Biology 313 Iowa State University Exam 5/Final Previous Exam

Which molecular genetic technology does NOT include DNA synthesis by the activity of a DNA polymerase?

A) Cutting and joining DNA fragments

B)PCR

C) Sanger DNA sequencing

D) Next-gen DNA sequencing (pyrosequencing)

E) Oligonucleotide-directed mutagenesis

A) Cutting and joining DNA fragments

A farmer is raising carp. The average body weight in his population of carp is 3 kg. The farmer selects the 10 largest carp, whose average body weight is 4 kg, and interbreeds them. Tf the heritability of body weight in the carp population is 0.7, then what is the expected body weight offspring among the selected carp?

A) 3.7

B) 0.7

C) 3.3

D) 0.3

A) 3.7

What is evolution?

A) A change, over time, in the allele frequencies in a population.

B) A change, over time, in the variance in a population.

C) The emergence of new, heritable phenotypes.

D) A theory about the origin of humans.

E) The genetic and phenotypic change that occurs in an individual over its lifespan.

A) A change, over time, in the allele frequencies in a population.

If the environmental variance (VE) INCREASES and all other variance components remain the same, then what will the effect be?

A) Narrow-sense heritability will decrease.

B) Broad-sense heritability will decrease, but narrow-sense heritability will increase.

C) Broad-sense heritability will increase.

D) Narrow-sense heritability will increase.

E) Broad-sense heritability will increase, but narrow-sense heritability will decrease.

A) Narrow-sense heritability will decrease.

Which statement is false?

A) Reproduction alone is sufficient to drive evolution.

B) A population cannot evolve if it meets the H-W assumptions.

C) Mutation is the only process that creates new alleles in a gene pool.

D) Natural selection is the principal force that shifts allele frequencies within large populations.

E) Genetic drift occurs purely due to chance, it requires no outside selective force.

A) Reproduction alone is sufficient to drive evolution.

Which of the following is not an assumption of the Hardy-Weinberg law?

A) Allele frequencies (p and q) are equal in the population

B) The population is random mating

C) The population is large

D) There is no natural selection occurring on the population

E) There is no migration occurring on the population

A) Allele frequencies (p and q) are equal in the population

A cell in G1 of interphase contains 6 chromosomes. How many chromosomes and DNA molecules will be found in this cell during G2?

a. 6 chromosomes and 12 DNA molecules

b. 12 chromosomes and 12 DNA molecules

c. 3 chromosomes and 6 DNA molecules

d. 3 chromosomes and 3 DNA molecules

e. 6 chromosomes and 6 DNA molecules

a. 6 chromosomes and 12 DNA molecules

A test cross is carried out to determine the genotype of a parent with the dominant tall phenotype. The test cross produces progeny that are 1⁄2 tall and 1⁄2 dwarf. What is the genotype of the parent?

A) Dd

B) DD

C) dd

D) D

E) d

A) Dd

Alkaptonuria is a metabolic disorder in which affected persons produce black urine. Alkaptonuria results from a disease allele (a) that is recessive to the allele for normal metabolism (A). Sally has normal metabolism, but her brother has alkaptonuria. Sally's father has alkaptonuria, and her mother has normal metabolism.

If Sally's parents have another child, what is the probability that the child will have alkaptonuria?

A) 1/2

B) 1/4

C) 0

D) 1

E) 3/4

A) 1/2

Which of the following molecules are purines?

A) Molecules 1 and 5

B) Molecules 1 and 3

C ) Molecules 2 and 3

D) Molecules 3 and 5

E) Molecules 1 and 2

A) Molecules 1 and 5

Which of the following proteins is the most abundant in chromosomes of eukaryotic organisms?

A) histone H2A

B) telomerase

C) DNA polymerase

D) RNA polymerase

E) transcriptional regulatory proteins

A) histone H2A

DNA polymerase I possesses three different enzymatic activities, namely:

5'→3' polymerase

5'→3' exonuclease

3'→5' exonuclease

Which of these activities is utilized to remove RNA primers at the ends of Okazaki fragments during the DNA replication process?

A) 5'→3' exonuclease

B) 5'→3' polymerase

C) 3'→5' exonuclease

D) All three of these activities are involved in removing the RNA primers

E) None of these activities are involved because DNA polymerase I is not the enzyme that removes RNA primers

A) 5'→3' exonuclease

Small interfering RNAs (siRNA) function to inactivate specific target genes. How do siRNAs accomplish this activation?

A) siRNAs cause the mRNA product of the target gene to be degraded.

B) siRNAs cause the protein product of the target gene to be degraded.

C) siRNAs interfere with pre-mRNA processing so that incorrect splice sites are selected and incorrect proteins are produced.

D) siRNAs cause early termination of transcription of the target gene.

E) siRNAs interfere with assembly of RNA polymerase at the promoter so that the target gene is not transcribed at the normal frequency.

A) siRNAs cause the mRNA product of the target gene to be degraded.

The yeast genes GAL80, GAL4, and GAL3 are all involved in transcription initiation regulation at genes that are required for utilization of galactose. How does this system respond to the presence of galactose in the growth medium?

A) GAL3 binds galactose, then interacts with the GAL4/GAL80 complex and causes its structure to change so that GAL4 can interact with a mediator complex that in turn interacts with the basal transcription complex.

B) GAL4 is a transcriptional activator that binds to the promoters of its target genes only when it is bound to galactose

C) GAL4 is a transcriptional repressor that binds DNA and blocks RNA polymerase activity. When galactose is present GAL4 binds to it and then releases from the target DNA.

D) GAL4 is a DNA protein that binds DNA when galactose is present and also binds to GAL3 and GAL80. GAL3 is a histone deacetylase and GAL80 is a DNA methyltransferase, and these modify chromatin structure at the target genes, allowing transcription to occur.

E) GAL3 binds galactose, then interacts with the GAL4/GAL80 complex and causes its structure to change so that GAL4 can interact directly with RNA polymerase.

A) GAL3 binds galactose, then interacts with the GAL4/GAL80 complex and causes its structure to change so that GAL4 can interact with a mediator complex that in turn interacts with the basal transcription complex.

How do amino acids in regulatory proteins such as activators or repressors interact with DNA at regulatory element sequences?

A) by forming hydrogen bonds with atoms in DNA bases exposed in the major or minor groove of the double helix

B) by forming covalent bonds with DNA bases

C) by forming hydrogen bonds with the deoxyribose groups on the exterior of the double helix

D) by opening the double helix and forming base pairs with one of the exposed single strands

E) by forming hydrogen bonds with nucleosome proteins

A) by forming hydrogen bonds with atoms in DNA bases exposed in the major or minor groove of the double helix

How does the lytic life cycle of a bacteriophage differ from the lysogenic life cycle?

A) In the lytic life cycle the bacteriophage genome never integrates into the host cell chromosome, whereas in the lysogenic life cycle the phage genome does integrate into the host chromosome.

B) In the lytic life cycle there can be many generations of host cell division between the initial infection and multiplication of viral particles.

C) In the lytic life cycle the bacteriophage can infect eukaryotic cells, whereas in the lysogenic life cycle it can infect only prokaryotic hosts.

D) Fragments of the host cell chromosome can be incorporated into the bacteriophage genome during the lytic life cycle, but this cannot occur during the lysogenic life cycle.

E) The lysogenic life cycle results in rapid cell lysis, whereas in the lytic life cycle the host cell persists for many generations before lysis occurs.

A) In the lytic life cycle the bacteriophage genome never integrates into the host cell chromosome, whereas in the lysogenic life cycle the phage genome does integrate into the host chromosome.

A trait shows a genetic maternal effect, controlled by the M gene, with a recessive m phenotype and a dominant M phenotype.

Consider this cross:

mother mm X MM father >>>>>> all offspring are mM, and as expected they all show the recessive phenotype.

About the phenotype of the mother, we can say she ________________.

A) must have shown the dominant phenotype

B) may have shown dominant or recessive phenotype, we don't know

C) must have shown the recessive phenotype

D) must have shown codiminat phenotype

E) may have shown a codiminant or incompletely dominant phenotype, we don't know

B) may have shown dominant or recessive phenotype, we don't know

In a cross between an Aa Bb F1 individual and an aa bb tester, the following progeny were recovered. Alleles indicated by capital letters are dominant, and alleles indicated by small letters are recessive.

Aa bb 76

aa bb 9

Aa Bb 7

aa Bb 80

Are the alleles in the F1 individual in coupling or in repulsion?

A) coupling

B) repulsion

C) both coupling and repulsion

D) the alleles could be in either configuration depending on which parent was the female and which was the male

E) cannot tell from the information given

B) repulsion

The lac repressor protein, lacI, determines that the lac operon is transcribed only when lactose is present. How is this accomplished?

A) When lactose is present, lacI protein assists RNA polymerase binding to the promoter by binding to DNA near the promoter and interacting with the polymerase.

B) When lactose is present, lacI protein undergoes an allosteric change in structure so that it can no longer bind to the operator site and block RNA polymerase binding.

C) When lactose is present, lacI protein assists RNA polymerase activity by unwinding the DNA template.

D) lacI protein is an enzyme that generates the signal molecule that indicates lactose is present.

E) When lactose is absent, lacI protein prevents binding of the catabolite activator protein CAP.

B) When lactose is present, lacI protein undergoes an allosteric change in structure so that it can no longer bind to the operator site and block RNA polymerase binding.

What is a "probe" in molecular biology?

A) An instrument used to manipulate cells in culture

B) A type of vector system

C) A DNA or an RNA molecule used in hybridization reactions

D) A molecule that is injected into knock-in mice

C) A DNA or an RNA molecule used in hybridization reactions

You start with a gene A from species X, and want to find the same gene in species Y (i.e. you want to find its ortholog). Which of the following would NOT be a step in your search?

A) build and screen a genomic DNA library

B) build and screen a cDNA library

C) perform in situ hybridization in species X

D) produce a probe using the species X copy of gene A

E) perform DNA sequencing and analysis of cloned fragments

C) perform in situ hybridization in species X

Which process is least likely to affect allele frequencies within a population?

A) Mutation

B) Migration

C) Random mating

D) Natural selection

C) Random mating

Which of the following terms cannot be described in terms of nucleotide base sequence within a DNA molecule?

A) gene

B) allele

C) phenotype

D) genome

E) centromere

C) phenotype

What is the function of DNA ligase in the DNA replication mechanism?

A) removing ribonucleotide primers and replacing them with deoxyribonucleotides

B) synthesis of the leading and lagging strands

C) joining the 3' end of one Okazaki fragment to the 5' end of the next Okazaki fragment by forming a phosphodiester bond between them

D) unwinding double stranded DNA at the replication origin

E) removal of supercoils ahead of the replication fork

C) joining the 3' end of one Okazaki fragment to the 5' end of the next Okazaki fragment by forming a phosphodiester bond between them

The figure shows the structure of a short polypeptide. How many nucleotides within a mRNA molecule are required to code for this sequence of amino acids?

A) 3

B) 6

C) 9

D) 12

E) Cannot tell from the information provided

C) 9

Two-dimensional gel electrophoresis is used in proteomics to

A) Observe a protein in two dimensions

B) Separate RNA fragments

C) Separate DNA fragments

D) Separate different proteins

E) Determine a protein'samino acid sequence

D) Separate different proteins

Which of the following is an example of genetic drift?

A) Allele g for fat production increases in a small population because birds with more body fat survive harsh winters better.

B) Random mutation increases the frequency of allele A in one population but not in another.

C) Allele R reaches a frequency of 1.0 because individuals with genotype rr are sterile.

D) Allele m is lost when a virus kils all but a few individuals and just by chance, none of the survivors possess allele m.

E) The frequency of allele K increases dramatically when a land bridge forms and leads to the introduction of many breeding individuals from a neighboring island

D) Allele m is lost when a virus kils all but a few individuals and just by chance, none of the survivors possess allele m.

A scientist determines the complete genome and proteome of a liver cell, and the complete genome and proteome of a muscle cell, where both cells came from the same person. What do you expect for the genomes and proteomes of these two cell types?

A) the proteomes are the same, the genomes are different

B) the proteomes are the same, the genomes are the same

C) the proteomes are different, the genomes are different

D) the proteomes are different, the genomes are the same

D) the proteomes are different, the genomes are the same

Gene cloning requires placing the DNA of interest into a cloning vector. Which of the following is NOT a feature of a typical plasmid vector? We are talking about the raw plasmid, before any target DNA has been inserted into it.

A) origin of replication

B) selectable marker(s)

C) unique restriction site(s)

D) modest size, such as less than 5,000 base pairs

E) phage conjugation site

E) phage conjugation site

Which of the following are types of quantitative characteristics (choose the one best answer)?

A) meristic

B) continuous

C) treshold

D) meristic and continuous

E) meristic and threshold

F) meristic, continuous, and threshold

G) continuous and threshold

F) meristic, continuous, and threshold

Ten male Harvard students were weighed in 1916. Their weights are given here in kilograms.

45, 69, 69, 57, 61, 57, 75, 88, 68, 61

Calculate the variance for these weights.

A) 65.0

B) 136.7

C) 11.7

D) 123.0

E) 11.1

B) 136.7

Vitamin A content in corn kernels is a quantitative trait with continuous variation.

A corn breeder crosses inbred strain 1 that is low in vitamin A (0.2 %) with inbred strain 2 that is high in vitamin A (1.8 %). The F1 show an intermediate level of Vitamin A (1.0 %). Among 2,000 F2 progeny, the breeder observes a range of vitamin A levels, from 0.5% up to 1.5%.

Assume vitamin A levels in corn are controlled by multiple genes, each with two alleles of similar, additive effect.

Approximately how many genes control vitamin A levels in this breeding population (choose the one best answer)?

A) more than 5

B) 11

C) more than 11

D) There is not enough information to estimate the number of genes.

E) less than 5

A) more than 5

Seven male Harvard students were weighed in 1916. Their weights are given here in kilograms.

48, 69, 69, 57, 61, 57, 73

Calculate the variance for these weights.

A) 77.7

B) 136.7

C) 65.4

D) 114.3

E) 8.8

A) 77.7

The diagram below shows a simplified structure of a typical prokaryotic gene. Which of the lettered boxes in the figure indicates the site where RNA polymerase would bind?

A) Box A

B) Box B

C) Box C

D) Box D

E) Box E

A) Box A

The figure represents formation of the first peptide bond during protein synthesis. In the subsequent cycles of protein synthesis, the growing peptide chain is _______________________.

A) transferred from the tRNA in the P site to an amino acid attached to a tRNA in the A site.

B) transferred from the tRNA in the A site to an amino acid attached to a tRNA in the P site.

C) transferred in either direction depending on which amino acid is attached to the tRNA in the A site.

D) transferred from the 30S subunit of the ribosome to the 50S subunit.

E) transferred from the 50S subunit of the ribosome to the 30S subunit.

A) transferred from the tRNA in the P site to an amino acid attached to a tRNA in the A site.

Which of the following statements about repressible genes or inducible genes is FALSE?

A) Inducible genes are always controlled by positive regulators and repressible genes are always controlled by negative regulators

B) When the signal is absent, inducible genes are inactive and repressible genes are active

C) When the signal is present, inducible genes are active and repressible genes are inactive

D) Inducible genes and repressible genes can both be controlled by negative regulators

E) Inducible genes and repressible genes can both be controlled by positive regulators

A) Inducible genes are always controlled by positive regulators and repressible genes are always controlled by negative regulators

A yellow pea plant with round seeds has the genotype GgWw.

If this plant is crossed to itself, then what proportion of the offspring will be green with round seeds?

A) 3/16

B) 9/16

C) 1/16

D) 0

E) 3/8

A) 3/16

Assume that you are looking at a case of lethal alleles. Crossing two green corn plants results in 2/3 green progeny and 1/3 white progeny. From this result we know that for the color phenotype, the G allele is dominant to the g allele. For the lethal phenotype, the G allele is __________ to the g allele.

A) recessive

B) completely dominant

C) epistatic

D) imprinted

E) codominant

A) recessive

We know that all humans do not have the same DNA sequence, for example there are many SNPs (Single Nucleotide Polymorphisms) between any two randomly selected individuals. But what about gene content?

True or false: All humans have exactly the same genes, and exactly the same number of alleles of each gene (that is, two alleles).

false

The diagram shows a microarray expression analysis from the textbook, that we discussed in lecture.

microarray expt

If a spot on the microarray contains a gene normally expressed in all cells but whose expression is eliminated only in cancer cells, then what color will the spot be after the hybridization step?

A) red

B) green

C) yellow

D) no color, the spot will be blank due to no hybridization

E) white, due to over-hybridization

B) green

What is the specific term that describes the loss of a single chromosome (2n - 1)?

A) trisomy

B) monosomy

C) aneuploidy

D) polyploidy

E) triploidy

B) monosomy

Which type of mutation is searched for when genetic methods are used to discovery the components of ordered biochemical pathways within cells?

A) intragenic suppressor mutations

B) intergenic suppressor mutations

C) large-scale chromosomal mutations

D) somatic mutations

E) neutral mutations

B) intergenic suppressor mutations

Which of the following is not an assumption of the Hardy-Weinberg law?

A) Allele frequencies (p and q) in the population follow p + q = 1

B) The population is random mating

C) The population is relatively small

D) There is no natural selection occurring on the population

E) There is no genetic drift occurring on the population

C) The population is relatively small

All of the following processes may lead to a change allele frequencies.

Which process is much more likely to occur just by chance when the population is small?

A) Mutation

B) Migration

C) Genetic drift

D) Natural selection

C) Genetic drift

The top part of the figure below shows the structure of an A base involved in both 5' → 3' and 5' → 2' phosphodiester bonds, which is a part of the mechanism used to remove introns from pre-mRNAs. The bottom part of the figure shows the sequence of a pre-mRNA including two exons with an intron in between them. Which base in the lower part of the figure is the one that ends up with the two different phosphodiester bonds that is indicated in the top part of the figure?

A) Base A, an A base located at the end of exon 1 close to the 5' splice site

B) Base B, an A base located at the beginning of the intron, close the 5' splice site

C) Base C, an A base located at a consensus sequence internal to the intron

D) Base D, an A base located at the 3' end of the intron, close to the 3' splice site

E) Base E, a randomly selected A base located within exon 2

C) Base C, an A base located at a consensus sequence internal to the intron

In eukaryotes the ribosome finds the start codon for translation by ______________________.

A) forming double stranded nucleic acid structure between a segment of the 16S rRNA and the Shine-Delgarno sequence in the mRNA

B) base pairing between the 16S rRNA and the start codon

C) binding the CAP structure at the 5' end of the mRNA and scanning in the 3' direction until an AUG start codon is found

D) binding the CAP structure at the 5' end of the mRNA and scanning in the 3' direction until a Shine-Dalgarno sequence is found

E) binding the 3' end of the mRNA and scanning in the 5' direction until a start codon is found

C) binding the CAP structure at the 5' end of the mRNA and scanning in the 3' direction until an AUG start codon is found

A mutation in the gene for the yeast protein GAL4 causes yeast to grow poorly when galactose is its sole food source. What is the function of GAL4?

A) GAL4 transports galactose into yeast cells

B) GAL4 binds to a transcriptional activator protein and causes it to bind to a sequence element within the regulatory promoter of structural genes used to metabolize galactose

C) GAL4 is a transcriptional activator protein that stimulates transcription of structural genes when galactose is present

D) GAL4 is a transcriptional repressor protein that represses transcription of structural genes when galactose is absent

E) GAL4 is a structural gene that is used for metabolism of galactose

C) GAL4 is a transcriptional activator protein that stimulates transcription of structural genes when galactose is present

Which one of these statements is true about BOTH mitosis & meiosis?

A) Crossing over occurs during mitosis and meiosis.

B) The cells at the end of Mitosis, and at the end of Meiosis II, are diploid.

C) DNA replication must occur before the process starts.

D) Cytokinesis occurs in mitosis but not meiosis.

E) Both processes involve a reduction in chromosome number.

C) DNA replication must occur before the process starts.

Consider the inheritance of phenotypes outlined in this figure:

If an F1 red pepper is crossed by a cream, then what segregation ratio do you expect in the offspring?

A) 1:1 for red:cream

B) 9:3:3:1 for red:peach:orange:cream

C) 1:1:1:1 for red:peach:orange:cream

D) all red

E) 9:4:3 for red:peach:orange

C) 1:1:1:1 for red:peach:orange:cream

Consider the following pedigree. Assume the trait is rare (non-family members do not have an allele for the trait).

For the next child of I-1 x I-2, what is the probability the child will be a female AND be affected by the trait?

A) 0

B) 1/8

C) 1/4

D) 1/2

E) None of these is correct

C) 1/4

In the PCR technique, which component provides the key specificity, to ensure that only the correct subsegment of DNA is amplified?

A) Taq DNA polymerase

B) The four dNTPs (dATP, dCTP, dGTP, dTTP)

C) Template DNA

D) Short DNA primers

E) DNA ligase

D) Short DNA primers

The figure shows the reaction catalyzed by RNA polymerase. Which of the following statements about this reaction is FALSE?

A) The α-phosphate of the incoming NTP undergoes nucleophilic attack by the 3' hydroxyl group of the growing RNA molecule.

B) The product of the RNA polymerase reaction is a phosphodiester bond.

C) The incoming NTP is selected according to base pairing with the template strand of the gene.

D) The template strand is RNA.

E) Addition of the new base is at the 3' end of the growing RNA molecule.

D) The template strand is RNA.

When would you find fully-replicated chromosomes, each with 2 sister chromatids held together by a single centromere?

A) Beginning of S phase

B) Anaphase of mitosis

C) G1

D) G2

E) End of cytokinesi

D) G2

This figure shows how color is inherited in summer squash:

Assume that the Y and W genes show no genetic linkage, like what Mendel saw.

In a dihybrid F2, what is the ratio of green : yellow : white ?

Hint: a dihybrid F1 has the genotype WwYy.

A) 12:1:3

B) 12:3:1

C) 3:12:1

D) 1:3:12

E) 1:12:3

D) 1:3:12

Which of the indicated atoms in guanine has a partial negative charge?

A) atom A

B) atom B

C) atom C

D) atom D

E) both atoms A and C

E) both atoms A and C

Which of the following statements about poly-A polymerase is FALSE?

A) Poly-A polymerase is an RNA polymerase that is distinct from other such enzymes because it does not require a template.

B) Poly-A polymerase acts to modify pre-mRNAs at the 3' end at the same time that RNA polymerase II is continuing transcription from that gene.

C) Poly-A polymerase adds only A ribonucleotides to the 3' end of pre-mRNA molecules.

D) Poly-A polymerase is attracted to the pre-mRNAs partly by association with RNA polymerase II.

E) Poly-A polymerase adds A bases at the 3' end of pre-mRNAs, pre-tRNAs, and pre-rRNAs.

E) Poly-A polymerase adds A bases at the 3' end of pre-mRNAs, pre-tRNAs, and pre-rRNAs.

From metagenomics we now understand much more about microbial communities, like the organisms in the human gut or the microbes living in the soil in a location (for example, see figure above). Why has metagenomics been particularly useful for these studies?

A) Only a small percentage of bacteria can be grown in the lab, so taking environmental samples and extracting DNA avoids the need to culture the organisms first.

B) Metagenomics takes into account all genes in a bacterium, instead of just targeting a single gene.

C) In general, microbial communities consist primarily of organisms that harbor RNA as their genetic material.

D) Microbes are very small, so it is hard to get genetic material out of them using traditional techniques.

E) Most microbes live in an environment where it is physically hard to extract their DNA.

A) Only a small percentage of bacteria can be grown in the lab, so taking environmental samples and extracting DNA avoids the need to culture the organisms first.

With the human genome now sequenced, scientists were initially surprised that the number of genes in the human genome was about 20,000, which is not many more than a worm and fewer than many plants. The surprise was that humans have a low gene number yet a more complex biology than worms or plants. This observation may be explained by:

A) humans have more protein domains that they combine in more ways and more regulatory sequences that influence when and how genes are expressed.

B) actually, worms are as complicated as humans.

C) there is apparently no need for a huge number of genes to make a complicated organism.

D) humans have more protein domains and are able to combine them in more ways.

E) humans have more regulatory sequences that can influence when and how genes are expressed

A) humans have more protein domains that they combine in more ways and more regulatory sequences that influence when and how genes are expressed.

The members of a small population of six bunnies were weighed last week. Their weights are given here in kilograms:

8, 4, 4, 7, 3, 10

Calculate the variance for these weights.

A) 7.6

B) 6

C) 7

D) 38

E) 6.3

A) 7.6

Consider these four statements:

(1) An individual can evolve during his or her lifetime

(2) We can measure heritability in an individual

(3) A population can evolve over time

(4) We can measure heritability in a population

Which of them are true statements?

A) (3) and (4) only

B) (1) and (2) only

C) (2) and (4) only

D) (1) and (3) only

E) (1), (3) and (4) only

A) (3) and (4) only

Microarrays can be used to determine the levels of gene expression. In one type of microarray, hybridization of the red (experimental) and green (control) cDNAs is proportional to the relative amounts of mRNA in the samples. Red indicates the overexpression of a gene, green indicates the underexpression of a gene in the experimental cells relative to the control cells, yellow indicates equal expression in experimental and control cells, and no color indicates no expression in either experimental or control cells.

In one experiment, mRNA from a strain of antibiotic-resistant bacteria (experimental cells) is converted into cDNA that is labeled with red fluorescent nucleotides; mRNA from a nonresistant strain of the same bacteria (control cells) is converted into cDNA that is labeled with green fluorescent nucleotides. The cDNAs from the resistant and nonresistant cells are mixed and hybridized to a chip containing spots of DNA from genes 1 through 25. The results are shown in the following illustration.

microarray

What conclusions can you make about which genes might be involved in antibiotic resistance in these bacteria?

A) Genes 2, 4, 17, 22, and 24 may be involved in antibiotic resistance.

B) Genes 1, 13, 14, and 21 may be involved in antibiotic resistance.

C) Only genes 2 and 24 may be involved in antibiotic resistance.

D) Only genes 4, 12, and 17 may be involved in antibiotic resistance.

E) Genes 1, 6, 11, 16 and 21 may be involved in antibiotic resistance.

A) Genes 2, 4, 17, 22, and 24 may be involved in antibiotic resistance.

The imported question text for this question was too long.

A) 6

B) 4

C) more than 6

D) 5

E) less than 4

A) 6

Which stage of meiosis is characterized by synapsis and crossing over?

A) Prophase I

B) Metaphase I

C) Anaphase II

D) Telophase I

E) Prophase II

A) Prophase I

An allele would be expected to be recessive if it _______________

A)encoded a defective protein.

B) encoded a starch debranching enzyme.

C) encoded part of the ribosome.

D) was located on the X chromosome.

E) was located on the Y chromosome

A)encoded a defective protein.

A black labrador retriever with the genotype BB EE is crossed to a yellow labrador retriever with the genotype bb ee. The F1 progeny are then intercrossed, yielding the following phenotype and genotype ratios.

\Which type of genetic interaction explains this difference from the expected ratio of 9:3:3:1?

A) The e allele at gene E is recessively epistatic to the B locus.

B) The e allele at gene E is dominantly epistatic to the B locus.

C) The E locus shows additive inheritance with the B locus.

D) Expression of the E and B genes varies depending on environmental effects.

E) Some combinations of alleles at the E and B loci are lethal.

A) The e allele at gene E is recessively epistatic to the B locus.

In normal Mendelian inheritance the expression of any gene in a progeny individual does not depend on which parent was the source of that allele. In some instances this is not true, and only the allele that is inherited from the male parent is expressed. Which term correctly describes this phenomenon?

A) Genomic imprinting

B) Maternal inheritance

C) Epistasis

D) Codominance

E) Cytoplasmic inheritance

A) Genomic imprinting

Why is it that over time, retrotransposon copies frequently accumulate to high levels in an organism's genome, so that they may make up a very large percentage of the chromosome contents?

A) retrotransposons move by a replicative, copy-and-paste mechanism that involves an RNA intermediate

B) retrotransposons move by a non-replicative, copy-and-paste mechanism that involves an RNA intermediate

C) retrotransposons move by a non-replicative, cut-and-paste mechanism that involves an RNA intermediate

D) retrotransposons move by a replicative, cut-and-paste mechanism that involves an RNA intermediate

E) retrotransposons only insert into promoter regions

A) retrotransposons move by a replicative, copy-and-paste mechanism that involves an RNA intermediate

What is the function of telomerase?

A) telomerase is a specialized type of DNA polymerase that elongates the ends of chromosomes using a single stranded RNA molecule as the template

B) telomerase hydrolyzes DNA and shortens the ends of chromosomes when they get too long owing to repeated rounds of DNA replication

C) telomerase attaches the centromere to the chromosome segregation machinery

D) telomerase is a component of RNA polymerase

E) telomerase unwinds DNA within the replication fork as part of the DNA replication mechanism

A) telomerase is a specialized type of DNA polymerase that elongates the ends of chromosomes using a single stranded RNA molecule as the template

In many nucleic acid molecules the frequency of G bases equals that of C bases. In some nucleic acids, however, the frequency of G does not match that of C. What is the most likely explanation for the second type of nucleic acid molecule?

A) the second type of molecule is single stranded

B) the second type of molecule uses amino acids instead of heterocyclic bases to form a helix

C) the second type of molecule is from a prokaryotic species

D) the second type of molecule is circular DNA

E) the second type of molecule is from a space alien

A) the second type of molecule is single stranded

The enzymatic activity possessed by DNA polymerase that gives it proof-reading capability is:

A) 3' → 5' exonuclease activity

B) 5' → 3' exonuclease activity

C) 5' → 3' polymerase activity

D) telomerase activity

E) primase activity

A) 3' → 5' exonuclease activity

Which of the following sequence elements is NOT present on a mature mRNA molecule from a prokaryotic organism?

A) promoter

B) 5' untranslated region

C) 3' untranslated region

D) coding region

E) Triphosphate group at the 5' end.

A) promoter

Consider a relatively simple eukaryotic gene with two exons separated by a single intron. What is the first step in splicing of the 3' end of exon 1 to the 5' end of exon 2 during pre-mRNA processing?

A) attack of a 2'-OH group from within the intron on the phosphodiester bond at the end of exon 1

B) attack of a 3'-OH group from within the intron on the phosphodiester bond at the end of exon 1

C) attack of a 2'-OH group from within the intron on the phosphodiester bond at the beginning of exon 2

D) attack of a 3'-OH group from within the intron on the phosphodiester bond at the beginning of exon 2

E) hydroylsis of a phosphodiester bond within the intron

A) attack of a 2'-OH group from within the intron on the phosphodiester bond at the end of exon 1

During the translation process, the mRNA is read from in the ________ direction and protein synthesized in the __________________ direction.

A) 5′-to-3′; N-to-C

B)3′-to-5′; C-to-N

C) 5′-to-3′; C-to-N

D) 3′-to-5′; N-to-C

E) 3′-to-5′ in prokaryotes, 5′-to-3′ in eukaryotes; N-to-C

A) 5′-to-3′; N-to-C

In a monohybrid F2, what is the expected ratio of phenotypes?

A) 1 : 2 : 1

B) 3 : 1

C) 9 : 3 : 3 : 1

D) 1 : 1 : 1 : 1

B) 3 : 1

The boxed figure shows the structure of cytidine. Which of the other bases shown in the figure base pair with cytidine in double stranded DNA?

A) base A

B) base B

C) base C

D) base D

E) base E

B) base B

Which of the following isotopes could be used to specifically label DNA, and not protein, in a DNA-protein complex?

A) 14C

B) 32P

C) 35S

D) 18O

E) 15N

B) 32P

What would be the effect of a mutation in a prokaryotic promoter that changes a base within the ‑35 consensus sequence so that RNA polymerase bound to the sequence less tightly than normal?

A) Transcription would initiate more frequently than normal.

B) Transcription would initiate less frequently than normal.

C) Transcription would initiate normally but would terminate prematurely.

D) σ factor would no longer be required for specific initiation at that promoter.

E) Transcription elongation would occur at a slower rate than normal.

B) Transcription would initiate less frequently than normal.

The figure represents an electron micrograph observed after a mixture of a segment of double stranded DNA from within a gene and the mature mRNA made from that gene was heated and then slowly cooled to allow re-annealing of double stranded structures. Which strand in the figure is contains an intron sequence?

A) strand A

B) strand B

C) both strands A and B

D) neither strand A nor strand B

E) not enough information provided to determine the answer

B) strand B

How are eukaryotic structural genes that cooperate in the same physiological process coordinately regulated at the level of transcription initiation when a signal is present?

A) the structural genes are grouped together in operons and so all are regulated by the same transcriptional event

B) the structural genes all possess the same response element DNA sequence in their regulatory promoters and so respond to the same transcriptional regulatory protein

C) the structural genes all have the same epigenetic modifications

D) the structural genes all share the same basal transcription factors

E) each set of structural genes uses its own RNA polymerase

B) the structural genes all possess the same response element DNA sequence in their regulatory promoters and so respond to the same transcriptional regulatory protein

Fine spines (s), smooth fruit (tu), and uniform fruit color (u) are three recessive traits in cucumbers. The genes responsible for these three traits are linked on the same chromosome. A plant heterozygous for the recessive and dominant alleles at all three genes is used in a testcross and the following progeny are produced.

S U Tu 2

s u Tu 70

S u Tu 13

s u tu 4

S U tu 82

s U tu 17

s U Tu 21

S u tu 21

TOTAL 230

What is the genetic map distance between the S and Tu genes? (The calculator function on your workstation is available.)

A) 2.6 map units

B) 13.0 map units

C) 15.7 map units

D) 18.3 map units

E) 20.9 map units

C) 15.7 map units

The figure illustrates the duplication of a region of chromosome. How do chromosomal duplications of this type arise?

A) A chromosome break and reattachment so that a section of one chromosome is added to another chromososome

B) Loss of a telomere

C) Unequal crossing over between repeated sequences on the same chromosome

D) Chromosome nondisjunction during meiosis I or meiosis II

E) Loss of the centromere

C) Unequal crossing over between repeated sequences on the same chromosome

In prokaryotes, which organism below would likely have the most genes?

A) Bacterium Z, genome size 1.4 million base pairs

B) Archaeum R, genome size 3.1 million base pairs

C) Bacterium P, genome size 0.75 million base pairs

D) Archaeum W, genome size 8.2 million base pairs

E) There is not enough information to estimate relative gene count.

D) Archaeum W, genome size 8.2 million base pairs

Consider this cross involving trihybrids:

Rr tt hH X rR tT hh

What is the probability that the first offspring will have the R t H phenotype?

A) 1/16

B) 1/8

C) 3/64

D) 3/16

E) 1/64

D) 3/16

This figure (above) shows the results of a genome-wide association study (GWAS) for Alzheimer's disease. Genome-wide association studies _________________ .

A) correlate SNPs to diseases.

B) identify linkage between SNPs and traits.

C) can suggest the genetic basis for complex traits (e.g., polygenic and quantitative traits).

D) require many individuals for analysis.

E) All of the above.

E) All of the above.

The genome sequences of two randomly chosen, individual humans will likely:

A) be identical at 99.9% of their bases.

B) differ at more than 3 million base pairs.

C) have a single nucleotide polymorphisms on average every 1,000 bases.

D) have most differences in DNA regions that do not code for proteins.

E) All of the above.

E) All of the above.

Suppose that some cells are grown in culture in the presence of radioactive nucleotides for many generations so that both strands of every DNA molecule include radioactive nucleotides. The cells are then harvested and placed in new medium with nucleotides that are not radioactive so that newly synthesized DNA will not be radioactive. What proportion of DNA molecules will contain radioactivity after TWO rounds of replication?

A) 0

B) 1/8

C) 1/4

D) 1/3

E) 1/2

E) 1/2

Miniature wings in Drosophila melanogaster result from an X-linked allele (Xm) that is recessive to the allele for long wings (X+). Brown eyes are produced by an autosomal allele (b) that is recessive to an allele for red eyes (b+). A female fly that has miniature wings and brown eyes is crossed with a male that has long wings and is homozygous for red eyes, to make an F1. In the F2, what proportion of the offspring will be miniature-winged, brown-eyed, males?

A) 3/8

B) 1/32

C) 1/4

D) 1/8

E) 1/16

E) 1/16

The figure below shows the initial steps of a PCR experiment, starting with a double-stranded DNA molecule at the top of the figure:

In the bottom part of the figure, which of the lettered boxes represent a combination of primers that would amplify the starting DNA segment shown at the very top of the figure?

A) B and D

B) D and C

C) A and B

D) there is more than one correct combination shown

E) A and C

A) B and D

You start with a gene A from species X, and want to find the same gene in species Y (i.e. you want to find the ortholog in species Y). Which of the following would NOT be a helpful experimental step in your search?

A) build and screen a cDNA library

B) produce a probe using the species X copy of gene A

C) perform forward genetics in species X

D) build and screen a genomic DNA library

E) perform DNA sequencing and analysis of cloned fragments

C) perform forward genetics in species X

The figure shows East's classic experiment on inheritance of flower tube length in tobacco. Parental strains A and B were inbred strains. Suppose flower tube length was known to have heritability H2 = 0.5 in East's greenhouse. If we use one greenhouse with uniform environmental conditions, where we grow all three of East's strains (the two parentals and the F1), then what can we predict about the expected phenotypic variance in the three strains A, B and F1?

A) We expect total phenotypic variance is the same for A, B and the F1.

B) We expect total phenotypic variance is the same for A and B, and roughly twice as much for the F1.

C) We expect total phenotypic variance is the same for A and B, and roughly four times as much for the F1.

D) We expect total phenotypic variance is the same for A and B, and roughly half as much for the F1.

E) We expect total phenotypic variance is the same for A and B, and roughly one fourth as much for the F1.

A) We expect total phenotypic variance is the same for A, B and the F1.

If the environmental variance (VE) DECREASES and all other variance components remain the same, then what will the effect be?

A) Narrow-sense heritability will decrease.

B) Broad-sense heritability will decrease.

C) Broad-sense heritability will increase, but narrow-sense heritability will decrease.

D) Narrow-sense heritability will increase.

E) Broad-sense heritability will decrease, but narrow-sense heritability will increase.

D) Narrow-sense heritability will increase.

A population of rabbits was divided up according to the color of their fur, where color is determined by a single locus with two alleles (B for the dominant brown allele and b for the recessive white allele). This is the phenotype distribution:

BB (brown fur) 100

Bb (brown fur) 88

bb (white fur) 25

Calculate the allele frequencies of the fur color locus for this population of rabbits.

A) f(B) = 0.68; f(b) = 0.32

B) f(B) = 0.44; f(b) = 0.27

C) f(BB) = 0.50; f(Bb) = 0.42; f(bb) = 0.12

D) f(B) = 0.75; f(b) = 0.32

E) f(B) = 0.47; f(b) = 0.53

A) f(B) = 0.68; f(b) = 0.32

Into which of the squares should we correctly place the process of Mutation?

A) 1 and 2

B) 1 and 2 and 3 and 4

C) 2 and 3

D) 3 and 4

E) 1 and 4

A) 1 and 2

Into which of the squares should we correctly place the process of Natural Selection?

A) 1 and 2 and 3 and 4

B) 3 and 4

C) 2 and 3

D) 1 and 2

E) 1 and 4

A) 1 and 2 and 3 and 4

Which quantitative characteristic is likely due to only environmental factors?

A) one genotype, many phenotypes

B) one genotype, one phenotype

C) many genotypes, many phenotypes

D) None of the answers is correct.

E) many genotypes, one phenotype

A) one genotype, many phenotypes

Some DNA-binding proteins will associate with DNA at any location in the molecule. Which of the following statements correctly describes an expected feature of this type of DNA-binding protein ?

A) The overall charge of the DNA-binding protein is likely to be positive.

B) The DNA binding protein is likely to contain a small RNA molecule that hybridizes to nucleic acid by base pairing.

C) The overall charge of the DNA-binding protein is likely to be negative.

D) The DNA-binding protein is likely to be made up of multiple polypeptide subunits.

E) The DNA-binding protein is likely to interact with DNA by hydrogen bonding to specific sequences of nucleotide bases.

A) The overall charge of the DNA-binding protein is likely to be positive.

Retrotransposons appear to have evolved from retrovirus. Which of the following statements about these two related genetic elements is FALSE?

A) Retrovirus and retrotransposons both move between cells within an organism as part of their normal life cycle.

B) Retrovirus and retrotransposons both can cause mutations when they integrate into the genome.

C) Retrovirus and retrotransposons both require reverse transcriptase as part their replication mechanism.

D) Retrovirus and retrotransposons both integrate into the genome at random locations.

E) Retrovirus and retrotransposons both contain genes that code for proteins within their DNA sequences.

A) Retrovirus and retrotransposons both move between cells within an organism as part of their normal life cycle.

Fine spines (s), smooth fruit (tu), and uniform fruit color (u) are three recessive traits in cucumbers. The genes responsible for these three traits are linked on the same chromosome. A plant heterozygous for the recessive and dominant alleles at all three genes is used in a testcross and the following progeny are produced.

S U Tu 2

s u Tu 70

S u Tu 13

s u tu 4

S U tu 82

s U tu 17

s U Tu 21

S u tu 21

TOTAL 230

Which gene is located in between the other two in the genetic map?

A) Cannot tell from the information provided.

B) Tu

C) U

D) S

B) Tu

This figure shows how color is inherited in summer squash:

Assume that the Y and W genes show no genetic linkage, like what Mendel saw.

In a dihybrid F2, what is the ratio of white : green : yellow ?

Hint: a dihybrid F1 has the genotype WwYy.

A) 12:1:3

B) 12:3:1

C) 1:3:12

D) 1:12:3

E) 3:12:1

A) 12:1:3

In the pedigree directly above, assume that gene A determines a maternal effect phenotype. The recessive allele is a, and the dominant allele is A. In the pedigree some of the genotypes are shown, and none of the phenotypes are shown.

Listed in order, what are the phenotypes of II-3, II-4 and IV-3?

A) dominant, dominant, recessive

B) dominant, dominant, dominant

C) recessive, recessive, dominant

D) dominant, recessive, dominant

E) dominant, recessive, recessive

A) dominant, dominant, recessive