Chapter 12

Which of the following statements is false? Select one: a. Hox genes occur in clusters. b. Hox genes that are found in different animals are very different from each other. c. Hox genes control the normal development of an animal. d. Mutations do not occur in hox genes.

b. Hox genes that are found in different animals are very different from each other.

During transcription, Select one: a. translation occurs. b. RNA is produced. c. DNA is replicated. d. proteins are synthesized.

b. RNA is produced.

DNA codes for DNA polymerase. & Without regulatory sites, the expression of a gene would not be controlled. Select one: a. F&F b. T&T c. F&T d. T&F

b. T and T

The function of an operator is to Select one: a. control the process of transcription within the nucleus. b. regulate access of RNA polymerase to specific genes. c. turn on and off the molecules of tRNA. d. generate amino acids for protein synthesis.

b. regulate access of RNA polymerase to specific genes.

Transcription factors are Select one: a. None of the above b. regulatory proteins. c. enhancers. d. promoters.

b. regulatory proteins.

A point mutation is the failure of a chromosome pair to separate during mitosis. Select one: True False

False

A repressor binds to the operator region when lactose is present. Select one: True False

False

Errors in nucleotide sequencing that occur during replication cannot be corrected. Select one: True False

False

Mutations that result from the substitution of one nitrogen base for another are called deletions. Select one: True False

False

Only DNA molecules contain the nitrogen base called uracil. Select one: True False

False

Only ribosomal RNA plays a role in translation. Select one: True False

False

Repressor proteins are bound to the DNA in front of each gene, readily allowing transcription to take place as the RNA polymerase moves along that gene. Select one: True False

False

The five-carbon sugar in DNA nucleotides is called ribose. Select one: True False

False

The genetic code is different in nearly all organisms. Select one: True False

False

During transcription, the information on a DNA molecule is "rewritten" into an mRNA molecule. Select one: True False

True

Franklin's X-ray diffraction images suggested that the DNA molecule resembled a tightly coiled spring, a shape called a helix. Select one: True False

True

The operator portion of the lac operon controls RNA polymerase's access to lactose-metabolizing genes. Select one: True False

True

The enzymes that unwind DNA are called Select one: a. DNA helicases. b. forks. c. double helixes. d. phages.

a. DNA helicases.

Avery's experiments showed that bacteria are transformed by Select one: a. DNA. b. proteins. c. carbohydrates. d. RNA.

a. DNA.

A laclac repressor turns off the genes by Select one: a. binding to the operator. b. binding to the promoter. c. DNA polymerase. d. binding to the lac genes.

a. binding to the operator.

Transcription proceeds when RNA polymerase Select one: a. binds to a strand of DNA. b. attaches to a promoter molecule. c. attaches to a ribosome. d. binds to a strand of RNA.

a. binds to a strand of DNA.

Transfer RNA Select one: a. carries an amino acid to its correct codon. b. converts DNA into mRNA. c. synthesizes amino acids as they are needed. d. produces codons to match the correct anticodons.

a. carries an amino acid to its correct codon.

Purines and pyrimidines are Select one: a. classification groups for nitrogen bases. b. names of specific types of DNA molecules. c. able to replace phosphate groups from defective DNA. d. nitrogen bases found in amino acids.

a. classification groups for nitrogen bases.

The strands of a DNA molecule are held together by hydrogen bonding between adenine with guanine molecules and cytosine with thymine molecules. Select one: True False

False

Typically, during replication only one error occurs for every 10,000 nucleotides. Select one: True False

False

When mRNA leaves the nucleus and enters the cytoplasm, it has a complete set of both introns and exons. Select one: True False

False

Which of the following include all the others? Select one: a. histones b. chromosomes c. nucleosomes d. DNA molecules

b. chromosomes

DNA replication results in two DNA molecules, Select one: a. one with two new strands and the other with two original strands. b. each with one new strand and one original strand. c. each with two original strands. d. each with two new strands.

b. each with one new strand and one original strand.

The function of rRNA is to Select one: a. transfer amino acids to ribosomes. b. form ribosomes. c. synthesize mRNA. d. synthesize DNA.

b. form ribosomes.

mRNA : nucleus :: Select one: a. nucleus : ribosomes b. protein : nucleus c. nucleus : protein d. protein : cytoplasm

d. protein : cytoplasm

RNA differs from DNA in that RNA Select one: a. is single-stranded. b. contains the nitrogen base uracil. c. All of the above d. contains a different sugar molecule.

c. All of the above

Watson and Crick built models that demonstrated that Select one: a. thymine forms hydrogen bonds with cytosine. b. guanine forms hydrogen bonds with adenine. c. DNA and RNA have the same structure. d. DNA is made of two strands that twist into a double helix.

d. DNA is made of two strands that twist into a double helix.

codon : mRNA :: Select one: a. ribosome : DNA molecules b. DNA : protein c. P site : RNA molecules d. anticodon : tRNA

d. anticodon : tRNA

In E. colilac, the operon controls the Select one: a. breakdown of glucose. b. production of glucose. c. production of lactose. d. breakdown of lactose.

d. breakdown of lactose.

During translation, the type of amino acid that is added to the growing polypeptide depends on the Select one: a. anticodon on the tRNA to which the amino acid is attached only. b. anticodon on the mRNA only. c. codon on the mRNA only. d. codon on the mRNA and the anticodon on the tRNA to which the amino acid is attached.

d. codon on the mRNA and the anticodon on the tRNA to which the amino acid is attached.

Which of the following is NOT a gene mutation? Select one: a. substitution b. insertion c. deletion d. inversion

d. inversion

DNA : mRNA :: Select one: a. ribosome : RNA polymerase b. rRNA : nuclelous c. tRNA : p site d. mRNA : amino acids

d. mRNA : amino acids

During transcription, the genetic information for making a protein is "rewritten" as a molecule of Select one: a. translation RNA. b. transfer RNA. c. ribosomal RNA. d. messenger RNA.

d. messenger RNA.

The part of the molecule for which deoxyribonucleic acid is named is the Select one: a. None of the above b. phosphate group. c. nitrogen base. d. sugar.

d. sugar.

Most scientists at that time agreed with Avery's experiments because of their extensive knowledge of DNA. Select one: True False

False

Multiple replication forks tend to slow down replication. Select one: True False

False

An enhancer is a sequence of nucleotides that, when bound by transcription factors, aids in shielding the RNA polymerase binding site of a specific gene. Select one: True False

False

Bacteriophage is a type of bacteria that infects viruses. Select one: True False

False

Before a DNA molecule can replicate itself, it must make itself more compact. This is accomplished by the double helix coiling up on itself. Select one: True False

False

Despite years of research, the actual structure of the DNA molecule is still unknown. Select one: True False

False

Gene expression is prevented when a repressor binds to the group of genes involved in the same function. Select one: True False

False

Helicases unwind the double helix of DNA by breaking the nitrogen bonds that link the hydrogen bases. Select one: True False

False

In all living things, DNA replication must occur after cell division. Select one: True False

False

Introns are deleted before a gene is transcribed from DNA into mRNA. Select one: True False

False

Introns are the portions of a gene that actually get translated into protein. Select one: True False

False

It has been discovered that each species of organism has its own unique genetic code for synthesis of its proteins. Select one: True False

False

It has been discovered that proteins are the genetic material, rather than DNA, because proteins are more complex than DNA. Select one: True False

False

A codon signifies either a specific amino acid or a stop signal. Select one: True False

True

A nucleotide consists of a sugar, a phosphate group, and a nitrogen base. Select one: True False

True

After replication, the nucleotide sequences in both DNA molecules are identical to each other and to the original DNA molecule. Select one: True False

True

Cells regulate gene expression so that each gene will be transcribed only when it is needed. Select one: True False

True

Chargaff observed that the amount of adenine in an organism always equaled the amount of thymine. Select one: True False

True

DNA polymerases have the ability to check for errors in nucleotide pairings. Select one: True False

True

The two areas on either end of the bacterial DNA molecule where the double helix separates are called replication forks. Select one: True False

True

When a tRNA anticodon binds to an mRNA codon, the amino acid detaches from the tRNA molecule and attaches to the end of a growing protein chain. Select one: True False

True

Wilkins and Franklin were the first to suggest that the DNA molecule resembled a tightly coiled helix. Select one: True False

True

X-ray diffraction photographs by Wilkins and Franklin suggested that Select one: a. DNA molecules are arranged as a tightly coiled helix. b. DNA and RNA are the same molecules. c. DNA and proteins have the same basic structure. d. DNA is composed of either purines or pyrimidines, but not both.

a. DNA molecules are arranged as a tightly coiled helix.

The TATA box in eukaryotes helps to ensure transcription. & In fruit flies, the hox gene that controls the development of the wings is located before the hox gene that controls the development of the eye and before the hox gene that controls the development of the tail. Select one: a. T&F b. F&F c. T&T d. F&T

a. T and F

What did Griffith observe when he injected a mixture of heat-killed, disease-causing bacteria and live harmless bacteria into mice? Select one: a. The mice developed pneumonia. b. The mice were unaffected. c. The disease-causing bacteria changed into harmless bacteria. d. The harmless bacteria died.

a. The mice developed pneumonia.

Hox genes determine an animal's Select one: a. basic body plan. b. skin color. c. eye color. d. size.

a. basic body plan.

Hox genes Select one: a. determine the location of a dog's ears. b. are found in bacteria. c. are regulated by operons. d. are not found in humans.

a. determine the location of a dog's ears.

A mutation that involves a single nucleotide is called a(an) Select one: a. point mutation. b. inversion. c. translocation. d. chromosomal mutation.

a. point mutation.

Genes contain instructions for assembling Select one: a. proteins. b. nucleosomes. c. pyrimidines. d. purines.

a. proteins.

In order for translation to occur, mRNA must migrate to the Select one: a. ribosomes. b. lac operon. c. enhancer. d. RNA polymerase.

a. ribosomes.

Which of the following is NEVER a frameshift mutation? Select one: a. substitution b. insertion c. deletion d. point mutation

a. substitution

All of the following are true of the viruses Hershey and Chase used in their study except Select one: a. they destroyed the DNA of the infected bacteria. b. they consisted of DNA surrounded by a protein coat. c. they caused infected bacteria to make many new viruses. d. they injected their DNA into cells.

a. they destroyed the DNA of the infected bacteria.

Unlike DNA, RNA contains Select one: a. uracil. b. adenine. c. thymine. d. phosphate groups.

a. uracil.

Avery : transformation :: Select one: a. Hershey : bacteriophage b. Chargraff : base pairing c. Watson : x-ray diffraction d. Griffith : proteins

b. Chargraff : base pairing

The enzymes responsible for adding nucleotides to the exposed DNA template bases are Select one: a. None of the above b. DNA polymerases. c. replicases. d. helicases.

b. DNA polymerases.

Avery and his research team concluded that Select one: a. protein bases were the genetic material. b. DNA was the genetic material. c. DNA and RNA were found in the human nucleus. d. RNA was the genetic material.

b. DNA was the genetic material.

What happens during the process of translation? Select one: a. Transfer RNA is made from messenger RNA. b. The cell uses information from messenger RNA to produce proteins. c. Messenger RNA is made from DNA. d. Copies of DNA molecules are made.

b. The cell uses information from messenger RNA to produce proteins.

Which of the following is not true about DNA replication? Select one: a. The double strand unwinds and unzips while it is being duplicated. b. The process is catalyzed by enzymes called DNA mutagens. c. It must occur before a cell can divide. d. Two complementary strands are duplicated.

b. The process is catalyzed by enzymes called DNA mutagens.

Of the four nitrogen bases in DNA, which two are purines and which two are pyrimidines? Select one: a. adenine—thymine; guanine—cytosine b. adenine—guanine; thymine—cytosine c. adenine—thymine; uracil—cytosine d. uracil—thymine; guanine—cytosine

b. adenine—guanine; thymine—cytosine

Gene regulation in eukaryotes Select one: a. is simpler than in prokaryotes. b. allows for cell specialization. c. includes the action of an operator region. d. usually involves operons.

b. allows for cell specialization.

At the very beginning of translation, the first tRNA molecule Select one: a. connects an amino acid to its anticodon. b. attaches to the P site of the ribosome. c. attaches directly to the DNA codon. d. binds to the ribosome's A site.

b. attaches to the P site of the ribosome.

Griffith's experiments showed that Select one: a. harmful bacteria were hardier than harmless bacteria. b. genetic material could be transferred between dead bacteria and living bacteria. c. dead bacteria could be brought back to life. d. heat caused the harmful and harmless varieties of bacteria to fuse.

b. genetic material could be transferred between dead bacteria and living bacteria.

The non-coding portions of DNA that are separated from the portions of DNA actually used during transcription are called Select one: a. mutons. b. introns. c. exons. d. exposons.

b. introns.

In eukaryotes, DNA Select one: a. is circular. b. is located in the nucleus. c. floats freely in the cytoplasm. d. is located in the ribosomes.

b. is located in the nucleus.

Avery's experiments showed that transformation Select one: a. causes protein to become DNA. b. is prevented by DNA-destroying enzymes. c. is caused by a protein. d. is prevented by protein-destroying enzymes.

b. is prevented by DNA-destroying enzymes.

Many biologists believe that having the genes of eukaryotic cells interrupted by introns Select one: a. causes severely damaging mutations. b. provides evolutionary flexibility. c. ensures that replication occurs correctly. d. prevents the code from being copied.

b. provides evolutionary flexibility.

When E. coli are grown on glucose, Select one: a. the lac genes are transcribed. b. the laclac repressor binds to the operator of the operon. c. lactose molecules bind to the lac repressor. d. RNA polymerase binds to the promoter of the lac operon.

b. the laclac repressor binds to the operator of the operon.

How many main types of RNA are there? Select one: a. thousands b. hundreds c. 3 d. 1

c. 3

What would Hershey and Chase have concluded if both radioactive 32P and 35S were found in the bacteria in their experiment? Select one: a. The virus's DNA was not injected into the bacteria. b. Genes are made of protein. c. Both the virus's protein coat and its DNA were injected into the bacteria. d. The virus's protein coat was not injected into the bacteria.

c. Both the virus's protein coat and its DNA were injected into the bacteria.

During DNA replication, a DNA strand that has the bases CTAGGT produces a strand with the bases Select one: a. GAUCCA. b. TCGAAC. c. GATCCA. d. AGCTTG.

c. GATCCA.

Which of the following statements is true? Select one: a. mRNA molecules made from the same gene are always edited the same way. b. A promoter is part of an intron. c. Introns have complementary sequences in DNA. d. A pre-mRNA molecule is longer than the gene from which the molecule was transcribed.

c. Introns have complementary sequences in DNA.

Transcription is the process by which genetic information encoded in DNA is transferred to a(n) Select one: a. DNA molecule. b. transposon. c. RNA molecule. d. uracil molecule.

c. RNA molecule.

What is produced during transcription? Select one: a. DNA molecules b. RNA polymerase c. RNA molecules d. proteins

c. RNA molecules

The presence of a repressor protein prevents the action of what enzyme? Select one: a. DNA polymerase b. lactase c. RNA polymerase d. permease

c. RNA polymerase

A tRNA anticodon could bind to an mRNA codon but amino acids would not connect to each other, therefore not forming a protein. & When mRNA leaves the nucleus and enters the cytoplasm, it has a complete set of both introns and exons. Select one: a. F&F b. T&T c. T&F d. F&T

c. T and F

In prokaryotes, an operon is a group of genes that are operated together. & Gene regulation in eukaryotes is less complex than in prokaryotes. Select one: a. F&F b. F&T c. T&F d. T&T

c. T and F

In eukaryotes, DNA replication proceeds in one general direction down the DNA molecule. & The replication of a DNA molecule results in two new copies of the same gene. Select one: a. T&F b. F&F c. T&T d. F&T

c. T and T

Why is it possible for an amino acid to be specified by more than one kind of codon? Select one: a. Some codons have the same sequence of nucleotides. b. Some codons do not specify an amino acid. c. There are 64 different kinds of codons but only 20 amino acids. d. The codon AUG codes for the amino acid methionine and serves as the "start" codon for protein synthesis.

c. There are 64 different kinds of codons but only 20 amino acids.

Watson and Crick : DNA Select one: a. Avery : nucleotides b. Chargaff : X rays c. Wilkins and Franklin : DNA d. Hershey and Chase : protein

c. Wilkins and Franklin : DNA

A nucleotide consists of Select one: a. a sugar, a protein, and adenine. b. a starch, a phosphate group, and a nitrogen base. c. a sugar, a phosphate group, and a nitrogen base. d. a sugar, an amino acid, and starch.

c. a sugar, a phosphate group, and a nitrogen base.

Many thousands of proteins may have arisen from only a few thousand exons because Select one: a. one gene can code for hundreds of different proteins. b. there really is no difference between one protein and another. c. an exon may be used by many different genes. d. an exon does not actually code for any meaningful information.

c. an exon may be used by many different genes.

Many thousands of proteins may have arisen from only a few thousand exons because Select one: a. there really is no difference between one protein and another. b. an exon does not actually code for any meaningful information. c. an exon may be used by many different genes. d. one gene can code for hundreds of different proteins.

c. an exon may be used by many different genes.

A repressor protein Select one: a. destroys amino acids before protein synthesis occurs. b. prevents DNA synthesis. c. blocks movement of RNA polymerase. d. attaches to ribosomes during translation.

c. blocks movement of RNA polymerase.

Each of the following is a type of RNA except Select one: a. messenger RNA. b. ribosomal RNA. c. carrier RNA. d. transfer RNA.

c. carrier RNA.

Griffith's transformation experiments Select one: a. were designed to show the effect of heat on bacteria. b. resulted in DNA molecules becoming proteins. c. caused harmless bacteria to become deadly. d. changed proteins into DNA.

c. caused harmless bacteria to become deadly.

During transcription, an RNA molecule is formed Select one: a. that is complementary to both strands of DNA. b. that is identical to part of a single strand of DNA. c. inside the nucleus. d. that is double-stranded.

c. inside the nucleus.

During mitosis, the Select one: a. DNA molecules become more tightly coiled. b. DNA molecules unwind. c. nucleosomes become less tightly packed. d. histones and DNA molecules separate.

c. nucleosomes become less tightly packed.

Which of the following is NOT generally part of a eukaryotic gene? Select one: a. enhancer sequences b. promoter sequences c. operon d. TATA box

c. operon

In bacteria, a group of genes that code for functionally related enzymes, their promoter site, and the operator that controls them all function together as a(n) Select one: a. ribosome. b. intron. c. operon. d. exon.

c. operon.

In bacteria, a group of genes that code for functionally related enzymes, their promoter site, and the operator that controls them all function together as a(n) Select one: a. ribosome. b. intron. c. operon. d. exon.

c. operon.

DNA is copied during a process called Select one: a. transformation. b. translation. c. replication. d. transcription.

c. replication.

During translation, the amino acid detaches from the transfer RNA molecule and attaches to the end of a growing protein chain when Select one: a. the ribosomal RNA anticodon binds to the messenger RNA codon. b. the protein chain sends a signal through the nerve cells to the brain. c. the transfer RNA anticodon binds to the messenger RNA codon. d. a "stop" codon is encountered.

c. the transfer RNA anticodon binds to the messenger RNA codon.

Cells must control gene expression so that Select one: a. their genes will never be expressed. b. their genes will always be expressed. c. their genes will be expressed only when needed. d. genetic disorders can be corrected.

c. their genes will be expressed only when needed.

A ribosome has Select one: a. no binding sites since the proteins must detach. b. one binding site for DNA. c. three binding sites used during translation. d. four binding sites for tRNA

c. three binding sites used during translation.

Where on the lac operon does a repressor molecule bind when lactose is absent? Select one: a. to the regulator b. to the promoter c. to the operator d. to a structural gene

c. to the operator

If a specific kind of protein is not continually used by a cell, the gene for that protein is Select one: a. always transcribed. b. not regulated. c. turned on and off at different times. d. never expressed

c. turned on and off at different times.

Which of the following is not found in DNA? Select one: a. adenine b. None of the above c. uracil d. cytosine

c. uracil

Using radioactive tracers to determine the interactions of bacteriophages and their host bacteria, Hershey and Chase demonstrated without question that Select one: a. DNA and proteins are actually the same molecules located in different parts of cells. b. genes are composed of protein molecules. c. bacteria inject their DNA into the cytoplasm of bacteriophages. d. DNA is the molecule that stores genetic information in cells.

d. DNA is the molecule that stores genetic information in cells.

helicase : replication fork Select one: a. ligase: template strand b. lead strand : lag strand c. primase : okazaki fragments d. DNA polymerase : complementary strand

d. DNA polymerase : complementary strand

Hershey and Chase were the first two scientists to prove that genetic material is composed of proteins. & Chargaff observed that the amount of adenine in an organism always equaled the amount of thymine. Select one: a. T&F b. F&F c. T&T d. F&T

d. F and T

Which of the following is a nucleotide found in DNA? Select one: a. ribose + phosphate group + uracil b. ribose + phosphate group + thymine c. deoxyribose + phosphate group + uracil d. deoxyribose + phosphate group + cytosine

d. deoxyribose + phosphate group + cytosine

Specialized cells regulate the expression of genes because they Select one: a. cannot control translation. b. do not carry the complete genetic code in their nuclei. c. do not want the genes to become worn out. d. do not need the proteins that are specified by certain genes.

d. do not need the proteins that are specified by certain genes.

The portions of DNA molecules that actually code for the production of proteins are called Select one: a. mutons. b. introns. c. exposons. d. exons.

d. exons.

adenine : thymine Select one: a. Watson : Crick b. protein : DNA c. adenine : DNA d. guanine : cytosine

d. guanine : cytosine

rough colony : smooth colony :: Select one: a. injected : inhaled b. heat killed : living c. pneumonia : mouse d. harmless : deadly

d. harmless : deadly

Which of the following terms is LEAST closely related to the others? Select one: a. tRNA b. anticodon c. polypeptide d. intron

d. intron

Which of the following are copied from DNA? Select one: a. mRNA only b. mRNA and tRNA only c. proteins d. mRNA, tRNA, and rRNA

d. mRNA, tRNA, and rRNA

Molecules of DNA are composed of long chains of Select one: a. fatty acids. b. amino acids. c. monosaccharides. d. nucleotides.

d. nucleotides.

Which of the following are found in both DNA and RNA? Select one: a. phosphate groups, guanine, and thymine b. ribose, phosphate groups, and adenine c. deoxyribose, phosphate groups, and guanine d. phosphate groups, guanine, and cytosine

d. phosphate groups, guanine, and cytosine

Because of base pairing in DNA, the percentage of Select one: a. purines in DNA is much greater than the percentage of pyrimidines. b. adenine molecules in DNA is about equal to the percentage of guanine molecules. c. cytosine molecules in DNA is much greater than the percentage of guanine molecules. d. pyrimidines in DNA is about equal to the percentage of purines.

d. pyrimidines in DNA is about equal to the percentage of purines.

A site : tRNA :: Select one: a. mRNA : amino acid b. codon : mRNA c. mRNA : P site d. tRNA : amino acid

d. tRNA : amino acid

DNA : histone :: Select one: a. nucleosome : structure b. double helix : base pairs c. supercoils : chromosome d. thread : spool

d. thread : spool

In RNA molecules, adenine is complementary to Select one: a. cytosine. b. thymine. c. guanine. d. uracil.

d. uracil.

RNA is chemically similar to DNA except that its sugars have an additional oxygen atom, and the base thymine is replaced by a structurally similar base called Select one: a. codon. b. cytosine. c. alanine. d. uracil.

d. uracil.