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Biology Chapter 16 and Chapter 17 Study Questions

For a couple of decades, biologists knew the nucleus contained DNA and proteins. The prevailing opinion was that the genetic material was proteins, and not DNA. The reason for this belief was that proteins are more complex than DNA. This is because:
a. proteins have a greater variety of three-dimensional forms than does DNA
c. proteins are made of 20 amino acids and DNA is made of four nucleotides
e. Only A and C are correct
In his transformation experiments, Griffith observed that
b. mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can concert some of the living cells into the pathogenic form
In trying to determine whether DNA or protein is the genetic material, Hershey and CHase made use of which of the following facts?
a. DNA does not contain sulfur, whereas protein does
b. DNA contains phosphorous, but protein does not
d. A and B only
Cytosine makes up 38% of the nucleotides in a sample of nucleotides in a sample of DNA from an organism. Approximately, what percentage of the nucleotides in this sample will be thymine?
a. 12
All of the following can be determined directly from X-ray diffraction photographs of crystallized DNA except the
a. diameter of the helix
b. helical shape of DNA
c. sequence of nucleotides
d. spaces of the nitrogenous bases along the helix
e. number of strands in a helix
c. sequence of nucleotides
What kind of chemical bond is found between paired bases of the DNA double helix?
a. hydrogen
In an analysis of the nucleotide composition of DNA, which of the following is true?
c. A + C = G + T
d. G + A = T + C
e. Both C and D
The strands that make up DNA are antiparallel. This means that
b. the 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand
Which enzyme catalyzes the elongation of a DNA strand in the 5' -> 3' direction?
c. DNA polymerase
Which of the following is least related to the others on the list?
a. Okazaki fragments
b. replication fork
c. telomerase
d. DNA polymerase
e. semiconservative model
c. telomerase
One of the reasons most scientists believed proteins were the carriers of genetic information was that
c. proteins were much more complex and heterogenous molecules than nucleic acids
Transformation involves
a. the uptake of external genetic material, often from one bacterial strain to another
The DNA of an organism has Thymine as 20% of it bases. What percentage of its bases would be Guanine?
b. 30%
In his work with pneumonia-causing bacteria, Griffith found that
d. some heat-stable chemical was transferred to harmless cells to transform them into pathogenic cells
When T2 phages are grown with radioactive sulfure
b. their proteins are tagged

(proteins contain sulfur, DNA does NOT!)
Meselson and Stahl
a. provided evidence for the semiconservative model of DNA replication
Watson and Crick concluded that each base could not pair with itself because
b. the uniform width of 2nm would not permit two purines or two pyrimidines to pair together
The joining of nucleotides in the polymerization of DNA requires energy from
e. the hydrolysis of the pyrophosphates removed from nucleoside triphosphates
Continuous elongation of a new DNA strand along one strand of DNA
c. occurs on the leading strand
Which of the following statements about DNA polymerase is incorrect?
a. It forms the bonds between complementary base pairs
b. It is able to proofread and correct for errors in base-pairing
c. It is unable to initiate synthesis; it requires an RNA primer
d. It only works in the 5'->3' direction
e. It is found in eukaryotes and prokaryotes
a. It forms bonds between complementary base pairs
How does DNA synthesis along the lagging strand differ from that on the leading strand?
d. Okazaki fragments, which each grow 5' -> 3' direction, must be joined along the lagging strand
Which of the following enzymes or proteins is paired with an incorrect or inaccurate function?
e. Primase - form DNA primer to start replication
T2 phage is grown in E. coli with radioactive phosphorous and then allowed to infect other E. coli. The culture is blended to separate the viral coats from the bacterial cells and centrifuged. Which of the following best describes the expect results of such an experiment?
d. Viral DNA is labeled; radioactivity is found in the pellet
What are telomeres and what do they do?
a. ever-shortening tips of chromosomes that may signal cells to stop dividing at maturity
b. highly repetitive sequences at tips of chromosomes that protect the lagging strand during replication
e. Both A and B are correct
Transcription involves the transfer of information from
a. DNA to RNA
If the 5' -> 3' nucleotide sequence on the complementary (noncoding) DNA strand is CAT, what is the corresponding codon on mRNA?
c. GUA
RNA polymerase
e. begins transcription at a promoter sequence and moves along the template strand of DNA, elongating an RNA molecule in a 5' -> 3' direction
How is the template strand for a particular gene determined?
c. It depends on the orientation of RNA polymerase, whose position is determined by particular sequences of nucleotides within the promoter
Which enzyme synthesizes tRNA?
b. RNA polymerase
Which of the following is true of RNA processing?
c. Assemblies of protein and snRNPs, called spliceosomes, may catalyze splicing
Which of the following is not involved in the formation of a eukaryotic transcription initiation complex?
a. TATA box
b. transcription factors
c. snRNA
d. RNA polymerase II
e. promoter
c. snRNA
A prokaryotic gene 600 nucleotides long can code for a polypeptide chain of how many amino acids long (at most)?
b. 200

(remember, 3 bases = 1 amino acid)
All of the following are transcribed from DNA except
a. exons
b. introns
c. tRNA
d. rRNA
e. promoter
e. promoter
What might introns have to do with the evolution of new proteins?
d. Introns provide more area where crossing over may occur (without interfering with the coding sequences) and thus increases the probability of exon shuffling between alleles
A ribozyme is
d. an RNA molecule that functions as an enzyme
All of the following would be found in a prokaryotic cell except
a. mRNA
b. rRNA
c. simultaneous transcription and translation
d. snRNA
e. RNA polymerase
d. snRNA
Which of the following is transcribed and then translated to form a protein product?
c. gene for a transcription factor
Transfer RNA
b. binds to its specific amino acid in the active site of an aminoacyl-tRNA synthetase
Place the following events in the synthesis of polypeptide in the proper order:
1) A small subunit binds to an mRNA and an initiator tRNA
2) The large subunit attaches to the small subunit, with the initiator tRNA in the P site
3) An aminoacyl tRNA matches its anticodon to the codon in the A site
4) A peptide bond forms
5) A tRNA translocates from the A to the P site, and an unattached tRNA leaves the ribosome from the E site
Translocation in the process of translation involves
a. the hydrolysis of a GTP molecule
b. the movement of the tRNA in the A site to the P site
c. the movement of the mRNA strand one triplet length
d. the release of the unattached tRNA from the E site
e. all of the above
Which of the following type of molecule catalyzes the formation of a peptide bond?
b. rRNA
Which of the following is not true of an anticodon?
a. it consists of 3 nucleotides
b. It lines up in the 5'->3' direction along the 5'->3' mRNA strand
c. It extends from one loop of a tRNA molecule
d. It may pair with more than one codon
e. Its base uracil base-pairs with adenine
b. It lines up in the 5'->3' direction along the 5'->3' mRNA strand
Changes in a polypeptide following translation may involve:
a. the addition of sugars or lipids to certain amino acids
Several proteins may be produced at the same time from a single mRNA by
a. the action of several ribosomes in a string, called a polyribosome
A signal peptide
d. would be the first 20 or so amino acids of a protein destined for a membrane location or secretion from the cell
A base deletion early in the coding sequence of a gene may result in
a. a nonsense mutation
b. a frameshift mutation
c. multiple missense mutations
d. a nonfunctional protein
e. all of the above
Base pair substitutions may have little effect on the resulting protein for all of the following reasons, except:
a. the redundancy of the code may result in silent mutation
b. the substitution must involve three nucleotide pairs, otherwise the reading frame is altered
c. the missense mutation may not occur in a critical part of the protein
d. the new amino acid ma have similar properties to the replaced one
e. the wobble phenomenon could result in no change in translation
b. the substitution must involve three nucleotide pairs, otherwise the reading frame is altered