Genetics Final Review (past exam questions)
What information is required for a breeder to determine how a population will respond to artificial selection?
Narrow-sense heritability and selection differential
How do genes function in cells?
One-gene-one-enzyme model
What is the most likely mode of inheritance for the human pedigree shown here, under the assumption of full penetrance?
autosomal recessive
lacI is a gene that encodes
repressor
Within the RNA-Induced Silencing Complex (RISC), the active form of a miRNA or siRNA is a
single-stranded RNA
The human genome contains _______________________ genes located on 23 pairs of chromosomes.
~20-25,000
trisomy is an example of
aneuploidy
mutations
are best discussed in terms of heritable changes to the DNA of cells or organisms
In mismatch repair, the repair machinery distinguishes between template and newly synthesized DNA strands based on their
methylation status
The primary structure of a protein is determined by ___________________ which are formed by _____________________.
peptide bonds; condensation
Which of the following are methods of reverse genetics?
phenocopying and targeted mutagenesis
When using forward genetics, we begin our analysis with
phenotypic variation
A particular genotype at the lac operon is: I- P+ Oc Z+ Y- _______________ I- P+ O+ Z- Y+ Which genes will be active in the absence of lactose or IPTG (non-inducing conditions)?
Both LacZ and LacY
This is a:
Tetrad (in the middle)
"The parents produce offspring with characteristics that are intermediate between those of the parents." Which theory or law is described above?
The Blending Theory of Inheritance
The A and B alleles of the ABO blood groups in humans exhibit:
D. Codominance
A 9:3:4 ratio from a dihybrid self cross is an example of:
D. Recessive epistasis
How many Ori's per chromosome?
D. Several hundred
translation DNA synthesis uses a __________ to bypass the mutation and thus is ___________.
bypass polymerase; error-prone
what is the allosteric effector of lacI (the repressor)?
cAMP
The image above shows hybridization between an RNA molecule and DNA from a eukaryotic organism. The arrow is pointing to a(n) _______________.
intron
The genetic code is _____________________, and there are _______________ codons that code for amino acids.
overlapping; 61
During translation, UGA codons are recognized by _______________.
release factors
In yeast, the GAL80 protein inhibits gene expression of galactose metabolism genes by ____________________.
specifically binding to GAL4 and preventing activation.
Aneuploidy can be caused by
nondisjunction.
An ornamental plant shows a variegated phenotype due to a mutation in the chloroplast genome. You expect flowers on white branches, after crossing to pollen from green branches, to produce seeds giving ______ plants. When pollen from white branches is crossed to emasculated flowers from green branches, you expect the resulting plants to be _______.
white; green
Proto-oncogenes are genes
with very important roles in the control of the cell cycle.
What is the diploid number of muntjac chromosomes?
C.6
The genetic code is _______.
Non-overlapping
transpose is:
a protein
Which of the following are characteristics that apply to tumor-suppressor genes?
- An inherited loss-of-function mutation, at the heterozygous state, represents a very high risk of cancer. - Loss-of-function mutations are typically recessive.
Which of the following is a mutagen?
- Nitrosoguanidine - UV - Transposon
Which of the following is a source of genetic variation that can play a significant role in evolution?
- Polyploidy - Gene duplication and divergence - Horizontal DNA transfer
Which of the following can give rise to mutations?
- Spontaneous base hydrolysis - Irradiation with UV light - Replication slippage - Transposon insertion
Nearly half the human genome consists of DNA that ca n be classified by sequence as "transposable elements." Yet, in most humans, these sequences have no noticeable negative effect because
- accumulation of mutations in transposon-derived sequences have made the sequences inactive and immobile - many of these sequences are located within the introns of protein-coding genes. - they are kept silent and immobile by host regulatory mechanisms.
In her research with maize, Barbara McClintock discovered that insertion of a transposable element in to a gene was associated with
- an unstable mutant phenotype. - chromosome breakage.
quantitative traits
- are influenced by multiple genes - are influenced by environmental factors - exhibit continuous variation in natural populations
a goal of bioinformatics is to identify sequences in genomic data that encode proteins. Which of the following represent methods and/or resources for identifying such sequences?
- computational approaches to identify start codons and stop codons - cDNA sequences obtained from reverse transcribing mRNA - EST
Loss of a particular character in population could be explained by
- loss of gene function by deletion of all or part of the coding region of gene. - loss of gene function by deletion of a regulatory element for a gene. - loss of gene function by a change in sequence within a regulatory element of a gene.
A given allele that results in a disease state in humans may nevertheless be propagated in the population because:
- the disease has a late onset, typically after affected individuals have already reproduced - an individual heterozygous for the disease allele and a wild-type allele has a reproductively selective advantage.
Darwin's theory of evolution requires that
- there be variation among individuals in a population. - traits are heritable. - survival and reproductive success among individuals in a population will vary.
Chelsea has blood type O and her husband, David, has blood type AB. What is the probability of David and Chelsea having a baby with blood type AB?
0
In the following cross: a/a; B/b; C/c; d/d; E/e x A/a; B/b; c/c; D/d; E/E What is the expected proportion of progeny that are homozygous recessive at each locus? (a/a; b/b; c/c; d/d; e/e)
0
An experiment was conducted examining flowering time in a wild plant population. The phenotypic variance was determined to be 26; the dominance variance was determined to be 7.8; and the environmental variance was determined to be 15.6. What is the narrow-sense heritability of flowering time in the population?
0.1
In a particular population there are 510 AA individuals, 420 Aa individuals, and 70 aa individuals. What is the frequency of the a allele?
0.28
For a given IQ test, an individual is considered a genius if their score falls more than three standard deviations from the mean. Assuming the population of 680 individuals fits a normal deviation, how many individuals can you expect to be considered a genius?
1
From a presumed testcross of a purple-flowered with a white-flowered pea plant (P/p x p/p) in which P represents purple flower color and p represents white flower color, you observe 190 purple and 210 white flowered plants. The chi-square value is ________.
1.0
A plant breeder has the following collection of plants with certain numbers of flowers: 4 plants each with three flowers 3 plants each with two flowers 2 plants each with a flower 2 plants each with no flower What is the variance of the flower number in this collection?
1.24
A rare autosomal recessive disorder affects two individuals in the pedigree shown above. The depicted couple is expecting their first child (diamond with question mark). The expectant parents ask you to calculate the probability of them having a baby with this disorder. You calculate the following: ____________.
1/12
In the cross A/a; B/b; c/c; D/d; e/e G/g x A/a; b/b; C/c; D/d; e/e g/g, what will be the expected frequency of a/a; b/b; c/c; d/d; e/e g/g?
1/128
In Labrador retrievers (Labs) the e allele for yellow coat color exhibits recessive epistasis over the B/b alleles for black/brown coat color. You cross a black Lab of genotype B/B E/e with a yellow Lab of genotype B/b e/e, what will be the probability of yellow puppies? (Note that capital letters represent dominant alleles and lower case letters represent recessive alleles.)
1/2
Manx cats are tailless and carry one copy of a recessive lethal gene. If two Manx cats are bred, what fraction of their live kittens will have a normal tail?
1/3
A couple is expecting a child. If both parents have blood type AB and are heterozygous for alleles IA and IB what is the probability of a baby with blood type B?
1/4
Duchenne muscular dystrophy is an X-linked recessive disease. In the pedigree on the right, what is the probability that the unborn child (individual with question mark) will have the disease?
1/8
What is the inbreeding coefficient (F) for individual "I" in the following pedigree (half-sibling mating)?
1/8
For an X-linked dominant disorder, what is the probability of the affected male (generation III of the pedigree above) passing on the disorder to his children, assuming that the mother of his children is not affected?
100% of his daughters will be affected; 0% of his sons will be affected.
A Recombination Frequency (RF) of 0.13 or 13% is equal to a map distance of ____________.
13 cM
A Drosophila strain of genotype AB/ab is testcrossed with ab/ab, resulting in four different phenotypes of the offspring: AB, Ab, aB, and ab The distance between genes A and B is 30 cM. What is the predicted percentage of Ab progeny?
15%
The Meselson-Stahl centrifugation experiment used _______________ to label the DNA and indicated that replication is ________________.
15N; semi-conservative
An Arabidopsis plant of genotype AB/ab is testcrossed with ab/ab, resulting 1000 total offspring as follows: AB 280 ab 320 aB 180 Ab 220 You decide to use a X2 Test to evaluate possible linkage of A and B. The null hypothesis that you will use for your calculation is __________:
1:1:1:1
The Class ______ transposable elements typically comprise the largest fraction of eukaryotic genomes because their ______ mode of transposition enables them to become more abundant
1; copy-and-paste
After a mutant screen, m1 was found to complement m2, while m1 did not complement m3 nor m4. In parallel crosses, m5 was unable to complement m2. How many genes are present among the mutants?
2
One chromatid= one double stranded DNA molecule one dyad = _____ chromatids; = _____ DNA molecules
2,2
A Drosophila strain of genotype AB/ab is testcrossed with ab/ab. If the distance between A and B is 40 map units (m.u.), what is the predicted percent of the progeny that will be a B?
20%
A plant scientist studies a diploid species with 20 chromosomes in a haploid set. All the possible _____ monosomic lines missing each chromosome were generated and found to be viable. The resulting lines are expected to carry ______ chromosomes. Each monosomic line was crossed to a homozygous recessive mutant (a/a). The cross with chromosome 8 monosomic line generated ______ % progeny with the mutant phenotype. It was concluded that the mutant gene a is located on chromosome 8.
20, 39, 50
The human genome contains an estimated __________ genes on 23 pairs of chromosomes.
20,000-25,000
A gene from Mus musculus has 26 introns. How many exons does it have?
27
What is the expected number of phenotypic classes from a hybrid self cross, given that the number of genes is n?
2^n
How many generations are involved in genetic analysis? In which generation are all the individuals homozygous? In which generation are all the individuals heterozygous? in which generation are different phenotype/genotypes segregating?
3 P F1 F2
The human genome is approximately 3.2 billion bases in length, which is equivalent to
3,200 Mb
An 900 bp open reading frame (ORF) in a mRNA has _______ codons, and this mRNA codes for a polypeptide that has _______amino acids.
300; 300
If the AT content of a DNA molecule is 36%, what is the percentage of Cytosine (C) residues?
32%
How many different tRNAs are found in the cell?
35
If a DNA molecule has 15% adenines, what is percentage of guanine residues?
35%
A trihybrid testcross was performed with maroon-eyed (m) vestigial-winged (vg) bulldog (b) Drosophila from Starkville, Mississippi. You analyze the following data for 1000 offspring: m+ vg+ b+ 316 m vg b 334 m+ vg b+ 73 m vg+ b 67 m vg b+ 102 m+ vg+ b 98 m+ vg b 4 m vg+ b+ 6 What is the map distance between b and vg?
36cM
You observe a 1:1:1:1 phenotypic ratio from a dihybrid test cross, A/a; B/b x a/a; b/b, How many genotypic classes are represented?
4
One chromatid equals one double-stranded DNA molecule. One tetrad = _____ chromatid(s); = _____DNA molecule(s).
4; 4
In diploid (2N) cells undergoing mitosis, the amount of DNA is _______ after DNA synthesis prior to cell division.
4N
Within a ribonucleotide or nucleotide, a phosphate group is attached to the __________ of the ribose or deoxyribose.
5' Carbon
Which of the following components is not needed for the initiation of translation in the prokaryotes?
5' cap
If the sequence and polarity of one short strand of a DNA-RNA hybrid is 3'-A-A-G-T-G-A-C-T-T-5', then what is the sequence and polarity of the other strand?
5'-U-U-C-A-C-U-G-A-A-3'
Researchers in Fort Worth, Texas, have sequenced the genome of the Horned Frog. To find all of the genes in its genome, they will need to scan _______ possible open reading frames.
6
The hoatzin (Opisthocomus hoazin) "reptile bird", a tropical species that lives in South America, is genetically enigmatic. Little is known about its evolutionary origin. To learn more, you decide to sequence its genome. To find all of the genes in its genome, you will need to scan _______ possible open reading frames.
6
You are annotating a region of the fruit fly genome. The bioinformatics tool you're using identifies a potential open reading frame that is 180 bp in length. This open reading frame could potentially encode up to ________ amino acids in a row.
60
How many amino acids are encoded in the following sequence? To solve this problem you will need to identify the START and STOP codons of the sequence. 5'-C-A-U-U-G-C-C-A-U-G-A-C-G-G-C-U-U-C-U-A-A-C-U-U-A-U-G-G-U-A-G-U-G-A-A-A-U-G-C-C-G-A-3'
7
What is the molecular nature of the 5'-cap of a messenger RNA?
7-methylguanosine
Below is an mRNA molecule that codes for a small polypeptide. How many amino acids are present in the polypeptide encoded by the following mRNA? (Use the first available START codon when translating the mRNA.) 5'-A-A-G-U-A-C-U-A-U-G-G-C-A-G-A-G-U-G-G-A-U-U-G-C-G-C-A-U-C-A-C-U-A-A-U-G-A-3'
8
From a dihybrid self cross, A/a; B/b x A/a; B/b, you observe a 9:3:3:1 phenotypic ratio. How many genotypic classes are represented in the corresponding genotypic ratio?
9
miRNA genes are often found in intergonic DNA. What percentage of human genes encode miRNAs?
B. approxiamtely 5% (around 1000 genes)
Which of the following best describes a haplotype?
A combination of alleles at multiple loci on the same chromosome
What are the differences between RNA and DNA?
A. DNA has deoxyribose, RNA has ribose sugar B. RNA is mostly single stranded, DNA is mostly double stranded C. RNA is unstable but DNA is very stable D. RNA has uracil, DNa has thymine E. All of the above CORRECT
In addition to heat H-bonds are destabilized by:
A. PH extremes B.low salt concentration C.Some organic solvents D. all of the above CORRECT
Why is homologous paring so important?
A. Permits Recombination B. Ensures homologs separate C. Both are true CORRECT
The regulatory regions of a gene control:
A. When the gene is transcribed during the life of an organism B. in which cells the gene is transcribed C. where transcription begins. D. where transcription terminates E. all of the above CORRECT
What did we learn from the genetic analysis of the white flower?
A. White flower mutant is the result of a mutation in a single-gene B. White flower mutant is recessive to wild type C. The gene is haplosufficient D. All of the above CORRECT
An error in metabolism could lead to disease if:
A. a toxic intermediate builds up and itself toxic. B. Lack of the product is deleterious C. the intermediate is converted into something else that is toxic D.All of the above = CORRECT
Histone acetyl transferase (HAT) activity is associated with _____ of gene expression.
A. activation
A DNA double helix is said to be in a(n) ___________________ arrangement and the strand are _______________.
A. antiparallel, complementary
How is the amino acid sequence determined?
A. by the nucleotide sequence of mRNA B. by the nucleotide sequence of the DNA C. A and B CORRECT
examples of epigenetic marks are _______.
A. cytosine methylation b. histone acetylation c. histone methylation D. a,b,c CORRECT
A difference between the natural gene-silencing mechanisms of miRNAs and siRNAs is that _______.
A. miRNAs prevent expression of other endogenous genes od eukaryotic genomes, whereas siRNAs act in silencing the genes of invading viruses
R group (side chains) of amino acids determine ________.
A. protein folding (hydrophobic effect, ionic interactions) B. Protein function (catalytic activity, ability to bind other molecules (i.e., RNA polymerase + DNA) C. A and B CORRECT
Why is the NLS (nuclear localization sequence) not cleaved froma protein after it moves to the nucleus?
A. there is no enzyme to cleave it. B. due to mitosis and nuclear envelope breakdown, the protein will need to re-enter the nucleus C. A and B CORRECT
How are x-linked recessive traits different from autosomal recessive traits
A. they are seen more often in males
X and Y are 3 cM apart, X and Z are 3 cM apart. What is the predicted gene order of the three genes?
A.Z-X-Y B. Y-X-Z D.A and B CORRECT
An organism that is trisomic would be best described by which of the following chromosomal constitutions?
AABBCCC
Which of the following is an autonomous transposon?
Ac and P-element
example of a bulky adduct
Aflotoxin B1
Which of the following is true regarding all transposons of prokaryotes?
All create a target-site duplication when they insert into the host DNA
Which model organism does the schrick lab use?
Arabidopsis
Which of the following species is an example of a plant model organism?
Arabidopsis thaliana
IF 5 mutants are analyzed for complementation wiht the following results: m1 and m3 fail to complement, m2 and m4 fail to complement, m5 and m1 fail to compliment. m1 and m2 complement one another. How many genes are involved? What would you predict in a complementation test of m1 and m4? Do you need to test m5 and m2?
B. 2 A. Completion NO
Replication starts at very specific positions in the circular E. coli chromosome called the origin of replication. Would it be more efficient, (i.e. easier to get started) if the Ori is GC or AT rich?
B. AT rich
In cloning of mammals, a somatic cell nucleus is injected into an enucleated ______ cell.
B. Egg
Pedigree of a mitochondrial disease Inheritance is:
B. Only from the mother
One kind of miRNa typically binds to th e3'UTR (or other mRNA region) of __________
B. a group of genes. in this way gene expression can be coordinated
In many eukaryotes, another form of epigenetic inheritance involves DNA methylation on which nucleotide base?
B. cytosine
In humans we have _________.
B. fewer genes than proteins
if tryptophan levels are _______, a stem-loop structure forms in the _______, resulting in termination of transcription.
B. high, RNA
The specific aminoacyl tRNA synthetase enzyme for serine _____________.
B. will bind to all the tRNASer's
Mutations in which of the following regions of a protein would affect its localization within a cell:
B.Signal sequence C.NLS E. B and C CORRECT
In general the 'ground state' of a eukaryotic gene is ______.
B.off
Why can't retrotransposons move from one cell to another like retroviruses?
Because they do not encode the Env protein.
Why are transposable elements found much more often in introns than in exons?
Because transposable elements insert into both introns and exons but selection removes exon insertions.
It is estimated that _____ of the human genes are targets of miRNAs.
C. 1/3 (6666-8333 genes)
if a eukaryotic gene has six (6) exons, how many introns does it have?
C. 5
A 1500 bp mRNA has _______ codons and codes for a polypeptide that has ____ amino acids
C. 500; 500
Next gerneration WGS sequencing differs from traditional sequencing in that next-gen WGS does not require
C. Prior construction of genomic libraries in microbial hosts.
What does independent assortment refer to?
C. The blue chromosomes segregate independent of the red or green chromosomes
in a pedigree how might one tell the difference between a dominant and a recessive trait?
C. recessive traits skip generation, dominant traits show in every generation
What is the signal present in eukaryotiv mRNA that specifies where to add a polyA tail?
C.AAUAAA
If two genes are tightly linked so that no crossing over occurs between them:
C: all progeny will be parentals
A wild type chromosome has the structure CDEF*GHIJKL, where the asterisk (*) represents the position of the centromere. Which of the following best describes a paracentric inversion?
CDEF*GHILKJ
how is information stored DENA decoded to synthesize proteins?
Central dogma of molecular biology
Which of the following is NOT a type of reverse genetics?
Chromatim Immunoprecipitation (ChIP)
When is interference likely to be higher, when genes are closer or farther apart?
Closer
Which of the following is not a component of the transcriptional system in cells?
D. Shine-Dalgarno sequence
A human disease associated with dysfunction of mitochondria resulting from a mutation in a single autosomal gene locus in nuclear DNA is most likely to:
D. Show Mendelian inheritance pattern
Transcription of the lac operon is maximally activated when _____________.
D. lactose is present and glucose is absent
Which of the following is not an example of a functional RNA?
D. mRNA
In eukaryotic cells, DNA is _______.
D. packaged into nucleosomes
A __________ is added to the __________ end of the growin chain during transcription
D. ribonucleotide, 3'
Which macromolecule type is the "transforming principle"?
D.DNA
In the CRISPR genome editing system, the single guide RNAs (sgRNAs) complementary base-pair to their target ________.
DNA
Meiosis take place in
Diploid cells only
What is the allosteric effector of CAP (the activator)?
E. cAMP
Sequences representing the 5' and 3' ends of cDNAs are referred to as
ESTs
Which of the following represents the probability that two alleles in an individual are identical by descent (IBD)?
F
In which of the following generations are all the individuals heterozygous?
F1
Considering hybrid vigor in corn, all the plants from the _________ generation exhibit increased biomass and increased grain yield in comparison to the __________ generation.
F1;P
Mutations are always dominant to wild type
FALSE
True or false. in eukaryotic cells tRNA is synthesized in the cytoplasm
FALSE
True or False. Crossing over between sister chromatids, or crossing over in homozygotes, is detected by observing the phenotypes of offspring from a test cross.
False
True or False. In the lac operon from E. coli, the P (Promoter) is an example of a trans regulatory element.
False
True or false. AT-Rich DNA melts at a higher temperature than GC-rich DNA.
False
True or false. the transcriptional START site is at the AUG
False
mammalian X-chromosome inactivation occurs in _______.
Females
Which of the following statements is (are) accurate?
Genetic drift increases homozygosity Genetic drift can result in loss or fixation of alleles in a population
You have an Arabidopsis plant that has a wild-type phenotype H (genotype H/-) with respect to trichome (hair) formation. When you perform a testcross (H/-xh/h) to a mutant that lacks hairs, the resulting offspring are 100% wild-type. What is the genotype of the Arabidopsis plant that you began with?
H/H
P elements in Drosophila
Have been modified to be useful as vehicles for transferring donor genes into the Drosophila genome.
Frameshifts are most likely to occur because of
INDEL mutations
____________ increases the probability that rare deleterious alleles will be found in ____________ condition.
Inbreeding; homozygous
What is the most reasonable explanation for the observation that transposons in many multicellular genomes are more often found in nongenic sequences such as the centric heterochromatin rather than in genic sequences?
Insertion into nongenic DNA is less likely to do harm to the host.
Which is FALSE about the nucleotide excision repair mechanism?
It involves replicative DNA polymerase.
Which metabolic intermediate would mutant c most likely accumulate
KANK
Which is FALSE about the trisomic individuals?
Kleinfelter syndrome patients (XXY) generally express 50% more proteins from X chromosome.
In an E. coli strain, the genotype at the lac operon is the following: Is P+ O+ Z+ Y- _________________ I+ P+ Oc Z- Y+ Which genes are transcribed and functional (+) in the absence of lactose or IPTG (non-inducing conditions)?
LacY only
In an E. coli strain, the genotype at the lac operon is the following: I- P+ O+ Z+ Y- _________________ I+ P- O+ Z+ Y+ Which genes are transcribed and functional (+) in the presence of lactose or IPTG (inducing conditions)?
LacZ only
What is the allosteric effector of lacl (the repressor)?
Lactose
What kind of RNA codes for protein?
Messenger RNA (mRNA)
Assume that a human chromosome contains 2000 genes. In view of alternative splicing, how many different proteins will be encoded by those 2000 genes?
More than 2000 proteins
Which is FALSE about the mismatch repair mechanism?
MutH methylates template DNA strand.
alters base structure through the addition of an alkyl group
NG or EMS
Are complimentary tests performed with dominant alleles?
NO
A particular genotype at the lac operon is I- P- O+ Z+ Y+ _______________ Is P+ Oc Z- Y- Which genes will be active in the presence of lactose or IPTG (non-inducing conditions)?
Neither LacZ nor LacY
Also known as bread mold, ______________ is a genetic model organism that was used by Beadle and Tatum in forward genetic screens leading up to the one-gene-one-enzyme hypothesis.
Neurospora
Two black Labrador retrievers were mated and over several years produced 9 black puppies and 3 brown puppies. What are the predicted genotypes of the parents and the puppies?
Parents = B/b x B/b, Puppies: 1 B/B: 2 B/b: 1 b/b
__________ inversions span the centromeric region of a chromosome whereas __________ inversions occur outside of the centromeric region.
Pericentric; paracentric
If the heritability of a given trait is H^2 = 0.5, which of the following statements is true regarding the factors that influence phenotypic variation in that trait?
Phenotypic variance is influenced both by environmental and genetic factors
Self-splicing introns are comprised of __________ and are examples of ______________.
RNA; ribozymes
You construct a genetic linkage map by the following allele combinations of three genes, X, Y and Z. you determine that X and Y are 3 cM apart, X and Z are 3 cM apart, and y and Z are 6 cM apart. These cM numbers are most likely based on:
Recombination frequencies
Which experiment showed that RNA interference prevents transposon movement?
Screening in C. elegans for genes responsible for Tc1 movement.
Two segregation ratios are characteristic of single gene inheritance. Using the A and a symbols, what are the crosses and the progeny genotypes for each?
Self Cross A/a x A/a → 1 A/A: 2 A/a: 1 a/a ; Test Cross A/a x a/a → 1 A/a: 1 a/a
In humans having the blood type AB, alleles IA and IB exhibit
codominance
Which statement is FALSE about P-elements?
Some P-elements are retrotransposons
The figure below illustrates the chromosome structure and cross-shaped pairing configuration for a reciprocal translocation heterozygote. Which of the following is correct with regard to segregation patterns and meiotic products? (up, upward movement to the cell on top; down, downward movement to the cell on bottom)
T1 + T2 up; N1 + N2 down = complete and viable gametes
Which of the following statements about pi-clusters in animal systems such as mammals and Drosophila is correct?
TEs that insert into pi-clusters enable the host genome to target those TE variants genome-wide for inactivation
If a null mutation is recessive to wild type, then the gene is said to be haplosufficient
TRUE
How does the ras oncogene cause cancer?
The glycine-to-valine substitution at its 12th amino acid makes the protein constitutively active.
A scientist discovers a mouse with hairy ears. She crosses it to a wild type (naked-eared) mouse and after several litters she counts 125 hairy-eared mice and 129 naked-eared mice. What can she determine from these results?
The hairy-eared form is dominant to wild type.
Which of the following statements about IBD alleles is (are) false?
The probability of alleles being IBD in offspring of a half-sib mating is higher than that for a full-sib mating Inbreeding decreases the probability that two alleles in an individual will be IBD
You perform a mapping experiment to identify QTL with 10 markers (M1-M10) for a trait and obtain the results shown below. What is the most accurate conclusion you can make from these data?
There might be two QTL for the trait: one lies near M3. The other might be near M7, but is not quite statistically significant
Which statement is true of pairs of BOTH orthologous genes and paralogous genes?
They are homologs they share a common ancestor BOTH- CORRECT
__________ are an example of balanced chromosomal rearrangements whereas __________ are an example of unbalanced chromosomal rearrangements.
Translocations; duplications
Down syndrome can be caused by
Trisomy 21 and Robertsonian translocation
True or false. 2,3, and 4 levels of protein structure are held together primarily by hydrogen, electrostatic/ ionic, and Van der Waals (weak) bonds.
True
True or false. The 5' UTR is at the beginning of the transcript
True
True or false. in prokaryotes, transcription and translation are coupled.
True
common cause of cyclobutane pyrimidine dimers
UV light
Each beagle has identical genotype S^P/S^P for piebald spotting. this is example of:
Variable expressivity
This question provides you with an answer and requires you choose the best question. Answer: Where two species (together with their common ancestor) share chromosomal structural patterns in which chromosomal blocks possess the same genes in the same order.
What is conserved synteny?
A child with Turner Syndrome is found to be colorblind (an X linked recessive trait). The child's mother and father both have a normal chromosome number and have normal vision (i.e., are not colorblind). The sex chromosome number makeup of this child is _________. The nondisjunction resulting in the child with Turner Syndrome must have occurred in her _________.
XO; father
For the DNA double helix shown below, would it matter if the DNA is transcribed from right to left (top strand) or left to right (bottom strand)? 5'-A-T-T-C-G-C-A-G-G-C-T-C-G-C-C-T-3' 3'-T-A-A-G-C-G-T-C-C-G-A-G-C-G-G-A-5'
Yes, the mRNA sequences will be different.
For the DNA double helix shown below, would it matter if the DNA is transcribed from right to left (top strand) or left to right (bottom strand)? 5'-A-T-T-C-G-C-A-G-G-C-T-C-G-C-C-T-3'3'-T-A-A-G-C-G-T-C-C-G-A-G-C-G-G-A-5'
Yes, the mRNA sequences will be different.
Which of the following is not a chromosome pairing possibility in an autotetraploid?
a bivalent plus a univalent
Which of the following best describes a DNA sequence with an important regulatory function?
a non-coding sequence that is highly conserved across species
from a dihybrid testcross you receive the following data fro 160 offspring, and you decide to examine whether the A and B genes are genetically linked or are assorting independently. A/a & B/b 60 a/a & b/b 50 A/a & b/b 30 a/a & B/b 20 a) What is the degree of freedom value for the above example? b) What is the chi-square value for the above example?
a) 3 b) 25
Which of the following is an example of a pure breeding genotype?
a/a;B/B
In humans, phenylketonuria (PKU) results from _______________ phenylpyruvic acid leading mental retardation in affected individuals who are not given a low-protein diet.
accumulation of
One example of an epigenetic mark in the eukaryotes involves ________________________________.
acetylation of lysine on histone H3
In yeast, GAL4 is a(n)__________________ protein that binds to a UAS, which is a(n) ________________.
activator; enhancer
The GAL4___________ from yeast is an example of a _____ regulatory protein.
activator; trans
Narrow-sense heritability (h^2) is a quantification of the proportion of total phenotypic variance due to
additive genetic variance
Which of following statements about the human genome is (are) incorrect?
all statements are incorrect
Mendel's law of equal segregation refers to
alleles of the same gene on one homologous pair of chromosomes
a likely explanation for abnormal human phenotypes associated with trisomies is
altered gene dosage
Genome size is most closely correlated with
amount of noncoding, often repetitive DNA such as transposon sequences
Based on the above information, which of these three genes is the first gene/enzyme in the biochemical pathway relative to the other two?
arg-8
A tRNA with the anticodon 3′-UUG-5′ would carry the amino acid ________________.
asparagine
How is the information in mRNA read?
b. by an adaptor molecule to link codons and amino acids
Most of the unmethylated CpG islands (p=phosphodiester bond) are found in clusters near gene promoters
b. inactive
Streptococcus pneumonia is a/an:
bacteria
Has different pairing properties when ionized or protonated
base analog
lacZ is a gene that encodes
beta-galactosidase
In E. coli, the trp operon encodes genes required for the _________ of tryptophan. If tryptophan levels inside the cell are high, a stem-loop structure forms in the _______, resulting in termination of transcription.
biosynthesis; mRNA
During replication, DNA polymerase III
catalyzes the synthesis of DNA on both the leading and lagging strand.
Factors shaping gene variants in recent human evolution are related to_______________.
climate, diet and pathogens
In eukaryotes, addition of the polyA tail to the mRNA is __________ and occurs in the ___________.
co-transcriptional; nucleus
examining syntenic blocks of genes in wolves and foxes would be an example of a
comparative genomics study
The Basic Local Alignment Search Tool (BLAST) enables a researcher to?
compare a DNA sequence to a larger database of previously generated DNA sequences
A genetic screen was conducted to identify new trichome mutants that affect hair formation on leaves in Arabidopsis. Each mutant shows single gene inheritance of a recessive mutation. To determine the number of genes represented among the mutants you perform
complementation tests
The figure below depicts __________ transposition of a bacterial transposon.
conservative
A set of overlapping sequences is known as a
contig
The figure to the right illustrates how a genome region can be assembled following whole-genome sequencing. In this figure, the regions marked "A" are ______ and the regions marked "B" are _________.
contigs; paired-end reads
A haplotype in a given chromosomal region will be passed on intact to progeny unless
crossing over occurs
Which of the following best describes the lesion shown below?
deamination
The genome of a cancer patient was investigated. This patient has a couple of potential cancer-causing mutations that are genetically inherited. The genome of the patient's cancer tissue showed that the copy number of one of the mutated genes was decreased - a phenomenon called loss of heterozygosity. The ____ of the wild-type gene appeared to uncover the ______ phenotype. This gene is a candidate for _______.
deletion, recessive, tumor suppressor gene
which of the following types of chromosomal mutation result in the formation of a loop structure during meiosis
deletions and inversion
The structure shown here contains a sugar that is a _____________ and a nitrogen base that is a ______________.
deoxyribose; pyrimidine
If two populations with identical genetic makeup are raised in different environments, the narrow-sense heritability of a trait of interest is expected to be
different in the two populations
Which of the following is not an assumption of Hardy Weinberg equilibrium?
dominant alleles are more common than recessive alleles
In Digitalis purpurea (foxglove) plants that are self-crossed, the W/w and D/d genes assort independently to produce white:dark red:light red flowers in a 12:3:1 ratio. This presents an example of ______________ for the W allele.
dominant epistasis
In Drosophila, individual X-linked genes are expressed at an approximately 2-fold higher level in males versus in females. A consequence of this is that X-linked genes are expressed at similar levels in males (XY) and females (XX). This phenomenon is known as
dosage compensation
gene paralogs arise by ___ events whereas gene orthologs arise because of ___ events
duplication; speciation
In the CRISPR genome editing system, the Cas9 (CRISPR-associated 9) enzyme has the function of a(n) _______________.
endonuclease
The presence of a signal sequence in a protein will result in localization to the ___________, followed by cleavage of the signal sequence and secretion of the protein.
endoplasmic reticulum
a triploid is
euploid
Large pigmented spots on corn kernels result from __________ events of either Ac or Ds elements into (out of) the C gene __________ during kernel development
excision; early
Which is NOT the safe heaven for transposons?
exons
Association mapping utilizes controlled crosses in which to look for nonrandom associations between values of quantitative traits and SNP genotypes.
false
Inversion heterozygotes and translocation heterozygotes can only produce unbalanced gametes.
false
Linkage equilibrium is defined as the nonrandom association of alleles between two different loci.
false
Replicative transposition in bacteria involves transposition via an RNA intermediate.
false
The Luria and Delbruck fluctuation test demonstrated that mutations in E. coli that convey resistance to T1 phage occur in response to exposure of E. coli to the T1 phage.
false
True or False. Attenuation that occurs at the trp, phe or his operons of E. coli is a mechanism that acts before transcription initiation.
false
True or False. In a trihybrid testcross, if the observed number of double recombinants is equal to the expected number of double recombinants, the Interference (I) value will be 1.0.
false
True or False. In snapdragons, a heterozygote has pink flowers, intermediate between the two homozygotes having red and white flowers, respectively. The pink heterozygote demonstrates codominance.
false
True or False. In the eukaryotes, transcription and translation are coupled.
false
True or false. The image shown above provided experimental evidence that guanine and cytosine are present in equal amounts in a given organism.
false
True or false. in eukaryotes, the mRNA is translates in the nucleus
false
You are looking for a disease causing gene by association mapping. If you find a SNP significantly associated with the disease patients, this mutation directly affects the biological process causing the disease
false
variation in character from individual to individual will always have a genetic component
false
You suspect that gene X has been under positive selection. You sequence this gene for multiple individuals in both Species A and Species B. You determine the total number of synonymous and non-synonymous substitutions as classified within species (i. e. Polymorphism) and between species (i. e. Species differences). Your data are presented in the table below.
gene X has not been under positive selection
Klinefelter males (XXY) have a single Barr body, indicating one X has been subject to X chromosome inactivation. What is the most likely explanation for the observation that these males are not completely normal?
gene dosage very early in embryogenesis, prior to X chromosome inactivation, is critical for proper development.
Reverse transcriptase is crucial to the transposition of retrotransposons because it
generates a double stranded DNA molecule from a single stranded mRNA
Which of the following forces would cause an increase in variation between two populations of a species?
genetic drift
In humans, what kind of mutations would most likely cause cancer?
genetically inherited mutation(s) and induced mutation(s).
Which of the following best describes the C - value paradox?
genome size is not correlated with the complexity of an organism: more complex organisms can have large or small genomes and less complex organisms can have large or small genomes
A population is reproductively isolated. Which of the following is primarily responsible for the introduction of new alleles at genetic loci into the population?
germ line mutation
When two genes, A and B, show linkage in meiosis, the percentage (%) of parentals from the AB/ab x ab/ab testcross is expected to be __________.
greater than 50%
"Wobble" in the third position of the codon is due to relaxed base pairing, in which a uracil in the anticodon complementary base pairs with codons that have an adenine or a ______________ in the third position.
guanine
In a cross, A/a x A/a, we observe a 3:1 phenotypic ratio of normal (A/-) to mutant (aa) among the progeny. This is an example where A is a __________________ gene, and the a allele is ________________.
haplosufficient; recessive
In humans, males are the ____________________ sex, and females are the ______________________ sex.
heterogametic; homogametic
A study of the geographic distribution of the hemoglobin S (HbS) mutation in Africa demonstrated that
heterozygotes for this allele have a survival advantage in areas where malaria occurs.
________ Pair and segregate during meiosis 1
homologous chromosomes
Which of the following represents an approach used in reverse genetics?
homologous recombination
the diagram at the right illustrates how...
homologous recombination can be used in targeted mutagenesis
The phenotype of a heterozygous genotype helps to determine whether a gene is haplosufficient or haploinsufficient because
if the phenotype looks like wild type, the gene is haplosufficient.
In mammals, the Xist RNA is a 17-kb functional RNA associated with the _________ chromosome in normal _________.
inactive X; females
Heterochromatin is associated with _____________ gene expression and euchromatin is associated with ______________ gene expression.
inactive; active
intercalating agents generally cause
indels
Can result in single base pair insertions and frameshifts
intercalating
Will a 3 bp insertion that occurs in the coding region of a gene result in a frameshift mutation?
it depends on whether the 3 bp insertion occurs within an existing codon or between adjacent codons
A post-translational modification called phosphorylation can change the activity of a protein. Phosphorylation of proteins requires the function of an enzyme called a _____________.
kinase
The allosteric effector of the lacI repressor protein is _________________.
lactose
The lacIs (super repressor) is unable to bind________________, and therefore results in ___________ gene expression of the lac operon structural genes.
lactose; inactive
During DNA replication, Okazaki fragments are associated with the
lagging strand
Smaller spots of purple will occur when the Ds leaves the C pigment gene ______ kernel development.
later in
Human transposons
may be derived from an endogenous gene, as in the case with the Alu sequences .
nondisjunction occurs most often during ______________ and is often due to a failure of proper chromosome pairing and proper crossing over
meiosis I
A tRNA with the anticodon 3′-UAC-5′ would carry the amino acid ________________.
methionine
In a specific mutation, one codon is changed from GAA to GTA, causing glutamic acid to be substituted for valine. This mutation would be classified as
missense and non-conservative
In plants, when a trait is transmitted from a female to all of the offspring, but never from the pollen to the offspring, what is the possible mode of inheritance?
mitochondrial gene or chloroplast gene
Turner syndrome patients (XO) are best described as
monosomic, with one sex chromosome completely missing
to determine if a human trait is heritable, we would best study
monozygotic twins that were raised separately, in different environments
According to the neutral theory of evolution
most fixed mutations in the DNA sequence of a protein-coding gene do not change the function of the protein.
The fluctuation test of Luria and Delbruck demonstrated that
mutations can arise spontaneously before exposure to the selecting agent
Which of the following is primarily responsible for the frequency with which an allele is present in the population?
natural selection
In a gene encoding a critical enzyme, which of the following types of mutation likely would have the MOST deleterious effect on the resulting protein product if the mutation occurred at the beginning (toward the 5' end) of the gene?
nonsense
A __________ mutation will result in the translation of a ___________ protein, while a ___________ will result in the translation of ___________ protein
nonsense, truncated; frameshift, novel
The ____________strand of the DNA double helix has the same 5'-3' polarity as the mRNA.
nontemplate
The nucleosome core complex, which winds up the DNA ~1.8 turns, is an example of a(n) ____________.
octomer
The Meselson-Stahl centrifugation experiment using heavy nitrogen (15N) to label DNA indicated that replication produces two DNA molecules each composed of ________________.
one new strand and one old strand.
Shown here is a schematic illustration of the ara operon from E. coli. This operon produces ________ mRNA(s) during transcription and _________ protein(s) during translation.
one; three
Dicentric bridges and acentric fragments are produced during meiosis in a(n)
paracentric inversion heterozygote
You find two homologous genes in the genome of the organism you are interested in. They are
paralogues.
lacY is a gene that encodes
permease
In the classic Hershey-Chase experiment in which it was shown that the DNA entered the E. coli cells after infection with T2 bacteriophage, the DNA was labeled with radioactive ____________.
phosphorus
In human populations, which of the following is not an example of polygenic inheritance?
polydactyly
QTL mapping is done with
populations with know pedigrees or control
An activator ___________affects gene expression and a repressor __________ affects gene expression.
positively; negatively
Which of the following is not considered to be an epigenetic mark?
protein phosporylation
association mapping is done with
random-mating populations
INDEL mutations are common in regions of repetitive DNA because
replication slippage is more common in regions of repetitive DNA due to 'loop' structures that form and are stabilized during replication
Which of the following types of transposition events in bacteria would be expected to increase the genome copy number of the transposon most rapidly?
replicative transposition
when a protein undergoes an allosteric transition, there is a change in __________ of the protein
shape
In the eukaryotes, a repressor protein binds to a(n) ___________sequence on the DNA.
silencer
SNP is an acronym for a ___________.
single nucleotide polymorphism
Which of the following represents a repair mechanism for double-stranded break that is error-free?
synthesis-dependent strand annealing
A displacement loop (D-loop) is most likely to form during
synthesis-dependent strand annealing (SDSA)
Recently, CRISPR/cas system is frequently used to delete or change a specific site of the genome. Based on this description, the CRISPR/cas system is an example of methods used in
targeted mutagenesis
Werner's syndrome is an autosomal recessive disease that leads to premature aging. The function of the Werner protein is in the ________________.
telomeric cap structure
Which of the following best describes a phylogeny?
the evolutionary history of a group
Which of the following statements about cDNA is incorrect?
the full sequence composition of a gene's introns can be determined from that gene's cDNA
A negative consequence of transposable element activity for the host genome can be the mutagenic effects of new transposable element insertions. In Drosophila, the R1 and R2 LINE elements preferentially insert into the genes encoding ribosomal RNA. These genes are found in long tandem arrays on the chromosome. The preferential insertion of R1 and R2 LINE elements into these ribosomal RNA genes tends not to have a highly deleterious effect on the host because
the long tandem arrays of ribosomal RNA genes typically consist of many copies, and insertions into some of these copies is tolerated by the host
When an organism is able to better survive in an environment due to a new mutation we can conclude
the mutation occurred at random with respect to the phenotypic change it caused.
The term coverage, when applied to genomics, means sequencing...
the same base pair multiple times
When comparing genomes of different species, 'synteny' is defined as
the same genes in the same order along a chromosome
The 'proteome' is defined as
the sequence and expression of all proteins
A researcher would initiate a genetic screen using a transposon as a mutagen most likely because
the transposon may insert into a gene, resulting in a mutant phenotype and providing a molecular "tag" of the gene.
If a rare allele (b) is found to have a frequency of 0.05 in a population, what is the frequency of the heterozygous genotype (Bb) in that same population? (You can assume there are only two alleles at the B locus).
there's not enough info to answer this question
which of the following statements about base analogs is incorrect
they cause mutations through the addition of ethyl or methyl groups
The fact that certain transposon sequences have accumulated to very high levels in genomes is thought to be due primarily to the fact that
they have found a means to increase in copy number without harming the host.
Synthesis-dependent strand annealing (SDSA) is considered an error free mechanism and requires homologous chromosome for repair. Bacteria can perform SDSA because
they use sister chromatids as template immediately following DNA replication.
polyploidy that occurs in nature is
thought to be a driving force behind evolution, and is the basis for many examples of speciation
MicroRNAs (miRNAs) act in ________, and typically bind to the ________ of a messenger RNA.
trans; 3'-UTR
lacA is a gene that encodes
transacetylase
A key characteristic of eukaryotic mRNAs that is not observed for prokaryotic mRNAs is that:
transcription generates mRNAs that contain both introns and exons.
A ________ found in the third position of mRNA codon triplets often causes _______ mutation.
transition, synonymous
The following relationship describes the Central Dogma of Molecular Biology: DNA ----> mRNA ----> Protein What is the name of the process during which protein is synthesized from mRNA?
translation
Which of the following DNA repair mechanisms would be considered error-prone?
translesion DNA synthesis and nonhomologous end-joining
Which of the following types of chromosomal mutation does not result in the formation of a loop structure during meiosis?
translocation
For nonautonomous DNA transposons to be mobile, they require a functional __________ enzyme encoded by a __________.
transposase; different DNA transposon
the type of mutation in which a purine is substituted for a pyrimidine
transversion
A cell that undergoes mitosis can be a haploid or a diploid. True or False?
true
A gene-inactivating mutation can rise to a high frequency in a population when a change in habitat or lifestyle makes the function of that specific gene unnecessary
true
A null mutation would most likely occur in the functional domain
true
Allopolyploids possess homeologous chromosome sets that originate from individuals of different species
true
An individual's absolute fitness is measured by the total number of offspring produced.
true
If a population is in Hardy-Weinberg equilibrium, allele frequencies and genotype frequencies will remain constant from one generation to the next.
true
The heritability of a trait can vary depending on the environment in which the trait is measured.
true
Transposable elements are considered as mutagens.
true
True or False. Chiasmata (or crossovers) occur less frequently between two genes (A and B) when the genes are close together on the same chromosome.
true
True or False. Histone deacetylase (HDAC) activity is associated with inactivation of gene expression in the eukaryotes.
true
True or False. MicroRNAs (miRNA) are synthesized by RNA Pol II in the nucleus.
true
True or False. The new point mutation in the child's genomic DNA originated from the father.
true
True or false. Bacteria that live in hot springs have genomes that are likely to be GC rich.
true
True or false. the TATA box has a similar function as the -10 and -35 sequences in prokaryotes.
true
true or false. differences in gene expression may be due to environmental factors
true
The disease symptoms of Turner syndrome patients (XO) are caused by
unbalanced gene expression from chromosome X early in human development.
gaps in the assembly of a whole-genome shotgun sequencing effort can be closed by
using paired-end reads to identify cloned inserts that span the gaps
