Weinberg equilibrium for a population with two alleles? A. p2 + 2pq + q2 = 1 B. p + q = 1 C. p2 + q2 = 1 D. 2p + 2q = 1

Answer 31

A. p2 + 2pq + q2 = 1

Question 32

32. If the frequency of the recessive allele (q) is 0.3 in a large, randomly mating population, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium? A. 0.09 B. 0.21 C. 0.42 D. 0.49

Answer 32

C. 0.42

Question 33

33. Which of the following is true about the population in Hardy-Weinberg equilibrium? A. It is evolving rapidly. B. Allele frequencies remain constant from generation to generation. C. It is experiencing strong natural selection. D. There is a high rate of mutation.

Answer 33

B. Allele frequencies remain constant from generation to generation.

Question 34

34. In a population of 1000 individuals, the frequency of allele A is 0.6 and allele a is 0.4. Assuming Hardy-Weinberg equilibrium, how many individuals would be expected to be homozygous dominant? A. 240 B. 360 C. 160 D. 600

Answer 34

B. 360

Question 35

35. Which of the following processes is most likely to increase the fixation of beneficial alleles in a population? A. Genetic drift B. Gene flow C. Mutation D. Natural selection

Answer 35

D. Natural selection