Biology Exam 3 Practice Test 40 Questions with Verified Answers
In the 1940s and 1950s scientists were performing experiments to discover what
... [Show More] molecule was
the inheritance material. The basis of that work was Griffith's transformation experiments with
the rough and smooth strains of Pneumococcus. Rough bacterial strains were transformed by
A. treatment with radiation.
B. infection with a virus.
C. uptake of protein from the environment.
D. uptake of DNA from the environment. - CORRECT ANSWER D. uptake of DNA from the environment.
There are 61 mRNA codons that specify an amino acid, but only 45 tRNAs. This is best explained by the fact that
A. some tRNAs have anticodons that recognize four or more different codons.
B. the rules for base pairing between the third base of a codon and tRNA are flexible.
C. many codons are never used, so the tRNAs that recognize them are dispensable.
D. the DNA codes for all 61 tRNAs but some are then destroyed - CORRECT ANSWER B. the rules for base pairing between the third base of a codon and tRNA are flexible.
Which of the following statements is False?
A. mutations are the source of new alleles.
B. without mutations, there would be no evolution.
C. mutations happen when there is a need for a new trait in a population.
D. radiation and chemical damage can cause mutations. - CORRECT ANSWER C. mutations happen when there is a need for a new trait in a population.
Which of the following statements about the DNA in one of your brain cells is true?
A. it is the same as the DNA in one of your heart cells.
B. many genes are grouped into operon-like clusters.
C. each gene lies immediately adjacent to an enhancer.
D. the majority of genes are likely to be translated. - CORRECT ANSWER A. it is the same as the DNA in one of your heart cells.
When a normal cell transforms into a cancer cell, which of the following is true about the
cancer cell?
A. a growth factor must be present for cell division to occur.
B. the cell no longer exhibits anchorage dependence.
C. the cells stop dividing after a single layer of cells is formed.
D. the cell continues to respond to internal and external signals. - CORRECT ANSWER B. the cell no longer exhibits anchorage dependence.
The DNA polymerases of all cellular organisms have proofreading capability. This capability tends to reduce the introduction of:
A. extra genes by gene duplication events.
B. chromosomal translocation.
C. genetic variation by mutations.
D. proofreading capability into prokaryotes - CORRECT ANSWER C. genetic variation by mutations.
Which of the following is true of RNA processing?
A. exons are removed before the mRNA is translated.
B. a 5' cap structure is added to the mRNA during translation.
C. the RNA transcript that leaves the nucleus may be much shorter than the original transcript.
D. introns are linked together to form the mature mRNA. - CORRECT ANSWER C. the RNA transcript that leaves the nucleus may be much shorter than the original transcript
DNA replication is semiconservative. This was shown through experiments by Meselson and
Stahl. First, they grew bacterial cells in medium that was 15 N-labeled (heavy) isotope. The
bacteria were then transferred to a medium with only 14 N-labeled (light) isotope. After the two
generations (two rounds of DNA replication), the DNA was observed via centrifugation and
found as
A. one band that was all heavy density.
B. one band that was all light density.
C. three bands; one heavy density, one hybrid density and one light density.
D. two bands, one hybrid density and one light density. - CORRECT ANSWER D. two bands, one hybrid density and one light density
A covalent bond is the result of
A. two atoms that are sharing a pair of valence electrons.
B. bonding between two oppositely charged ions.
C. bonding between a sodium atom and a chlorine atom.
D. many weak ionic attractions. - CORRECT ANSWER A. two atoms that are sharing a pair of valence electrons.
DNA and RNA are similar in that both
A. are double-stranded and form a double helix.
B. are found exclusively in the nucleus of eukaryotic cells.
C. contain the nitrogenous bases adenine, guanine, cytosine, and thymine.
D. have a sugar-phosphate "backbone" in their structure - CORRECT ANSWER D. have a sugar-phosphate "backbone" in their structure
DNA polymerase is the enzyme that catalyzes the synthesis of a new complementary strand
of DNA using an existing template strand of DNA. If the template strand sequence is
3' - ATTGCTGC - 5', the newly synthesized strand sequence would be
A. 5' - GCAGCAAT - 3'
B. 5' - TAACGACG - 3'
C. 5' - CGTCGTTA - 3'
D. 5' - ATTGCTGC - 3' - CORRECT ANSWER B. 5' - TAACGACG - 3'
A new DNA strand only elongates in the 5' to 3' direction because
A. DNA polymerase begins adding nucleotides at the 5 end.
B. Okazaki fragments prevent elongation in the 3' to 5' direction.
C. DNA polymerase adds nucleotides only to the free 3' end.
D. the polarity of the DNA molecule prevents the addition of nucleotides at the 3' end - CORRECT ANSWER C. DNA polymerase adds nucleotides only to the free 3' end.
A hypothesis
A. can be proven by inductive reasoning.
B. can be proven by deductive reasoning.
C. Is formulated in the scientific process after a question is asked.
D. Is formulated in the scientific process before observations are made - CORRECT ANSWER C. Is formulated in the scientific process after a question is asked.
Cellular membranes consist of a variety of components. Which component is necessary to
facilitate transport of ions and polar molecules across the membrane.
A. phospholipid.
B. cholesterol.
C. protein.
D. carbohydrate - CORRECT ANSWER C. protein.
The process of cellular respiration, which converts simple sugars such as glucose into CO 2
and water, is an example of
A. a catabolic pathway.
B. an energy releasing pathway.
C. a pathway in which the entropy of the system increases.
D. all the answer choices are correct. - CORRECT ANSWER D. all the answer choices are correct.
Which statement about the daughter cells resulting from mitosis is correct?
A. They are genetically identical to one another and to the parent cell.
B. They differ genetically from one another and from the parent cell.
C. They are genetically identical to one another but are different from the parent
cell.
D. Only one of the two daughter cells is genetically identical to the parent cell. - CORRECT ANSWER A. They are genetically identical to one another and to the parent cell.
Which of the following is used to make complementary DNA (cDNA) from RNA?
A. restriction enzymes.
B. DNA ligase.
C. reverse transcriptase.
D. primase. - CORRECT ANSWER C. reverse transcriptase.
in the absence of tryptophan the trp Operon is turned ______. In the presence of tryptophan
it is turned ______. This regulation is due to the trp _____________.
A. On; Off; Repressor protein.
B. Off; On; Inducer protein.
C. Off; On; Activator protein.
D. On; Off; Operator protein. - CORRECT ANSWER A. On; Off; Repressor protein.
A chromosome breakage can result in the alteration of the chromosome's structure. In some
cases, all of the same genes are present, but they no longer function properly because they are
in an alternate order. This type of alteration to the chromosome structure is called
A. multi-duplication.
B. inversion.
C. translocation.
D. reverse-deletion - CORRECT ANSWER B. inversion.
The role of restriction enzymes in DNA technology is to
A. produce cDNA from mRNA.
B. produce a cut at a specific sequence on DNA.
C. reseal sticky ends after base paring of complementary nucleotides.
D. denature DNA into single strands that can hybridize with complementary sequences. - CORRECT ANSWER B. produce a cut at a specific sequence on DNA.
What is the most logical sequence of steps for splicing foreign DNA (non-plasmid) into a
plasmid and inserting the plasmid into a bacterium?
I. transform bacteria with recombinant DNA molecule.
II. cut the plasmid DNA and non-plasmid DNA using the same restriction enzyme.
III. obtain plasmid DNA and non-plasmid DNA.
IV. allow plasmid DNA to base-pair with non-plasmid DNA fragments at their complementary
sticky ends.
V. use ligase to seal plasmid DNA to non-plasmid DNA
A. I, II, IV, III, V
B. II, III, V, IV, I
C. III, II, IV, V, I
D. III, IV, V, I, II - CORRECT ANSWER C. III, II, IV, V, I
The polymerase chain reaction is important because it allows us to
A. make DNA from RNA transcripts.
B. make many copies of a specific polypeptide.
C. insert eukaryotic genes into a prokaryotic cell.
D. make many copies of a specific DNA sequence. - CORRECT ANSWER D. make many copies of a specific DNA sequence.
Transfer RNA (tRNA)
A. is found only within the nucleus of eukaryotic cells.
B. has a specific amino acid attached to it.
C. has a double-stranded helix structure similar to that of DNA.
D. is associated exclusively with the process of transcription. - CORRECT ANSWER B. has a specific amino acid attached to it.
Barring mutation, a diploid cell that undergoes meiosis will normally produce ______
daughter cells that are genetically ______.
A. two haploid; different.
B. two diploid; identical.
C. four haploid; different.
D. four haploid; identical. - CORRECT ANSWER C. four haploid; different.
Ribosomes
A. are very rare in eukaryotes.
B. are used directly to detoxify alcohol and other drug compounds.
C. are the organelles that synthesize proteins.
D. all the answer choices are correct. - CORRECT ANSWER C. are the organelles that synthesize proteins.
RNA Processing involves addition of a 5' Cap, a poly-A tail and _______________.
A. occurs in the cytoplasm.
B. requires a termination signal.
C. the removal of introns.
D. the removal of exons. - CORRECT ANSWER C. the removal of introns.
Which of the following statements is FALSE?
A. glycolysis can occur with or without oxygen.
B. glycolysis occurs in the mitochondria.
C. glycolysis requires an input of energy in the form of ATP.
D. glycolysis produces 2 ATP, 2 NADH, and 2 pyruvate - CORRECT ANSWER B. glycolysis occurs in the mitochondria.
Proto-oncogenes are
A. abnormal genes responsible for cell division.
B. a type of tumor suppressor gene.
C. genes that cause cancer.
D. genes responsible for normal cell division - CORRECT ANSWER D. genes responsible for normal cell division
The "central dogma" of biology states that
A. protein is translated to RNA, and RNA is transcribed to DNA.
B. RNA is transcribed to DNA, and DNA is translated to protein.
C. DNA is translated to RNA, and RNA is transcribed to protein.
D. DNA is transcribed to RNA, and RNA is translated to protein. - CORRECT ANSWER D. DNA is transcribed to RNA, and RNA is translated to protein.
Photosynthesis is the process by which
A. the potential energy of simple sugars is transferred to ATP molecules.
B. simple sugars are gradually broken down to form lactic acid or alcohol.
C. two simple sugar molecules combine to form maltose and water.
D. light energy is converted into the chemical energy of simple sugars. - CORRECT ANSWER D. light energy is converted into the chemical energy of simple sugars.
Transcription of the structural genes in an inducible operon
A. is constitutive.
B. starts when the pathway's substrate is present.
C. starts when the pathway's product is present.
D. stops when the pathway's product is present. - CORRECT ANSWER B. starts when the pathway's substrate is present.
Which of the following best describes an oncogene?
A. a gene that regulates cell division.
B. a gene that causes uncontrollable cell divisions.
C. a gene that stimulates apoptosis in cells.
D. a gene that no longer makes a viable protein - CORRECT ANSWER B. a gene that causes uncontrollable cell divisions.
DNA (Genetic) profiling can be used to identify an assailant from small amounts of blood,
semen, or tissue left at the scene of a crime. Which of the following techniques is NOT
typically involved in this analysis?
A. restriction fragment length polymorphism (RFLP) analysis.
B. polymerase chain reaction (PCR).
C. gel electrophoresis.
D. expression of recombinant proteins. - CORRECT ANSWER D. expression of recombinant proteins.
The CRISPR-Cas9 system can be used to:
A. disable ("knock out") a normal gene.
B. amplify a specific region of the genome.
C. repair a gene that has acquired a mutation.
D. both "A" and "C". - CORRECT ANSWER D. both "A" and "C".
The lactose operon is likely to be transcribed when
A. the cyclic AMP and lactose levels are both high within the cell.
B. there is more glucose in the cell than lactose.
C. the cyclic AMP levels are low.
D. there is glucose but no lactose in the cell. - CORRECT ANSWER A. the cyclic AMP and lactose levels are both high within the cell.
Which is an INCORRECT statement about STRs (Short tandem repeats)?
A. They are tandemly repeated units of 5-10 amino acid sequences.
B. The number of repeats is polymorphic from person to person.
C. Two alleles of an STR may differ in an individual.
D. They occur in specific regions of the genome. - CORRECT ANSWER A. They are tandemly repeated units of 5-10 amino acid sequences.
During transcription, the DNA coding strand (non-template strand) sequence is
5' - ATGCATGC - 3'. What is corresponding mRNA sequence?
A. 3' - UACGUACG - 5'
B. 5' - UACGUACG - 3'
C. 3' - GCAUGCAU - 5'
D. 5' - AUGCAUGC - 3 - CORRECT ANSWER D. 5' - AUGCAUGC - 3
n eukaryotes, what is active transcription generally associated with?
A. heterochromatin.
B. very tightly packed DNA.
C. euchromatin.
D. highly methylated DNA - CORRECT ANSWER C. euchromatin.
During the Seeds of Dissension Case Study, you analyzed the results of a PCR. Which of the
following best describes the complete sequence of steps occurring during every cycle of a
PCR performed in a thermal cycler?
1. the primers hybridize to the target DNA.
2. the mixture is heated to a high temperature to denature the double stranded target DNA.
3. fresh RNA polymerase is added.
4. DNA polymerase extends the primers to make a copy of the target DNA.
A. 2, 1, 4.
B. 1, 2, 4.
C. 2, 3, 4.
D. 3, 4, 2. - CORRECT ANSWER A. 2, 1, 4.
A mutation in what sequence of the DNA could influence the binding of RNA polymerase to
the DNA.
A. operon.
B. intron.
C. promoter.
D. repressor. - CORRECT ANSWER C. promoter. [Show Less]