17 October 2012

BIO 106 Cell Biology Unit 2 Test


This is a conglomeration of Three tests that culminate into one UNIT 2 exam.
Answers posted here

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BIO 106                                 Print Name:   (Last name first)                                                                 

EXAM II, 3/11/2011                       


MULTIPLE CHOICE.  Choose the one alternative that best completes the statement or answers the question.

1) Which type of interaction stabilizes the alpha (α) helix and the beta (β) pleated sheet structures of proteins?

A) peptide bonds                              B) hydrogen bonds               C) hydrophobic interactions

D) nonpolar covalent bonds                        E) ionic bonds

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2) A strong covalent bond between amino acids that functions in maintaining a polypeptide's specific three-dimensional shape is a (an)

A) hydrophobic interaction.                       B) hydrogen bond.                C) disulfide bond.

D) ionic bond.                                    E) van der Waals interaction.
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3) Which of the following descriptions best fits the class of molecules known as nucleotides?

A) a nitrogenous base and a phosphate group     B) a nitrogenous base and a pentose sugar

C) a pentose sugar and a purine or pyrimidine    D) a phosphate group and an adenine or uracil

E) a nitrogenous base, a phosphate group, and a pentose sugar
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4) The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA

A) contains one less oxygen atom.           

B) is a six-carbon sugar and the sugar in RNA is a five-carbon sugar.

C) has a six-membered ring of carbon and nitrogen atoms.

D) can form a double-stranded molecule.

E) can attach to a phosphate.
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5) In his transformation experiments, what did Griffith observe? (pathogenic = deadly)

A) Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic.

B) Mutant mice were resistant to bacterial infections.

C) Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains.

D) Mice infected with a pathogenic strain of bacteria can spread the infection to other mice.

E) Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.
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6) What is meant by the description "antiparallel" regarding the strands that make up DNA?

A) One strand is positively charged and the other is negatively charged.

B) The twisting nature of DNA creates nonparallel strands.

C) The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.

D) Base pairings create unequal spacing between the two DNA strands.

E) One strand contains only purines and the other contains only pyrimidines.
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7) For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA, rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger signal than labeling the phosphates. Why won't this experiment work?

A) Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.

B) Although there are more nitrogens in a nucleotide, labeled phosphates actually have 16 extra neutrons; therefore, they are more radioactive.

C) Radioactive nitrogen has a half-life of 100,000 years, and the material would be too dangerous for too long.

D) Avery et al. have already concluded that this experiment showed inconclusive results.

E) There is no radioactive isotope of nitrogen.
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8) The leading and the lagging strands differ in that

A) the leading strand is synthesized at twice the rate of the lagging strand.

B) the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.

C) the lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together.

D) the leading strand is synthesized by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5' end.
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9) The correct sequence of events occurring during transcription is ______.

A) capping, tailing, splicing                         B) splicing, capping, tailing C) elongation, initiation, termination

D) tailing, capping, splicing                         E) initiation, elongation, termination
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10) The DNA of telomeres has been found to be highly conserved throughout the evolution of eukaryotes. What does this most probably reflect?

A) that the critical function of telomeres must be maintained

B) that new evolution of telomeres continues

C) the low frequency of mutations occurring in this DNA

D) that mutations in telomeres are relatively advantageous

E) the inactivity of this DNA
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11) Which of the following best describes the addition of nucleotides to a growing DNA chain?

A) A nucleoside triphosphate is added to the 5' end of the DNA, releasing a molecule of pyrophosphate.

B) A nucleoside triphosphate is added to the 3' end of the DNA, releasing a molecule of pyrophosphate.

C) A nucleoside monophosphate is added to the 5' end of the DNA.

D) A nucleoside diphosphate is added to the 5' end of the DNA, releasing a molecule of phosphate.

E) A nucleoside diphosphate is added to the 3' end of the DNA, releasing a molecule of phosphate.
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12) Which of the following statements describes the eukaryotic chromosome?

A) The number of genes on each chromosome is different in different cell types of a single organism.

B) It is composed of DNA alone.

C) Active transcription occurs on heterochromatin.

D) It consists of a single linear molecule of double-stranded DNA.

E) It is composed of a single closed circular molecule of double-stranded DNA.
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13) The nitrogenous base adenine is found in all members of which group?

A) proteins, triglycerides, and testosterone       B) proteins, carbohydrates, and ATP

C) ATP, RNA, and DNA                                           D) alpha glucose, ATP, and DNA

E) proteins, ATP, and DNA
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14) A particular triplet of bases in the template strand of DNA is 5' AGT 3'. The corresponding codon for the mRNA transcribed is

A) 5' TCA 3'.            B) 3'ACU 5'.                         C) 5' UGA 3'.            D) 3' UCA 5'.           E) 5’ AGU 3’.
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15) What amino acid sequence will be generated, based on the following mRNA codon sequence?

5' AUG-UCU-UCG-UUA-UCC-UUG 3'

A) met-ser-ser-leu-ser-leu              B) met-glu-arg-arg-gln-leu C) met-arg-glu-arg-glu-arg

D) met-leu-phe-arg-glu-glu                         E) met-ser-leu-ser-leu-ser
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16) In which of the following actions does RNA polymerase differ from DNA polymerase?

A) RNA polymerase binds to single-stranded DNA, and DNA polymerase binds to double-stranded DNA.

B) RNA polymerase can initiate RNA synthesis, but DNA polymerase requires a primer to initiate DNA synthesis.

C) RNA polymerase is much more accurate than DNA polymerase.

D) RNA polymerase uses RNA as a template, and DNA polymerase uses a DNA template.

E) RNA polymerase does not need to separate the two strands of DNA in order to synthesize an RNA copy, whereas DNA polymerase must unwind the double helix before it can replicate the DNA.
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17) Which of the following help(s) to stabilize mRNA by inhibiting its degradation?

A) 5' cap and poly (A) tail B) introns       C) spliceosomes         D) RNA polymerase E) TATA box
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18) Each eukaryotic mRNA, even after post-transcriptional modification, includes 5' and 3' UTRs. What are UTRs?

A) the U translation sites that signal the beginning of translation

B) the cap and tail at each end of the mRNA

C) the U attachment sites for the tRNAs

D) the U — A pairs that are found in high frequency at the ends

E) the untranslated regions at either end of the coding sequence
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19) A mutant bacterial cell has a defective aminoacyl synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of a phenylalanine. The consequence of this for the cell will be that

A) the ribosome will skip a codon every time a UUU is encountered.

B) the cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons.

C) proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU.

D) none of the proteins in the cell will contain phenylalanine.

E) None of the above will occur; the cell will recognize the error and destroy the tRNA.
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20) From the following list, which is the first event in translation in eukaryotes?

A) base pairing of activated methionine-tRNA to AUG of the messenger RNA

B) covalent bonding between the first two amino acids

C) the larger ribosomal subunit binds to smaller ribosomal subunits

D) elongation of the polypeptide

E) the small subunit of the ribosome recognizes and attaches to the 5' cap of mRNA
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21) Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?

A) starches   B) glucose                  C) steroids                 D) lipids         E) proteins
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22) Under which of the following conditions would you expect to find a cell with a predominance of free ribosomes?

A) a cell that is enlarging its vacuole                   B) a cell that is secreting proteins

C) a cell that is producing cytoplasmic enzymes             D) a cell that is digesting food particles

E) a cell that is constructing its cell wall or extracellular matrix
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23) In animal cells, hydrolytic enzymes are packaged to prevent general destruction of cellular components. Which of the following organelles functions in this compartmentalization?

A) peroxisome           B) lysosome               C) glyoxysome           D) chloroplast  E) central vacuole
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24) The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and therefore abundant in liver cells?

A) smooth ER                        B) Transport vesicles           C) Golgi apparatus

D) Nuclear envelope                         E) rough ER
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25) Which of the following contains its own DNA and ribosomes?

A) vacuole      B) mitochondrion      C) lysosome               D) peroxisome           E) Golgi apparatus
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26) Which of the following relationships between cell structures and their respective functions is correct?

A) chloroplasts: chief sites of cellular respiration        B) lysosomes: formation of ATP

C) chromosomes: cytoskeleton of the nucleus                D) cell wall: support, protection

E) ribosomes: secretion
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27) Which structure-function pair is mismatched?

A) nucleolus; production of ribosomal subunits B) lysosome; intracellular digestion

C) microtubule; muscle contraction                      D) Golgi; protein trafficking

E) ribosome; protein synthesis
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28) You find a cell of a type you have never seen before. The cell has both a nucleus and a cell wall. Therefore, you conclude that it must be a ______ cell.

A) animal                   B) bacterial               C) liver           D) plant          E) prokaryotic
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29) The endomembrane system includes the ______.

A) Golgi apparatus, mitochondria, lysosomes, and transport vesicles

B) endoplasmic reticulum, Golgi apparatus, lysosomes, and transport vesicles

C) endoplasmic reticulum, mitochondria, lysosomes, and transport vesicles

D) endoplasmic reticulum, Golgi apparatus, lysosomes, and mitochondria

E) endoplasmic reticulum, Golgi apparatus, mitochondria, and transport vesicles
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30) Which of the following is a characteristic of chloroplasts that suggests that they might have evolved from free-living bacteria?

A) A single, highly folded plasma membrane surrounds chloroplasts.

B) Chloroplasts contain pigments.              C) Chloroplasts divide by meiosis.

D) Chloroplasts do not produce ATP.        E) Chloroplasts have their own DNA.
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31) (7 pts.) Draw a diagram indicating the correct direction of the flow of genetic information. Include the following terms: translation, RNA, transcription, protein, reverse transcription, replication, DNA
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32) (3 pts.) What is meant by “pharming”.
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33) (10 pts.) Draw and label a prokaryotic cell correctly showing the location of the following structures: chromosome, ribosome, plasma membrane, cell wall, capsule, flagella, cytoplasm, fimbriae, nucleoid region.   
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34) (10 pts.) Label the following structures at least once: nuclear membrane, DNA, tRNA, mRNA, ribosome, RNA polymerase, Aminoacyl-tRNA synthetase, amino acid, cytoplasm.

Is this a eukaryotic cell or a prokaryotic cell (Circle one)?  Click for Answer page


35) (10 pts.) Correctly label the following organelles and then label their membranes and compartments. (chloroplast, mitochondria, outer membrane (use this term 2X), inner membrane (use this term 2X), thylakoid membrane, thylakoid space, matrix, stroma, intermembrane space)
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MULTIPLE CHOICE.  Choose the one alternative that best completes the statement or answers the question.

(1.5 pts. each)


1) DNA and RNA are polymers composed of ______ monomers.

A) nucleic acid                         B) amino acid                C) nucleotide                D) carbohydrate           E) fatty acid
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2) The backbone of DNA consists of ______.

A) nitrogenous bases    B) a repeating ACTGACTG pattern       C) paired nucleotides

D) a repeating sugar-phosphate-sugar-phosphate pattern

E) a repeating sugar-nucleotide-sugar-nucleotide pattern
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3) The DNA double helix is ______.

A) composed of adenine and thymine    B) a puzzle to geneticists         C) composed of two chromosomes

D) composed of adenine and guanine     E) made up of two polynucleotide strands
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4) RNA contains ______, whereas DNA contains ______.

A) uracil . . . thymine                B) cytosine . . . guanine             C) nucleotides . . . nucleic acids

D) a deoxyribose sugar . . . a ribose sugar                     E) adenine . . . guanine
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5) If adenine makes up 20% of the bases in a DNA double helix, what percent of the bases are guanine?

A) 60%             B) 30%             C) 80%             D) 40%             E) 20%
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6) In a DNA double helix, adenine pairs with ______ and guanine pairs with ______.  

A) guanine . . . adenine                          B) uracil . . . cytosine                C) cytosine . . . uracil   

D) thymine . . . cytosine                        E) cytosine . . . thymine
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7) If one strand of a DNA double helix has the sequence 3'GTCCAT5', what is the sequence of the other strand?

A) 5'ACTTGC3'              B) 3'CAGGUA5'         C) 5'CAGGTA3'            D)3' TGAACG 5'
E)3' CUGGTU 5'
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8) What type of chemical bond joins the bases of complementary DNA strands?

A) covalent       B) hydrogen      C) hydrophilic D) hydrophobic            E) ionic
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9) After replication, ______.

A) each new DNA double helix consists of two old strands

B) each new DNA double helix contains 25% of the old DNA double helix

C) one new DNA double helix consists of two old strands and the other new DNA double helix consists of two new strands

D) each new DNA double helix consists of one old strand and one new strand

E) each new DNA double helix consists of two new strands
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10) During replication, ______ are the enzymes responsible for elongating the new DNA by joining nucleotides together.

A) DNA polymerases     B) DNA helicases          C) DNA gyrases            D) DNA ligases             E) DNases
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11) How many nucleotides make up a codon?

A) two              B) one               C) three                       D) four                         E) five
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12) Transcription is the ______.

A) manufacture of a strand of RNA complementary to a strand of DNA

B) manufacture of a new strand of DNA complementary to an old strand of DNA

C) manufacture of a protein based on information carried by RNA

D) manufacture of two new DNA double helices that are identical to an old DNA double helix

E) modification of a strand of RNA prior to the manufacture of a protein
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13) If a strand of DNA has the sequence AAGCTC, transcription will result in a(n) ______.

A) DNA double helix with the sequence AAGCTC for one strand and TTCGAG for the complimentary strand

B) RNA double helix with the sequence UUCGAG for one strand and AAGCUC for the complimentary strand

C) single RNA strand with the sequence UUCGAG

D) single DNA strand with the sequence TTCGAG

E) single RNA strand with the sequence TTCGAG
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14) Which of the following enzymes is responsible for RNA synthesis?

A) RNA ligase               B) RNase          C) RNA polymerase       D) RNA gyrase E) RNA helicase
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15) The region of DNA where RNA synthesis begins is the ______.

A) promoter     B) initiator       C) start codon              D) processor                 E) terminator
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16) The correct sequence of events occurring during transcription is ______.

A) splicing, capping, tailing       B) elongation, initiation, termination                C) tailing, capping, splicing

D) capping, tailing, splicing       E) initiation, elongation, termination
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17) What protects mRNA from attack by cytoplasmic enzymes in eukaryotic cells?

A) RNA splicing            B) the excision of exons           C) the lack of RNA-digesting enzymes in the cytoplasm

D) the excision of introns         E) a cap and tail
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18) The expressed (coding) regions of eukaryotic genes are called ______.

A) introns         B) exons           C) promoters                D) tails             E) caps
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19)Translation converts the information stored in ______ to  ______.

A) RNA . . . a polypeptide          B) DNA . . . RNA                       C) protein . . . DNA

D) RNA . . . DNA                       E) DNA . . . a polypeptide
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20) The RNA that is translated into a polypeptide is ______ RNA.

A) nucleolar     B) messenger    C) ribosomal                 D) nuclear                    E) transfer
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21) The DNA codon AGT codes for an amino acid carried by a tRNA with the anticodon ______.

A) TCA             B) AGT             C) UCA             D) AGU            E) TCU
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22) Peptide bonds form between ______.

A) amino acids                          B) an mRNA transcript and the small ribosomal subunit

C) a tRNA and the amino acid it is carrying      D) an mRNA codon and a tRNA anticodon

E) the small ribosomal subunit and the large ribosomal subunit
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23) Viruses that infect bacteria are ______.

A) retroviruses             B) enveloped viruses     C) proviruses    D) bacteriophages        E) emerging viruses
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24) The two basic types of cells are ______ and ______.

A) bacterial . . . protist                         B) bacterial . . . animal              C) plant . . . animal

D) prokaryotic . . . eukaryotic               E) nerve . . . muscle
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25) When using a light microscope to view a cell you obtained from scraping under your fingernails, you notice that the cell lacks a nucleus; therefore, you conclude that the cell must be a type of ______ cell.

A) fungal          B) animal          C) prokaryotic              D) plant            E) eukaryotic
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26) The difference between eukaryotic and prokaryotic cells is that eukaryotic cells ______ prokaryotic cells.

A) have a nucleus surrounded by a membrane, which is lacking in

B) lack the complexity seen in

C) have a nucleoid region, which is lacking in

D) have DNA, which is lacking in

E) have a plasma membrane, which is lacking in
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27) Which of the following is a function of the plasma membrane?

A) regulation of the passage of material into and out of the cell

B) control center of the cell

C) intracellular digestion

D) protein synthesis

E) fat synthesis
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28) In eukaryotic cells, what name is given to the region between the nucleus and the plasma membrane?

A) nucleoplasm                         B) gene             C) cytoplasm     D) phospholipid bilayer
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29) In eukaryotic cells, organelles are suspended within the ______.

A) phospholipid bilayer            B) cytosol         C) gene                         D) nucleoplasm
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30) The concept of a membrane as a fluid mosaic reflects the ability of ______.

A) phospholipids and proteins to drift about in the plane of the membrane

B) phospholipids but not proteins to drift about in the plane of the membrane

C) carbohydrates to drift into and out of the membrane structure

D) nucleotides to drift into and out of the membrane structure

E) proteins but not phospholipids to drift about in the plane of the membrane
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31) The nuclear envelope is composed of ______.

A) genes           B) a single lipid bilayer             C) DNA    D) a double lipid bilayer        E) carbohydrates
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32) What name is given to the cellular region that manufactures the components of ribosomes?

A) nucleus        B) chromosome             C) nucleolus      D) endoplasmic reticulum          E) cytoplasm
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33) Which of the following organelles is NOT defined by a membrane?

A) chloroplast B) endoplasmic reticulum          C) ribosome      D) lysosome      E) Golgi apparatus
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34) Where does protein synthesis take place?

A) in the nucleolus                   B) in the nucleus           C) on smooth endoplasmic reticulum

D) in the Golgi apparatus          E) on ribosomes
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35) The endomembrane system includes ______.

A) Golgi apparatus, lysosomes, ribosomes, and the endoplasmic reticulum

B) Golgi apparatus, lysosomes, vacuoles, and the endoplasmic reticulum

C) Golgi apparatus, lysosomes, vacuoles, and ribosomes

D) ribosomes, lysosomes, vacuoles, and the endoplasmic reticulum

E) Golgi apparatus, ribosomes, vacuoles, and the endoplasmic reticulum
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36) A hormone destined for secretion from the cell would be manufactured by ribosomes _____.

A) suspended in the nucleoplasm                      B) attached to the endoplasmic reticulum

C) attached to the plasma membrane                D) suspended in the cytosol

E) attached to the Golgi apparatus
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37) Functions of the smooth endoplasmic reticulum include ______.

A) steroid synthesis, protein synthesis, and drug detoxification

B) lipid synthesis, steroid synthesis, protein synthesis, and drug detoxification

C) lipid synthesis, protein synthesis, and drug detoxification

D) lipid synthesis, steroid synthesis, and drug detoxification

E) lipid synthesis, steroid synthesis, and protein synthesis
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38) Which of the following is a function of the Golgi apparatus?

A) protein synthesis                 B) intracellular digestion          C) protein modification

D) drug detoxification                         E) cellular respiration
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39) Lysosomes are responsible for ______.

A) protein synthesis                 B) lipid synthesis          C) intracellular digestion         

D) photosynthesis                     E) cellular respiration
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40) A bacterial cell's DNA is found in its ______.  

A) nucleoid region        B) ribosomes                 C) nucleus                     D) peroxisome              E) capsule
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41) Consider the figure of the nucleotide.

a. Circle and label the nitrogenous base, ribose sugar and phosphate group in the following figure.

B. Accurately number the carbons on the sugar.

C. Is the nitrogenous base is a pyrimidine or a purine?

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42) Draw a diagram indicating the correct direction of the flow of genetic information. Include the following terms: translation, RNA, transcription, protein, reverse transcription, replication, DNA
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43) Correctly label the following parts of the mRNA molecule shown below.

(Start codon, 5’ cap, Stop codon, poly-A-tail, 3’ UTR, polyadenylation signal, protein –coding segment, 5 ‘ UTR)
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44) Correctly label the following organelles and then label their membranes and compartments. (chloroplast, mitochondria, outer membrane (use this term 2X), inner membrane (use this term 2X), thylakoid membrane, thylakoid space, matrix, stroma, intermembrane space)
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45) Draw a lipid bilayer. Indicate with brackets the regions that are hydrophobic and hydrophilic.
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46) Label the following structures at least once: nuclear membrane, DNA, tRNA, mRNA, ribosome, RNA polymerase, Aminoacyl-tRNA synthetase, amino acid, cytoplasm.
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Is this a eukaryotic cell or a prokaryotic cell (Circle one)? 







MULTIPLE CHOICE.  Choose the one alternative that best completes the statement or answers the question.

1) What is meant by the description "antiparallel" regarding the strands that make up DNA?

A) Base pairings create unequal spacing between the two DNA strands.

B) The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.

C) The twisting nature of DNA creates nonparallel strands.

D) One strand is positively charged and the other is negatively charged.

E) One strand contains only purines and the other contains only pyrimidines.
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2) In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts in their bacteriophage experiments?

A) DNA contains sulfur, whereas protein does not.

B) RNA includes ribose, whereas DNA includes deoxyribose sugars.

C) Proteins contain sulfur, whereas DNA does not.

D) DNA contains nitrogen, whereas protein does not.

E) DNA contains purines, whereas protein includes pyrimidines.
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3) Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?

A) One of the daughter cells, but not the other, would have radioactive DNA.

B) Neither of the two daughter cells would be radioactive.

C) All four bases of the DNA would be radioactive.

D) DNA in both daughter cells would be radioactive.

E) Radioactive thymine would pair with nonradioactive guanine.
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4) Which enzyme catalyzes the elongation of a DNA strand in the 5' 3' direction?

A) DNA polymerase                  B) helicase       C) primase        D) topoisomerase                      E) DNA ligase
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5) The leading and the lagging strands differ in that

A) the leading strand is synthesized by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5' end.

B) the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.

C) the leading strand is synthesized at twice the rate of the lagging strand.

D) the lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together.
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6) A new DNA strand elongates only in the 5' to 3' direction because

A) the polarity of the DNA molecule prevents addition of nucleotides at the 3' end.

B) Okazaki fragments prevent elongation in the 3' to 5' direction.

C) replication must progress toward the replication fork.

D) DNA polymerase begins adding nucleotides at the 5' end of the template.

E) DNA polymerase can only add nucleotides to the free 3' end.
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7) Which of the following help(s) to hold the DNA strands apart while they are being replicated? 

A) exonuclease             B) primase        C) DNA polymerase  D) ligase    E) single-strand binding proteins
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8) What is the function of topoisomerase?

A) relieving strain in the DNA ahead of the replication fork

B) elongating new DNA at a replication fork by adding nucleotides to the existing chain

C) unwinding of the double helix

D) stabilizing single-stranded DNA at the replication fork

E) adding methyl groups to bases of DNA
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9) What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

A) It catalyzes the lengthening of telomeres.              B) It synthesizes RNA nucleotides to make a primer.

C) It unwinds the parental double helix.                       D) It joins Okazaki fragments together.

E) It stabilizes the unwound parental DNA.

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10) In the late 1950s, Meselson and Stahl grew bacteria in a medium containing "heavy" nitrogen (15N) and then transferred them to a medium containing 14N. Which of the results in the figure above would be expected after one round of DNA replication in the presence of 14N?

A) A                 B) B                  C) C                  D) D                 E) E
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11) What kind of chemical bond is found between paired bases of the DNA double helix?

A) ionic            B) covalent       C) sulfhydryl                D) phosphate                E) hydrogen
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12) Which of the following best describes the flow of information in eukaryotic cells?

A) DNA RNA proteins      B) DNA proteins RNA       C) RNA proteins DNA

D) RNA DNA proteins      E) proteins DNA RNA
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13) Which of the following descriptions best fits the class of molecules known as nucleotides?

A) a nitrogenous base, a phosphate group, and a pentose sugar    B) a phosphate group and an adenine or uracil

C) a pentose sugar and a purine or pyrimidine                               D) a nitrogenous base and a pentose sugar

E) a nitrogenous base and a phosphate group
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14) If a DNA sample were composed of 10% thymine, what would be the percentage of guanine?

A) 20               B) 80                C) 10                D) 40                E) impossible to tell from the information given
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15) In the double helix structure of nucleic acids, cytosine hydrogen bonds to

A) thymine.      B) adenine.       C) ribose.                      D) deoxyribose.                        E) guanine.
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16) Which of the following store and transmit hereditary information?

A) proteins                   B) nucleic acids            C)carbohydrates                      D) lipids
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17) Which component is not directly involved in translation?

A)  tRNA          B) ribosomes                 C) GTP              D) mRNA          E) DNA
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18) Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA?

A) 5'-A-G-C-T-3' with 5'-T-C-G-A-3'

B) 5'-purine-pyrimidine-purine-pyrimidine-3' with 3'-purine-pyrimidine-purine-pyrimidine-5'

C) 5'-G-C-G-C-3' with 5'-T-A-T-A-3'

D) 5'-A-T-G-C-3' with 5'-G-C-A-T-3'

E) All of these pairs are correct.
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19) The backbone of DNA consists of ______.

A) a repeating sugar-nucleotide-sugar-nucleotide pattern        B) a repeating ACTGACTG pattern

C) paired nucleotides                D) a repeating sugar-phosphate-sugar-phosphate pattern

E) nitrogenous bases
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20) What is the function of reverse transcriptase in retroviruses?

A) It uses viral RNA as a template for DNA synthesis.

B) It uses viral RNA as a template for making complementary RNA strands.

C) It converts host cell RNA into viral DNA.

D) It translates viral RNA into proteins.

E) It hydrolyzes the host cell's DNA.
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21) The nitrogenous base adenine is found in all members of which group?

A) α glucose, ATP, and DNA                                         B) proteins, ATP, and DNA

C) proteins, triglycerides, and testosterone                  D) ATP, RNA, and DNA

E) proteins, carbohydrates, and ATP
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22) What is a ribozyme?

A) an RNA with enzymatic activity

B) an enzyme that synthesizes RNA primers during DNA replication

C) an enzyme that synthesizes RNA as part of the transcription process

D) an enzyme that catalyzes the association between the large and small ribosomal subunits

E) an enzyme that uses RNA as a substrate
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23) What is the name given to the process in which pre-mRNA is edited into mRNA

A) RNA processing                   B) gene expression                    C) polypeptide formation         

D) transcription                        E) translation
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24) Polypeptides are assembled from

A) hexoses       B) glycerol        C) nucleotides              D) proteins                   E) amino acids
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25) A codon consists of             bases and specifies which                    will be inserted into the polypeptide chain.

A) two…nucleotides                  B) four…fatty acid                               C) three…amino acids  

D) four…amino acids                 E) three…nucleotides
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26) What is the process called that converts the genetic information stored in DNA to an RNA copy?

A) Translocation          B) Replication               C) Translation              D) Transcription
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27) Transcription begins at a promoter. What of the following is the best description of a promoter?

A) Part of the RNA molecule itself      B) A site in DNA that recruits the RNA polymerase

C) A site found on the RNA polymerase            D) A nontranscribed sequence on the DNA

E) A site where many different proteins will bind nonspecifically
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28) The direction of synthesis of an RNA transcript is                       

A) 1’ à 5’          B) 5’ à 3’          C) 2’ à 4’          D) 3’ à 5’         E) 1’ à 3’         
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29) What is the function of RNA polymerase?

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

B) It proceeds slowly along the DNA strand, requiring about a minute to add two nucleotides to the growing mRNA molecule.

C) It adds nucleotides to the 5’ end of the growing mRNA nucleotide

D) It relies on other enzymes to unwind the double helix.

E) All of the above
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30) During RNA processing a(n)                                     is added to the 5’ end of the RNA.

A) 3’ untranslated region          B) modified guanine nucleotide             C) coding segment

D) 5” untranslated region         E) a long strand of adenine nucleotide
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31) The RNA segments joined to one another by spliceosomes are                    .

A) caps             B) snRNPs         C) introns         D) exons           E) tails
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32) Translation occurs in the                          

A) nucleus        B) nucleoplasm              C) mitochondrion          D) cytoplasm                E) lysosome
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33) Translation converts the information stored in ______ to  ______.

A) RNA . . . DNA                       B) DNA . . . RNA                       C) protein . . . DNA      

D) DNA . . . a polypeptide          E) RNA . . . a polypeptide
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34) The RNA that is translated into a polypeptide is ______ RNA.

A) ribosomal                 B) nuclear         C) nucleolar                  D) transfer                   E) messenger
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35) Where is translation accomplished?

A) nucleoli                    B) sER              C) peroxisomes             D) ribosomes                E) lysosomes
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36) Peptide bonds form between ______.

A) an mRNA transcript and the small ribosomal subunit

B) amino acids

C) a tRNA and the amino acid it is carrying

D) the small ribosomal subunit and the large ribosomal subunit

E) an mRNA codon and a tRNA anticodon
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37) A mutation within a gene that will insert a premature stop codon in mRNA would ______.

A) result in an amino acid substitution

B) result in a shortened polypeptide chain

C) result in a polypeptide that is one amino acid shorter than the one produced prior to the mutation

D) alter the reading frame

E) alter the location at which transcription of the next gene begins
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38) How can bacteriophage DNA be spread from cell to cell without causing cell death?

A) via a lysogenic cycle                        B) by altering the way a cell splices its RNA

C) via a lytic cycle                    D) via a Calvin cycle                  E) by altering its DNA
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Please read the following scenario to answer the following question(s).


While working with cultured mouse cells, a researcher unknowingly treated her cells with a mutagen that although rare, causes deletion or insertion of individual bases in DNA. Subsequently, she isolated and cultured a single cell from this group and noticed that the progeny of this cell were not producing a certain protein and this was having an effect on their viability.


39) The mutation would be most harmful to the cells if it resulted in  ______.

A) substitution of a base pair

B) a single nucleotide deletion near the end of the coding sequence

C) a single nucleotide insertion near the start of the coding sequence

D) a single nucleotide in the middle of the intron

E) deletion of a triplet near the middle of the gene                            
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40) All of the following are part of a prokaryotic cell except

A) an endoplasmic reticulum.                B) DNA.            C) ribosomes.    D) a cell wall.    E) a plasma membrane.
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41) If radioactive deoxythymidine triphosphate (dTTP) is added to a culture of rapidly growing bacterial cells, where in the cell would you expect to find the greatest concentration of radioactivity?

A) ribosomes    B) nucleus         C) endoplasmic reticulum          D) cytoplasm                E) nucleoid region
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42) Which organelle or structure is absent in bacterial cells?

A) microtubules            B) mitochondria            C) peroxisomes             D) Golgi vesicles   

E) all of the above would be absent   
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43) Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?

A) nucleic acids            B) cellulose                   C) glycogen                   D) proteins                   E) lipids
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44) A cell with a predominance of free ribosomes is most likely

A) digesting large food particles.                     B) producing primarily proteins for secretion.

C) producing primarily cytoplasmic proteins.     D) constructing an extensive cell wall or extracellular matrix.

E) enlarging its vacuole.
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45) Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, and steroids?

A) contractile vacuole                          B) lysosome                                          C) ribosome     

D) mitochondrion                                  E) smooth endoplasmic reticulum
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46) Hydrolytic enzymes must be segregated and packaged to prevent general destruction of cellular components. Which of the following organelles contains these hydrolytic enzymes in animal cells?

A) chloroplast B) lysosome      C) glyoxysome D) central vacuole        E) peroxisome
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47) Which structure is the site of the synthesis of proteins that may be exported from the cell?

A) lysosomes    B) free cytoplasmic ribosomes     C) plasmodesmata     D) Golgi vesicles         E) rough ER
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48) The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and therefore abundant in liver cells?

A) Golgi apparatus        B) rough ER      C) transport vesicles     D) nuclear envelope      E) smooth ER
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49) Which organelle is the primary site of ATP synthesis in eukaryotic cells?

A) lysosome      B) peroxisome   C) mitochondrion          D) Golgi apparatus        E) vacuole
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50) Which plant cell organelle contains its own DNA and ribosomes?

A) glyoxysome B) peroxisome   C) vacuole                     D) mitochondrion          E) Golgi apparatus
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51) Thylakoids, DNA, and ribosomes are all components found in

A) mitochondria.          B) nuclei.                      C) lysosomes.                D) chloroplasts.            E) vacuoles.
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52) In a plant cell, DNA may be found

A) in the nucleus, mitochondria, and chloroplasts.                    B) only in the nucleus and mitochondria.

C) only in the nucleus.                           D) in the nucleus, mitochondria, chloroplasts, and peroxisomes.

E) only in the nucleus and chloroplasts.
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53) A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from

A) an animal, but not a plant.                            B) any multicellular organism, like a plant or an animal.

C) nearly any eukaryotic organism.                    D) a bacterium.

E) any kind of organism.
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54) Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?

A) ribosomes                                        B) cytoskeletal structures        C) membrane proteins

D) cellulose fibers in the cell wall        E) sites of energy production in cellular respiration
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55) Which structure is not part of the endomembrane system?

A) plasma membrane     B) nuclear envelope       C) Golgi apparatus        D) ER                E) chloroplast
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56) Which structure is common to plant and animal cells?

A) mitochondrion         B) central vacuole         C) wall made of cellulose          D) chloroplast E) centriole
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57) Which of the following is present in a prokaryotic cell?

A) ribosome      B) ER                C) chloroplast               D) mitochondrion          E) nuclear envelope
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58) What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?

A) ER lysosomes vesicles that fuse with plasma membrane             B) ER Golgi nucleus

C) Golgi ER lysosome          D) ER Golgi vesicles that fuse with plasma membrane

E) nucleus ER Golgi
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59) Similar to the nucleus, chloroplasts and mitochondria are ______.

A) manufactured by the nucleolus        B) green           C) able to synthesize lipids

D) surrounded by two membranes         E) not bounded by membrane
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60) What name is given to the cellular region that manufactures the components of ribosomes?

A) nucleus        B) chromosome             C) nucleolus      D) endoplasmic reticulum          E) cytoplasm
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61) (5 pts.) Consider the figure of the nucleotide.

a. Circle and label the nitrogenous base, ribose sugar and phosphate group in the following figure.

B. Accurately number the carbons on the sugar.

C. Is the nitrogenous base is a pyrimidine or a purine?
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62) (10 pts.) Place the following phrases in the appropriate locations in the diagram of the DNA replication fork to describe the name or function of each structure.
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A.    Relaxes supercoiled DNA         

B.     Coats single-stranded DNA

C.     Synthesizes RNA primers on leading and lagging strand

D.    Synthesizes DNA 5’ to 3” on the leading and lagging strands

E.     Breaks hydrogen bonds, unwinding DNA double helix

F.     Catalyzes phosphodiester bond formation, joining DNA fragments

G.    Replaces RNA primers with DNA nucleotides

H.    Leading strand

I.     Lagging strand

J.    Draw an arrow indicating the overall direction in which the replication fork is moving

63) (10 pts.) Label the following structures at least once: nuclear membrane, DNA, tRNA, mRNA, ribosome,

RNA polymerase, Aminoacyl-tRNA synthetase, amino acid, cytoplasm, nuclear pore complex.
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64) Is this a eukaryotic cell or a prokaryotic cell?  Briefly explain

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65) Label and give a function for each of the indicated structures in the eukaryotic animal cell.  There are multiple possible correct answers for the function of each structure; you just need to provide one.

A.                                                                                                                                                        

B.                                                                                                                                                        

C.                                                                                                                                                        

D.                                                                                                                                                        

E.                                                                                                                                                        

F.                                                                                                                                                        

G.                                                                                                                                                        

H.                                                                                                                                                        

I.                                                                                                                                                         

J.                                                                                                                                                        

K.                                                                                                                                                        

L.                                                                                                                                                         

M.                                                                                                                                                       

N.                                                                                                                                                        

O.                                                                                                                                                        




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