Genetics MCQs

Genetics MCQs

Answer these 400+ Genetics  MCQs and assess your grip on the subject of Genetics. Scroll below and get started!

1: ____ is an accessory protein that acts to chaperone nucleosome assembly.

A.   Histone 3.3

B.   Nucleoplasmin/N1

C.   Histone H1

D.   CAF1/Asf1

2: ________ is to transcription as ________ are to translation.

A.   Alternative splicing ; pre-mRNA

B.   RNA polymerase; ribosomes

C.   Ribosomes ; RNA polymerase

D.   Pre-mRNA ;RNA polymerase

3: A 1:1:1:1 ratio of offspring from a dihybrid testcross indicates that ___________.

A.   The genes are not linked or are more than 50 map units apart.

B.   Have the same order of genes but different intergenic distances.

C.   Recessive, and that these genes are located 4 map units apart.

D.   None of these

4: A change from uug to uag would thus be a(n) _______ mutation.

A.   Silent; missense

B.   Nonsense; silent

C.   Frame-shift; missense

D.   Silent; nonsense

E.   Nonsense; frame-shift

5: A cross that involves two traits is called a ______ cross.

A.   Monohybrid

B.   Dihybrid

C.   Punnett

D.   Test

E.   Homozygous

6: A ddntp, used often in dna sequencing, lacks a(n) ________ at the ________ and ________ carbons.

A.   True

B.   OH; 2'; 3'

C.   DNA sequencing

D.   Filter-bound DNA

7: A dominant allele is best defined as ________.

A.   An allele that stops or hides the expression of the other allele

B.   The person has two identical alleles for the gene responsible for the trait

C.   Carriers are not eliminated by the disease before passing the defective alleles on to their offspring

D.   Incomplete dominance

E.   Phenotype

8: A gene is usually _____.

A.   The same thing as a chromosome

B.   The information for making a polypeptide

C.   Made of RNA

D.   Made by a ribosome

9: A gene made of __________ is transcribed into __________ and then translated to form a __________.

A.   DNA ... RNA ... protein

B.   U ... A....D

C.   DNA → RNA → protein

D.   Substitution of one nucleotide

10: A genetic locus has two alleles. one has a frequency of 0.12; the other has a frequency of _______.

A.   0.81

B.   0.88

C.   0.89

D.   0.87

11: A human female has _____ chromosomes in each skin cell and _____ chromosomes in each egg.

A.   46; 23

B.   23; 46

C.   46; 46

D.   23; 23

12: A monohybrid cross is made between plants that _____.

A.   Have experienced only one hybrid generation

B.   Differ in only one trait

C.   Are identical

D.   Are self-pollinated

13: A phenotypic ratio of 9:3:3:1 in the offspring of a cross indicates that _____.

A.   Both parents are heterozygous for both genes

B.   Calculate the probability of a child having either sickle-cell anemia or cystic fibrosis if parents are each heterozygous for both.

C.   In rabbits and many other mammals, one genotype (ee) prevents any fur color from developing.

D.   Skin pigmentation in humans

14: A plant with the genotype aabbcc is __________.

A.   Homozygous recessive individual

B.   Homozygous for two different genes

C.   The gene for hemophilia is sex-linked

D.   All of the dominant phenotype

15: A plasmid differs from the bacterial chromosome in that it is __________.

A.   Plasmids contain genes that are NOT essential for cellular growth and replication.

B.   Catalyze the formation of phosphodiester bonds between ribonucleotides.

C.   Additional genetic traits that are needed only under certain circumstances

D.   Allows coordinated expression of multiple related genes in prokaryotes.

16: A ribozyme is __________.

A.   An RNA molecule that functions as an enzyme

B.   The location in a cell where ribosomal RNAs (rRNAs) are made

C.   An example of rearrangement of exons caused by alternative RNA splicing

D.   An exception to the one gene-one enzyme hypothesis

E.   A cutting enzyme involved in DNA damage repair

17: A robertsonian translocation is considered non-reciprocal because _______.

A.   A copy of the insertion sequence becomes integrated at a new location

B.   Two haploid gametes fuse to form a diploid cell

C.   The smaller of the two reciprocal products of translocated chromosomes is lost

D.   They may be sterile and unable to produce offspring.

18: A stretch of 150 nucleotides in a coding region would code for _______ codons.

A.   30

B.   50

C.   150

D.   450

E.   750

19: Aabb × aabb is an example of ____.

A.   Fertilization

B.   DNA polymerase

C.   Incomplete dominance


E.   A dihybrid cross

20: According to chargaff's rules, ___ always pairs with ____, and _____ always pairs with _____.

A.   A; G; T; C

B.   A; T; G; C

C.   A; C; G; T

D.   C; T; G; A

E.   G; U; A; C

21: "all of the following are dna sequencing techniques except _____. select all that apply.

A.   DNA fingerprinting

B.   Maxam and Gilbert method

C.   Chain termination method

D.   Mullis chain-terminating sequencing

22: All of the following are required in complementation testing in yeast except _______.

A.   Mutations that are recessive

B.   Diploid cells

C.   Two or more mutations that affect a single phenotype

D.   An auxotrophic organism

A.   Telomerase enzyme

B.   Links to the aging process

C.   Being found in eukaryotes and prokaryotes

D.   Short tandem repeats located at the ends of telomeres

24: All of the following conditions are required for hardy-weinberg equilibrium except __________.

A.   Duplication

B.   Natural selection

C.   Balancing selection

D.   Mutation

E.   Human fingerprints

25: An mrna molecule has 540 codons. it must have at least _______ nucleotides.

A.   180

B.   270

C.   540

D.   1,080

E.   1,620

26: Bacterial dna polymerase i does not have ________ activity?

A.   3' to 5' exonuclease activity

B.   5' to 3' exonuclease activity

C.   Endonuclease activity

D.   5' to 3' DNA synthesis activity

27: Bergman’s rule suggests that there is a correlation between temperature and ________________.

A.   Size

B.   Pressure

C.   Space

D.   Mass

28: Brca1 and brca2 are considered to be tumor-suppressor genes because _____.

A.   Turned off whenever tryptophan is added to the growth medium.

B.   Starts when the pathway's substrate is present.

C.   Their normal products participate in repair of DNA damage.

D.   The occurrence of mRNAs for the production of tissue-specific proteins

29: Codons are base pair sequences that ________.

A.   Prevent mRNA synthesis

B.   Code for amino acids

C.   Alterations in the DNA base sequence

D.   Deoxyadenosine

30: Crossing over ________ genes into assortments of ________ not found in the parents.

A.   Recombines linked; alleles

B.   Combines unlinked; alleles

C.   Combines linked; genes

D.   Recombines unlinked; genes

31: Crossing over ____________ the number of recombinant offspring.

A.   Decreases

B.   Not assort independently.

C.   Increases

D.   Coupling

32: Disruptive selection favors individuals at ______ of variation

A.   One extreme

B.   Both extremes

C.   In the middle

D.   None of the above

33: During replication dna _____

A.   Remains intact

B.   Makes rna

C.   Is copied

D.   Directs protein synthesis

34: During telophase ______.

A.   Carry genes controlling the same inherited characteristics

B.   Homologous chromosomes line up in the middle of the cell

C.   The events of prophase are reversed

D.   Chromosomes line up in the middle of the cell

35: During the transcription of a given portion of a dna molecule _____.

A.   Manufactured proteins to be short and defective

B.   During transcription

C.   A silent or neutral mutation

D.   Cleavage of a polypeptide into two or more chains

E.   MRNA is synthesized on only one of the chains

36: During translation, _____ is synthesized in the _____.

A.   DnaA, opens the complex

B.   Exons, introns

C.   Nucleus, introns

D.   Polypeptides, mRNA sequences and cellular machinery

37: Each round of pcr ______.

A.   Increases the amount of DNA by 2n, where n = primer length

B.   Doubles the amount of DNA

C.   Increases the amount of DNA by 2n, where n = reaction temperature

D.   Cuts a new set of DNA fragments

38: Environmental factors typically influence inheritance of ________.

A.   Multiple alleles

B.   Codominance

C.   Trihybrid crosses

D.   Polygenic traits

39: Eric has blue eyes. since the gene for blue eyes is recessive, eric must be ______ for that trait.

A.   Dizygotic

B.   Embryonic

C.   Monozygotic

D.   Homozygous

40: Gene flow is accomplished by ______.

A.   Genetic drift

B.   Sexual recombination

C.   Mutation

D.   Migration

E.   Natural selection

41: Genes provide the information needed to produce _____ in the cell.

A.   Enzymes

B.   Lipids

C.   Ribosomes

D.   Glucose

42: Genetic drift is _____.

A.   An important microevolutionary mechanism in large populations

B.   The mechanism by which new alleles originate

C.   More likely to have an impact on small populations

D.   Adaptive

43: Genetic drift is the result of ______.

A.   Chance

B.   Environmental variation

C.   Natural selection

D.   A large gene pool

E.   Differential reproductive success.

44: Genetic drift produces variation for evolution when ________.

A.   A gene pool decreases because a smaller group establishes a new population

B.   Chance events cause allele frequencies to fluctuate unpredictably

C.   Sudden change in environment drastically reduces the gene pool

D.   A population has heritable traits better suited to the environment

45: Genetic variation _____

A.   Is created by the direct action of natural selection

B.   Must be present in a population before natural selection can act upon the population

C.   Tends to be reduced by when diploid organisms produce gametes

D.   Arises in response to changes in the environment

46: Genetic variation in bacterial populations cannot result from __________.

A.   Transformation

B.   Transduction

C.   Meiosis

D.   Conjugation

E.   Mutation

47: Hiv and phage lambda both __________.

A.   Surrounds the nucleic acid of a virus

B.   Integrate their DNA into the host's chromosome

C.   Considered to be alive

D.   Moves from the nucleus to the cytoplasm following RNA processing

48: If a disease is caused by a dominant allele, it means that a person with the disease ________.

A.   In the sequence of bases

B.   Polygenic inheritance.

C.   Huntington disease

D.   Could be either homozygous or heterozygous for the allele

E.   Hydrogen bonds between bases

49: If an allele is dominant in one sex and recessive in another, it is an example of ___________.

A.   Incomplete dominance

B.   Codominance

C.   Simple Mendelian inheritance

D.   Sex-limited inheritance

E.   Sex-influenced inheritance

50: If the dna in a cell consists of 20% adenine, then it will also contain ___ guanine.

A.   40%

B.   50%

C.   30%

D.   20%