Genetics

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Familial Down syndrome is similar to primary Down syndrome in that it is caused by trisomy 21. However, in familial Down syndrome, all or part of the third copy of chromosome 21 has translocated onto another autosome, typically chromosome 14. In cases of familial Down syndrome, one of the parents of the affected child is often a carrier of a translocated chromosome. The translocation carrier parent does not have Down syndrome because he or she has a total of two copies of chromosome 21. Suppose that a woman is a translocation carrier of chromosome 21 on chromosome 14. She conceives six zygotes with a normal man who carries no aneuploidies. Match the description of the chromosomes inherited by each zygote with the viability of the zygote. categories: - viable normal, or translocation carrier - viable with down syndrome - inviable offspring: - two normal copies of 14, two normal copies of 21 -one normal copy of 14, one normal copy of 21, one 21 to 14 translocation - one 21 to 14 translocation, two normal copies of 21, one normal copy of 14 - one normal copy of 14, two normal copies of 21 - two normal copies of 14, one normal copy of 21 - one normal copy of 21, one 21 to 14 translocation, two normal copies of 14

- viable normal, or translocation carrier: * two normal copies of 14, two normal copies of 21 * one normal copy of 14, one normal copy of 21, one 21 to 14 translocation - viable with down syndrome * one 21 to 14 translocation, two normal copies of 21, one normal copy of 14 - inviable * one normal copy of 14, two normal copies of 21 * two normal copies of 14, one normal copy of 21 * one normal copy of 21, one 21 to 14 translocation, two normal copies of 14

Assume that long earlobes in humans are an autosomal dominant trait that exhibits 30% penetrance. A person who is heterozygous for long earlobes mates with a person who is homozygous for normal earlobes. What is the probability that their first child will have long earlobes? Use two decimal places for the answer.

.15

why would elephants be a poor choice as model organisms for studying uterine cancer

1) They are needlessly large when smaller, more easily handled organisms, such as mice, are available. 2) They have a long pregnancy of around two years and are also too dangerous for experiments. 3) They produce very few offspring at a time and thus require a lot of time to collect meaningful data

How do modern geneticists address medical, social and industrial problems?

1) studying viral genetics to learn how to control the spread of infectious diseases 2) developing genetic tests for conditions so that patients can receive appropriate preventive care 3) improving the nutritional value of agricultural crops through genetic modification

Which of the statements can be concluded from Gregor Mendel's experiments with pea plants? 1. Allelic combinations for different genes may differ between parents and their offspring. 2. A heterozygous phenotype is the same as a homozygous dominant phenotype. 3. Parents with dominant phenotypes always have offspring with dominant phenotypes. 4. The pair of alleles for each gene stay together during gamete production.

1. Allelic combinations for different genes may differ between parents and their offspring. 2. A heterozygous phenotype is the same as a homozygous dominant phenotype.

In watermelons, bitter fruit (B) is dominant over sweet fruit (b), and yellow spots (S) are dominant over no spots (s). The genes for these two characteristics assort independently. A homozygous plant that has bitter fruit and yellow spots is crossed with a homozygous plant that has sweet fruit and no spots. The F1 are intercrossed to produce the F2. If an F1 plant is backcrossed with the sweet, nonspotted parent, what phenotypes and proportions are expected in the offspring?

1/4 bitter fruit, yellow spots; 1/4 bitter fruit, no spots; 1/4 sweet fruit, yellow spots; and 1/4 sweet fruit, no spots

Two mutations that affect plaque morphology in phages (a− and b−) have been isolated. Phages carrying both mutations (a− b−) are mixed with wild-type phages (a+ b+) and added to a culture of bacterial cells. Subsequent to infection and lysis, samples of the phage lysate are collected and cultured on bacterial cells. The numbers of plaques are observed in the table. Using the data given in the table, calculate the recombination frequency between the a and b genes. Plaque phenotype Number 𝑎+𝑏+ 2043 𝑎+𝑏−. 320 𝑎−𝑏+ 357 𝑎−𝑏−. 2134

13.9%

What will be the genotypic ratio in the offspring of two Aa parents that are crossed with each other?

1:2:1

The principle of independent assortment involves at least how many different gene pairs?

The number of hydrogen bonds between complementary G−CG−C pairs is

Which is not a type of pre‑mRNA processing in eukaryotes? 5' cap addition splicing RNA editing polyadenylation 3' mRNA degradation

3' mRNA degradation

Match each vector type to the DNA fragment size that vector may clone. 4 kb plasmid 20 kb bacteriophage λ 35 kb cosmid 100 kb bacterial artificial chromosome (BAC)

4 kb plasmid 20 kb bacteriophage λ 35 kb cosmid 100 kb bacterial artificial chromosome (BAC)

Choose the DNA sequence of the strand that is complementary to 5' GTATCTGCCA 3'. 5' TGGCAGATAC 3' 5' GUAUCUGCCA 3' 5' UGGCAGAUAC 3' 5' ACCGTCTATG 3' 5' CATAGACGGT 3'

5' TGGCAGATAC 3'

The diagram represents DNA that is part of the RNA‑coding sequence of a transcription unit. The bottom strand is the template strand. 5′-GCATATGCGGTAC-3′ 3'-CGTATACGCCATG-5' Give the sequence found on the RNA molecule that is transcribed from the above DNA molecule. Enter your answer from 5′ to 3′.

5'- GCAUAUGCGGUAC -3'

The somatic cell of a sheep contains 54 chromosomes54 chromosomes (2𝑛=54).(2n=54). How many chromosomes and how many DNA molecules would the primary oocyte of this sheep have?

54 chromosomes and 104 DNA molecules

A sample of DNA containing the wild type sequence is treated with hydroxylamine. 5′−ATGT−3′ 3′−TACA−5′ 5′−ATGT−3′ 3′−TACA−5′ Select the mutant sequence that is most likely to be observed after two rounds of replication. 5′−ATAT−3′ 3'−TATA−5′ 5'−ATGT−3′ 3'−TACA−5′ 5′−AAGT−3′ 3'−TTCA−5′ 5'−ATTT−3′ 3'−TAAA−5′ 5′−GTGT−3′ 3'−CACA−5′

5′−ATAT−3′ 3'−TATA−5′

9/16 bitter fruit, yellow spots; 3/16 bitter fruit, no spots; 3/16 sweet fruit, yellow spots; and 1/16 sweet fruit, no spots

In humans, oculocutaneous (OCA) albinism is a collection of autosomal recessive disorders characterized by an absence of the pigment melanin in skin, hair, and eyes. That is, normal pigmentation (𝐴) is dominant over albino characteristics (𝑎). For this question, assume the phenotype is determined by a single gene with two alleles. If both parents have normal pigmentation, what are all of the possible genotypes that may be observed in their offspring?

AA, Aa, or aa

Which is an example of a transversion mutation? Thymine is replaced by uracil. Thymine binds to a neighboring thymine base. Cytosine is replaced by thymine. Adenine is replaced by thymine. Guanine is replaced by adenine.

Adenine is replaced by thymine.

In watermelons, bitter fruit (B) is dominant over sweet fruit (b), and yellow spots (S) are dominant over no spots (s). The genes for these two characteristics assort independently. A homozygous plant that has bitter fruit and yellow spots is crossed with a homozygous plant that has sweet fruit and no spots. The F1 are intercrossed to produce the F2. If an F1 plant is backcrossed with the bitter, yellow‑spotted parent, what phenotypes and proportions are expected in the offspring?

All bitter fruit with yellow spots

A researcher treats a DNA sample and a plasmid with the ampR and lacZ (for the enzyme β‑galactosidase) genes with the restriction enzyme PstI with the goal of making recombinant DNA molecules. The researcher places the lacZ gene in the cloning region so that it is disrupted by DNA inserts. Place the remaining steps for this process in the correct order. Not all steps will be used. Treat DNA with the restriction enzyme. All the fragments have identical sticky ends: 5′−TGCA−3′5′−TGCA−3′ . Use DNA ligase to join the sticky ends of the DNA sample and the plasmid. Grow cells containing the recombinant plasmid in a medium with ampicillin and X‑gal (a galactose derivative). White colonies that survive on the culture medium contain the recombinant plasmid. Remove colonies containing the recombinant plasmid from the culture medium and continue growing.

All the fragments have identical sticky ends: 5′−TGCA−3′5′−TGCA−3′ . Use DNA ligase to join the sticky ends of the DNA sample and the plasmid. Grow cells containing the recombinant plasmid in a medium with ampicillin and X‑gal (a galactose derivative). White colonies that survive on the culture medium contain the recombinant plasmid. Remove colonies containing the recombinant plasmid from the culture medium and continue growing.

When population size is small, what are the consequences? Allele frequencies change rapidly and randomly, and one eventually becomes fixed in the population. The population becomes more heterozygous, and an allele never becomes fixed in the population. There is more genetic variation within the population and less genetic variation between populations. It is easy to predict which allele will become fixed in the population. Evolution cannot occur.

Allele frequencies change rapidly and randomly, and one eventually becomes fixed in the population.

Select the best description of forward genetics. Screen for individuals with a specific phenotype of interest. Sequence the genome of a wild‑type individual. Beginning with a genotype, determine the phenotype. Beginning with a phenotype, determine the genetic basis.

Beginning with a phenotype, determine the genetic basis.

Which statement about chromosome inversions is correct? Chromosome inversions lead to an increase in crossovers. Chromosome inversions can reduce the number of chromosomes in a cell. Chromosome inversions do not affect gene expression. Chromosome inversions flip a segment of a chromosome 180 degrees.

Chromosome inversions flip a segment of a chromosome 180 degrees.

Which one of the statements accurately describes gel electrophoresis? Larger DNA fragments move more quickly than smaller fragments. Cellulose is used for the gel material. It requires the use of DNA probes. DNA moves through the gel toward the positive electrode. Fragments can be visualized by use of infrared light.

DNA moves through the gel toward the positive electrode.

The end‑replication problem (telomere problem) exists in eukaryotic chromosomes and is characterized by the chromosomes shortening with each round of DNA replication. Select the statements that best explain why the end-replication problem exists in eukaryotic chromosomes. DNA polymerase requires a primer for DNA synthesis. The lagging strand is synthesized from the 3′ end to the 5′ end. The RNA primer is removed in a 3′ to 5′ direction. DNA polymerase synthesizes DNA from the phosphate end to the hydroxyl end. DNA ligase links the 5' OH group of one fragment to the 3′ phosphate group of an adjacent fragment.

DNA polymerase requires a primer for DNA synthesis DNA polymerase synthesizes DNA from the phosphate end to the hydroxyl end.

The Siamese cat breed has a light‑colored body and dark‑colored head, tail, and feet, all of which are called points. The Burmese cat breed has a dark‑colored body and points that are almost the same color as the body. Crossing Siamese with Burmese can produce the Tonkinese cat breed, which has coat and point color that is intermediate to the Siamese and Burmese parents. In all three breeds, a temperature‑sensitive enzyme is responsible for the dark coloration of the points. However, it is active only at the extremes of the body where it is coolest.

Development of points in Burmese demonstrates incomplete penetrance. Intermediate point color in Tonkinese demonstrates incomplete dominance.

The genetic code is considered to be generally nonoverlapping. Select the best description of a nonoverlapping genetic code. Multiple reading frames are possible for an mRNA. Each codon specifies a single amino acid. DNA uses thymine, whereas RNA uses uracil. Each nucleotide is part of a single codon.

Each nucleotide is part of a single codon.

Which of the statements describes what happens during mismatch repair of DNA? Enzymes copy the correct DNA sequence from the DNA in another cell, import the DNA sequence, and use the imported DNA sequence to repair the mismatched nucleotides. Enzymes identify the newly synthesized DNA strand, remove a segment surrounding the mismatched nucleotides, and resynthesize the DNA segment correctly. Enzymes identify the newly copied DNA strand, delete the mismatched nucleotide, pull the gap closed, and join the nucleotides on either side of the gap together. Enzymes cut out both strands of DNA containing the mismatched sequence, copy the same sequence from the homologous chromosome, and insert the copied sequence.

Enzymes identify the newly synthesized DNA strand, remove a segment surrounding the mismatched nucleotides, and resynthesize the DNA segment correctly.

Which statements describe Y‑linked traits?

Female offspring cannot inherit the trait. All male offspring of affected fathers will express the trait.

Use the codon table to identify which of the following amino acid changes could result from the alteration of a single nucleotide. For each change that could result from the alteration of a single nucleotide, determine which position of the codon (first, second, or third nucleotide) in the mRNA must be altered. First nucleotide altered Phe to Ile Pro to Ala Second nucleotide altered Leu to Gln Phe to Ser Ile to Asn Third nucleotide altered Asn to Lys

First nucleotide altered Phe to Ile Pro to Ala Second nucleotide altered Leu to Gln Phe to Ser Ile to Asn Third nucleotide altered Asn to Lys

Arrange the steps of DNA replication in the order that they occur. First step Helicase unwinds the DNA double helix. Single‑stranded DNA‑binding proteins bind to each template strand. RNA primers are added. DNA polymerase synthesizes DNA. RNA primers are removed. DNA ligase joins DNA fragments together. Last step

First step Helicase unwinds the DNA double helix. Single‑stranded DNA‑binding proteins bind to each template strand. RNA primers are added. DNA polymerase synthesizes DNA. RNA primers are removed. DNA ligase joins DNA fragments together. Last step

Of the following ideas postulated by Gregor Mendel, which one requires at least two genes to be demonstrated?

Genes assort independently in diploids.

Which statement about mutations is incorrect? Mutations are a source of all genetic variation. Somatic mutations are numerous, occurring at a rate one per every million cell division. Germ-line and somatic mutations are both passed on to offspring. Mutations can be used to examine biological processes. Gene mutations affect a single gene, whereas chromosome mutations affect the number or structure of chromosomes.

Germ-line and somatic mutations are both passed on to offspring.

How does anaphase I of meiosis differ from anaphase of mitosis?

Homologous chromosomes separate in meiosis, whereas sister chromatids separate in mitosis.

hosphorous is required to synthesize the deoxyribonucleoside triphosphates used in DNA replication. A geneticist grows some E. coli in a medium containing nonradioactive phosphorous for many generations. A sample of the bacteria is then transferred to a medium that contains a radioactive isotope of phosphorus (32P). Samples of the bacteria are removed immediately after the transfer and after one and two rounds of replication. Assume that newly synthesized DNA contains 32P and the original DNA contains nonradioactive phosphorous. What will be the distribution of radioactivity in the DNA of the bacteria in each sample? Immediately after the transfer: No 32P incorporated into the DNA. After one round of replication: One strand has 32P incorporated. After two rounds of replication 50% of the DNA molecules have 32P in both strands. 50% of the DNA molecules have 32P in one strand.

Immediately after the transfer: No 32P incorporated into the DNA. After one round of replication: One strand has 32P incorporated. After two rounds of replication 50% of the DNA molecules have 32P in both strands. 50% of the DNA molecules have 32P in one strand.

Comparing sequences between genes and between species allows for the evaluation of mutation rates. Which event has been observed? Introns have a higher mutation rate than exons. Exons have a higher mutation rate than introns. Synonymous mutations occur at the same rate as nonsynonymous mutations. Coding sequences have the same mutation rate as noncoding sequences. All mutations occur at the same rate.

Introns have a higher mutation rate than exons.

Select which examples are induced mutations. Transposition causes the formation of insertions. Ionizing radiation causes chromosomal fragmentation. Errors in DNA replication cause the formation of point mutations. Nitrous acid causes the deamination of adenine to hypoxanthine.

Ionizing radiation causes chromosomal fragmentation. Nitrous acid causes the deamination of adenine to hypoxanthine.

Which statement best describes an F' bacterial cell? It is not able to grow on complete medium. It has lost the ability to undergo conjugation with an F-cell. It does not contain the F factor. It contains an F factor that is integrated into the chromosome of the host cell. It contains an F plasmid that includes some bacterial genes.

It contains an F plasmid that includes some bacterial genes.

Duchenne muscular dystrophy is caused by a mutation in a gene that comprises 2.5 million base pairs and specifies a protein called dystrophin. However, less than 1% of the gene actually encodes the amino acids in the dystrophin protein. On the basis of what you now know about gene structure and RNA processing in eukaryotic cells, provide a possible explanation for why less than 1% of the gene encodes the dystrophin protein. It is likely that during the splicing process, a majority of the pre‑mRNA is removed in an effort to splice out all the exons. It is likely that the 5′ cap serves as an indicator for a smaller region of the gene to be used for translation of the protein. It is likely that the addition of the 5′ cap contributes to the majority of the mRNA degrading, preventing its ability to be used for protein production.It is likely that during the splicing process, a majority of the pre‑mRNA is removed in an effort to splice out all the introns.

It is likely that the addition of the 5′ cap contributes to the majority of the mRNA degrading, preventing its ability to be used for protein production.It is likely that during the splicing process, a majority of the pre‑mRNA is removed in an effort to splice out all the introns.

Select each of the characteristics that are key features of genetic material. It must have heritable traits that can be passed to offspring. It must differentiate in each cell type. It must be able to replicate and transmit to progeny. It must encode the blueprint to form proteins and other structures. It must be variable through infrequent mutation.

It must be able to replicate and transmit to progeny. It must encode the blueprint to form proteins and other structures. It must be variable through infrequent mutation.

Which statement describes the conservative model of DNA replication correctly? It proposes that the entire double‑stranded DNA molecule serves as a template for a whole new molecule of DNA. It proposes that the two nucleotide strands unwind and each serves as a template for a new DNA molecule. It proposes that both nucleotide strands break down into fragments, which then serve as templates for the synthesis of new DNA molecules.

It proposes that the entire double‑stranded DNA molecule serves as a template for a whole new molecule of DNA.

Which statement describes the semiconservative model of DNA replication correctly? It proposes that the two nucleotide strands unwind and each serves as a template for a new DNA molecule. It proposes that the entire double‑stranded DNA molecule serves as a template for a whole new molecule of DNA. It proposes that both nucleotide strands break down into fragments, which then serve as templates for the synthesis of new DNA molecules.

It proposes that the two nucleotide strands unwind and each serves as a template for a new DNA molecule.

How does direct repair return DNA errors to their original sequences? It uses an exonuclease to remove the incorrect sequence and replace it. It replaces altered nucleotides with the correct nucleotides. It removes functional groups or bonds from the altered nucleotide to restore the original structure. It uses the other copy of the DNA molecule to replicate the original sequence. The base is first removed before the entire nucleotide is replaced.

It removes functional groups or bonds from the altered nucleotide to restore the original structure.

Match each function to the appropriate type of RNA. Messenger RNA (mRNA) contains the coding sequence for the polypeptide sequence Ribosomal RNA (rRNA) enzymatic amide bond synthesis Transfer RNA (tRNA) hydrogen bonds with codon transports amino acids to the ribosome

Messenger RNA (mRNA) contains the coding sequence for the polypeptide sequence Ribosomal RNA (rRNA) enzymatic amide bond synthesis Transfer RNA (tRNA) hydrogen bonds with codon transports amino acids to the ribosome

A nontemplate strand of bacterial DNA has the base sequence 5′−ATGATACTAAGGCCC−3′5′−ATGATACTAAGGCCC−3′ Determine the amino acids that will be encoded by this sequence. Add the amino acids from left to right in the order the amino acids will be translated. Met Ile Leu Arg Pro

Met Ile Leu Arg Pro

In order to determine whether radiation associated with the atomic bombings of Hiroshima and Nagasaki produced recessive germ‑line mutations, scientists examined the sex ratio of the children of the survivors of the blasts. Why might an increase in germ‑line mutations be expected to alter the sex ratio? More males than females are expected to die because of recessive lethal mutations on the Y chromosome. More females than males are expected to die of sex‑linked recessive lethal mutations because females have two X chromosomes. More males than females are expected to die of sex‑linked recessive lethal mutations because males have only one X chromosome. More females than males are expected to die because females do not have a Y chromosome that suppresses X‑linked recessive lethal mutations.

More males than females are expected to die of sex‑linked recessive lethal mutations because males have only one X chromosome.

How many Barr bodies would you expect to see in a human cell containing the following chromosomes? Number of Barr bodies in XX: Number of Barr bodies in XY: arr bodiesNumber of Barr bodies in XO: Number of Barr bodies in XXY: Number of Barr bodies in XXYY: Number of Barr bodies in XXXY: Number of Barr bodies in XYY: Number of Barr bodies in XXX: Number of Barr bodies in XXXX:

Number of Barr bodies in XX: 1 Number of Barr bodies in XY: 0 Number of Barr bodies in XO: 0 Number of Barr bodies in XXY: 1 Number of Barr bodies in XXYY: 1 Number of Barr bodies in XXXY: 2 Number of Barr bodies in XYY: 0 Number of Barr bodies in XXX: 2 Number of Barr bodies in XXXX: 3

Suppose Louise wants to breed parakeets that are yellow with patterned feathers. However, when she bred several parakeets that were yellow with patterned feathers, she found that there were four different offspring phenotypes. Based on the offspring data provided, determine the number of genes and alleles that control these phenotypes. Phenotype Number patterned yellow wings 18 solid yellow wings 6 patterned white wings 6 solid white wings 2 Number of genes and alleles? Which phenotypes are coded for by the same gene?

Number of genes and alleles?: 2 genes, 2 alleles each gene Which phenotypes are coded for by the same gene?: yellow and white ; pattered and solid feathers

Coat color in cats is determined by genes at several different loci. At one locus on the X chromosome, one allele (X+) encodes black fur and another allele (Xo) encodes orange fur. Females can be black (X+X+), orange (XoXo), or a mixture of orange and black called tortoiseshell (X+Xo). Males are either black (X+Y) or orange (XoY). Bill has a female tortoiseshell cat named Patches. One night, Patches escapes from Bill's house, spends the night out, and mates with a stray male. Patches later gives birth to the following kittens: one orange male, one black male, two tortoiseshell females, and one orange female. What are the genotypes of Patches, the stray male, and the kittens? Patches Stray Male Orange Male Kitten Black Male Kitten Tortoiseshell female kitten orange female kitten

Patches: X+Xo Stray Male: XoY Orange Male Kitten: XoY Black Male Kitten: X+Y Tortoiseshell female kitten: X+Xo orange female kitten: XoXo

What division of genetics is essentially a study of evolution?

Population Genetics

What is the difference between positive and negative supercoiling?

Positive supercoiling is overrotation and negative supercoiling is underrotation.

Identify whether the reproductive isolating mechanisms are prezygotic or postzygotic.

Prezygotic ecological temporal mechanical behavioral gametic Postzygotic hybrid inviability hybrid sterility hybrid breakdown

Classify the examples as prezygotic or postzygotic barriers.

Prezygotic barrier One frog species mates in the spring, whereas another frog species mates in the summer. One goat species prefers flat land, whereas another goat species prefers mountainous terrain. Postzygotic barrier Individuals from two different species mate, but the resulting embryo dies before birth. A horse and donkey mate to produce a sterile mule.

What is the difference between prezygotic and postzygotic reproductive isolating mechanisms? Prezygotic mechanisms prevent the formation of a zygote, whereas postzygotic mechanisms prevent gene flow after the formation of a zygote . Prezygotic mechanisms prevent anagenesis, whereas postzygotic mechanisms prevent cladogenesis within a population. Prezygotic mechanisms prevent gene flow after the formation of a zygote, whereas postzygotic mechanisms prevent the formation of a zygote. Prezygotic mechanisms prevent sympatric speciation, whereas postzygotic mechanisms prevent allopatric speciation within a population.

Prezygotic mechanisms prevent the formation of a zygote, whereas postzygotic mechanisms prevent gene flow after the formation of a zygote

Which of the statements describes purines and pyrimidines in DNA molecules? Pyrimidines form covalent bonds with purines. Adenine and guanine are pyrimidines. Pyrimidines consist of a one-ring structure. Purines form hydrogen bonds with purines. Pyrimidines form hydrogen bonds with purines.

Pyrimidines consist of a one-ring structure. Pyrimidines form hydrogen bonds with purines.

In pea plants, the allele for round seed shape, R, is completely dominant to the allele for wrinkled seed shape, r. Complete the Punnett square showing the genotypes possible among the offspring when two heterozygous individuals are crossed. Use the information from the Punnett square to answer the second question. R r R r In this cross between two heterozygous pea plants, what are the chances that an offspring with wrinkled seeds will be produced?

R r R RR Rr r Rr rr 25%

Which statement about RNA is not true? RNA is a more stable molecule than DNA. RNA is thought to have dominated early life on earth, serving as both genetic information and as a catalyst. RNA typically consists of a single polynucleotide strand with distinct secondary structures. RNA possesses catalytic activity, which earned it the name "ribozyme." Uracil is found in RNA as one of the two pyrimidine nitrogenous bases.

RNA is a more stable molecule than DNA.

Complementary DNA (cDNA) is a double‑stranded molecule. In the laboratory, how is cDNA generated from a eukaryotic messenger RNA (mRNA)? Reverse transcriptase generates a single‑stranded cDNA and then DNA polymerase synthesizes the complementary strand. Reverse transcriptase generates a single‑stranded cDNA and then DNA ligase synthesizes the complementary strand. Reverse transcriptase generates two single‑stranded cDNA copies of the same mRNA which hybridize to form double‑stranded cDNA. Reverse transcriptase generates a single‑stranded cDNA and then uses that cDNA as a template to synthesize a complementary RNA strand.

Reverse transcriptase generates a single‑stranded cDNA and then DNA polymerase synthesizes the complementary strand.

In humans, red blood cells have a number of proteins embedded in the cell membrane. One type of protein, the Rh factor, is controlled by a single gene and is either present or missing from the red blood cells. If present, the individual has the Rh+ phenotype. If missing, the individual has the Rh− phenotype. Rh+ is the dominant to Rh−. Suppose that, in the Welsh population, the frequency of the Rh− phenotype is 0.04.0.04. Using the Hardy-Weinberg equations, calculate the frequency of the Rh+ allele to at least two decimal places.

Rh+ allele frequency: .8

When Mendel crossed a plant homozygous for round seeds to another plant homozygous for wrinkled seeds, he found that all the progeny had round seeds. How is this explained?

Segregation of alleles in the two parents produced gametes with both alleles

With the genic sex‑determination mechanism, which of the statements is true?

Sex is determined by genes on undifferentiated chromosomes.

Which of the statements is not a difference between mitosis and meiosis?

Sister chromatids separate during mitosis but not during meiosis.

What happens during anaphase II of meiosis?

Sister chromatids separate from each other and migrate to opposite ends of the cell.

Place the following components of CRISPR‑Cas systems in the order in which they function during generation of CRISPR‑Cas immunity. Spacers are incorporated into the CRISPR array The CRISPR array is transcribed into a long CRISPR precursor RNA CRISPR precursor RNA is cleaved and processed into CRISPR RNAs CRISPR RNA combines with Cas protein to form an effector complex The effector complex binds to the foreign DNA The Cas protien in the effector complex cleaves the foreign DNA

Spacers are incorporated into the CRISPR array The CRISPR array is transcribed into a long CRISPR precursor RNA CRISPR precursor RNA is cleaved and processed into CRISPR RNAs CRISPR RNA combines with Cas protein to form an effector complex The effector complex binds to the foreign DNA The Cas protien in the effector complex cleaves the foreign DNA

What are the three stages by which CRISPR‑Cas immunity occurs, and what takes place during each stage? Stage 1: adpatation Foreign DNA is cleaved and incorporated into the CRISPR‑Cas array as spacers Stage 2: expression The CRISPR array is transcribed and processed to produce CRISPR RNA that combines with a Cas protein to form an effector complex. Stage 3: interference The effector complex binds to foreign DNA and the Cas protein cleaves the foreign DNA, which is then degraded.

Stage 1: adpatation Foreign DNA is cleaved and incorporated into the CRISPR‑Cas array as spacers Stage 2: expression The CRISPR array is transcribed and processed to produce CRISPR RNA that combines with a Cas protein to form an effector complex. Stage 3: interference The effector complex binds to foreign DNA and the Cas protein cleaves the foreign DNA, which is then degraded.

Which statement explains why HIV has been so difficult to eradicate since it was discovered in the early 1980s? The HIV genome is permanently integrated into the host genome. HIV has a double viral envelope that cloaks it from the immune system. The HIV RNA genome is used as an mRNA template for rapid translation in the host cell. HIV does not need to bind to a receptor to gain entry into a cell.

The HIV genome is permanently integrated into the host genome.

Use the Natural Selection interactive, select the light brown background, and advance the interactive until the end of the trial. Considering the inheritance of color in these beetles, could the population of beetles ever be composed of only light brown beetles? The entire population of beetles could be light brown because the higher fitness in the light brown environment results in elimination of the homozygous genotypes. The entire population of beetles could not be light brown because underdominance will result in the same allelic frequency. The entire population of beetles could be light brown because directional selection will occur and one allele will be favored over the other. The entire population of beetles could not be light brown because the beetles with a light brown phenotype are heterozygotes.

The entire population of beetles could not be light brown because the beetles with a light brown phenotype are heterozygotes

Which of the statements about the genetic code are most accurate? The genetic code is generally overlapping. The genetic code is generally‑non‑overlapping. An initiation codon sets the reading frame. The promoter sets the reading frame. Three initiation codons set the three possible reading frames.

The genetic code is generally‑non‑overlapping. An initiation codon sets the reading frame.

What happens during telophase II of meiosis?

The nuclear membrane begins to form around haploid sets of chromosomes.

DNA molecules of different sizes are often separated with the use of a technique called electrophoresis. With this technique, DNA molecules are placed in a gel, an electrical current is applied to this gel, and the DNA molecules migrate toward the positive pole of the current. What aspect of its structure causes a DNA molecule to migrate toward the positive pole?

The phosphate groups of the backbone have a negative charge.

Which statement best describes the effect of mutation on allele frequencies? Reverse mutation is usually more frequent than forward mutation. Allele frequencies change rapidly when mutation is the driving evolutionary force. Forward mutation changes allele frequencies but reverse mutation does not. The relative rates of forward and reverse mutation will determine the equilibrium allele frequency. Recurrent mutation results in eventual fixation of the mutant allele.

The relative rates of forward and reverse mutation will determine the equilibrium allele frequency.

What does the term antiparallel mean? The strands separate in opposite directions. The strands run in the same direction. The strands run in opposite directions. The 5' end of one strand is opposite the 3' end of the second strand. The 5' end of one strand is opposite the 5' end of the second strand.

The strands run in opposite directions. The 5' end of one strand is opposite the 3' end of the second strand.

What contribution did James Watson and Francis Crick make to our understanding of DNA?

They modeled the structure of DNA based on the limited data available.

Which statement about retroviruses is NOT true? They have three genes in common, and each gene can produce more than one type of protein. They can make a DNA copy of their genome that integrates into the host cell genome. They may contain oncogenes. They replicate their DNA genomes in the cytoplasm of host animal cells. They produce the enzyme reverse transcriptase.

They replicate their DNA genomes in the cytoplasm of host animal cells.

Select the best description of the end‑replication problem. Replication near chromosome ends is significantly slower because of a lack of replication origins. When replicating linear DNA, the end primer cannot be replaced because of a lack of adjacent 3'−OH When replicating circular DNA, winding of the helix can stall the completion of replication until unwound. When replicating completely around circular DNA, the end primer must be incorporated into the DNA. Telomere extension cannot occur when telomeres have been shortened by rounds of replication.

When replicating linear DNA, the end primer cannot be replaced because of a lack of adjacent 3'−OH

Use the Mutation interactive to answer the questions. In the lower half of the interactive, change the template DNA strand such that the sequence ...ACAAAC... is changed to ...ACATAC... Which of the terms correctly describes this type of mutation? substitution insertion inversion deletion If this mutation occurred in a protein‑coding gene, how would it be classified? silent mutation frameshift mutation missense mutation nonsense mutation

Which of the terms correctly describes this type of mutation? substitution If this mutation occurred in a protein‑coding gene, how would it be classified? missense mutation

Use the Mutation interactive to answer the question. In the lower half of the interactive, change the template DNA strand such that the sequence ...AACCTG......AACCTG... is changed to ...AACTTG......AACTTG... Which of the terms correctly describes this type of mutation? insertion deletion substitution duplication If this mutation occurred in a protein‑coding gene, how would it be classified? silent mutation frameshift mutation missense mutation nonsense mutation

Which of the terms correctly describes this type of mutation? substitution If this mutation occurred in a protein‑coding gene, how would it be classified? nonsense mutation

A left‑handed form of DNA is the

Z‑DNA.

Autosome

a chromosome that does not determine sex

Which statement does not describe a Mendelian population? a group of interbreeding individuals a group of individuals of interest to population geneticists a population that cannot evolve a group of individuals whose set of genes constitute the population's gene pool a group of sexually reproducing individuals

a population that cannot evolve

In humans, oculocutaneous (OCA) albinism is a collection of autosomal recessive disorders characterized by an absence of the pigment melanin in skin, hair, and eyes. That is, normal pigmentation (𝐴) is dominant over albino characteristics (𝑎). For this question, assume the phenotype is determined by a single gene with two alleles. If both parents display the albino phenotype, what are all of the possible genotypes that may be observed in their offspring?

aa only

Transposons are movable elements of DNA that insert into new positions within the genome. A transposon may disrupt normal gene function, confer an evolutionary advantage, or have no effect on the organism. Select all scenarios in which a transposon has positively contributed to the evolution of the host's genome. acquisition of a transposon carrying a gene resistant to penicillin into a bacterium aquisition of a transposon carrying an adhesin gene into the Lactobacillus casei genome insertion of a transposon encoding a heat shock protein into the genome of a plant insertion of a transposon into the gene encoding Factor VIII, an essential blood‑clotting protein acquisition of a transposon that disrupts the promoter element of a breast cancer tumor‑suppressor gene

acquisition of a transposon carrying a gene resistant to penicillin into a bacterium aquisition of a transposon carrying an adhesin gene into the Lactobacillus casei genome insertion of a transposon encoding a heat shock protein into the genome of a plant

What are the multiple forms of one gene called?

alleles

Which form of gene regulation primarily occurs in eukaryotes? alteration of chromatin structure regulation of mRNA stability regulation of translation All of these forms of regulation occur equally in both prokaryotes and eukaryotes. regulation of transcription

alteration of chromatin structure

Which of the types of bacterial cells would normally be able to undergo conjugation with an F+ cell? either an F+ or an F' cell an F- cell another F+ cell an Hfr cell an F' cell

an F- cell

A plasmid that is capable of integrating into a bacterial chromosome is called

an episome

What is the definition of an auxotroph?

an organism that lacks the ability to synthesize a required metabolite

the addition or loss of less than a full set of chromosomes or chromosome pairs

aneuploidy

Which items are used as cloning vectors? Select all that apply. ribosomes artificial chromosomes schistosomes plasmids cosmids

artificial chromosomes plasmids cosmids

Biotechnology applications include all of the choices except gene therapy to treat genetic disorders. artificial selection for larger fruit size in crops. transgenesis to produce pest‑resistant crops. genetic testing for people. All of the applications listed are biotechnology applications.

artificial selection for larger fruit size in crops.

Which mutagens incorporate into DNA and frequently pair with the wrong base? base analogs alkylating agents oxidative radicals hydroxylamine deaminating chemicals

base analogs

Which of the techniques are examples of biotechnology? breeding different dog breeds for hunting or racing using viral DNA to harvest viral proteins for use in vaccines using yeast to ferment fruits or grains to make beer, wine, whiskey, or vodka developing transgenic crops to use as biofuels and reduce carbon emissions

breeding different dog breeds for hunting or racing using viral DNA to harvest viral proteins for use in vaccines using yeast to ferment fruits or grains to make beer, wine, whiskey, or vodka developing transgenic crops to use as biofuels and reduce carbon emissions

How is the transcription start site determined in bacteria? by the presence of a DNA bubble by the binding of RNA polymerase to the consensus sequences of the promoter by the presence of an enhancer element by the presence of the TATA box by the binding of the first primer

by the binding of RNA polymerase to the consensus sequences of the promoter

After separating a complex mixture of DNA fragments according to size, identifying a specific fragment of interest can be accomplished by Southern blotting. requires a probe that is complementary to the entire fragment of interest. is done on an electrophoretic gel directly. can be accomplished by Northern blotting. requires an antibody.

can be accomplished by Southern blotting.

Restriction endonucleases can be used to create pieces of DNA with cohesive ends. were identified as a protozoan defense mechanism against viruses. have no specific sequence requirements for recognition or cutting. are used in standard DNA sequencing reactions. are used to cut RNA at defined sequences.

can be used to create pieces of DNA with cohesive ends.

What is the constricted region of the chromosome where the kinetochore forms?

centromere

The fruit fly Drosophila melanogaster has four pairs of chromosomes, whereas the housefly Musca domestica has six pairs of chromosomes. How many different combinations of chromosomes are possible in the gametes of the fruit fly? How many different combinations of chromosomes are possible in the gametes of the house fly? Based on chromosome number, in which species would you expect to see more genetic variation among the progeny?

chromosome combinations in fruit flies: 16 chromosome combination in house flies more genetic variation in house fly

Which method of gene transfer in bacteria requires physical contact between donor and recipient cells? specialized transduction conjugation replication transformation generalized transduction

conjugation

Meiosis results in genetic variation among its product cells. One source of this genetic variation is the random distribution of maternal and paternal chromosomes, and the other source of genetic variation is

crossing over occurring at prophase I.

In humans, mitochondrial genetic disorders are inherited from only the mother. The severity of such diseases can vary greatly, even within a single family. What form of inheritance does this represent?

cytoplasmic inheritance

Genotype and allele frequencies describe the gene pool of the population. can only be calculated where there are two alleles at a locus. are used to know how many individuals live in the population. are always determined by counting every individual in the population. describe the genetic structure of the population.

describe the gene pool of the population. describe the genetic structure of the population.

What is a cross that occurs between two individuals that differ in two characteristics?

dihybrid cross

During meiosis, errors can occur during chromosome replication. Which term describes the addition of genetic material to a chromosome through extra replication of a chromosomal section?

duplication

Which of the reproductive isolating mechanisms listed in the table have partly evolved between apple and hawthorn host races of Rhagoletis pomonella, the apple maggot fly? ecological behavioral mechanical gametic temporal

ecological temporal

Arrange the components of translation in the approximate order in which they would appear or be used in prokaryotic protein synthesis, from first to last. First fMet‑tRNAfMet initiation factor 3 30S initiation complex 70S initiation complex elongation factor Tu elongation factor G release factor 1 Last

fMet‑tRNAfMet initiation factor 3 30S initiation complex 70S initiation complex elongation factor Tu elongation factor G release factor 1

Arrange the components of translation in the approximate order in which they would appear or be used in prokaryotic protein synthesis, from first to last. fMet‑tRNAfMet initiation factor 3 30S initiation complex 70S initiation complex elongation factor Tu elongation factor G release factor 1

fMet‑tRNAfMet initiation factor 3 30S initiation complex 70S initiation complex elongation factor Tu elongation factor G release factor 1

Which enzyme separates the two complimentary strands of DNA during DNA replication? primase helicase DNA polymerase ligase

helicase

How does the concept of molecular clocks contribute to addressing the question of genetic identity between different species? identifies which species are closely related helps estimate time since species had a common ancestor projects how long it will be until a species will diverge determines how long it takes for mRNA to be transcribed into a protein

helps estimate time since species had a common ancestor

Which term describes the situation, for X‑linked genes, in human and Drosophila males who have only one X chromosome?

hemizygous

Which term best describes crossing over with the formation of heteroduplex DNA? Holliday junction mismatch repair nonhomologous recombination homologous recombination bidirectional replication

homologous recombination

What information can the chi‑square goodness‑of‑fit test provide?

how well the observed results of a genetic cross fit the expected values

Inbreeding can have harmful effects in populations because mating between related individuals results more frequently in homozygotes with two alleles that are identical by state. increases the chance that deleterious and lethal recessive alleles will combine to produce homozygotes with harmful traits. results in more frequent cases of inbreeding depression in individuals in the population. results more frequently in homozygotes with two alleles that are identical by descent. causes a reduction in heterozygosity in the population.

increases the chance that deleterious and lethal recessive alleles will combine to produce homozygotes with harmful traits. results more frequently in homozygotes with two alleles that are identical by descent. causes a reduction in heterozygosity in the population.

sort these traits into inherited or acquired: blue eyes attached earlobes muscle mass gained from strength cystic fibrosis language fluency small stature due to malnourishment face shape fetal alcohol syndrome

inherited: blue eyes, attached earlobes, cystic fibrosis, face shape acquired: language fluency, muscle mass gained from strength, small stature due to malnourishment, fetal alcohol syndrome

Which of the examples listed is not a DNA repair mechanism? insertion sequence repair base‑excision repair direct repair nucleotide‑excision repair mismatch repair

insertion sequence repair

Which enzyme joins fragments of DNA into a continuous strand? DNA polymerase primase helicase ligase

ligase

Which class of RNA serves as the coding instruction read by the ribosome to produce a polypeptide chain? mRNA tRNA miRNA snRNA rRNA

mRNA

Alternative splicing produces mRNAs of different lengths from the same amino acid sequences genes of different lengths from the same DNA pre‑mRNAs of different lengths from the same DNA pre‑mRNAs of different lengths from the same mRNA mRNAs of different lengths from the same pre‑mRNA

mRNAs of different lengths from the same pre‑mRNA

A fruit fly, Drosophila melanogaster, that has only one sex chromosome (XO) and two sets of autosomes would have which sexual phenotype?

male

Mendel's principle of segregation can be explained by what process?

meiosis

What process involves the separation of chromosomes in the division of somatic, nonsex, cells?

mitosis

determine whether it focuses on transmission genetics, molecular genetics, or population genetics: mechanisms that ensure a high degree of accuracy during DNA replication

molecular genetics

determine whether it focuses on transmission genetics, molecular genetics, or population genetics: examination of the nucleotide sequence found at the end of chromosomes

molecular genetics

Migration does not result in an eventual equilibrium of allele frequencies in all populations involved in migration. gene flow between populations. more genetic variation between populations. populations becoming more genetically similar. more genetic variation within populations.

more genetic variation between populations.

What is an environmental agent that significantly increases the rate of mutation above the spontaneous rate called? mutagen tautomer transposon Ames agent missense agent

mutagen

Failure to separate for homologous chromosomes or sister chromatids is referred to as _______________________.

nondisjunction

Which term describes the process of sister chromatids not separating at the centromere during cell division?

nondisjunction

Which term does not change allele frequencies in a population? natural selection nonrandom mating genetic drift migration mutation

nonrandom mating

Proteins are composed of linked together by ______ bonds. genes; phosphodiester nucleic acids; phosphodiester enzymes; peptide amino acids; peptide RNA; hydrogen

nucleic acids; phosphodiester

How many different mRNA sequences can encode a polypeptide chain with the amino acid sequence Met‑Leu‑Arg? Include the stop codon in the mRNA sequence. Use the codon table to identify the codons. number of mRNA sequences:

number of mRNA sequences: 108

Suppose two independently assorting genes are involved in the pathway that determines fruit color in squash. These genes interact with each other to produce the squash colors seen in the grocery store. At the first locus, the W allele codes for a dominant white phenotype, whereas the w allele codes for a colored squash. At the second locus, the allele Y codes for a dominant yellow phenotype, and the allele y codes for a recessive green phenotype. The phenotypes from the first locus will always mask the phenotype produced by the second locus if the dominant allele (W) is present at the first locus. This masking pattern is known as dominant epistasis. A dihybrid squash, Ww Yy, is selfed and produces 128128 offspring. How many offspring are expected to have the white, yellow, and green phenotypes? number of white offspring: number of yellow offspring: number of green offspring:

number of white offspring: 96 number of yellow offspring: 24 number of green offspring: 8

George Beadle and Edward Tatum used mutant strains of Neurospora to formulate the one-gene-one-enzyme hypothesis. Researchers later updated this hypothesis to propose that one gene encodes one polypeptide because proteins can have multiple subunits. Consider a homodimeric protein. How many genes are required to form this protein? six three four two one

one

Which is not a characteristic of transposable elements? able to insert at many different locations throughout a genome short flanking direct repeats present on both side of a transposon staggered breaks made in the target DNA during insertion only found in plants can take place through a DNA intermediate in some cases

only found in plants

According to the biological species concept, what is the definition of a species? members from populations that share a similar appearance organisms that can interbreed in nature to produce healthy offspring individuals occupying a single lineage in an evolutionary tree organisms that use the same niche in an environment

organisms that can interbreed in nature to produce healthy offspring

In butterflies, sex is determined by the ZW sex‑determination system. Female butterflies are heterogametic and have both a Z sex chromosome and a W sex chromosome for sex determination. In contrast, male butterflies are homogametic and have two Z sex chromosomes. Select all of the relatives from which a female butterfly could have inherited her Z sex chromosome.

paternal grandmother and father

Which organism did Gregor Mendel use to discover the basic principles of genetics?

pea plant pisum sativum

What is the physical appearance or manifestation of a characteristic called in genetics?

phenotype

Eukaryotic cells that contain more than two sets of genetic information are referred to as

polyploid.

When mRNAs are being translated simultaneously by multiple ribosomes, the structure is known as a(n) polyribosome. copolymer. polytene. polycistron. operon.

polyribosome.

determine whether it focuses on transmission genetics, molecular genetics, or population genetics: effects of nonrandom mating on the distribution of genotypes among a group of animals

population genetics

Utilizing a genetic library requires all of the steps except All the steps listed are required when utilizing genetic libraries. transforming cells so that, in the pool of cells, all genes are represented. cloning a large number of DNA fragments including the one of interest. positional cloning. screening the library with a probe for a gene of interest.

positional cloning.

Which of the genes are specifically transcribed by eukaryotic RNA polymerase II? crRNAs pre‑mRNAs tRNAs small rRNAs large rRNAs

pre‑mRNAs

Which processes ensure the high accuracy of replication? proofreading mismatch repair nucleotide selection linear replication replication licensing

proofreading mismatch repair nucleotide selection

A cell in prophase II of meiosis contains 12 chromosomes. How many chromosomes are present in a cell from the same organism during the prophase step of mitosis? How many chromosomes are present in a cell from the same organism in prophase I of meiosis?

prophase step of mitosis # of chromosomes: 24 prophase 1 of of meiosis# of chromosomes: 24

What changes does UV light produce in DNA molecules? transversion mutations pyrimidine dimers analog substitutions purine dimers deamination

pyrimidine dimers

Which is an example of gene therapy? generating an attenuated virus to use in a live vaccine inserting a new gene into bacteria so that it produces therapeutic proteins replacing a disease-causing allele for a gene with a wild‑type allele altering the DNA of a rat embryo to generate a model for a disease inserting a new gene into a plant that confers herbicide resistance

replacing a disease-causing allele for a gene with a wild‑type allele

Which of the proteins are directly responsible for ensuring that eukaryotic DNA is replicated precisely once in each round of replication, even though there are thousands of replication origins? initiator protein single‑strand‑binding proteins replication licensing factor DNA primase DNA polymerase δ

replication licensing factor

How does DNA supercoiling arise?

rotation during DNA replication and transcription

The way that proteins fold into beta pleated sheets and alpha helices is dependent on their quaternary structure. tertiary structure. peptide bonds. secondary structure. primary structure.

secondary structure.

A recessive mutant allele of an autosome gene in a species of mouse results in a shorted tail in males when homozygous. However, when homozygous in females, this genotype has no effect, and the mice have normal tails. What is this genetic phenomenon called?

sex‑limited characteristic

Additional copies of a gene ___ cause cellular problems.

sometimes

In Africa, Lake Victoria is home to many distinct species of cichlid fish that vary in color from blue to red. Cichlid fish species that live in shallow water are blue and prefer to mate with other blue fish, whereas cichlid fish species that live in deep water are red and prefer to mate with other red fish. All of the cichlid fish species evolved from a single ancestrial species and live together in the same habitat. The cichlid fish in Lake Victoria are an example of which type of speciation? parapatric speciation allopatric speciation adaptive radiation sympatric speciation

sympatric speciation

J. W. McKay crossed a stock melon plant that produced tan seeds with a plant that produced red seeds.1 The results are documented in the table. Cross: tan x red F1: 13 tan seeds F2: 93 tan seeds, 24 red seeds Which phenotype is dominant? Assign genotypes to the following plants: Tan seed-producing parent Red seed-producing parent F1 tan seed-producing offspring F2 tan seed-producing offspring F2 tan seed-producing offspring

tan phenotype is dominant Tan seed-producing parent: RR Red seed-producing parent: rr F1 tan seed-producing offspring: Rr F2 tan seed-producing offspring: RR or Rr F2 tan seed-producing offspring: rr

Which enzyme is responsible for the replication of chromosome ends in germ cells and certain proliferating somatic cells? DNA ligase telomerase topoisomerase DNA polymerase δ geminin

telomerase

Recombinant DNA technology is a set of molecular methods used to isolate, manipulate, and study DNA. What does recombinant mean, in this case? that the DNA used is often derived from two or more sources and combined that the DNA used was edited using the CRISPR‑Cas system that the DNA used does not contain introns that the DNA used was cut with restriction enzyme or enzymes that the DNA used has undergone homologous recombination

that the DNA used is often derived from two or more sources and combined

What are telomeres?

the DNA located at the ends of eukaryotic DNA molecules

Select the function of the centromere in the transmission of genetic information.

the attachment point for sister chromatids

What is the function of a telomere? to proofread newly replicated DNA and excise incorrect nucleotide pairs to contain repetitive sequences that allow for primer annealing to protect the ends of linear DNA from premature shortening to detect and repair DNA errors that arise during replication

to protect the ends of linear DNA from premature shortening

The compound camptothecin and its derivatives are used as effective chemotherapeutic drugs for treating cancer. Which enzyme is the target of camptothecin for disruption of DNA replication in cancer cells? topoisomerase I DNA polymerase δ replication licensing factor DNA primase DNA ligase

topoisomerase I

Which item contains the TATA‑binding protein (TBP)? transcription factor TFIID sigma subunit Rho complex Rut enzyme bacterial RNA polymerase

transcription factor TFIID

Which term describes the rearranging of genetic material between nonhomologous chromosomes without a net loss or gain of genetic material?

translocation

determine whether it focuses on transmission genetics, molecular genetics, or population genetics

transmission genetics

determine whether it focuses on transmission genetics, molecular genetics, or population genetics: analysis of pedigrees to determine the probability of someone inheriting a trait

transmission genetics

Barbara McClintock is known for her discovery of the Ames test. tautomers. transposons. intercalating agents. base analogs.

transposons.

In Avery, MacLeod, and McCarty's experiments, homogenates from heat‑killed bacteria were treated with different enzymes, and then the ability of those homogenates to transform bacteria was assayed. Under which condition would transformation not occur?

treatment with DNase

True or false: All chromosomes of the same species would have the same centromeric positions.

true

Genetic engineering, wherein a gene transferred between species encodes the same polypeptide, is made possible due to which feature of the genetic code? overlapping genetic code isoaccepting tRNAs universality synonomous codons

universality

In a species of bird, the allele for the striped trait is recessive to the allele for the speckled trait. Suppose that a coastal bird population has a striped phenotype frequency of 0.140.14 and an inland population has a striped phenotype frequency of 0.67.0.67. The two populations are isolated and in Hardy-Weinberg equilibrium. Let 𝑞coastal represent the allele frequency of the coastal population and 𝑞inland represent the allele frequency of the inland population. Calculate the allele frequency for the striped allele for each population. Round your answers to the nearest hundredth. 𝑞coastal= 𝑞inland=

𝑞coastal= .37 𝑞inland= .82

After an exceptionally rainy spring, there is no longer a barrier between the populations, and some individuals migrate inland from the coast. Consequently, 30%30% of individuals in the new inland population are originally from the coastal population. Calculate the striped allele frequency for the inland population after migration, 𝑞combined. Round the answer to the nearest hundredth. 𝑞combined=

𝑞combined= .685

Which statement about aneuploidy is true?

One form of aneuploidy is a loss of both members of a homologous pair of chromosomes.

The products of mitosis normally

are genetically identical to the parent cell

Pioneering work in the field of genetics began prior to the 20th century. However, much of the early work relied only upon simple observation. Select the genetics concepts that were discovered before the year 1900.

1) theory of the principles of heredity 2)preservation of beneficial traits

108

Assume that a cell has six chromosomes while it is in the G1 stage of the cell cycle. How many chromosomes and how many DNA molecules will it have in the G2 stage?

6 chromosomes and 12 DNA molecules

definition of preformationism

A gamete contains a fully formed miniature adult organism

Normally in humans, a mutant gene on the Y chromosome will be inherited in which way?

All of the sons of a parent with the mutant gene will receive it but none of the daughters will.

How is anagenesis different from cladogenesis?

Anagenesis occurs within a single lineage results in evolution of a species Cladogenesis occurs when a lineage diverges results in speciation

Select all that apply. All of the choices are DNA sequencing techniques except DNA fingerprinting. Illumina sequencing. pyrosequencing. Sanger dideoxy sequencing. Mullis chain‑terminating sequencing.

DNA fingerprinting. Mullis chain‑terminating sequencing.

Which organism would not be considered a useful model genetic organism?

Bos taurus (the cow)

How did Mendel use self‑pollination and cross‑pollination techniques in his experiments with flower color to observe the basic patterns of inheritance?

By cross‑pollinating a parental generation of plants with different‑colored flowers and allowing the F1 generation to self‑pollinate, Mendel observed the basic patterns of inheritance in the F2 generation.

Place the steps of eukaryotic DNA replication in order, from when a germ cell enters gap 1 (G1)(G1) phase to the cell cycle termination. Cell enters gap 1 Prereplication complex forms at one of many origins of replication. The initiation complex creates an active replication fork as helicase unwinds DNA. RNA primers are added to provide a 3' end for elongation. 5' to 3' synthesis of the leading and lagging strands is carried out by DNA polymerase. RNA is replaced with DNA and lagging strands are joined. Active telomerase can extend the lost telomere region. Cell cycle termination

Cell enters gap 1 Prereplication complex forms at one of many origins of replication. The initiation complex creates an active replication fork as helicase unwinds DNA. RNA primers are added to provide a 3' end for elongation. 5' to 3' synthesis of the leading and lagging strands is carried out by DNA polymerase. RNA is replaced with DNA and lagging strands are joined. Active telomerase can extend the lost telomere region. Cell cycle termination

Who was a nineteenth‑century biologist who put forth the theory of evolution through natural selection and published his idea in the book entitled On the Origin of Species?

Charles Darwin

Suppose a species of tulip has three alleles for the gene that codes for flower color. The 𝐶𝑅 allele produces red tulips, the 𝐶𝑝 allele produces purple tulips, and the 𝐶𝑤 allele produces white tulips. 𝐶𝑅 is dominant over 𝐶𝑝 and 𝐶𝑤 , and 𝐶𝑝 is dominant over 𝐶𝑤. For each cross, determine the expected phenotype ratio of offspring flower color. CrCp x CpCw CrCw x CpCw

CrCp x CpCw: 2 red, 2 purple, 0 white CrCw x CpCw: 2 red, 1 purple, 1 white

Identify the key structural features of a DNA molecule. DNA contains the nucleotide bases adenine, thymine, guanine, cytosine, and uracil. DNA bases are always paired purine with pyrimidine. DNA is most often found as a left-handed helix, commonly referred to as Z‑DNA. The backbone of DNA is made of a sugar and a phosphate molecule. DNA strands are antiparallel and include a 5′5′ end and a 3′3′ end. Strong ionic bonds and hydrophobic interaction hold DNA together.

DNA bases are always paired purine with pyrimidine. The backbone of DNA is made of a sugar and a phosphate molecule. DNA strands are antiparallel and include a 5′5′ end and a 3′3′ end.

About 0.3% of human live births are trisomic. In contrast, only 0.02% of human live births are monosomic. Select the best explanation for why the occurrence of monosomics is less than that of trisomics.

Deleterious recessive alleles are always expressed on the monosomic chromosome but not on the trisomic chromosomes.

What happens during anaphase I of meiosis?

Homologous chromosomes separate, but sister chromatids remain joined at their centromeres.

Identify all of the true statements about RNA interference. Duplex RNA can be intentionally inserted into an organism to suppress a gene. siRNAs are short, 21‑ to 28‑nucleotide long duplexes. RNA interference can temporarily suppress the expression of a target gene. siRNA is cleaved by the Dicer enzyme complex. siRNAs suppress gene expression by interfering with transcription.

Duplex RNA can be intentionally inserted into an organism to suppress a gene. siRNAs are short, 21‑ to 28‑nucleotide long duplexes. RNA interference can temporarily suppress the expression of a target gene.

Match each characteristic to the proper bacterial fertility factor type. F- bacterium does not contain the F factor sequences recipient of DNA during bacterial conjugation F+ bacterium contains a plasmid with only the F factor F' bacterium contains a plasmid with the F factor and some genomic DNA Hfr bacterium bacteria with F factor integrated into genome

F- bacterium does not contain the F factor sequences recipient of DNA during bacterial conjugation F+ bacterium contains a plasmid with only the F factor F' bacterium contains a plasmid with the F factor and some genomic DNA Hfr bacterium bacteria with F factor integrated into genome

Who discovered the basic principles of heredity?

Gregor Mendel

What happens during prophase I of meiosis?

Homologous chromosomes form, and crossing over occurs between them.

Classify each description as applying to either heterochromatin or euchromatin. Heterochromatin the highly compressed form of chromatin the form chromatin takes most often when transcription is not occurring Euchromatin the expanded form of chromatin the form chromatin takes most often during transcription

Heterochromatin the highly compressed form of chromatin the form chromatin takes most often when transcription is not occurring Euchromatin the expanded form of chromatin the form chromatin takes most often during transcription

Are all eukaryotic genes colinear? Yes, because all codons in a eukaryotic gene are translated into a protein. No, because there are often several genes that code for the same protein. Yes, because all genes produce protein products. Yes, because the order of the codons and amino acids is the same in eukaryotes. No, because some eukaryotic genes have introns that are not translated.

No, because some eukaryotic genes have introns that are not translated.

What early concept of heredity proposed that genetic information in the form of particles called gemmules travels from different parts of the body to reproductive organs?

Pangenesis

Are the central dogma and the theory of inheritance of acquired characteristics consistent?

They are not consistent because inheritance of acquired characteristics demands a reverse flow of information, which violates the central dogma.

Which statement about polyploidy is not true? Polyploidy results from failure to separate a whole set of chromosomes during cell division. Polyploidy is possible only between the members of the same species. Polyploidy is a major mechanism by which new plant species have evolved. Polyploidy often results in larger cell size. Polyploidy is found in many of the food crop plants we enjoy, such as bananas and strawberries.

Polyploidy is possible only between the members of the same species.

What is a shorthand method for predicting outcomes of genetic crosses?

Punnett square

What material is analyzed by the technique of Northern blotting? modified proteins proteins DNA molecules RNA molecules

RNA molecules

In which stage of the cell cycle does the cell duplicate its DNA?

There are 64 codons, 20 different amino acids, and approximately 30-50 tRNAs. Which statement does not help explain these numbers? Flexibility, or wobble, between the anticodon and the codon allows one tRNA to pair with multiple codons. The 3' base of the anticodon on the tRNA can pair weakly with the 5' codon base. Many amino acids are coded for by more than one of the 61 sense codons. Synonymous codons code for the same amino acid. Isoaccepting tRNAs can carry the same amino acid.

The 3' base of the anticodon on the tRNA can pair weakly with the 5' codon base.

If a plant has a genotype of Aa, we would assume which is true?

The A allele is dominant to the a allele.

Which was NOT shown by Watson and Crick's model of DNA? There could be a means for DNA to easily replicate itself. One adenine would pair with one thymine. The strands run in opposite directions. The helices are right handed. The bases face outside for easy access.

The bases face outside for easy access.

A cell has a circular chromosome and histone proteins associated with its DNA, but lacks a nuclear membrane. Choose the domain of the cell with the best justification

The cell belongs to Archaea because it has histone proteins, which are present in Archaea and Eukaryota but absent in Eubacteria.

Which statement is not correct about how siRNAs and miRNAs function? They interact with the RISC complex. They can repress translation from specific mRNA molecules. They are found in eukaryotes. They can integrate into DNA sequences of specific genes. They can mediate the destruction of specific mRNA molecules.

They can integrate into DNA sequences of specific genes.

Which is not a valid statement about the characteristics that make bacteria and viruses advantageous for many genetic studies? Techniques are available for isolating and manipulating their genes. Reproduction is rapid, and many progeny are produced. They have large and complex genomes. Mutants are easily obtained and studied. Different strains that have been isolated are easy to grow under laboratory conditions.

They have large and complex genomes.

How would the deletion of the Shine-Dalgarno sequence affect a bacterial mRNA? Translation would not occur. Translation would occur at a slower rate. Transcription would not occur. DNA replication would not occur. Transcription would occur at a slower rate.

Translation would not occur.

Humans with only one sex chromosome (XO) usually have underdeveloped sexual characteristics and are sterile. What is this condition called?

Turner syndrome

Which statement is false? The archaea are a diverse group of prokaryotes often found in extreme environments. Prokaryotes consist of the archaea and the eubacteria (bacteria). Unlike eukaryotes, bacteria do not have proteins to help condense their DNA. The archaea are more similar to eukaryotes than to eubacteria for some genetic and molecular processes. Most prokaryotes are unicellular organisms that lack nuclear membranes.

Unlike eukaryotes, bacteria do not have proteins to help condense their DNA.

Which statement best describes the difference between virulent phages and temperate phages?

Virulent phages can go through only the lytic cycle, whereas temperate phages can undergo either the lytic cycle or the lysogenic cycle

What is the clear patch of lysed cells on a continuous layer of bacteria on the agar surface of a petri plate called?

a plaque

In Drosophila melanogaster, white eye is an X‑linked recessive trait, and red eye is an X‑linked dominant trait. Assume that the flies have a diploid set of autosomes (2A). Allele Xw codes for white eye, and allele X codes for red eye. Match each of the genotypes with the expected sex and eye color. XX XwX XwY XO XwXY XwXwX

XX: female red XwX: female red XwY: male white XO: male red XwXY: female red XwXwX: metafemale red

Chromosome

a DNA and protein structure that carries and transmits genetic information

What is a purine? Select all that apply. a base with two rings adenine or guanine a base with one ring cytosine or uracil a nucleoside

a base with two rings adenine or guanine

Select the definition of polyploidy.

a chromosomal complement with at least three complete sets of homologous chromosomes

Genome

a complete set of genetic information on an organism

pleitropy

a gene affecting more than one phenotype

Which characteristic would not be considered a useful for a model genetic organism?

a long generation time

What is a conditional mutation? a mutation that affects the genotype only under certain conditions a mutation that occurs only under certain conditions a mutation that affects the phenotype only when the organism is ill a mutation that makes it easier for organisms to contract diseases a mutation that affects the phenotype only under certain conditions

a mutation that affects the phenotype only under certain conditions

An individual unit of replication is referred to as a double helix. a negative supercoil. antiparallel. a replicon. a replication fork.

a replicon.

sex-influenced traits

a trait determined by an autosomal gene that is more easily expressed in one sex

sex-limited trait

a trait determined by an autosomal gene that is only expressed in one sex

polygenic trait

a trait determined by genes at many loci

phenocopy

a trait that is determined by an environmental effect and has the same phenotype as a genetically determined trait

A boy has blood type MN with a genotype of LMLN. His red blood cells possess both the M antigen and the N antigen. What is the relationship between his two alleles for this gene?

codominance

Which molecule holds sister chromatids together during mitosis and meiosis?

cohesin

a complete chromosome set or an exact multiple of the haploid chromosome set

euploidy

Which statement identifies what The Green Revolution relied upon genetic applications to accomplish?

expand the world's food production

In flowering plants, meiosis in the male portion of the flower produces

four microspores that will divide mitotically to form male gametophytes.

Human α‑globin and β‑globin genes evolved through intron shuffling. genome duplication. gene duplication. horizontal gene transfer. exon shuffling.

gene duplication.

A phage cross is made with phage T2. One of the parents was h+r− and the other parent was h−r+. What would be the two recombinant classes of progeny from this cross?

h+r+ and h-r-

In order to pass the G2/M checkpoint the cell must

have its DNA completely replicated and undamaged.

What is the complete set of genetic instructions for an organism?

its genome

The spread of a complete metaphase chromosome set presented for diagnostic purposes is called a _________.

karyotype

determine whether it focuses on transmission genetics, molecular genetics, or population genetics: study of people on a small island to determine why a genetic form of asthma is so prevalent on the island

population genetics

Which does the termination of translation require? terminator tRNA release factors GTP E site of the ribosomal complex stop codon on the mRNA

release factors GTP stop codon on the mRNA

Which of these is not involved in the initiation of translation in bacteria? small and large ribosomal subunits tRNA carrying the next amino acid that will occupy the A site GTP and initiation factors tRNA carrying N-formylmethionine that will occupy the P site mRNA

tRNA carrying the next amino acid that will occupy the A site

What is necessary for the addition of the poly(A) tail? mRNA chaperone proteins the consensus sequence, AAUAAA the Shine-Dalgarno sequence at least one intron at the end of the pre‑mRNA mRNA degradation enzymes

the consensus sequence, AAUAAA

genomic imprinting

the expression of a trait affected by the sex of the parent that transmits the gene to the offspring

genetic maternal affect

the influence of the genotype of the maternal parent on the phenotype of the offspring

With genetic maternal effect, the phenotype of an individual is determined by which of the statements?

the nuclear genotype of the maternal parent

penetrance

the percent of individuals with a particular genotype that express the expected phenotype

What is penetrance?

the percentage of individuals having a particular genotype who express the expected phenotype

When a population is in Hardy-Weinberg equilibrium, this means individuals do not change over time. allele frequencies, but not genotype frequencies, can change. the gene pool will change over time. the population might experience migration, drift, mutation or natural selection. the population is large and randomly mating.

the population is large and randomly mating.

How does the structure of DNA encode genetic information

the sequence of bases

What is the definition of population genetics

the study of the collective genes present in a group of the same species

definition of transmission genetics (classical genetics)

the study of the relationship between genes, chromosomes, and heredity

A key discovery leading to the structure of DNA was done by Chargaff. He found that ____. Select all that apply. the tetranucleotide hypothesis was false the amount of A equals the amount of T, and the amount of G equals the amount of C the amount of A equals the amount of G, and the amount of C equals the amount of T the amount of A equals the amount of C, and the amount of G equals the amount of T

the tetranucleotide hypothesis was false the amount of A equals the amount of T, and the amount of G equals the amount of C

Genetics

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