Cotransduction of genes is an indication that the genes are linked.
A bivalent at pachytene contains four chromatids.
Translocations may be pericentric or paracentric.
For a given locus, in a population with two alternative alleles, the allele frequencies p +
q = 1.0.
Reverse transcriptase is often used as the heat-stable enzyme in PCR.
The trp operon is typically characterized as being both under negative control and
repressible.
A knockout animal, in the context of recombinant DNA technology, is one that has been
completely anesthetized.
There are two types of retinoblastoma, familial and sporadic. In the familial form, one
generally inherits a defective gene from one parent.
An Hfr cell can initiate chromosome transfer from one E. coli to another.
The meiotic cell cycle involves two cell divisions but only one DNA replication.
The lac operon consists of three structural genes as well as the adjacent region of DNA
known as the regulator.
In general, the main goal of cloning is to include as many different genes as possible in
a single cloning vector.
A 9:3:3:1 phenotypic ratio is expected from a dihybrid testcross.
The Genetic Testing Registry is designed to restrict public access to a variety of genetic
processes.
Of the two cell lines that can contain a mutation in an organism, somatic and germ line,
the latter is more consequential to subsequent generations.
A conditional mutant is one whose expression is influenced by some environmental
condition.
In studies attempting to determine a genetic basis for a given behavior, if the
environment is held constant, and behavioral differences directly correlate with genetic
differences, a genetic basis for the behavioral state is supported.
The gene p53 is called the “guardian of the genome” because it corrects mutations in
the spindle apparatus before nondisjunction can occur.
Gene duplications provide an explanation for the origin of gene families.
If a gene has three alleles in a population, their frequencies must add up to 1.5.
Introns are found only in prokaryotic genomes.
A missense mutation causes premature chain (protein) termination.
In the case of complete dominance in a population in equilibrium, we cannot tell which
individuals are homozygous dominants and which are heterozygous, but by knowing
the frequency of the homozygous recessives, we can estimate the frequency of
homozygous dominant and heterozygous genotypes.
Telomerase is an RNA-containing enzyme that adds telomeric DNA sequences onto the
ends of linear chromosomes.
Amniocentesis is preferred over chorionic villus sampling because recombinant DNA
screening can be achieved with amniocentesis but not with chorionic villus sampling.
Research on alcoholism indicates that at least in mouse and animal models, a single
dominant gene is responsible.
Familial Down syndrome can be caused by a translocation between chromosomes 1 and
14.
Evolution is dependent on genetic diversity in the evolving population.
Restriction fragment length polymorphisms (RFLPs), microsatellites, and
single-nucleotide polymorphisms (SNPs) were used by Morgan and Sturtevant to
discover linkage in Drosophila.
Normally in humans, all the sons of a female homozygous for a sex-linked recessive
gene will inherit that trait.
The cross GE/ge x ge/ge produces the following progeny: GE/ge 404; ge/ge 396; gE/ge
97; Ge/ge 103. From these data one can conclude that the G and E loci assort
independently.
In Drosophila melanogaster (2n = 8), a fly with seven chromosomes could be called a
haplo-IV.
E. coli is a common YAC.
Familial Down syndrome is caused by a translocation involving chromosome 21.
When treating an organism with a mutagen, although it is possible that homozygous
mutations will occur, it is more likely that most new mutations will be heterozygous or
hemizygous.
What term would be applied to a regulatory condition that occurs when protein is
associated with a particular section of DNA and greatly reduces transcription?
A) negative control
B) positive control
C) induction
D) activation
E) stimulation
The genes for zeste eyes and forked bristles are located on the X chromosome in
Drosophila melanogaster. Both genes are recessive. A cross is made between a
zeste-eyed female and a forked-bristled male.
a) If 200 offspring from this cross were obtained, present the expected number, sex,
genotype, and phenotype in each class of the F1.
b) If the F1 offspring were crossed to produce 800 flies of an F2 generation, present the
expected number, sex, and phenotype in each class. Assume no crossing over.
An intron is a section of ________.
A) protein that is clipped out posttranslationally
B) RNA that is removed during RNA processing
C) DNA that is removed during DNA processing
D) transfer RNA that binds to the anticodon
E) carbohydrate that serves as a signal for RNA transport
The genetic code is said to be triplet, meaning that there ________.
A) are three amino acids per base in mRNA
B) are three bases in mRNA that code for an amino acid
C) may be three ways in which an amino acid may terminate a chain
D) are three “nonsense” triplets
E) none of the above
Assume that the gene trpA in an auxotrophic strain of E. coli is located at 27 minutes,
whereas the gene pyrE is located at 81 minutes.
a) How are minutes arrived at in this context?
b) Present an experimental scheme that would allow you to convert one of the
auxotrophic strains to a prototrophic strain.
The two major components of the immune system are humoral and cellular immunity.
The humoral component ________.
A) is involved in the production of antibodies
B) allows the T cells to produce antigens that then stimulate antibody production
C) plays a major role in the production of antigens
D) suppresses the production of T cells
E) is responsible for allowing horizontal gene transfer
List three forms of DNA.
Two formal terms used to describe categories of mutational nucleotide substitutions in
DNA are ________.
A) base analogs and frameshift
B) error prone and spontaneous
C) transversions and transitions
D) euchromatic and heterochromatic
E) sense and antisense
The accompanying figure is a pedigree of a fairly common human hereditary trait in
which the boxes represent males and the circles represent females. Shading symbolizes
the abnormal phenotype.
Given that one gene pair is involved:
a) Is the inheritance pattern X-linked or autosomal, recessive or dominant?
b) Give the genotype of each individual in the pedigree. If more than one genotypic
possibility exists, present all possible alternatives.
rDNA is the portion of a genome that is involved in the production of ribosomal RNA.
Most of the bacterial genomes described in the text have fewer than ________.
A) 10,000 genes
B) 5000 base pairs
C) 500 genes
D) 10,000 base pairs
E) 50 genes
The accompanying figure is a pedigree of a fairly common human hereditary trait; the
boxes represent males and the circles represent females. Filled in symbols indicate the
abnormal phenotype. Given that one gene pair is involved,
a) Is the inheritance pattern X-linked or autosomal?
b) Give the genotype of each individual in the pedigree. If more than one genotypic
possibility exists, present all possible alternatives.
The human genome contains approximately 20,000 protein-coding genes, yet it has the
capacity to produce several hundred thousand gene products. What can account for the
vast difference in gene number and product number?
A) Alternative splicing occurs.
B) There are more introns than exons.
C) There are more exons than introns.
D) Much of the DNA is in the form of trinucleotide repeats, thus allowing multiple start
sites for different genes.
E) Every gene can be read in both directions, and each gene can have inversions and
translocations.
List three criteria indicating that a human disorder may be attributable to genetically
altered mitochondria.
Assume that you are told that a particular organism, Drosophila, has the XO
chromosome complement. You are also told that the autosomal complement is a normal
2n. You know that in humans the XO complement is female determining. Would you be
correct in assuming that the Drosophila sex for XO is also female? Choose the answer
that includes the correct explanation.
A) Yes, because sex determination in humans and insects is essentially the same.
B) No, sex determination in Drosophila is dependent on the presence or absence of the
Y chromosome.
C) No, the chromosomal basis for sex determination in Drosophila is based on the
balance between the number of X chromosomes and haploid sets of autosomes.
D) Yes, the presence of an X chromosome determines a female in both organisms.
E) No, it takes two X chromosomes to produce a female in humans and a Y
chromosome to produce a male in Drosophila.
A mutant gene that produces brown eyes (bw) is located on chromosome #2 of
Drosophila melanogaster, whereas a mutant gene producing bright red eyes, scarlet (st),
is located on chromosome #3. Phenotypically, wild-type flies (with dull red eyes),
whose mothers had brown eyes and whose fathers had scarlet eyes, were mated. The
800 offspring possessed the following phenotypes: wild type (dull red), white, scarlet
(bright red), and brown. Most of the 800 offspring had wild-type eyes, whereas those
with white eyes were the least frequent.
a) Using standard symbolism, diagram the cross from the P generation
and the F1 generation. Be certain to provide
the alleles of the mutant genes.
b) From the information presented above, how many white-eyed flies would you expect
in the F2 generation?
A plaque is a substance that causes mutation in bacteria.
The discontinuous aspect of replication of DNA in vivo is caused by ________.
A) polymerase slippage
B) trinucleotide repeats
C) the 5″ to 3″ polarity restriction
D) topoisomerases cutting the DNA in a random fashion
E) sister-chromatid exchanges
The relationship between a gene and a messenger RNA is that ________.
A) genes are made from mRNAs
B) mRNAs are made from genes
C) mRNAs make proteins, which then code for genes
D) all genes are made from mRNAs
E) mRNA is directly responsible for making Okazaki fragments
What term is given to the total genetic information carried by all members of a
population?
A) gene pool
B) genome
C) chromosome complement
D) breeding unit
E) race
Polydactyly is expressed when an individual has extra fingers and/or toes. Assume that
a man with six fingers on each hand and six toes on each foot marries a woman with a
normal number of digits. Having extra digits is caused by a dominant allele. The couple
has a son with normal hands and feet, but the couple’s second child has extra digits.
What is the probability that their next child will have polydactyly?
A) 1/32
B) 1/8
C) 7/16
D) 1/2
E) 3/4
Assume that a cross is made between AaBb and aabb plants and that the offspring occur
in the following numbers: 106 AaBb, 48 Aabb, 52 aaBb, 94 aabb. These results are
consistent with the following circumstance:
A) sex-linked inheritance with 30% crossing over.
B) linkage with 50% crossing over.
C) linkage with approximately 33 map units between the two gene loci.
D) independent assortment.
E) 100% recombination.
In 1964, Nirenberg and Leder used the triplet binding assay to determine specific codon
assignments. A complex of which of the following components was trapped in the
nitrocellulose filter?
A) ribosomes and DNA
B) free tRNAs
C) charged tRNA, RNA triplet, and ribosome
D) uncharged tRNAs and ribosomes
E) sense and antisense strands of DNA
List two especially useful characteristics of cloning vectors.
A) high copy number and antibiotic resistance gene(s)
B) virulence and lysogenicity
C) ability to integrate into the host chromosome and then causing a lytic cycle
D) nonautonomous replication and transposition
E) reverse transcriptase and ligase activities
In humans, the genetic basis for determining the sex “male” is accomplished by the
presence of ________.
A) a portion of the Y chromosome
B) one X chromosome
C) a balance between the number of X chromosomes and the number of haploid
D) sets of autosomes
E) high levels of estrogen
F) multiple alleles scattered throughout the autosomes
Mutations that eliminate a contiguous region in the Drosophila embryo’s segmentation
pattern are called ________.
A) homeodomains
B) gap genes
C) compartment genes
D) linkage genes
E) segment genes
A recessive allele in tigers causes the white tiger. If two normally pigmented tigers are
mated and produce a white offspring, what percentage of their remaining offspring
would be expected to have normal pigmentation?
A) 25%
B) 50%
C) about 66%
D) 75%
E) about 90%
For the purposes of this question, assume that a G1 somatic cell nucleus in a female
Myrmecia pilosula contains 2 picograms of DNA. How much DNA would be expected
in a metaphase I cell of a female?
A) 16 picograms
B) 32 picograms
C) 8 picograms
D) 4 picograms
E) Not enough information is provided to answer the question.
Regarding the structure of DNA, the covalently arranged combination of a deoxyribose
and a nitrogenous base would be called a(n) ________.
A) nucleotide
B) ribonucleotide
C) monophosphate nucleoside
D) oligonucleotide
E) nucleoside
Which of the following is a fundamental characteristic of the Notch pathway?
A) It works through nuclear signals involving the lac operon.
B) It works through direct cell to cell contact.
C) It allows mRNAs to accumulate in the posterior portion of the Drosophila embryo.
D) It directs mRNAs to antisense systems in the posterior portion of all organisms.
E) It provides symmetry to plant flowers.
Genetic regulation in prokaryotes can involve alterations in RNA secondary structure.
What phenomenon occurs in the trp operon that involves such alterations?
A) transcription
B) capping
C) polyadenylation of the 3″ end of the mRNAs
D) intron processing
E) attenuation
In an organism with 52 chromosomes, how many bivalents would be expected to form
during meiosis?
A) 13
B) 26
C) 52
D) 104
E) 208
In general, the organization of genes in bacteria is different from that in eukaryotes. In
E. coli, approximately 27 percent of all genes are organized into contiguous,
functionally related units containing multiple genes under coordinate control that are
transcribed as a single unit. Such contiguous gene families are called ________.
A) transcriptomes
B) proteomes
C) contigs
D) operons
E) pseudogenes
In what way might a virus contribute to cancer formation?
How does an auxotroph differ from a prototroph?
What can cause phenotypic mosaicism for X-linked genes in female mammals?
What is a tumor-suppressor gene? What are oncogenes? What is the normal
(nonmutant) cellular version of an oncogene called?
Two terms, reductional and equational, generally refer to which stages of meiosis (I or
II)?
Chronic myelogenous leukemia appears to be associated with a chromosomal
rearrangement. How is a chromosomal rearrangement responsible for this disease?
What single event is probably common to all occurrences of speciation?
In what way do segregational petite mutations differ from neutral petites?
What is the difference between a polynucleotide and an oligonucleotide?
Given that DNA is the genetic material in prokaryotes and eukaryotes, what other
general structures (macromolecules) and substances made by the cell are associated
with the expression of that genetic material?
The cAMP-CAP complex and RNA polymerase bind more efficiently to the lac operon
together than either does alone. What term is applied to this increased efficiency of
binding?
There is a fear that preconception genetic testing may lead to “designer babies.” What
historical practice comes to mind regarding the production of such babies?
Pattern baldness is determined by a single autosomal gene pair. When females are
homozygous for this gene pair, can they show pattern baldness?
Which class of genes controls the developmental identity of segments along the
anterior-posterior axis?
Regarding the ABO blood group system in humans, if an individual is genetically IBi
and yet expresses the O blood type, which genotype is it likely to have?
Describe the function of N-formylmethionine in prokaryotes.