Genetics Final 2013 someone elses

Prokaryotic genome

-Genes are densely packed -Many polycistronic transcription units -No introns

Eukaryotic genome

-Genes are not densely packed -Mostly organized as single transcription units -Often contain introns

Which of the following statements is true regarding heritability of cancer?

At least two mutational events are required for a cell to become cancerous

Growth factors enter the cell nucleus.

Cells divide when division is favored by the sum of multiple signals.

Which is the first step in whole-genome shotgun sequencing?

Entire chromosomes are cut into short, overlapping fragments.

The genome of __________ was the first functional synthetic genome to be synthesized.

Mycoplasma mycoides

Which condition is evaluated at the G2/M checkpoint?

Precise replication of DNA

T/F 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

In a microarray analysis used to compare sporulating and nonsporulating yeast, a spot that appears yellow at a given time point is associated with a gene that is _______.

is expressed roughly equally in both sporulating and nonsporulating yeast )Yellow signal is the result of roughly equal parts red and green signals combined. This indicates roughly equal expression levels of the corresponding gene in both yeast samples.)

When are the major regulatory points in the cell cycle?

late G1 phase (G1/S checkpoint) late G2 phase (G2/M checkpoint) M phase (M checkpoint)

Is the PM3 polymorphism likely to result in a neutral missense mutation or a silent mutation?

neutral missense mutation silent mutation

To use RFLP analysis to detect a SNP, the SNP must _______.

occur within a restriction enzyme recognition sequence Addition or removal of a restriction site by a SNP will result in DNA fragments of different lengths (RFLPs) upon restriction enzyme digestion.

Mutant versions of genes that are normally involved in promoting the cell cycle are known as _______

oncogenes

Which one of the following are not hallmarks used to identify genes in an unknown eukaryotic sequence?

operator sequences

In general, the organization of genes in bacteria is different from that in eukaryotes. In E. coli, approximately 27 percent of all genes are organized into contiguous, functionally related units containing multiple genes under coordinate control that are transcribed as a single unit. Such contiguous gene families are called ________.

operons

Which protein appears to regulate the entry of cells into an S phase? This protein is also known as the "guardian of the genome."

p53

Driver mutations provide a growth advantage to a tumor cell. Which type of mutation is known to accumulate in cancer cells but has no direct contribution to the cancer phenotype?

passenger mutations

Which of the following three general mechanisms appear to be involved in the conversion of proto-oncogenes to oncogenes?

point mutations, translocations, overexpression

The feature of DNA fragment preparation that ensures fragment end overlap is _______.

random breakage of genomic DNA by physical shearing

In what ways can proto-oncogenes be converted to oncogenes?

repositioning of regulatory sequences point mutations gene amplification translocations

A DNA microarray (also called a DNA chip) can be used to ________.

scan a population of nucleic acids for abundance and mutations

Map-based genome sequencing

-It is a better approach for repetitive sequences -Starts with libraries of large, overlapping DNA fragments -Requires subcloning of large fragments into smaller clones for sequencing -Uses genetic recombination data to help arrange sequences correctly

what is the correct order the steps involved in creating a fully transgenic plant?

1. Introduce engineered Ti plasmid into bacteria. 2. Infect plant cells with transformed bacteria. 3. Grow plants from cuttings taken from infected plants. 4. Collect seeds produced by cutting-generated plants.

The correct order of the whole genome shotgun

1. Isolation and shearing of genomic DNA 2. Insertion of genomic fragments into cloning vector 3. Transformation of E. coli with cloning vector 4. Sequencing of cloned fragment ends 5. Sequence assembly

BamHI cuts the sequence 5′ G|GATCC 3′. Which of the following sequences would not be recognized by this enzyme?

3′ TCTTAAG 5′ This sequence does not contain the BamHI recognition site.

If there are five molecules of DNA containing the target region at the beginning of a PCR reaction, how many copies of the target will be present after three rounds of amplification?

40 The number of target sequences is doubled with each replication cycle.

Which of the following DNA sequences is one strand of a restriction enzyme recognition sequence?

5' GGATCC 3' The 5' 3' sequence of the complementary strand would be the same as the 5' 3' sequence of this strand; i.e., this sequence is symmetrical about the midpoint.

Which one of the following are not hallmarks used to identify genes in an unknown prokaryotic sequence? operator sequences promoters 5' and 3' intron splice sites termination sequences

5' and 3' intron splice sites

It is important to consider the ethical, legal, and social implications of DNA research because __________.

Although many genetic diseases can now be detected, technology has not given us the power to cure them. Information that an individual may develop a fatal disease may not be desirable and is also prone to misuse. Information that an individual may develop a fatal disease may not be desirable and is also prone to misuse.

What is BLAST used for?

BLAST is used to search through databases of DNA and protein sequences to identify portions that align with or are the same as existing sequences.

What are the similarity between map-based genome sequencing and whole-genome shotgun sequencing?

Both sequencing methods -Requires chromosome fragments to overlap for contig assembly -Requires sequences to be annotated after contig assembly

Which of the following features on an engineered Ti plasmid ensures the production of a significant amount of mRNA from the introduced gene? Antibiotic resistance gene Nuclear localization signal Petunia chloroplast targeting sequence CaMV promoter

CaMV promoter

Genomic libraries are often screened using probes derived from organisms that are different than the one from which the library was generated. Therefore, there are often mismatches between the probe and the most similar matching clones in the library. As a result, it's possible that no matching clones may initially be identified by hybridization. Which of the following methods would likely increase the chances of identifying the most similar matching clones?

Create smaller probes using regions of your DNA of interest that are thought to be more highly conserved. Alter the hybridization conditions such that hybridizations with a few mismatches are tolerated.

Why are cyclins expressed at different times and at different levels during the cell cycle?

Different cyclins combine with protein kinases at different stages of the cell cycle to affect the cell cycle. Cyclin B combines with CDK1 to move the cell cycle past the G2/M transition. Other cyclins combine with CDK1 to move the cell cycle from G1 to S.

Which program in the Human Genome Project was designed to ensure that personal genetic information would not be used in discriminatory ways?

ELSI

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?

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

T/F Biotechnology has yet to produce a single useful product for a human health condition.

False

T/F Gene therapy will probably be used predominantly for correcting germ-line mutations because fewer ethical issues are associated with that than with somatic cell gene therapy.

False

T/F Humans have more DNA and more genes than any other organism.

False

T/F Introns are found only in prokaryotic genomes.

False

T/F The genome of humans is remarkably stable, so much so that there are no cancers known to result from genomic instability.

False

T/F The genomic organization of all living creatures is identical.

False

T/F The terms proteomics and genomics mean essentially the same thing.

False

T/FIn humans, no genes are larger than 2 kb.

False

T/FMost carcinogens are artificial substances created by humans.

False

T/FThere are several checkpoints in the mitotic cell cycle. All occur in the S phase.

False

T/F Restriction endonucleases cut DNA at specific recognition sequences and then bond two strands covalently with the same "sticky ends."

False Restriction endonucleases cut DNA at specific sequences, but DNA ligase must be used to bond two strands covalently with the same "sticky ends."

T/F The longest stage of interphase is G2.

False.The longest stage of interphase is S; cells typically spend about 7 hours in this stage. The shortest stage of interphase is G2 (3 hours), although the shortest stage of the entire cell cycle is mitosis (1 hour).

During which stage can cells either exit the cell cycle or become committed to completing the cell cycle?

G1

How do translocations such as the Philadelphia chromosome contribute to cancer?

Genetic mapping established that certain genes were combined to form a hybrid oncogene ( BCR/ABL ) that encodes a 200kDa protein that has been implicated in the formation of chronic myelogenous leukemia.

Many instances involving genetically modified organisms, especially food crops, will be entering the human food chain in the years to come. On what basis are genetically modified foods considered safe to eat?

Genetically modified food products are considered safe if they are found to be not toxic or allergenic or have other negative physiological effects.

Which of the following is not a factor in the regulation of cell division in normal cells?

Growth factors enter the cell nucleus.

Which of the following experimental questions is least suited to testing through microarray analysis? Are there groups of genes that behave as though they may be under the control of a common regulator or regulators? Which human genes are abnormally expressed in lung tumors? Are there genes that are expressed in developing rat embryos that are not expressed in adult rats? How does the number of genes in the human genome compare to the number of genes in the chimpanzee genome?

How does the number of genes in the human genome compare to the number of genes in the chimpanzee genome?

Which of the following statements about genomes is FALSE? Bacterial genomes contain operons. Humans share about 50% of their genes with dogs. The human and chimp genome sequences differ by less than 2%. Human and Neanderthal genomes are 99% identical.

Humans share about 50% of their genes with dogs.This statement is false. Humans share about 75% of their genes with dogs.

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?

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.

Which of the following statements about the use of gene therapy to treat a genetic disorder in an individual is true? It involves introducing normal alleles into the somatic cells of an affected individual. It involves injecting structural proteins directly into nonfunctioning tissue. It involves transferring normal gene products such as insulin into the bloodstream. It involves transferring normal alleles into the germ cells of an affected individual.

It involves introducing normal alleles into the somatic cells of an affected individual. This methodology treats the affected individual, who may still pass on the allele for the disease.

Which of the following is a characteristic of the human genome? a majority of genes with no known function almost no duplicated regions larger and more intron-rich genes than in genomes of invertebrates uniform distribution of genes along chromosome arms

Larger and more intron-rich genes than in genomes of invertebrates. Both gene size and intron content tend to increase with complexity of the organism.

Genetic tests that detect mutations in the BRCA1 and BRCA2 oncogenes are widely available. These tests reveal a number of mutations in these genes - mutations that have been linked to familial breast cancer. Assume that a young woman in a suspected breast cancer family takes the BRCA1 and BRCA2 genetic tests and receives negative results. That is, she does not test positive for the mutant alleles of BRCA1 or BRCA2. Can she consider herself free of risk for breast cancer?

No, she will still have the general population risk of about 10 percent

Distinguish between oncogenes and proto-oncogenes.

Oncogenes are genes that induce or maintain uncontrolled cellular proliferation associated with cancer. They are mutant forms of proto-oncogenes, which normally function to regulate cell division.

A portion of the β‑globin allele responsible for sickle‑cell anemia contains the sequence CCTGTGGAG, whereas the same region of the normal β‑globin allele contains the sequence CCTGAGGAG. Which allele would be cut by the restriction enzyme DdeI, which cuts at the sequence CTNAG, where N is any base?

Only the normal allele will be cut.

Northern blots are used to study what type of molecule?

RNA fragments are separated using gel electrophoresis and blotted onto a nylon membrane. Labeled nucleic acid fragments are used to probe the filter and identify hybridizing sequences.

Which of the following is a consequence of inactivation of both p53 alleles in a cell?

Reduction of p21 synthesis

T/F Restriction endonucleases typically recognize palindromic DNA sequences and often generate "sticky ends" or single-stranded DNA overhangs at cut sites.

T

Which of the following is the most accurate comparison of the two yeast samples studied in the microarray analysis at the time of sporulation? The number of different genes expressed in sporulating yeast is likely to be greater than the number of different genes expressed in nonsporulating yeast. cDNAs from sporulating yeast were applied to a microarray spotted with Cy-5-labeled gene segments. cDNAs from nonsporulating yeast were applied to a microarray spotted with Cy-3-labeled gene segments. The two yeast samples share a common genome, but display differences in their transcriptomes. The two yeast samples share a common transcriptome, but display differences in their genomes.

The two yeast samples share a common genome, but display differences in their transcriptomes.

Which of the following components of the strategy ensures that sequence reads are obtained from the ends of cloned fragments?

The use of primers that anneal to vector sequences near vector/cloned fragment boundaries

You are the couple's genetic counselor. When consulting with you, they express their conviction that they are not at risk for having an affected child because they each carry different mutations and cannot have a child who is homozygous for either mutation. What would you say to them?

There is a 25% chance that their child will be a carrier of the ∆508 mutation. There is a 50% chance that their child will be a carrier of a CF mutation. There is a 25% chance that their child will develop CF. There is a 25% chance that their child will be a carrier of the R117 mutation.

What is the function of restriction endonucleases in bacteria?

They provide a defense mechanism against infection by viruses. Restriction endonucleases recognize and degrade viral DNA, thus preventing viral infections.

The mutation resulting in the allele for sickle‑cell anemia removes a restriction site from the β‑globin gene such that a specific probe hybridizes to one 1.3‑kb fragment instead of two fragments of 1.1 kb and 0.2 kb. What restriction pattern will be seen in sickle‑cell carriers?

Three fragments of 1.3, 1.1, and 0.2 kb The restriction pattern of sickle‑cell carriers would show three bands; the 1.3 kb band corresponds to the sickle‑cell allele, whereas the 1.1 and 0.2 kb bands correspond to the normal allele

T/F An RFLP marker that cosegegrates with a disorder exists in most people who have the disorder and is absent in most people who don't have the disorder.

True

T/F Any agent that causes damage to DNA is a potential carcinogen.

True

T/F One of the problems associated with the generation of transgenic plants is that the ecological parameters of many plants are not completely understood.

True

T/FA retrovirus uses reverse transcriptase to make a DNA copy of RNA.

True

T/FThere are two types of retinoblastoma, familial and sporadic. In the familial form, a defective gene is generally inherited from one parent.

True

T/F In the presence of DNA lesions in the cell, the stability of p53 protein increases.

True p53 blocks progression of the cell cycle—a response that is appropriate in the presence of unrepaired DNA lesions.

What is meant by a neutral polymorphism?

a difference in DNA sequence that has no physiological effect

What is the definition of a clone?

an identical organism, cell, or molecule that has been derived from a single ancestor

In the context of molecular genetics, reverse transcription PCR (RT-PCR) refers to ________.

assembling a DNA sequence from an mRNA

Which term is commonly used to describe the production of valuable proteins in genetically modified plants and animals?

biopharming

Which type of DNA library represents the genes expressed by a given cell at a certain time?

cDNA libraries represent expressed genes from specific cell types under specific conditions. Noncoding sequences are not included.

The Human Genome Project, which got underway in 1990, is an international effort to ________

construct a physical map of the billions of base pairs in the human genome

Which protein combines with cyclins to exert local control of the cell cycle?

cyclin-dependent kinase

One of the primary reasons for generating a large number of clones in a eukaryotic genomic library is that ________.

each vector can take up only a relatively small fraction of the eukaryotic DNA

Cancer is best described as a __________.

genetic disorder at the cellular level

List two especially useful characteristics of cloning vectors.

high copy number and antibiotic resistance gene(s)

Nucleic acid blotting is widely used in recombinant DNA technology. In a Southern blot, one generally ________.

hybridizes filter-bound DNA with a DNA probe

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 _______.

identify bacteria that contain a recombinant plasmid Correct. Colonies produced from cells containing a recombinant plasmid are white, whereas colonies from cells containing a nonrecombinant plasmid are blue.

What was the first human protein to be produced by recombinant DNA technology?

insulin

Is the PM2 polymorphism likely to result in a neutral missense mutation or a silent mutation?

silent mutation

Restriction endonucleases are especially useful if they generate "sticky" ends. What makes an end sticky?

single-stranded complementary tails

Compared with eukaryotic chromosomes, bacterial chromosomes are ________

small, with high gene density

What naturally occurring feature of the Ti plasmid makes it useful in genetic engineering of plants?

t is capable of introducing exogenous genes into plant genomes.T-DNA genes are removed from the Ti plasmid and are replaced with the gene of interest.

The role that p53 protein plays in suppressing inappropriate progression through the cell cycle depends on all of the following EXCEPT _______.

the ability of p53 to bind DNA lesions

Which of the following characteristics describes metastasis?

the ability to form secondary tumors at another site Cells from malignant tumors can break off from the main tumor, travel through the blood or lymph, and establish secondary tumors at another site.

One advantage of allele-specific oligonucleotide (ASO)-based over RFLP-based detection of human genetic disease is that _______.

the mutation need not be located within a restriction enzyme recognition site

The binding of extracellular growth factors to cell surface receptors ultimately results in the expression of a specific gene or genes. This fact suggests all of the following except that _______.

the signal cannot be turned off

Molecular tests for Huntington's disease, cystic fibrosis, and Tay-Sachs disease are possible because _______.

there has been sufficient information gathered on the DNA sequences of both the mutant and normal alleles

The role of the primers in PCR is _______.

to define the target region and provide a 3' end that can be extended by taq polymerase Primers bind to end of the target DNA strands, then taq polymerase synthesizes a new strand using the target DNA as a template.

Which term describes plants or animals that carry a foreign gene?

transgenic

The retinoblastoma protein (pRB), like p53, serves as a(n) ________ in regulating the cell cycle.

tumor suppressor

Which of the following characteristics do SNPs have?

variable base sequences, variable in the population