The term spliceopathy would be a reasonable term to signify a genetic condition caused
by a defect in the regulation of RNA splicing.
Traits such as height, general body structure, skin color, and some behavioral traits are
probably caused primarily by genes that behave codominantly or epistatically.
Drosophila can learn and remember.
An autotriploid may arise when three sperm cells are involved in fertilization of a single
egg.
The primary structure of a protein is composed of the sequence of amino acids in that
protein.
It appears as if about 5000 functional genes is the minimum genome size necessary for
life of a prokaryote.
When the normal retinoblastoma protein is dephosphorylated, it acts to suppress cell
division by binding to and inactivating the E2F transcription factor.
A pericentric inversion includes the centromere.
A common term for a plasmid or other DNA element that serves as a cloning vehicle is
vector.
rDNA in eukaryotes is typically redundant.
Lysogeny is most likely associated with transduction.
G-quartets are G-rich single-stranded tails that loop back on themselves forming G-G
double stranded sections. Such looping is involved in aligning chromosomes for
homologous recombination.
An organism with a diploid chromosome number of 46 will produce 223 combinations
of chromosomes at the end of meiosis.
Alternative RNA processing generates different mRNAs, which can direct the synthesis
of different polypeptides.
Concordance refers to the frequency with which members of a twin pair express a
different trait.
The centromere of a chromosome separates during anaphase.
State whether the following statement is true or false, then give your reasoning. The
terminating “hairpin” loop occurs in the trp operon when sufficient tryptophan is
present.
Mendel’s postulate of independent assortment is supported by a 1:1:1:1 testcross ratio.
Determination is the process whereby a cell’s eventual developmental fate is set.
Loss-of-function mutations eliminate the function of a gene product and may be
dominant or recessive.
To isolate a bacterium with a plasmid that carries a desired DNA fragment cloned
within the ampicillin resistance gene, we should grow bacteria in a medium that
contains ampicillin.
Different domains in proteins impart different functional capabilities.
A 2-aminopurine is an alkylating agent.
Nondisjunction is viewed as a major cause of aneuploidy.
A symbiotic relationship between a phage and a bacterium apparently occurs in the
process of lysogeny.
Chorionic villus sampling (CVS) is sometimes preferred to amniocentesis because
results can be provided earlier in the pregnancy.
An example of organelle heredity involves pigmentation inMirabilis jalapa.
Mutations are regarded as a strong evolutionary mechanism for changing allelic
frequencies.
Exchanges occur between homologous chromosomes, but never between sister
chromatids.
The code is nonoverlapping, meaning that, assuming “standard translation,” a given
base participates in the specification of one and only one amino acid.
Mendel’s Law of Segregation is supported by a 1:1 testcross ratio.
A 9:7 ratio indicates incomplete dominance.
A typical epistatic ratio is 9:3:4.
It is safe to say that a maternal effect is caused by the genotype, not the phenotype, of
the parent producing the egg.
Inversions suppress crossing over by providing a chemical imbalance because of
breakpoints within certain genes.
The accompanying sketch depicts a cell from an organism in which 2n = 2 and each
chromosome is metacentric.
a) Circle the correct stage for the cell in this sketch:
anaphase of mitosis
anaphase of meiosis I
anaphase of meiosis II
telophase of mitosis
b) Given that each G1 nucleus from this organism contains 16 picograms of DNA, how
many picograms of chromosomal DNA would you expect in the cell shown below?
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is inherited as an X-linked
recessive gene in humans. A woman whose father suffered from G6PD marries a
normal man.
a) What proportion of their sons is expected to be G6PD?
b) If the husband were not normal, but were G6PD deficient, would you change your
answer in part (a)?
Assume that a black guinea pig crossed with an albino guinea pig produced 5 black
offspring. When the albino was crossed with a second black guinea pig, 4 black and 3
albino offspring were produced. What genetic explanation would apply to these data?
A) albino = recessive; black = recessive
B) albino = dominant; black = incompletely dominant
C) albino and black = codominant
D) albino = recessive; black = dominant
E) None of the answers listed are correct.
Transposons, or jumping genes, are DNA elements that move within the genome. In
which organismic groups are transposons found?
A) bacteria
B) eukaryotes
C) mammals
D) ancient bacteria
E) all organismic groups
A recessive gene for red-green color blindness is located on the X chromosome in
humans. Assume that a woman with normal vision (her father is color blind) marries a
color-blind male. What is the likelihood that this couple’s first son will be color blind?
A) 0%
B) 25%
C) 50%
D) 75%
E) 100%
Poky strains in yeast result from suppressive mutations in chloroplast DNA.
The PCR (polymerase chain reaction) protocol that is currently used in laboratories was
facilitated by the discovery of a bacterium called Thermus aquaticus in a hot spring
inside Yellowstone National Park, in Wyoming. This organism contains a heat-stable
form of DNA polymerase known as Taq polymerase, which continues to function even
after it has been heated to 95oC. Why would such a heat-stable polymerase be
beneficial in PCR?
A) Each cycle includes a “hot” saturation phase (95C), which allows the primers to
anneal to the target DNA.
B) Each cycle includes a “hot” denaturation phase (95C), which serves to sterilize the
culture.
C) Each cycle includes a “hot” denaturation phase (95C), which activates the Taq
polymerase.
D) Each cycle includes a “hot” denaturation phase (95C), which separates the hydrogen
bonds that hold the strands of the template DNA together.
E) More than one of the above are correct.
The term peptidyl transferase relates to ________.
A) base additions during mRNA synthesis
B) peptide bond formation during protein synthesis
C) elongation factors binding to the large ribosomal subunit
D) discontinuous strand replication
E) 5″ capping of mRNA
Tightly curled or wooly hair is caused by a dominant gene in humans. If a heterozygous
curly-haired person marries a person with straight hair, what percentage of their
offspring would be expected to have straight hair?
A) 25% curly
B) 50% straight
C) 75% curly
D) 100% straight
E) It is impossible to predict the outcome.
Methods for determining the linkage group and genetic map in humans involve which
of the following?
A) DNA markers
B) twin spots and tetrad analysis
C) tetrad analysis and bromodeoxyuridine
D) zygotene and pachytene DNA synthesis
E) chiasmatype and classical analyses
The sex of birds, some insects, and other organisms is determined by a ZW
chromosomal arrangement in which the males have like sex chromosomes (ZZ) and
females are ZW (similar to XY in humans). Assume that a recessive lethal allele on the Z
chromosome causes death of an embryo in birds. What sex ratio would result in the
offspring if a cross were made between a male heterozygous for the lethal allele and a
normal female?
A) 4:1 male to female
B) 2:1 male to female
C) 3:1 male to female
D) 1:2 male to female
E) 1:1 male to female
What term refers to a contiguous genetic complex that is under coordinated control?
A) lysogen
B) prototroph
C) operon
D) allosteric
E) attenuation
A bacterial polygenic transcription unit ________.
A) contains information for one protein product
B) contains information for more than one protein product
C) is capped at the 5’end and carries a poly-A tail at the 3’end
D) is void of start (AUG) and termination (UAA, UGA, UAG) triplets
E) None of the answers listed is correct.
Two organisms, AABBCCDDEE and aabbccddee, are mated to produce an F1 that is
self-fertilized. If the capital letters represent dominant, independently assorting alleles:
a) How many different genotypes will occur in the F2?
b) What proportion of the F2 genotypes will be recessive for all five loci?
c) Would you change your answers to (a) and/or (b) if the initial cross occurred between
parents?
d) Would you change your answers to (a) and/or (b) if the initial cross occurred between
parents?
What is the general position of the consensus sequence called the GC box? What is its
sequence?
A) promoter; CAAT
B) promoter; GGGCGG
C) terminator; CAAT
D) terminator; GGGCGG
E) attenuator; GGGCGG
UASs (upstream activating sequences) are DNase hypersensitive. This means that
________.
A) a UAS is constitutively open
B) more than one strand of DNA exists in each UAS
C) each UAS is likely to be single-stranded
D) each UAS has more histone-binding sites than non-UAS sites
E) any given UAS is composed of a double-stranded site with a bound repressor
Nutritional mutations can be defined as ________.
A) those mutations that do not allow a bacterium or fungus to grow on minimal medium
but do allow growth on complete medium
B) those mutations that change the composition of the medium
C) those mutations belonging to the group called prototrophs
D) those mutations caused by site-specific mutagenesis
E) all strains that are not auxotrophic
Assume that a cross is made between a heterozygous tall pea plant and a homozygous
short pea plant. Fifty offspring are produced in the following frequency:
30 = tall
20 = short
a) What frequency of tall and short plants is expected?
b) To test the goodness of fit between the observed and expected values, provide the
needed statement of the null hypothesis.
c) Compute a Chi-square value associated with the appropriate test of significance.
d) How many degrees of freedom are associated with this test of significance?
The fundamental Mendelian process that involves the separation of contrasting genetic
elements at the same locus would be called ________.
A) segregation
B) independent assortment
C) continuous variation
D) discontinuous variation
E) dominance or recessiveness
The one-gene:one-enzyme hypothesis emerged from work on which two organisms?
A) E. coli and yeast
B) Drosophila and humans
C) Neurospora and Drosophila
D) E. coli and humans
E) All of the answers listed are correct.
A ddNTP, used often in DNA sequencing, lacks a(n) ________ at the ________ and
________ carbons.
A) OH; 2″; 3″
B) methyl; 2″; 3″
C) carboxyl; 5″; 3″
D) OH; 2″; 5″
E) None of the above is correct.
Which of the following terms best characterizes catabolite repression associated with
the lac operon in E. coli?
A) inducible system
B) repressible system
C) negative control
D) positive control
E) constitutive
Which types of phenotypic ratios are likely to occur in crosses when dealing with three
gene pairs for which all the genotypic combinations are of equal viability?
A) 27:9:9:9:3:3:3:1
B) 1:2:1, 3:1
C) 1:4:6:4:1, 1:1:1:1
D) 12:3:1, 9:7
E) 2:3, 1:2
Distinguish between F+ and F– bacteria.
The genetic code is fairly consistent among all organisms. The term often used to
describe such consistency in the code is ________.
A) universal
B) exceptional
C) trans-specific
D) overlapping
E) none of the above
What hypothesis concerns the evolutionary origin of eukaryotic organelles?
A) endosymbiont hypothesis
B) homologous hypothesis
C) analogous hypothesis
D) evolutionary hypothesis
E) Darwinian hypothesis
Significant in the deciphering of the genetic code was the discovery of the enzyme
polynucleotide phosphorylase. What is this enzyme used for?
A) manufacture of synthetic RNA for cell-free systems
B) ribosomal translocation
C) peptide bond formation
D) production of ribosomal proteins
E) degradation of RNA
Ultraviolet light causes pyrimidine dimers to form in DNA. Some individuals are
genetically incapable of repairing some dimers at “normal” rates. Such individuals are
likely to suffer from ________.
A) xeroderma pigmentosum
B) SCID
C) phenylketonuria
D) muscular dystrophy
E) Huntington disease
Nucleic acid blotting is widely used in recombinant DNA technology. In a Southern
blot, one generally ________.
A) hybridizes filter-bound DNA with a DNA probe
B) hybridizes filter-bound RNA with a DNA probe
C) examines amino acid substitutions with radioactive probes
D) cleaves RNA with restriction endonucleases
E) ligates DNA with DNA ligase
Because of the mechanism of sex determination, males of many species can be neither
homozygous nor heterozygous. Such males are said to be ________.
A) dominant
B) hemizygous
C) recessive
D) complementary
E) None of the answers listed are correct.
Although the most frequent forms of Down syndrome are caused by a random error,
nondisjunction of chromosome 21, Down syndrome occasionally runs in families. The
cause of this form of familial Down syndrome is ________.
A) an inversion involving chromosome 21
B) a chromosomal aberration involving chromosome 1
C) too many X chromosomes
D) a translocation between chromosome 21 and a member of the D chromosome group
E) a maternal age effect
The maternal effect in Lymnaea is such that the genotype of the egg determines the
direction of shell coiling regardless of the genotype of the offspring. Apparently, the
cause of this spectacular maternal effect results from ________.
A) orientation of the spindle apparatus in early cleavage
B) genophores present in the egg cytoplasm
C) the F factor exerting its influence on the centrosome
D) colicins “poisoning” one of the cleavage centers
E) allelic substitution as demonstrated from RNA injection experiments
What is the name of the protein that appears to regulate the entry of cells into an S
phase? This protein is also known as the “guardian of the genome.”
A) p34
B) p102
C) cyclin
D) p53
E) phosphokinase
Which protein class directly controls many of the metabolic reactions within a cell?
A) structural proteins
B) repressor proteins
C) operator proteins
D) enzymes
E) hydrophilic proteins
In the mouse, gene A allows pigmentation to be deposited in the individual coat hairs;
its allele a prevents such deposition of pigment, resulting in an albino. Gene B gives
agouti (wild-type fur); its allele b gives black fur.
a) Diagram the cross between a doubly heterozygous agouti mouse mated with a doubly
homozygous recessive white mouse.
b) What would be the expected phenotypic ratio in the progeny?
Mutations in the promoter region of the β-globin gene indicate that some areas are more
sensitive than others. When mutations occur in consensus sequences (modular elements
such as GC box, CAAT box, TATA box), does transcription usually increase or
decrease?
What is meant by complementarity in terms of the structure of DNA?
Name three consensus sequences or modular DNA sequences that exist upstream from
the coding regions of some eukaryotic genes.
Referring to the genetic code, what is meant by “wobble”?
Briefly describe what is meant by the term edible vaccine.
The trait of medium-sized leaves in iris is determined by the genetic condition PP’.
Plants with large leaves are PP, whereas plants with small leaves are P’P’. A cross is
made between two plants each with medium-sized leaves. If they produce 80 seedlings,
what would be the expected phenotypes, and in what numbers would they be expected?
What is the term for this allelic relationship?
What are the roles of the recBCD genes?
In the analysis of quantitative traits, positions on chromosomes called quantitative trait
loci (QTLs) are often discussed. In the same context, restriction fragment length
polymorphisms (RFLPs) are also discussed. What is the relationship between QTLs and
RFLPs?
Much effort has been expended to understand genetic involvement in brain function in
Drosophila. Why might this research be important in understanding the functioning of
the human brain?
What is meant by the term genetic code?
Of the following three types of nucleic acidsDNA, mRNA, tRNAwhich is most likely to
contain modified bases?
Suggest two problems with determining the genetic basis of a behavioral trait in
humans.
Describe how nucleosomes may influence gene transcription.
Organisms that are well understood from a scientific standpoint and are often used in
basic biological research are often called ________.
Provide a simple definition of a carcinogen.
In a Chi-square analysis, what condition causes one to reject (fail to accept) the null
hypothesis?
A cross is made between a female calico cat and a male cat having the gene for black
fur on his X chromosome. What fraction of the offspring would one expect to be calico?