Nucleic Acids

Name: 

Modified True/False
Indicate whether the statement is true or false.  If false, change the identified word or phrase to make the statement true.

It has been discovered that the genetic material is protein. _________________________

Hershey and Chase were the first two scientists to prove that genetic material is composed of proteins. _________________________

The five-carbon sugar in DNA nucleotides is called ribose. _________________________

After years of research, the structure of the DNA molecule is now known to be a double helix. _________________________

Franklin’s X-ray diffraction images suggested that the DNA molecule resembled a tightly coiled spring, a shape called a helix. _________________________

In all living things, DNA replication must occur after cell division. _________________________

Before a DNA molecule can replicate itself, it must coil up. _________________________

Helicases unwind the double helix of DNA by breaking the nitrogen bonds that link the base pairs. _________________________

Errors in nucleotide sequence that occur during replication cannot be corrected. _________________________

RNA molecules contain the five-carbon sugar ribose. _________________________

During transcription, the information on a DNA molecule is “rewritten” into an mRNA molecule. _________________________

When a tRNA anticodon binds to an mRNA codon, the amino acid detaches from the tRNA molecule and bonds to the end of a growing protein chain. _________________________

Multiple Choice
Identify the choice that best completes the statement or answers the question.

Griffith’s transformation experiments

a.	changed proteins into DNA.
b.	caused harmless bacteria to become deadly.
c.	resulted in DNA molecules becoming proteins.
d.	were designed to show the effect of heat on bacteria.

Griffith’s experiments showed that

a.	dead bacteria could be brought back to life.
b.	harmful bacteria were hardier than harmless bacteria.
c.	heat caused the harmful and harmless varieties of bacteria to fuse.
d.	genetic material could be transferred between dead bacteria and living bacteria.

Avery’s experiments showed that transformation

a.	is prevented by protein-destroying enzymes.
b.	is prevented by DNA-destroying enzymes.
c.	causes protein to become DNA.
d.	is caused by a protein.

Avery and his research team concluded that

a.	RNA was the genetic material.
b.	protein bases were the genetic material.
c.	DNA and RNA were found in the human nucleus.
d.	DNA was responsible for transformation.

Using radioactive tracers to determine the interactions of bacteriophages and their host bacteria, Hershey and Chase demonstrated without question that

a.	genes are composed of protein molecules.
b.	DNA and proteins are actually the same molecules located in different parts of cells.
c.	bacteria inject their DNA into the cytoplasm of bacteriophages.
d.	DNA is the molecule that stores genetic information in cells.

All of the following are true of the viruses Hershey and Chase used in their study except

a.	they consisted of DNA surrounded by a protein coat.
b.	they injected their DNA into cells.
c.	they destroyed the DNA of the infected bacteria.
d.	they caused infected bacteria to make many new viruses.

The scientist who worked with Martha Chase to prove that genetic material is composed of DNA was

a.	Alfred Hershey.	c.	Francis Crick.
b.	Oswald Avery.	d.	Rosalind Franklin.

Molecules of DNA are composed of long chains of

a.	amino acids.	c.	monosaccharides.
b.	fatty acids.	d.	nucleotides.

Which of the following is not part of a molecule of DNA?

a.	deoxyribose	c.	phosphate
b.	nitrogen base	d.	ribose

A nucleotide consists of

a.	a sugar, a protein, and adenine.
b.	a sugar, an amino acid, and starch.
c.	a sugar, a phosphate group, and a nitrogen base.
d.	a starch, a phosphate group, and a nitrogen base.

The part of the molecule for which DNA is named is the

a.	phosphate group.	c.	nitrogen base.
b.	sugar.	d.	hydrogen bonds.

Purines and pyrimidines are

a.	nitrogen bases found in amino acids.
b.	able to replace phosphate groups from defective DNA.
c.	names of specific types of DNA molecules.
d.	classification groups of nitrogen bases.

Of the four nitrogen bases in DNA, which two are purines and which two are pyrimidines?

a.	purines: adenine, thymine; pyrimidines: uracil, cytosine
b.	purines: adenine, thymine; pyrimidines: guanine, cytosine
c.	purines: adenine, guanine; pyrimidines: thymine, cytosine
d.	purines: uracil, thymine; pyrimidines: guanine, cytosine

The amount of guanine in an organism always equals the amount of

a.	protein.	c.	adenine.
b.	thymine.	d.	cytosine.

adenine : thymine ::

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

Watson and Crick built models that demonstrated that

a.	DNA and RNA have the same structure.
b.	DNA is made of two strands that twist into a double helix.
c.	guanine forms hydrogen bonds with adenine.
d.	thymine forms hydrogen bonds with cytosine.

The scientists credited with establishing the structure of DNA are

a.	Avery and Chargaff.	c.	Mendel and Griffith.
b.	Hershey and Chase.	d.	Watson and Crick.

X-ray diffraction photographs by Wilkins and Franklin suggested that

a.	DNA and RNA are the same molecules.
b.	DNA is composed of either purines or pyrimidines, but not both.
c.	DNA molecules are arranged as a tightly coiled helix.
d.	DNA and proteins have the same basic structure.

During DNA replication, a complementary strand of DNA is made from each original DNA strand. Thus, if a portion of the original strand is CCTAGCT, then the new strand will be

a.	TTGCATG.	c.	CCTAGCT.
b.	AAGTATC.	d.	GGATCGA.

Which of the following is not true about DNA replication?

a.	It must occur before a cell can divide.
b.	Two complementary strands are duplicated.
c.	The double strand unwinds and unzips while it is being duplicated.
d.	The new DNA molecule has two newly-made strands.

The attachment of nucleotides to form a complementary strand of DNA during replication

a.	is accomplished by DNA polymerase.
b.	is accomplished only in the presence of tRNA.
c.	prevents separation of complementary strands of RNA.
d.	is the responsibility of the proofreading enzymes.

The enzymes responsible for adding nucleotides to the exposed DNA bases during replication are

a.	replicases.	c.	helicases.
b.	DNA polymerases.	d.	template enzymes.

The enzymes that unwind DNA during replication are called

a.	double helixes.	c.	forks.
b.	DNA helicases.	d.	phages.

All of the following are true about DNA replication in prokaryotic cells except

a.	replication begins at many sites along the DNA.
b.	replication begins at one site along the DNA loop.
c.	replication occurs in two opposite directions.
d.	there are two replication forks.

Transcription, which is a stage of gene expression, is the process by which genetic information encoded in DNA is transferred to a(n)

a.	RNA molecule.	c.	uracil molecule.
b.	DNA molecule.	d.	tRNA molecule.

RNA differs from DNA in that RNA

a.	is double-stranded.	c.	contains the nitrogen base uracil.
b.	contains deoxyribose.	d.	does not contain adenine.

RNA is chemically similar to DNA except that the sugar in RNA has an additional

a.	oxygen atom.	c.	nitrogen base.
b.	phosphate group.	d.	carbon atom.

In RNA molecules, adenine is complementary to

a.	cytosine.	c.	thymine.
b.	guanine.	d.	uracil.

Each of the following is a type of RNA except

a.	carrier RNA.	c.	ribosomal RNA.
b.	messenger RNA.	d.	transfer RNA.

During transcription,

a.	proteins are synthesized.	c.	RNA is produced.
b.	DNA is replicated.	d.	translation occurs.

During transcription, the genetic information for making a protein is “rewritten” as a molecule of

a.	messenger RNA.	c.	transfer RNA.
b.	ribosomal RNA.	d.	translation RNA.

Transcription begins when RNA polymerase

a.	attaches to a ribosome.
b.	unwinds a strand of DNA.
c.	binds to a strand of RNA.
d.	attaches to the promoter sequence of a gene.

mRNA: CUCAAGUGCUUC

Refer to the illustration above. What is the portion of the protein molecule coded for by a piece of mRNA with the sequence CUCAAGUGCUUC?

a.	Ser—Tyr—Arg—Gly	c.	Leu—Lys—Cys—Phe
b.	Val—Asp—Pro—His	d.	Pro—Glu—Leu—Val

Refer to the illustration above. The anticodons for the codons in the mRNA with the sequence CUCAAGUGCUUC are

a.	GAG—UUC—ACG—AAG.	c.	CUC—GAA—CGU—CUU.
b.	GAG—TTC—ACG—AAG.	d.	CUU—CGU—GAA—CUC.

Refer to the illustration above. Which of the following would represent the strand of DNA from which the mRNA strand CUCAAGUGCUUC was made?

a.	CUCAAGUGCUUC	c.	GAGTTCACGAAG
b.	GAGUUCACGAAG	d.	AGACCTGTAGGA

mRNA codons	amino acid
UAU, UAC	tyrosine
CCU, CCC, CCA, CCG	proline
GAU, GAC	aspartic acid
AUU, AUC, AUA	isoleucine
UGU, UGC	cysteine

Refer to the illustration above. Suppose that you are given a protein containing the following sequence of amino acids: tyrosine, proline, aspartic acid, isoleucine, and cysteine. Use the portion of the genetic code given to determine which of the following contains a DNA sequence that codes for this amino acid sequence.

a.	AUGGGUCUAUAUACG	c.	GCAAACTCGCGCGTA
b.	ATGGGTCTATATACG	d.	ATAGGGCTTTAAACA

The function of rRNA is to

a.	synthesize DNA.	c.	form ribosomes.
b.	synthesize mRNA.	d.	transfer amino acids to ribosomes.

At the very beginning of translation, the first tRNA molecule

a.	binds to the mRNA’s anticodon.
b.	attaches directly to the DNA codon.
c.	connects an amino acid to its anticodon.
d.	binds to the mRNA’s start codon.

Transfer RNA

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

Which of the following does not affect the final outcome of gene expression?

a.	the environment of the cells
b.	the number of amino acids in the protein being produced
c.	the presence of other cells
d.	the timing of gene expression

Completion
Complete each statement.

Griffith’s experiment showed that live bacteria without capsules acquired the ability to make capsules from dead bacteria with capsules in a process Griffith called ____________________.

Avery’s prevention of transformation using DNA-destroying enzymes provided evidence that ____________________ molecules function as the hereditary material.

A DNA subunit composed of a phosphate group, a five-carbon sugar, and a nitrogen-containing base is called a(n) ____________________.

The name of the five-carbon sugar that makes up a part of the backbone of molecules of DNA is ____________________.

Due to the strict pairing of nitrogen bases in DNA molecules, the two strands are said to be ____________________ to each other.

Watson and Crick determined that DNA molecules have the shape of a(n) ____________________ ____________________.

Chargaff’s observations established the ____________________ rules, which describe the specific pairing between bases on DNA strands.

Watson and Crick used the X-ray diffraction photographs of ____________________ and ____________________ to build their model of DNA.

The process by which DNA copies itself is called ____________________.

Enzymes called ____________________ are responsible for unwinding the DNA double helix by breaking the hydrogen bonds that hold the complementary strands together.

Errors in nucleotide sequencing are corrected by enzymes called ____________________.

Transcription and translation are stages in the process of ____________________.

The second stage of gene expression is called ____________________.

The nitrogen-containing base that is found only in RNA is ____________________.

The enzyme responsible for making mRNA is called ____________________.

Messenger RNA is produced during the process of ____________________.

The sequence of three nucleotides that code for specific amino acids or stop signals in the synthesis of protein is called a(n) ____________________.

During translation, amino acids are brought to the ribosomes by molecules of ____________________.

Nucleotide sequences of tRNA that are complementary to codons on mRNA are called ____________________.

The information contained in a molecule of messenger RNA is used to make protein during the process of ____________________.