Deck 5: Genetics: a Review

Question 1

Sister chromatids of each pair of homologous chromosomes _____,or come into 'side-by-side contact' to form a tetrad.

A)crossing-over
B)locus
C)dyad
D)synapse

Answer 1

D

Question 2

A trait caused by genes at several loci is an example of which of these?

A)Multiple alleles at one locus
B)Epistasis
C)Pleiotropy
D)Polygenic inheritance

Answer 2

D

Question 3

Gene interactions in which an allele at one locus prevents the expression of an allele at another locus is called

A)complete dominance.
B)incomplete dominance.
C)epistasis.
D)pleiotropy.

Answer 3

C

Question 4

Which of the following is NOT part of Mendel's law of segregation?

A)Each individual contains two factors for each trait
B)One factor must be dominant and one factor recessive in each individual
C)Each gamete contains one copy of each factor
D)Fertilization restores the presence of the two factors

Question 5

Which of the following are sex chromosomes of a normal human male?

A)XY
B)XX
C)XO
D)YO

Question 6

The location of a gene on a chromosome is called the gene __________.

A)tetrad
B)locus
C)dyad
D)synapsis

Question 7

What was the relationship between Gregor Mendel's work and the growing understanding of cells and chromosomes?

A)Mendel's work immediately generated great interest in what was the genetic material
B)Mendel was unaware of chromosomes and genes,which were not identified for 30 years
C)Breakthroughs in cytology and the structure of chromosomes were the factor that led Mendel to his experiments
D)Mendel's work led cell biologists to discover the nucleus and its role

Question 8

In the case of tall and dwarf pea plants,if a pea plant shows a recessive phenotype,

A)it can be either TT or Tt.
B)it can be either Tt or tt.
C)it can be only TT.
D)it can be only tt.

Question 9

Which of the following is NOT correct about X-linked characteristics?

A)More males than females are affected.
B)If a female exhibits the trait,all of her sons will also inherit and exhibit it.
C)Females can be carriers of the gene without showing it.
D)Males have two copies of the alleles for the trait,but females have only one.

Question 10

In Mendel's pea plants,round seeds (R)were dominant,and wrinkled seeds (r)were recessive.The endosperm of the pea is also either starchy,a dominant gene (S),or waxy,the recessive allele (s).If these genes are not linked,which of the following is true of a heterozygous dihybrid cross?

A)It is impossible to obtain offspring that are homozygous for both dominant genes.
B)It is impossible to obtain offspring that are homozygous for both recessive genes.
C)It is impossible to obtain offspring that are homozygous dominant for one trait and homozygous recessive for the other trait.
D)It is possible to produce offspring that are homozygous dominant for both traits,homozygous dominant for one trait but not the other,and homozygous recessive for both traits.

Question 11

Since a testcross backcrosses with a pure homozygous recessive strain,the offspring of an Aa genotype crossed by an aa genotype would show which genotype(s)?

A)aa only
B)Aa only
C)AA and Aa
D)Aa and aa

Question 12

You expect to find a ratio of 9:3:3:1 among the F₂ offspring in which type of cross?

A)Monohybrid cross
B)Dihybrid cross
C)Test cross
D)Sex-linked cross

Question 13

If an egg of a worm contains 6 chromosomes following meiosis,it comes from a worm that has ______ chromosomes in each body cell.

A)3
B)6
C)12
D)24

Question 14

F₂ offspring of a monohybrid cross involving Aa genotype show which genotype(s)?

A)Aa only
B)AA and Aa
C)Aa and aa
D)AA,Aa,and aa

Question 15

In a cross of parents with AA and aa genotypes for a particular trait,F₁ offspring would show which genotype(s)?

A)AA and Aa
B)AA,Aa,and aa
C)AA only
D)Aa only

Question 16

What was the relationship between Gregor Mendel's work and Charles Darwin's publication on evolution?

A)Mendel's work came before Darwin's and gave Darwin a critical piece of the evolutionary puzzle
B)Mendel read Darwin's work and this inspired him to experiment with principles of heredity
C)Both were contemporaneous and worked back-and-forth,providing ongoing feedback for each other's work
D)Mendel's discoveries were shortly after Darwin's publication,but the implications of his work were not understood for over thirty years

Question 17

Which is a correct usage of phenotype and genotype?

A)Phenotype is the cause of genotype
B)Phenotype is restricted to characteristics involving size and color
C)One genotype may produce many phenotypes
D)Two different genotypes may produce the same phenotype

Question 18

If a gene is not on the sex chromosome,it is found on a(an)

A)autosome.
B)locus.
C)dyad.
D)asexual chromosome.

Question 19

Alleles are genes that

A)are linked.
B)are lethal when homozygous.
C)occupy corresponding places in homologous chromosomes.
D)are never heterozygous.

Question 20

At its simplest,meiosis could be described as

A)duplication-division.
B)duplication-duplication-division.
C)duplication-division-division.
D)division.

Question 21

Transfer RNA functions in

A)delivering amino acids to the mRNA-ribosome complex.
B)synthesizing mRNA.
C)delivering amino acids to DNA.
D)None of the choices is correct.

Question 22

Which of the following statements about DNA replication is NOT correct?

A)Replication occurs as each base is paired with another exactly like it.
B)Unwinding of the DNA molecule occurs as hydrogen bonds break.
C)DNA polymerase catalyzes DNA replication.
D)Complementary base pairs are held together with hydrogen bonds.

Question 23

Males are said to be ________ for traits carried on the X chromosome.

A)codominant
B)polygenic
C)hemizygous
D)homozygous

Question 24

Messenger RNA is transcribed using which strand of DNA?

A)Sense strand
B)Antisense strand
C)Messenger RNA is not transcribed from DNA
D)Both strands of DNA are typically used

Question 25

A codon is composed of _______ bases.

A)two
B)three
C)four
D)six

Question 26

What is the function of DNA ligase?

A)To carry DNA into a new cell.
B)To join the end of the new strand to the old one.
C)To make millions of copies of a specific segment of DNA.
D)To destroy damaged DNA.DNA ligase joins the ends of DNA strand fragments produced in DNA replication and mutation repair.It is also used for this function in recombinant DNA technologies.

Question 27

Down syndrome is an example of

A)aneuploidy.
B)changes in the liner arrangement of genes within one chromosome.
C)monosomy.
D)polyploidy.

Question 28

At which stage of meiosis does crossing-over occur?

A)Prophase of the first meiotic division
B)Anaphase of the first meiotic division
C)Prophase of the second meiotic division
D)Anaphase of the second meiotic division

Question 29

Sections of DNA that do not code for a final product,and which may intervene in a DNA sequence are

A)transcribed into tRNA.
B)exons.
C)introns.
D)interferons.

Question 30

Which RNA molecules carry genetic information away from DNA when it is needed for the construction of a protein?

A)Ribosomal RNA
B)Transfer RNA
C)Messenger RNA
D)Primary mRNA transcript

Question 31

What is a synaptonemal complex?

A)The internal structure of nucleoprotein that makes up a chromosome
B)A proteinaceous structure that holds together two sister chromatids
C)The spindle fibers that attach from pole to pole without binding chromosomes
D)The set of cells produced from a single original parent cell in oogenesis

Question 32

A complex of mRNA used to allow multiple molecules of the same protein to be synthesized concurrently is called a(n)_______________.

A)anticodon
B)transcription factor
C)intron
D)polysome

Question 33

On the cloverleaf-shaped tRNA,what is exposed to form base pairs with complementary codon bases in the mRNA?

A)A polysome
B)An intron
C)An anticodon
D)RNA polymerase

Question 34

What is the anticodon for GCG?

A)AUA
B)UAU
C)CGC
D)AGA

Question 35

Deletion of one chromosome,as in the case of XO or Turner syndrome,would be a case of

A)aneuploidy.
B)changes in the linear arrangement of genes within one chromosome.
C)trisomy.
D)polyploidy.

Question 36

A section of a chromosome breaks out and then reinserts itself into the gap it left,but in the opposite direction.What is this called?

A)Aneuploidy
B)An inversion
C)A translocations
D)A deletion

Question 37

Which type of RNA molecule forms the large and small subunits of the cytoplasmic structure that builds proteins?

A)Ribosomal RNA
B)Transfer RNA
C)Messenger RNA
D)Primary mRNA transcript

Question 38

Why is crossing-over important?

A)Crossing-over provides extra genetic material for the daughter cells.
B)Crossing-over increases the likelihood that daughter cells contain recombined genetic material.
C)Crossing-over increases chromosome condensation.
D)Crossing-over separates the homologous chromosomes.

Question 39

Which of the following processes synthesizes mRNA,tRNA,or rRNA?

A)Translation
B)Transcription
C)Transposition
D)None of the choices is correct

Question 40

The first control in gene activity is _______ control.

A)translational
B)transcriptional
C)gene rearrangement
D)DNA modification

Question 41

Aneuploidy is the addition or subtraction of a single _____________ to or from a diploid set.

Question 42

The phenomenon where an allele at one locus may mask or prevent the expression of an allele at another locus acting on the same trait is called ____________.

Question 43

To make recombinant DNA,

A)bacterial DNA is annealed with restriction endonucleases.
B)DNA is cleaved with restriction endonucleases and annealed together with plasmid or viral DNA.
C)plasmid or viral DNA is cloned in mammalian cells.
D)the "sticky ends" of the DNA must be annealed to the nuclear membrane.

Question 44

mRNA molecules attach themselves to a _______ for the production of proteins.

Question 45

_________ _________ are enzymes derived from bacteria;they cleave double-stranded DNA at a particular site determined by the particular base sequences (recognition site)at that point.

Question 46

The most familiar form of aneuploidy in humans results in Down Syndrome or ________ _________.

Question 47

You are a science journalist writing a piece on the history of our study of DNA.Your editor would like you to summarize your current work so she can evaluate it and determine the readiness of your work for publication.Compare the following statements and determine which best conveys the facts related to your study of DNA.

A)Statement 1 - 'The study of DNA has been ongoing since the time of Charles Darwin and Gregor Mendel.Those scientists used knowledge of DNA to determine the mechanisms of evolution and the principles of heredity,respectively.'
B)Statement 2 - 'The study of DNA has been ongoing since the time of Charles Darwin and Gregor Mendel.Their work on evolution and the principles of evolution led Beadle and Tatum to propose a link between DNA and metabolism.'
C)Statement 3 - 'The study of DNA has been ongoing since the time of Beadle and Tatum who,based on other work being completed in the decades surrounding their work,proposed a link between DNA and metabolism.'
D)Statement 4 - 'The study of DNA has been ongoing since the time of Beadle and Tatum who,based on other work being completed in the decades surrounding their work,proposed a link between DNA and the principles of heredity.'

Question 48

Body cells and gametes typically have the diploid and ____________ number of chromosomes respectively.

Question 49

Methylation of cytosine residues is involved in

A)feedback control.
B)translational control.
C)gene rearrangement.
D)DNA modification and control.

Question 50

Which level of control in gene activity involves delay in translation,such as the buildup of oocytes messenger RNA until fertilization activates egg metabolism?

A)Translational control
B)Transcriptional control
C)Gene rearrangement
D)DNA modification

Question 51

Males are said to be ___________ for traits carried on the X chromosome.

Question 52

Which type of molecule produces variable lengths of DNA with "sticky ends"?

A)DNA ligase
B)RNA polymerase
C)Reverse transcriptase
D)Restriction enzyme

Question 53

The polymerase chain reaction is

A)part of the normal process of DNA replication in the cell.
B)a way to amplify small samples of DNA when a short sequence is known.
C)a method for constructing complementary DNA by transcribing the base sequence with reverse transcriptase.
D)None of the choices is correct.