BIOL 1009 Reading Questions Lecture 14-18

Which of the following statements about the function of RNA polymerase is correct? a. It adds nucleotides to the 5′ end of the growing mRNA molecule. b. It relies on other enzymes to unwind the double helix. c. It proceeds slowly along the DNA strand, requiring about a minute to add two nucleotides to the growing mRNA molecule. d. It unwinds the double helix and adds nucleotides to a growing strand of RNA. e. All of the listed choices are correct. Submit

It unwinds the double helix and adds nucleotides to a growing strand of RNA.

DNA replication is said to be semiconservative. Which of the following statements correctly explains what this means? a. Each new double helix consists of one old and one new strand. b. Half of the old strand is degraded and half is used as a template for the replication of a new strand. c. One of the two resulting double helices is made of two old strands, and the other is made of two new strands. d. The old double helix is degraded and half of its nucleotides are used in the construction of two new double helices. e. One strand of the new double helix is made of DNA and the other strand is made of RNA. Submit

Each new double helix consists of one old and one new strand.

Who conducted the X-ray diffraction studies that were key to the discovery of the structure of DNA? a. Griffith b. Meselson and Stahl c. McClintock d. Chargaff e. Franklin

Franklin

Which of the following characteristics is unique to multigene families? a. A highly conserved gene found in a number of different species. b. Multiple genes whose products must be coordinately expressed. c. Genes whose sequences are very similar and that probably arose by duplication. d. Genes whose exons can be spliced in a number of different ways.

Genes whose sequences are very similar and that probably arose by duplication.

Cytoplasmic determinants are best described as having which of the following characteristics? a. They are tissue-specific transcription factors expressed in the early embryo. b. They are maternal substances in the egg that influence the course of early development. c. They are single-stranded RNA molecules capable of binding complementary sequences and altering translation. d. They are centromeric regions of DNA loosened for chromosomal replication by transcription factors.

They are maternal substances in the egg that influence the course of early development.

what is a ribozyme? a. a mutated ribosome b. an enzyme that holds open the DNA double helix while RNA polymerase adds nucleotides c. a DNA sequence near the promoter that assists in the binding of RNA polymerase d. a biological catalyst made of RNA e. a biological catalyst consisting of DNA

a biological catalyst made of RNA

What does a mutagen cause? a. a change in the sequence of DNA b. a reduction in the number of tRNA molecules available for protein synthesis c. problems with mitosis d. decreased enzyme activity throughout the cell e. decreased permeability of the nuclear envelope

a change in the sequence of DNA

What does a mutagen cause? a. a change in the sequence of DNA b. decreased enzyme activity throughout the cell c. problems with mitosis d. a reduction in the number of tRNA molecules available for protein synthesis e. decreased permeability of the nuclear envelope

a change in the sequence of DNA

Which of these is currently considered the best definition of a gene? a. a gene codes for a single polypeptide b. a gene codes for a single enzyme c. a gene codes for a single protein d. a gene codes for either a polypeptide or an RNA molecule e. a gene codes for a particular ribozyme

a gene codes for either a polypeptide or an RNA molecule

The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. What is the result of this type of mutation? a. a frameshift mutation b. a polypeptide missing its N-terminus c. a base-pair substitution d. a polypeptide missing an amino acid

a polypeptide missing an amino acid

In recombinant DNA experiments, what is used to cut pieces of DNA, and what joins the resulting fragments to form recombinant DNA? a. DNA ligase, a restriction enzyme b. a transposon, a plasmid c. a restriction enzyme, DNA ligase d. a transposon, a restriction enzyme e. a plasmid, DNA ligase

a restriction enzyme, DNA ligase

Plants are more readily manipulated by genetic engineering than are animals because a. plant cells have larger nuclei. b. a somatic plant cell can often give rise to a complete plant. c. more vectors are available for transferring recombinant DNA d. DNA into plant cells. e. plant genes do not contain introns.

a somatic plant cell can often give rise to a complete plant.

Which of the following would be most likely to lead to cancer? a. hyperactivity of a proto-oncogene and activation of a tumor-suppressor gene b. failure of a proto-oncogene to produce a protein and amplification of a tumor-suppressor gene c. amplification of a proto-oncogene and inactivation of a tumor-suppressor gene d. failure of both a proto-oncogene and a tumor-suppressor gene to produce proteins e. hyperactivity of both a proto-oncogene and a tumor-suppressor gene

amplification of a proto-oncogene and inactivation of a tumor-suppressor gene

Which of the following methods are used by eukaryotes to control gene expression but are not used by bacteria? a. organization of genes in operons b. limiting access to free nucleic acids c. regulatory proteins binding to promoter sequences and determining polymerase used d. control of both RNA splicing and chromatin remodeling

control of both RNA splicing and chromatin remodeling

How do cells become differentiated? a. different genes are expressed so that different proteins are produced b. some cells contain maternal chromosomes and some contain paternal chromosomes c. the DNA in each cell changes so that the appropriate proteins are produced d. they differentiate through the process of mitosis e. paternal effect genes begin the process of differentiation by providing positional information

different genes are expressed so that different proteins are produced

A section of DNA has the base sequence shown in #1. A mutation in this DNA strand results in the base sequence shown in #2. What type of mutation does this change represent? #1 5' - AGCGTTACCGT-3' #2 5'-AGGCGTTACCGT-3' a. a missense mutation b. frameshift mutation c. a point mutation d. a silent mutation

frameshift mutation

Which ingredients for PCR and for the dideoxy chain-termination method of DNA sequencing are the same? a. nucleic acid probes, DNA polymerase, and DNA ligasem b. RNA, reverse transcriptase, and free nucleotides c. template DNA, reverse transcriptase, and DNA primerse d. nucleated eggs, reverse transcriptase, and free nucleotides e. free nucleotides, DNA polymerase, and DNA primers

free nucleotides, DNA polymerase, and DNA primers

The flow of information in a cell proceeds in what sequence? a. from RNA to protein to DNA b. from RNA to DNA to protein c. from protein to RNA to DNA d. from DNA to RNA to protein e. from DNA to protein to RNA

from DNA to RNA to protein

In humans, the hormone testosterone enters cells and binds to specific proteins, which in turn bind to specific sites on the cells' DNA. What is the probable action of these proteins? a. unwind the DNA so that its genes can be transcribed b. help RNA polymerase transcribe certain genes c. alter the pattern of DNA splicing d. cause mutations in the DNA e. promote recombination

help RNA polymerase transcribe certain genes

If cells from a carrot are removed and placed in a culture medium, they can develop into a normal adult plant. This demonstrates that carrot cells _____. See Concept 20.3 (Page) a. are undifferentiated as adult cells b. retain all the genes that were in the zygote that developed into the original plant c. differ as mature cells d. differ genetically at maturity e. differentiate

retain all the genes that were in the zygote that developed into the original plant

How do retrotransposons differ from other transposons? a. retrotransposons have retained the ability to move about a genome, an ability that has been lost by other transposons b. retrotransposons move via an RNA intermediate, whereas other transposons do not c. retrotransposons are likely to be the remains of a viral infection d. retrotransposons have lost the ability to move about a genome e. only retrotransposons can affect gene expression

retrotransposons move via an RNA intermediate, whereas other transposons do not

What are the repetitive DNA sequences present at the ends of eukaryotic chromosomes called? a. polypeptides b. telomeres c. chromosomes d. centromeres e. sarcomeres

telomeres

What does the DNA methylation mechanism used by eukaryotes do? a. increase the rate of transcription b. terminate transcription c. facilitate the binding of DNA to intermediate filaments d. inactivate genes e. cause apoptosis

inactivate genes

Which of the following molecules binds with a repressor to alter its conformation and therefore affect its function? a. cAMP b. promoter c. inducer d. transcription factor

inducer

Which of the following is an example of recombinant DNA technology? a. combining alternate alleles of a gene in a single cell b. introducing a human gene into a bacterial plasmid c. alternate alleles assorting independently d. cloning genes from homologous pairs of chromosomes e. manipulating a meiotic crossing-over event

introducing a human gene into a bacterial plasmid

After an RNA molecule is transcribed from a eukaryotic gene, what are removed, and what are spliced together, to produce an mRNA molecule with a continuous coding sequence? a. exons, introns b. promoters, operators c. introns, exons d. operators, promoters e. silencers, enhancers

introns, exons

Which of the following is true of DNA during interphase? a. it is in the form of highly condensed chromosomes and is unavailable for gene expression b. it exists as chromatin and is unavailable for gene expression c. it exists as chromatin and is less condensed than mitotic chromosomes d. it exists as chromatin, it is completely uncoiled and loose e. it is in the form of highly condensed chromosomes and is called heterochromatin

it exists as chromatin and is less condensed than mitotic chromosomes

How has gene duplication played a critical role in evolution? a. it increases the likelihood of viral infection in cells b. it almost always introduces immediate benefits for the organism c. it increases the amount of DNA in the genome d. it produces redundant copies of existing genes, which are then free to mutate and adopt new functions e. it increases the number of pseudogenes in the genome

it produces redundant copies of existing genes, which are then free to mutate and adopt new functions

Where does RNA polymerase begin transcribing a gene into mRNA? a. it starts at one end of the chromosome b. it looks for the AUG start codon c. it starts after a certain nucleotide sequence called a promoter d. transfer RNA acts to translate the message to RNA polymerase e. the ribosome directs it to the correct portion of the DNA molecule

it starts after a certain nucleotide sequence called a promoter

What is the function of helicase in DNA replication? a. it relieves strain from twisting of the double helix as it is unwound b. it joins together Okazaki fragments c. it adds nucleotides to the new strand in the 5′ to 3′ direction d. it untwists the double helix and separates the two DNA strands e. it checks for errors in the newly synthesized DNA strand

it untwists the double helix and separates the two DNA strands

Gel electrophoresis separates DNA fragments on the basis of what characteristic? a. restriction sites b. charge c. mutations d. sequence e. length

length

cDNA is synthesized from what molecule, and using an enzyme known as what? a. HIV, RNA polymerase b. mRNA, reverse transcriptase c. DNA, DNA polymerase d. tRNA, RNA polymerase e. mRNA, DNA polymerase

mRNA, reverse transcriptase

In nucleotide excision repair, damaged DNA is excised by what enzyme(s)? a. ligase b. primase c. helicase d. nuclease

nuclease

What process repairs damage to a preexisting double helix? a. nucleotide excision repair b. operon repair c. transformation d. mismatch pair e. proofreading

nucleotide excision repair

Griffith's experiments with S. pneumoniae were significant because they showed that traits could be transferred from one organism to another. What else did he find that was significant? a. protein could not be the genetic material b. the transferred traits were heritable c. a virus made the bacteria pathogenic d. DNA was the genetic material e. heat kills bacteria

the transferred traits were heritable

A codon consists of __________ bases and specifies which __________ will be inserted into the polypeptide chain. a. four, amino acid b. three, nucleotide c. four, fatty acid d. two, nucleotide e. three, amino acid

three, amino acid

Archaeologists unearthed a human skull with a small dried fragment of the scalp still attached. They extracted a tiny amount of DNA from the scalp tissue. How could they obtain sufficient DNA for an analysis of the ancient human's genes? a. subject the DNA to electrophoresis b. subject the DNA to restriction enzymes c. subject the specimen to amniocentesis d. use the polymerase chain reaction e. use a nucleic acid probe

use the polymerase chain reaction

Why is the lac operon said to be an inducible operon? a. when allolactose is present, it induces the inactivation of the lac repressor b. when allolactose is present, it induces repression of gene expression c. when activated, the lac operon induces the production of lactose-digesting enzymes d. when activated, the lac operon induces repression of gene expression e. when allolactose is present, it induces the activation of the lac repressor

when allolactose is present, it induces the inactivation of the lac repressor

How is translation initiated? a. the large ribosomal subunit binds to the small one b. the start codon signals the start of translation c. the tRNA bearing methionine binds to the start codon d. the small ribosomal subunit binds to the mRNA e. All of the listed answers are correct. Submit

All of the listed answers are correct. Submit

Which of the following statements about CRISPR-Cas9 is NOT correct? a. CRISPR-Cas9 can be used to silence, or knock out, the expression of a gene if it is used to add one or more mutations to a gene. b. CRISPR-Cas9 can be used to silence, or knock out, the expression of a gene by destroying its mRNA transcripts or preventing their translation. c. CRISPR-Cas9 can be used to repair a defective gene in the genome. d. CRISPR-Cas9 can be used to genetically alter the gene(s) in insect pests resulting in reduced or eliminated disease transmission by those insects. e. All of the statements are correct.

CRISPR-Cas9 can be used to silence, or knock out, the expression of a gene by destroying its mRNA transcripts or preventing their translation.

What are chromosomes made of? a. DNA, RNA, and proteins b. DNA and proteins c. DNA, heterochromatin, and histone proteins d. DNA e. DNA and euchromatin Submit

DNA and proteins

Which of the following is true of the cytoplasm of an unfertilized egg? a. It does not contain substances that are important in directing development. Development is directed solely by the surrounding cells. b. It does not contain substances that are important in directing development. These substances are produced by the DNA of the fertilized zygote. c. It is a homogeneous mixture of mRNA, proteins, organelles, and other substances d. It does not contain substances that are important in directing development. These substances are supplied by the sperm. e. It is an unevenly distributed mixture of mRNA, proteins, organelles, and other substances.

It is an unevenly distributed mixture of mRNA, proteins, organelles, and other substances.

Which of the following statements about the DNADNA in one of your brain cells is true? a. Each gene lies immediately adjacent to an enhancer. b. Most of the DNADNA codes for protein. c. It is the same as the DNADNA in one of your heart cells. d. The majority of genes are likely to be transcribed.

It is the same as the DNADNA in one of your heart cells.

Which one of the following statements is true of tRNAs? a. tRNAs are double-stranded. b. Each tRNA binds a particular codon. c. There are four types of tRNA. d. tRNAs carry special sequences known as codons. e. None of the listed answers are correct.

None of the listed answers are correct.

You are a member of the jury for a murder case. The prosecution has presented DNA evidence linking the defendant to the crime scene. The defense claims that DNA evidence using STR analysis with 13 markers is not sufficient to reliably distinguish between people. What do you think? a. STR analysis is not sufficient. The defendant's entire genome should be sequenced. b. The defense is right. STR analysis with 13 markers gives a one in 1 million chance of two people having the same pattern, leaving a reasonable doubt. c. The prosecution is right. STR analysis with 13 markers gives a one in 10 billion or greater chance that two people will have the same pattern. This person was at the crime scene. d. The prosecution will have to consult a genomic library to make sure their DNA evidence is valid. e. DNA evidence is not generally accepted by legal experts.

The prosecution is right. STR analysis with 13 markers gives a one in 10 billion or greater chance that two people will have the same pattern. This person was at the crime scene.

Which of the following statements explains the observation that the number of different proteins a vertebrate produces may be larger than the number of genes found within their genome? a. Vertebrate genes contain both exons and introns. b. Chromosomal rearrangements have increased the number of protein coding regions. c. Pseudogenes provide alternative regions for translation initiation. d. Vertebrates can produce more than one polypeptide from a single gene.

Vertebrates can produce more than one polypeptide from a single gene.

Which of the following changes in an exon is most likely to result in a nonfunctional protein product? a. a codon deletion b. a base-pair deletion c. an addition of three nucleotides d. a substitution in the last base of a codon

a base-pair deletion

All your cells contain proto-oncogenes, which can change into cancer-causing genes. Why do cells possess such potential time bombs? a. proto-oncogenes protect cells from infection by cancer-causing viruses b. cells produce proto-oncogenes as a by-product of mitosis c. proto-oncogenes are genetic junk that have not yet been eliminated by natural selection d. proto-oncogenes are necessary for the normal control of cell growth and division e. proto-oncogenes are unavoidable environmental carcinogens

proto-oncogenes are necessary for the normal control of cell growth and division

In the Hershey and Chase experiment that helped confirm DNA, not protein, was the hereditary material, what was the key finding? a. radioactively-labeled phosphorus was found outside of the infected bacteria b. radioactively-labeled sulfur was present inside the infected bacteria c. radioactively-labeled phosphorus was present inside the infected bacteria d. radioactively-labeled sulfur was found outside of the infected bacteria e. radioactively-labeled carbon was present inside the infected bacteria

radioactively-labeled phosphorus was present inside the infected bacteria

Which of the following molecules is a protein produced by a regulatory gene? a. operator b. repressor c. operon d. promoter

repressor