Genetics Exam 4 Homework

What is the variable gene activity hypothesis?
A. The hypothesis states that a loss of function in one gene may change function in many other genes that are involved in growth or differentiation.
B. The hypothesis states that various cells have different genes that determine their function.
C. The hypothesis states that all somatic cells contain enough genetic information for the development of the whole organism.
D. The hypothesis states that all somatic cells in an organism contain equivalent genetic information, but the information is expressed differently in different cells.

D. The hypothesis states that all somatic cells in an organism contain equivalent genetic information, but the information is expressed differently in different cells.

What is meant by the term determination?
A. the action of a cell on another cell
B. the process by which the cell achieves its actual form
C. that a specific developmental fate for a cell is fixed in response to internal and external cues
D. the genetic response to the environment

C. that a specific developmental fate for a cell is fixed in response to internal and external cues

Which one of the following statements best describes the distinction between differentiation and determination during development?
A. Determination refers to early developmental and regulatory events by which cell fate is fixed.
Once fixed, differentiation is the manifestation of the determined state, in terms of genetic, physiological, and morphological changes.
B. Differentiation refers to early developmental and regulatory events by which cell fate is fixed.
Once fixed, determination is the manifestation of the differentiated state, in terms of genetic, physiological, and morphological changes.
C. Determination refers to early developmental and regulatory events that confer a spatially discrete identity on cells.
Differentiation is the manifestation of this spatial identity, in terms of genetic, physiological, and morphological changes.
D. Differentiation refers to early developmental and regulatory events that confer a spatially discrete identity on cells.
Determination is the manifestation of this spatial identity, in terms of genetic, physiological, and morphological changes.

A. Determination refers to early developmental and regulatory events by which cell fate is fixed. Once fixed, differentiation is the manifestation of the determined state, in terms of genetic, physiological, and morphological changes.

What are maternal-effect genes?
A. genes transcribed in the offspring that regulate expression of genes in the mother
B. genes inherited from the mother
C. genes transcribed in the mother that regulate expression of genes in the offspring
D. genes transcribed in the mother that negate the genes of the father

C. genes transcribed in the mother that regulate expression of genes in the offspring

In Drosophila, maternal-effect genes are influential in determining the anterior-posterior organization of the developing embryo. True or false?

true

What are the three subsets of segmentation genes that divide the embryo into segments along the anterior-posterior axis?
A. even-skipped, fushi tarazu, and hairy
B. gap, pair-rule, and segment polarity
C. anterior, posterior, and terminal
D. bithorax, ultrabithorax, and antennapedia

B. gap, pair-rule, and segment polarity

Mutations that eliminate a contiguous region in the Drosophila embryo’s segmentation pattern are called ________.
A. homeodomains
B. segment genes
C. compartment genes
D. gap genes
E. linkage genes

D. gap genes

The _____ genes specify adjacent broad regions of segments.

gap

The ______ genes specify boundaries consisting of about two segments wide.

pair-rule

The ______ genes specify boundaries of all fourteen segments and the orientation of each segment.

segment polarity

Which functions earlier in development: maternal-effect genes or zygotic genes?
A. maternal-effect genes
B. zygotic genes

A. maternal-effect genes

In Drosophila development, the effects of BICOID protein vary along the axis of the embryo. This is because _______.
A. BICOID is a transcription factor
B. BICOID mRNA exists in the egg prior to fertilization
C. there is an anterior to posterior gradient in BICOID protein concentration in the embryo
D. BICOID both activates and represses gene activity

C. there is an anterior to posterior gradient in BICOID protein concentration in the embryo

A set of known mutations in the BX-C genes in Drosophila results in the development of wings on a body segment that would not ordinarily have wings. This is an example of mutation in which class of developmental genes?
A. Lethal genes
B. Maternal effect genes
C. Segmentation genes
D. Homeotic genes

D. Homeotic genes

Maternal effect genes are transcribed in the egg after fertilization. True or false?

false

The regulation of gene expression in individual cells coordinates the development of multicellular organisms, ensuring that tissues and organs form in their characteristic places. Researchers can study how multicellular organisms develop their spatial organization by examining normal and mutant forms of organisms, such as the fruit fly, Drosophila.
Part A – Pattern formation
Which of the following statements about pattern formation are true?
Select the four statements that are true.
A. Positional information controls pattern formation.
B. Pattern formation begins in adult animals.
C. The process of pattern formation involves segmentation of the body but does not involve the development of segment-specific body parts.
D. Cells receive molecular signals that communicate their position in relation to other cells.
E. Differential gene expression affects the developmental process in animals.
F. Homeotic genes establish major body axes.
G. Homeotic genes code for transcription factors that control the development of segment-specific body parts.

A. Positional information controls pattern formation. D. Cells receive molecular signals that communicate their position in relation to other cells. E. Differential gene expression affects the developmental process in animals. G. Homeotic genes code for transcription factors that control the development of segment-specific body parts.

1. Do Hox gene clusters exist in humans?
A. yes
B. no
2. If so, how many are known to exist?

1. A. yes 2. Four

Which one of the following statements best describes dominant gain-of-function mutations?
A. A mutation whose gene product does not change the phenotype or the evolutionary fitness of the organism.
B. A single copy of the mutation in a diploid organism that reduces or eliminates the function of a gene product.
C. A single copy of the mutation in a diploid organism that creates a gene product with enhanced or new functions.
D. A mutation in which the organism gains genetic material due to nondisjunction during meiosis.

C. A single copy of the mutation in a diploid organism that creates a gene product with enhanced or new functions.

Which one of the following statements best describes how the Antennapedia gene changes antennae into legs?
A. The gain-of-function AntP mutation causes the wild type Antennapedia gene to be expressed in the eye-antenna disc.
B. The gain-of-function AntP mutation causes the wild type Antennapedia gene to only be expressed in the first two thoracic segments.
C. The gain-of-function AntP mutation causes the wild type Antennapedia gene to be expressed in the first two abdominal segments.
D. The loss-of-function AntP mutation causes the wild type Antennapedia gene not to be expressed in the eye-antenna disc.

A. The gain-of-function AntP mutation causes the wild type Antennapedia gene to be expressed in the eye-antenna disc.

Which one of the following statements does not describe zygotic genes?
A. They are activated or repressed depending on their response to maternal-effect gene products.
B. The contain three subsets genes including: gap genes, pair-rule genes, and segment polarity genes.
C. They divide the embryo into segments.
D. They are gene products (mRNA and protein) encoded by genes in the mother’s genome that have their gene products placed in eggs.

D. They are gene products (mRNA and protein) encoded by genes in the mother’s genome that have their gene products placed in eggs.

What is the phenotype associated with zygotic gene mutations?
A. viable adults with added body plan segments
B. viable adults missing body plan segments
C. no detectable phenotype
D. embryonic lethality

D. embryonic lethality

Does the maternal genotype contain zygotic genes?
A. yes
B. no

A. yes

If polar cytoplasm is transplanted into the anterior end of the egg just after fertilization, which one of the following statements best describe what would likely happen to nuclei that migrate into this cytoplasm at the anterior pole?
A. Since nuclei are not affected by cytoplasm, the resulting cells would retain their original fate.
B. Since the polar cytoplasm contains information to form thoracic segments, legs would form on the head.
C. Since the products of maternal effect genes are placed directly into nuclei of the developing embryo, the fate of these cells will depend on what maternal products are present and their relative amounts.
D. Since the polar cytoplasm contains information to form germ cells, germ cells would form in the anterior region.

D. Since the polar cytoplasm contains information to form germ cells, germ cells would form in the anterior region.

What properties do Hox genes have in common?
A. They have one property in common: encoding of transcription factors.
B. They have two properties in common: encoding of transcription factors and colinear gene expression.
C. They have one property in common: colinear gene expression.
D. They have no properties in common.

B. They have two properties in common: encoding of transcription factors and colinear gene expression.

Are all homeotic genes Hox genes?
Yes.
No.

No

Cancer is best described as a ________.
A. genetic disorder at the cellular level
B. bacterial disease at the somatic cell level
C. genetic disease at the gametic cell level
D. viral disease

A. genetic disorder at the cellular level

As more is learned about cancer, it has become clear that cancer, with few exceptions, has no genetic basis. True or false?

False

________ is NOT evidence of genomic instability
A. Chromosomal deletions
B. Chromosomal translocations
C. Rapid cell division
D. DNA amplification

C. Rapid cell division

Which of the following statements describes metastasis?
A. It is the ability to divide uncontrollably.
B. Loss of contact inhibition
C. The ability to form secondary tumors at another site
D. A class of genes that initiate apoptosis

C. The ability to form secondary tumors at another site

Which of the following three general mechanisms appear to be involved in the conversion of proto-oncogenes to oncogenes?
A. transdetermination, mutation, allosteric interactions
B. inversions, translocations, methylation
C. point mutations, translocations, overexpression
D. familial, sporadic, phosphorylation
E. suppression, tabulation, projection

C. point mutations, translocations, overexpression

Any agent that causes damage to DNA is a potential carcinogen. True or false?

True

Why are cyclins expressed at different times and at different levels during the cell cycle?
A. One or more cyclins must interact with each other to control the cell cycle.
B. Cyclins are involved in arresting the cell cycle. Removal of certain cyclins allows the cell cycle to proceed.
C. Cyclins are transcription factors responsible for the expression of crucial cell-cycle proteins.
D. Different cyclins combine with protein kinases at different stages of the cell cycle to affect the cell cycle.

D. Different cyclins combine with protein kinases at different stages of the cell cycle to affect the cell cycle.

What is the name of the protein that combines with cyclins to exert local control of the cell cycle?
A. phosphatase
B. hexokinase
C. integrase
D. ATPase
E. cyclin-dependent kinase

E. cyclin-dependent kinase

A protein that functions as a cell-cycle regulator causes cell death (apoptosis) under high sunlight exposure. What is the symbol given to this protein?
A. phosphokinase
B. p102
C. p34
D. cyclin
E. p53

E. p53

There are several checkpoints in the mitotic cell cycle. All occur in the S phase. True or false?

False

When are the major regulatory points in the cell cycle?
Select all that apply.
A. early G1 phase (M/G1 checkpoint)
B. late G1 phase (G1/S checkpoint)
C. S phase (S checkpoint)
D. early G2 phase (S/G2 checkpoint)
E. late G2 phase (G2/M checkpoint)
F. M phase (M checkpoint)

B. late G1 phase (G1/S checkpoint) E. late G2 phase (G2/M checkpoint) F. M phase (M checkpoint)

What is the relationship between proto-oncogenes and oncogenes?
A. Both are involved in arresting the cell cycle.
B. Oncogenes are versions of proto-oncogenes that have been permanently switched off.
C. Oncogenes are mutant forms of proto-oncogenes.
D. Both must be activated to halt cell division

C. Oncogenes are mutant forms of proto-oncogenes.

How does the Ras protein transmit a signal from outside the cell into the cytoplasm?
A. Inactivated Ras proteins transduce a signal, which inactivates the transcription of genes that supress cell division.
B. Activated Ras proteins transduce a signal, which activates the transcription of genes that start cell division.
C. Activated Ras proteins transduce a signal, which inactivates the transcription of genes that supress cell division.
D. Inactivated Ras proteins transduce a signal, which activates the transcription of genes that start cell division.

B. Activated Ras proteins transduce a signal, which activates the transcription of genes that start cell division.

What happens in cases where the ras gene is mutated?
A. It signals cell death.
B. It signals supression of cell division.
C. It continually signals cell division.
D. It has no effect on the cell.

C. It continually signals cell division.

What is the role of the p53 protein in the cell cycle in normal cells?
A. It prevents cells from exiting the cell cycle and undergoing apoptosis.
B. It causes cells to enter G0 and stop dividing.
C. It binds to cyclin-dependent kinases to selectively phosphorylate certain proteins.
D. It temporarily arrests the cell cycle in G1 before entering S.

D. It temporarily arrests the cell cycle in G1 before entering S.

Mutant versions of genes that are normally involved in promoting the cell cycle are known as ________.
A. oncogenes
B. attenuators
C. malignant genes
D. tumor suppressors
E. proto-oncogenes

A. oncogenes

What is the name of the protein that appears to regulate the entry of cells into an S phase? This protein is also known as the "guardian of the genome."
A. cyclin
B. p34
C. phosphokinase
D. p102
E. p53

E. p53

When the normal retinoblastoma protein is dephosphorylated, it acts to suppress cell division by binding to and inactivating the E2F transcription factor. True or false?

True

Of the two classes of genes associated with cancer, tumor-suppressor genes and oncogenes, mutations in which group can be considered gain-of-function mutations?
A. tumor-suppressor genes
B. oncogenes

B. oncogenes

In which group are the loss-of-function mutations?
A. tumor-suppressor genes
B. oncogenes

A. tumor-suppressor genes

When referring to tumor-suppressor genes and cancer, loss of heterozygosity is likely to suppress cancer formation. True or false?

False

There are two types of retinoblastoma, familial and sporadic. In the familial form, one generally inherits a defective gene from one parent. True or false?

True

Which of the following DNA sequences is one strand of a restriction enzyme recognition sequence?
A. 5′ AAACCC 3′
B. 5′ GGATCC 3′
C. 5′ GGGGGG 3′
D. 5′ GGGTTT 3′

B. 5′ GGATCC 3′

X-Gal is included in the growth medium on which cells transformed with bacterial plasmids are grown. The reason X-Gal is included is to _______.
A. eliminate bacteria that do not contain plasmid DNA
B. eliminate bacteria that do not contain recombinant plasmid
C. identify bacteria that contain a recombinant plasmid
D. minimize the chances that a vector will re-circularize without incorporating a fragment of foreign DNA

C. identify bacteria that contain a recombinant plasmid

Within a six-base DNA recognition sequence, an enzyme that cuts between the 3rd and 4th bases from the 5′ end will generate blunt ends. True or false?

True

DNA fragments cut by restriction enzymes can form two types of ends. What are these ends called?
A. Ligase and blunt ends
B. Salvage and sharp ends
C. Tails and heads
D. Sticky and blunt ends

D. Sticky and blunt ends

Restriction endonucleases typically recognize palindromic DNA sequences and often generate "sticky ends" or single-stranded DNA overhangs at cut sites. True or false?

True

Which of the following statements describes the properties of a cloning vector?
A. It must be a bacterial plasmid, contain an antibiotic resistance gene, contain several restriction sites, replicate independently, and be recoverable from the host cell.
B. A vector should require insertion into the host genome to replicate, contain a number of restriction enzyme cleavage sites, contain more than one cleavage position for a particular restriction enzyme, and be recoverable from the host cell.
C. It must contain a selectable maker, integrate into the host-cell chromosome, replicate along with the host cell DNA, contain restriction enzyme cleavage sites, and be recoverable from the host cell.
D. A vector should be able to replicate itself independently, contain a number of unique restriction sites that would enable the insertion of DNA fragments cut with the same enzyme, carry a selectable marker, and be easy to retrieve.

D. A vector should be able to replicate itself independently, contain a number of unique restriction sites that would enable the insertion of DNA fragments cut with the same enzyme, carry a selectable marker, and be easy to retrieve.

List two especially useful characteristics of cloning vectors.
A. nonautonomous replication and transposition
B. reverse transcriptase and ligase activities
C. virulence and lysogenicity
D. ability to integrate into the host chromosome and then causing a lytic cycle
E. high copy number and antibiotic resistance gene(s)

E. high copy number and antibiotic resistance gene(s)

___________ cut DNA at specific sites and often yield "sticky ends" for additional interaction with DNA molecules cut with the same class of enzyme.

Restriction enzymes

__________ are plasmids, bacterial phages, or cosmids that receive, through ligation, a piece or pieces of foreign DNA.

Vectors

________ are the cells that express foreign genes introduced in the recombinant DNA.

Host cells

Assume that one conducted a typical cloning experiment using a typical plasmid, transformed an appropriate host bacterial strain, and plated the bacteria on an appropriate X-gal medium. Blue and white colonies appeared. Which of the two types of colonies, blue or white, would most likely contain the recombinant plasmid?
A. blue
B. white

B. white

Which type of DNA library represents the genes expressed by a given cell at a certain time?
A. Genomic
B. Protein
C. cDNA
D. Chromosoma

C. cDNA

What is a probe in molecular biology?
A. A DNA or an RNA molecule used in hybridization reactions
B. A type of vector system
C. An instrument used to manipulate cells in culture
D. Probes are not used in molecular biology.

A. A DNA or an RNA molecule used in hybridization reactions

Which of the following molecules is not required for a PCR reaction?
A. Ligase
B. Primer
C. DNTPs
D. DNA

A. Ligase

The thermostability of Taq polymerase is required during the annealing phase of PCR. True or false?

False

What is the purpose of raising the temperature to 90-95°C at the beginning of each cycle of PCR?
A. To attach the primer
B. To extend the primer
C. To renature two single DNA strands
D. To separate the double‑stranded DNA

D. To separate the double‑stranded DNA

Which three steps constitute a PCR cycle?
A. Transfection, transformation, and transduction
B. Naturation, annealing, and photolysing
C. Denaturation, annealing, and extension
D. Inactivation, activation, and transfer

C. Denaturation, annealing, and extension

In a typical PCR reaction, describe what is happening in stages occurring at temperature ranges:
1. 90-95 ∘C
A. Heating to 90-95 ∘C allows the primers to bind to the denatured DNA.
B. Heating to 90-95 ∘C denatures the double-stranded DNA so that it dissociates into single strands.
C. Heating to 90-95 ∘C allows the heat stable DNA polymerase an opportunity to extend the primers by adding nucleotides to the 3’ends of each growing strand.
2. 50-70 ∘C
A. Lowering the temperature to 50-70 ∘C allows the heat stable DNA polymerase an opportunity to extend the primers by adding nucleotides to the 3’ends of each growing strand.
B. Lowering the temperature to 50-70 ∘C denatures the double-stranded DNA so that it dissociates into single strands.
C. Lowering the temperature to 50-70 ∘C allows the primers to bind to the denatured DNA.
3. 70-75 ∘C
A. Bringing the temperature to 70-75 ∘C denatures the double-stranded DNA so that it dissociates into single strands.
B. Bringing the temperature to 70-75 ∘C allows the primers to bind to the denatured DNA.
C. Bringing the temperature to 70-75 ∘C allows the heat stable DNA polymerase an opportunity to extend the primers by adding nucleotides to the 3’ends of each growing strand.

1. B. Heating to 90-95 ∘C denatures the double-stranded DNA so that it dissociates into single strands. 2. C. Lowering the temperature to 50-70 ∘C allows the primers to bind to the denatured DNA. 3. C. Bringing the temperature to 70-75 ∘C allows the heat stable DNA polymerase an opportunity to extend the primers by adding nucleotides to the 3’ends of each growing strand.

The PCR (polymerase chain reaction) protocol that is currently used in laboratories was facilitated by the discovery of a bacterium called Thermus aquaticus in a hot spring inside Yellowstone National Park, in Wyoming. This organism contains a heat-stable form of DNA polymerase known as Taq polymerase, which continues to function even after it has been heated to 95°C. Why would such a heat-stable polymerase be beneficial in PCR?
A. Each cycle includes a "hot" denaturation phase (95°C), which separates the hydrogen
bonds that hold the strands of the template DNA together.
B. Each cycle includes a "hot" denaturation phase (95°C), which serves to sterilize the
culture.
C. Each cycle includes a "hot" saturation phase (95°C), which allows the primers to
anneal to the target DNA.
D. Each cycle includes a "hot" denaturation phase (95°C), which activates the Taq
polymerase.
E. More than one of the above are correct.

A. Each cycle includes a "hot" denaturation phase (95°C), which separates the hydrogen bonds that hold the strands of the template DNA together.

In the context of molecular genetics, reverse transcription PCR (RT-PCR) refers to ________.
A. assembling a DNA sequence from an mRNA
B. assembling an RNA sequence from a DNA sequence
C. translating in the 3′ to 5′ direction
D. making an amino acid sequence from a DNA sequence
E. transcribing first, then translating

A. assembling a DNA sequence from an mRNA

A map provides the location of sites cleaved by restriction enzymes. True or false?

True

Northern blots are used to study what type of molecule?
A. Proteins
B. DNA
C. RNA
D. RNA and proteins

C. RNA

In the context of recombinant DNA technology, of what use is a probe?
A. Probes are used to identify a wide variety of pathogens.
B. Probes are used to determine nucleic acid structure..
C. Probes are used to identify a complementary nucleic acid sequence.
D. Probes are used to identify and/or locate a particular nucleic acid sequence among a pool of sequences.

D. Probes are used to identify and/or locate a particular nucleic acid sequence among a pool of sequences.

Which of the following statements about ddNTPs is true?
A. They have a free 3′‑hydroxyl group on the sugar.
B. They have an oxygen at the 2′ carbon of the sugar.
C. DNA polymerase can add a new dNTP to a 3′ ddNTP.
D. They have a hydrogen at the 3′ carbon of the sugar.

D. They have a hydrogen at the 3′ carbon of the sugar.

DNA fragments that are 600 bp long will migrate more quickly through a sequencing gel than fragments that are 150 bp long. True or false?

False

Which of the following statements about manual Sanger sequencing is true?
A. Each of the four terminating ddNTPs is labeled with a different fluorescent dye.
B. The DNA sequence obtained is complementary to the template strand.
C. The DNA sequence is read from the top of the gel to the bottom.
D. One sequencing reaction is performed.

B. The DNA sequence obtained is complementary to the template strand.

DNA sequencing by the Sanger method employs which of the following for chain termination?
A. Deoxynucleotides
B. Ribonucleotides
C. Dideoxynucleotides
D. Dinucleotides

C. Dideoxynucleotides

Pyrosequencing is a method of DNA sequencing that uses beads as a matrix for PCR. True or false?

True

Order of the steps involved in whole-genome shotgun sequencing:

1. Randomly cut the genome into numerous smaller segments. 2. Sequence DNA. 3. Align sequences to form contigs.

Order of the steps involved in sequencing using a map-based cloning approach:

1. Digest chromosomal DNA with restriction enzymes 2. Clone DNA into various large vectors to create overlapping contigs 3. Systematically sequence DNA. 4. Align sequences to assemble chromosomes.

Which of the following statements is not true?
A. Whole-genome sequencing has become the most common method for assembling genomes, with map-based cloning being used to resolve the problems often encountered during whole-genome sequencing.
B. Compared to whole-genome sequencing, the map-based approach is somewhat cumbersome and time-consuming.
C. Alignment can be difficult in repetitive regions of the genome.
D. Whole-genome sequencing relies on the generation of non-overlapping fragments that are sequenced and aligned to form contigs.

D. Whole-genome sequencing relies on the generation of non-overlapping fragments that are sequenced and aligned to form contigs.

How does shotgun cloning differ from the clone-by-clone method?
A. Computer software assembles the clones in the clone-by-clone method.
B. The location of the clone being sequenced is known relative to other clones within the genomic library in shotgun cloning.
C. No genetic or physical maps of the genome are needed to begin shotgun cloning.
D. The entire genome is sequenced in the clone-by-clone method; it is not in shotgun sequencing.

C. No genetic or physical maps of the genome are needed to begin shotgun cloning.

The study of orthologs would be useful to determine the function of a specific gene in a species. True or false?

True

Humans have more DNA and more genes than any other organism. True or false?

False

The study of genomic data collected from environmental samples is called ________.
A. transcriptome analysis
B. metagenomics
C. glycomics
D. proteomics

B. metagenomics

Proteomics is the ________.
A. harvesting of proteins from a cell to determine their economic value
B. manipulation of amino acid sequences in proteins to alter their function
C. process of defining the complete set of proteins encoded by a genome
D. rational design of drugs based on protein structure
E. changing of the terminal sequences of proteins to alter their function

C. process of defining the complete set of proteins encoded by a genome

The terms proteomics and genomics mean essentially the same thing. True of false?

False

Two-dimensional gel electrophoresis is used in proteomics to ________.
A. observe a protein in two dimensions
B. separate RNA fragments
C. separate different proteins
D. separate DNA fragments

C. separate different proteins

Annotation of the human genome sequence reveals a discrepancy between the number of protein-coding genes and the number of predicted proteins actually expressed by the genome. Proteomic analysis indicates that human cells are capable of synthesizing more than 100,000 different proteins and perhaps three times this number. What is the discrepancy, and how can it be reconciled?
A. Increased protein production from approximately 100,000 genes is probably related to alternative splicing and various posttranslational processing schemes. In addition, a particular DNA segment may be read in a variety of ways and in two directions.
B. Increased protein production from approximately 50,000 genes is probably related to alternative splicing and various posttranslational processing schemes. In addition, a particular DNA segment may be read in a variety of ways and in two directions.
C. Increased protein production from approximately 20,000 genes is probably related to alternative splicing and various posttranslational processing schemes. In addition, a particular DNA segment may be read in a variety of ways and in two directions.

C. Increased protein production from approximately 20,000 genes is probably related to alternative splicing and various posttranslational processing schemes. In addition, a particular DNA segment may be read in a variety of ways and in two directions.

Variable number tandem repeats (VNTRs) are repeating DNA sequences of about 15 to 100 bp in length, found both within and between genes. Why are they commonly used in forensics?
A. Such variety provides a dependable, consistent, and unique RNA fingerprint for forensic applications.
B. Such variety provides a dependable, consistent, and unique DNA fingerprint for forensic applications.
C. Such variety provides a dependable, consistent, and unique protein fingerprint for forensic applications.

B. Such variety provides a dependable, consistent, and unique DNA fingerprint for forensic applications.

Which of the following is NOT true about DNA fingerprinting?
A. VNTR-based DNA fingerprinting requires a relatively large sample of DNA for Southern blot analysis.
B. The majority of forensic DNA profiling is now done using commercial kits that amplify STR loci by PCR.
C. Y-chromosome STR profiling can be used to differentiate between fathers and sons, or male siblings.
D. Mitochondrial DNA profiles are useful for cases in which forensic samples are small, old, or degraded.

C. Y-chromosome STR profiling can be used to differentiate between fathers and sons, or male siblings.

Single-nucleotide polymorphisms (SNPs), which occur randomly (every 500 to 1000 nucleotides) throughout the genome and on mitochondrial DNA, can be used for DNA profiling of samples that are severely degraded. True or false?

True

The FBI and other law enforcement agencies have selected 13 STR loci to be used as a core for forensic analysis. However, the probability of a random match cannot be reduced by increasing the number of loci analyzed for a forensic DNA profile. True or false?

False

At present, the most developed aspect of personalized medicine is in the field of pharmacogenomics, which is the study of how an individual’s entire genetic makeup determines the body’s response to drugs. True or false?

True

On average, a drug will be effective in only about 50 percent of patients who take it. However, personalized pharmacogenomics is widely practiced in cancer diagnosis and treatment, and the efficacy of cancer drugs reaches about 75 percent. True or false?

True

Which statement is NOT true about genomics and personalized medicine?
A. Personalized medicine uses personal genome information for disease diagnosis and treatment.
B. Whole-genome sequencing has been widely used in personalized medicine to accurately predict which diseases one will develop.
C. Microarray gene tests have been used in personalized medicine to reduce adverse drug reactions.
D. Genome sequencing, SNP identification, and genome-wide association studies (GWAS) have begun to reveal some of the DNA variants that may contribute to the risk of complex diseases such as cancer, heart disease, and diabetes.

B. Whole-genome sequencing has been widely used in personalized medicine to accurately predict which diseases one will develop.

Since epigenetic traits arise from stable changes in gene expression rather than alterations in the DNA sequence, they are not mitotically and meiotically heritable phenotypes. True or false?

False

During its life span, an organism has one genome, but this genome can be modified in diverse cell types at different times to produce many epigenomes. True or false?

True

Which statement is NOT true about DNA methylation?
A. Differential DNA methylation is not involved in allele-specific imprinting and subsequent gene silencing.
B. The bulk of methylated CpG dinucleotides are not adjacent to genes, but are found in repetitive DNA sequences located in heterochromatic regions of the genome.
C. DNA methylation is one of the major epigenetic mechanisms that control gene expression.
D. Genes with adjacent methylated CpG islands may be transcriptionally silenced.
E. When compared with normal cells, cancer cells often show global hypomethylation of DNA.

A. Differential DNA methylation is not involved in allele-specific imprinting and subsequent gene silencing.

Which process, other than classical mutation, has recently been shown to have impact on tumor-suppressor gene expression and genomic instability in cancer cells?
A. DNA deamination
B. DNA methylation
C. DNA transposition
D. DNA recombination
E. DNA replication

B. DNA methylation

The epigenetic state of the genome is not affected by any environmental agents such as nutrition, chemicals, and physical factors. True or false?

False

All cells contain the same genetic information. Why cannot cells other than stem cells differentiate into various tissues?
A. Stem cells are the only cells that can be implanted.
B. As cells develop, some genes are turned off permanently.
C. Stem cells are the only cells that do not have an X or Y chromosome, and can thus go into either a male or female.
D. As cells develop, their genetic makeup changes.

B. As cells develop, some genes are turned off permanently.

Pluripotent stem cells have the potential to differentiate into some, but not all of the 220 different cell types in the human body. True or false?

False

What is the common source for isolation of human embryonic stem cells (hESTs)?
A. Umbilical cord cells
B. Inner cell mass of a blastocyst
C. Enucleated cells in an embryo
D. Cells in amniotic fluid
E. All cells in an embryo

B. Inner cell mass of a blastocyst

Which of the following is NOT an approach of nuclear reprogramming for producing pluripotent stem cells?
A. Expressing certain transcription-factor genes in somatic cells
B. Somatic cell nuclear transfer
C. Inducing global hypomethylation in somatic cells
D. Fusing somatic cells with stem cells

C. Inducing global hypomethylation in somatic cells

When injecting stem cells into a patient’s body, scientists now have full control over the stem cells regarding their potential spread into other places and their differentiation into other tissues. True or false?

False

Two classes of traits that do NOT show continuous variation are meristic traits, which do not have an infinite range of phenotypes, and threshold traits, which have a small number of discrete phenotypic classes. True or false?

True

Characteristics exhibited by continuously varying traits include ________.
A. a 9:3:3:1 ratio
B. 3:1 and 1:1 ratios
C. quantification by measuring, weighing, counting, etc.
D. autosomal genes only
E. sex-linked genes only

C. quantification by measuring, weighing, counting, etc.

Phenotypes that exhibit continuous variation are often the result of ________.
A. the effect of two genes
B. epistasis
C. multifactorial inheritance
D. multiple alleles

C. multifactorial inheritance

The multiple factor hypothesis suggests that many factors or genes contribute to the phenotype in a cumulative or quantitative manner. True or false?

True

All EXCEPT which of the following statements are major points in the multiple-gene hypothesis?
A. Each gene locus involved in the phenotype may be occupied by either an additive allele, which contributes to the phenotype, or a nonadditive allele, which offsets the additive alleles.
B. Together, the genes controlling the trait under study produce a wide range of phenotypic variations.
C. Each additive allele contributes roughly equally to the phenotype.
D. Analysis of multiple-gene traits requires the study of large numbers of progeny.

A. Each gene locus involved in the phenotype may be occupied by either an additive allele, which contributes to the phenotype, or a nonadditive allele, which offsets the additive alleles.

Assume that a cross is made between tall and dwarf tobacco plants. The F1 generation showed intermediate height, while the F2 generation showed a distribution of height ranging from tall to dwarf, like the original parents, and many heights between the extremes. These data are consistent with which one of the following modes of inheritance?
A. codominance
B. alternation of generations
C. hemizygosity
D. incomplete dominance
E. multiple-factor inheritance

E. multiple-factor inheritance

Height in humans depends on the additive action of genes. Assume that this trait is controlled by the four loci R, S, T, and U and that environmental effects are negligible. Instead of additive versus nonadditive alleles, assume that additive and partially additive alleles exist. Additive alleles contribute two units, and partially additive alleles contribute one unit to height.
Part A
Can two individuals of moderate height produce offspring that are much taller or shorter than either parent? If so, how?
A. Yes, the example of the crossing is: RRSSTTUU × RrSsTtUu
B. Yes, the example of the crossing is: rrSsTtuu × RrSsTtUu
C. Yes, the example of the crossing is: RRSSttuu × rrssTTUU
D. No.

Part B
If an individual with the minimum height specified by these genes marries an individual of intermediate or moderate height, will any of their children be taller than the tall parent? Why or why not?
A. Yes, if the individual of moderate height is RrSsTtUu.
B. Yes, if the individual of moderate height is rrSsTtUu.
C. Yes, if the individual of moderate height is RRSSttuu.
D. No, there is no way of having more than four uppercase alleles in the offspring.

Part A: B. Yes, the example of the crossing is: rrSsTtuu × RrSsTtUu Part B: D. No, there is no way of having more than four uppercase alleles in the offspring.

Bell-shaped distributions produced by plotting results of F2 and F3 crosses are typical of which type of inheritance?
A. multiple-factor inheritance
B. incomplete dominance
C. alternation of generations
D. codominance
E. hemizygosity

A. multiple-factor inheritance

Two samples with identical means do not necessarily have the same standard deviation. True or false?

True

Heritability is a measure of the degree to which the phenotypic variation of a given trait is due to genetic factors. True or false?

True

Which term is defined as "a measure of the variation in a phenotype (for a polygenic trait in a given population) due to genetic factors"?
A. Response
B. Broad-sense heritability
C. Narrow-sense heritability
D. Variance

B. Broad-sense heritability

Which term describes the procedure of selecting a specific group of organisms from an initially heterogeneous population for future breeding purposes?
A. Artificial selection
B. Narrow-sense heritability (h2)
C. Broad-sense heritability (H2)
D. Selection differential (S)

A. Artificial selection

Which of the following statements about twins and twin studies is FALSE?
A.Twin studies have been used to try to determine the role of heredity versus environment.
B. Dizygotic twins are an important control for any study using monozygotic twins.
C. If the concordance values for monozygotic twins are much higher than for dizygotic twins, the trait probably has a strong genetic basis.
D. Fraternal twins are as close genetically to each other as are monozygotic twins.

D. Fraternal twins are as close genetically to each other as are monozygotic twins.

What is the difference between an eQTL and a pQTL?
A. The term eQTL refers to twins that both express a given trait; the term pQTL refers to twins where only one twin expresses the trait.
B. A pQTL phenotype is the amount of protein produced; an eQTL phenotype is the amount of RNA produced.
C. An eQTL is a proportion of an F2 population carrying the dominant phenotype, and a pQTL is the proportion containing the recessive phenotype.
D. An eQTL phenotype is the amount of protein produced; a pQTL phenotype is the amount of RNA produced.

B. A pQTL phenotype is the amount of protein produced; an eQTL phenotype is the amount of RNA produced.

What term is given to the total genetic information carried by all members of a population?
A. chromosome complement
B. genome
C. gene pool
D. race
E. breeding unit

C. gene pool

n a population of 100 individuals, 49% are of the NN blood type. What percentage is expected to be MN assuming HardyWeinberg equilibrium conditions?
A. 9%
B. 42%
C. 21%
D. 51%
E. There is insufficient information to answer this question.

B. 42%

Albinism is an autosomal recessive trait in humans. Assume that there are 100 albinos (aa) in a population of 1 million. How many individuals would be expected to be homozygous normal (AA) under equilibrium conditions?
A. 100
B. 10,000
C. 19,800
D. 980,100
E. 999,900

D. 980,100

In the case of complete dominance in a population in equilibrium, we cannot tell which individuals are homozygous dominants and which are heterozygous, but by knowing the frequency of the homozygous recessives, we can estimate the frequency of homozygous dominant and heterozygous genotypes. True or false?

True

If the frequency of the M allele in the human MN blood group system is 0.65 in a population at equilibrium, then the frequency of the N allele must be 0.04. True or false?

False

If a recessive disease is found in 50 out of 100,000 individuals, what is the frequency of the heterozygote carriers for this disease?
A. 0.043
B. 0.0005
C. 0.956
D. 0.022

A. 0.043

In a population of birds in Africa, it was observed that birds with small or large beaks could efficiently crack and eat small or large seeds, respectively. Birds with intermediate beaks had trouble with both types of seeds. What type of selection would be expected to occur in this population if small and large seeds were the only types of food available to these birds?
A. Directional
B. Stabilizing
C. There would be no selection in this population.
D. Disruptive

D. Disruptive

Fitness is a measure of ________.
A. an organism’s physiological vigor
B. the reproductive output of organisms relative to the alternative genotypes
C. an organism’s ability to survive
D. the longevity of organisms with a particular genotype

B. the reproductive output of organisms relative to the alternative genotypes

Which of the following statements about directional selection is TRUE?
A. Improvement can continue as long as selection is applied.
B. The variance for a trait decreases.
C. Heterozygous individuals have the highest fitness.
D. The mean value of a trait increases.

B. The variance for a trait decreases.

Which of the following statements about mutations in population genetics is TRUE?
A. Except in situations of Hardy-Weinberg equilibrium, mutation plays a significant role in changing allelic frequencies.
B. Mutation frequencies can be calculated from the frequency of the homozygous recessive genotypic class alone.
C. The mutation rate is equal to the allelic frequency of the recessive allele divided by the initial frequency of the recessive allele.
D. Mutation is a major force in generating genetic variability, but by itself plays a relatively insignificant role in changing allelic frequencies.

D. Mutation is a major force in generating genetic variability, but by itself plays a relatively insignificant role in changing allelic frequencies.

In small isolated populations, gene frequencies can fluctuate considerably. The term that applies to this ircumstance is ________.
A. genetic drift
B. allelic separation
C. stabilizing selection
D. genetic isolation
E. natural selection

A genetic drift

A number of mechanisms operate to maintain genetic diversity in a population. Why is such diversity favored?
A. Genetic diversity may better adapt a population to inevitable changes in the environment.
B. Homozygosity is an evolutionary advantage.
C. Diversity leads to inbreeding advantages.
D. Greater genetic diversity increases the chances of haploidy.
E. Genetic diversity helps populations avoid diploidy.

A. Genetic diversity may better adapt a population to inevitable changes in the environment.

Scientists studying the number of different species in an ecosystem would be evaluating ________.
A. biodiversity
B. interspecific diversity
C. conservation genetics
D. intraspecific diversity

B. interspecific diversity

The shrinking of available habitat reduces populations of wild species and often also isolates them from one another. Individual populations become trapped in pockets of undeveloped land surrounded by areas of agriculture. This process is called ________.
A. overdevelopment
B. underdevelopment
C. stagnation
D. population fragmentation
E. isolation

D. population fragmentation

All EXCEPT which of the following could create a population bottleneck ________?
A. A small number of animals migrating from one geographic location to another, leaving behind the rest of the population
B. Overfishing of a particular species over a short period of time
C. Interbreeding between populations of the same species
D. Captive-breeding programs

C. Interbreeding between populations of the same species

A founder effect occurs when a new population derived from a small subset of individuals has less genetic diversity than the original population. True or false?

True

The "genetic load" of a population is ________.
A. The percentage of advantageous alleles carried by an individual
B. The amount of genetic variation in a population
C. The average number of alleles per locus found in a specific population
D. The number of deleterious alleles found segregating in a population

D. The number of deleterious alleles found segregating in a population