Bio Final

Front 1

The size of a molecule is on the order of __________, and the size of an average cell is
on the order of ____________.
A. nanometer (nm), micrometer (μm)
B. nanometer (nm), millimeter (mm)
C. micrometer (μm), millimeter (mm)
D. picometer (pm), millimeter (mm)
E. micrometer (μm), nanometer (nm)

Back 1

A

Front 2

Which is correct?
A. 1 m=1 x 103 nm.
B. 1 μm=1 x 10-6 m
C. 1 x 10-3 nm=1 μm
D. 100 mm= 1 m
E. A,B,&C

Back 2

B

Front 3

Fat cells, skin cells, bone cells, and nerve cells are different because each cell type contains unique DNA.
A. True
B. False

Back 3

B

Front 4

Which is the correct flow of genetic information in the cell?
A. DNA to RNA to protein (transcription followed by translation).
B. DNA to RNA to protein (translation followed by transcription).
C. RNA to DNA to protein (transcription followed by transcription II).
D. DNA to RNA to protein (translation followed by translation II).
E. None of the above.

Back 4

A

Front 5

Proteins are built from
A. mitochondria
B. microtubules
C. amino acids
D. nucleotides
E. none of the above

Back 5

C

Front 6

The cytoskeleton is static.
A. True
B. False

Back 6

B

Front 7

How are confocal fluorescence microscopes and conventional fluorescence microscopes different?
A. A confocal fluorescence microscope generates optical sections, eliminating out of focus light with a pinhole aperture.
B. A confocal fluorescence microscope has an emission filter that only passes wavelengths emitted by the fluorophore and blocks all other wavelengths.
C. A confocal fluorescence microscope does not use a laser beam.
D. A confocal fluorescence microscope does not generate optical sections.
E. A confocal fluorescence

Back 7

A

Front 8

How are fluorescent microscopes different from electron microscopes?
A. Fluorescent microscopes rely on fluorescent dyes or antibodies to stain cells.
B. Fluorescent microscopes require that the samples be very thin.
C. Fluorescent microscopes are the same as electron microscopes.
D. Fluorescent microscopes use magnetic coils to focus the light beams.
E. Fluorescent microscopes require that samples be stained with electron-dense heavy-
metals.

Back 8

A

Front 9

What is the advantage of electron microscopes?
A. They allow resolution on the order of nm.
B. Sample preparation is easy.
C. Cells do not need to be fixed.
D. Cells must be stained with a fluorescent dye.
E. Cells can be imaged live.

Back 9

A

Front 10

Fluorescent dyes absorb light at one wavelength and emit at another, shorter wavelength.
A. True
B. False

Back 10

B

Front 11

Tissues are often chemically fixed and cut into thin slices, or sections, for certain
types of microscopy. This is done because:
A. Most tissues are not small enough or transparent enough.
B. Most tissues require fixing for live cell imaging.
C. Fluorescent dyes require fixation for microscopy.
D. A and C.
E. All of the above.

Back 11

A

Front 12

Which of the following are examples of the cytoskeleton?
A. actin filaments, microtubules, and mitochondria
B. actin filaments, microtubules, and ribosomes
C. microtubules, mitochondria, and ribosomes
D. actin filaments, microtubules, and intermediate filaments
E. microtubules, intermediate filaments, and the endoplasmic reticulum

Back 12

D

Front 13

What role is NOT performed by the cytoskeleton?
A. Pulling duplicated chromosomes to opposite poles in dividing cells.
B. Transporting organelles and molecules from one place to another in the cytoplasm.
C. Generating chemical energy.<-- I’m not sure.
D. Controlling cell shape and cell movement.
E. All of the above are performed by the cytoskeleton.

Back 13

C

Front 14

Which yeast is popular as a minimal model eukaryote?
A. Escherichia cerevisiae
B. Saccharomyces cerevisiae
C. Escherichia coli
D. Drosophila
E. Arabidopsis cerevisiae

Back 14

B

Front 15

What is Drosophila?
A. A model prokaryotic cell.
B. A model yeast cell.
C. A model animal cell.
D. A model human cell.
E. A model plant cell.

Back 15

C

Front 16

Which model organism has a genome most similar to humans?
A. Escherichia cerevisiae
B. Saccharomyces cerevisiae
C. Escherichia coli
D. Drosophila
E. Arabidopsis cerevisiae

Back 16

C

Front 17

Cells in a multicellular organism contain (nearly) identical copies of DNA, but turn on
different sets of genes according to their developmental history and signals from outside
the cell.
A. True
B. False

Back 17

A

Front 18

What is the advantage of studying zebrafish?
A. These model procaryotes have the same number of chromosomes as human cells.
B. These model procaryotes have similar nuclear membranes as human cells.
C. These model procaryotes are transparent for the first 2 weeks of life, making them
ideal to make observations during development.
D. These model vertebrates are transparent for the first 2 weeks of life, making them ideal to make observations during development.
E. These model yeast are transparent for the first 2 weeks of life, making them ideal to make observations during development.

Back 18

D

Front 19

When are genes and gene products considered homologous?
A. If the genes from different organisms have similar DNA and thus likely descended from a common ancestral gene.
B. If the genes from different organisms have similar DNA and thus likely descended from Saccharomyces cerevisiae.
C. If the genes from different organisms have similar DNA and thus likely descended from Drosophila.
D. B&A
E. None of the above.

Back 19

A

Front 20

Bacteria can duplicate approximately every τ minutes. Assuming unabated growth with a
doubling time of exactly τ minutes and 50 bacteria at time t=0, which equation correctly
models the number of bacteria as a function of time (t) in minutes?
A. τ * 50 ^ (t / τ)
B. τ * 50 ^ (t)
C. 50 * 2 ^ (t *τ)
D. 50 * 2 ^ (t)
E. 50 * 2 ^ (t / τ)

Back 20

E

Front 21

Water exchanges what molecules to form hydronium ions and hydroxyl ions?
A. Oxygen
B. OH-
C. H-
D. H+
E. H3O+

Back 21

D

Front 22

Compound X has a molecular weight of 40 g/mol and we want to make 250mL of a 500mM solution. Neglecting volume displacement of X, what mass of X should we add to 250ml of water?
A. 2.5 milligrams
B. 5.0 milligrams
C. 2.5 grams
D. 5.0 grams
E. Not enough information to answer the question

Back 22

D

Front 23

Which list contains the four main families of small organic molecules in the cell?
A. Nucleotides, proteins, fatty acids, sugars
B. Nucleotides, proteins, lipids, sugars
C. Nucleotides, proteins, nucleic acids, sugars
D. Nucleotides, amino acids, fatty acids, sugars
E. Nucleic acids, amino acids, fatty acids, sugars

Back 23

D

Front 24

Which type of reaction occurs when two monosaccharides form a disaccharide?
A. Hydrolysis
B. Pericyclic
C. Condensation
D. Acid-Base
E. None of the above

Back 24

C

Front 25

Bond length is proportional to bond strength.
A. True
B. False

Back 25

B

Front 26

Which of the following lists different bond types in order of increasing bond strength?
(Weakest) (Strongest)
A. Covalent Ionic Hydrogen  van der Waals
B. Hydrogen  van der Waals  Ionic  Covalent
C. Ionic  Hydrogen  van der Waals  Covalent D. van der Waals  Hydrogen  Ionic  Covalent
E. None of the above

Back 26

D

Front 27

Which of the following is true?
A. Amino acids are grouped according to carboxyl group.
B. Amino acid side chains are either: acidic, basic, uncharged polar, or nonpolar.
C. Amino acids are grouped according to their amino group.
D. A&B.
E. B&C.

Back 27

B

Front 28

What is the difference between unsaturated fatty acids and saturated fatty acids?
A. The unsaturated fatty acids lack double bonds between C and H.
B. The saturated fatty acids lack double bonds between C and H.
C. The saturated fatty acids lack double bonds between carbon atoms.
D. The unsaturated fatty acids are responsible for high cholesterol in the blood.
E. The unsaturated fatty acids have kinked hydrocarbon tails because none of the carbons contain double bonds.

Back 28

C

Front 29

Amphipathic molecules contain regions that are:
A. Hydrophilic and hydrophobic
B. Hydrophilic and acidic
C. Hydrophilic and basic
D. Hydrophobic and acidic
E. Acidic and basic

Back 29

A

Front 30

Condensation of ATP to ADP provides energy to the cell to drive many cellular reactions.
A. True
B. False

Back 30

B

Front 31

_____ are to polysaccharides as amino acids are to _______.
A. Proteins; fatty acids
B. Proteins; sugars
C. Fatty acids; proteins
D. Sugars; proteins
E. Sugars; nucleic acids

Back 31

D

Front 32

RNA molecules and proteins must fold properly into 2-D shapes to maintain biological activity.
A. True
B. False

Back 32

B

Front 33

The second law of thermodynamics states that:
A. In any isolated system, entropy always increases.
B. In any isolated system, entropy always decreases.
C. In any isolated system, entropy is periodic.
D. In any isolated system, entropy is chaotic.
E. In any isolated system, entropy is unpredictable.

Back 33

A

Front 34

How do enzymes help drive reactions?
A. Enzymes change the activation energy from positive to negative.
B. Enzymes lower the activation energy.
C. Enzymes raise the activation energy.
D. Enzymes change the activation energy from negative to positive.
E. None of the above.

Back 34

B

Front 35

Energetically favorable reactions
A. Always include enzymes as catalysts.
B. Have a positive ΔG.
C. Do not obey the first law of thermodynamics.
D. Cannot occur spontaneously.
E. None of the above.

Back 35

E

Front 36

In a reaction where XY, when [X]=[Y]
A. The reaction is always at equilibrium.
B. ΔG=ΔG°
C. The rates of forward and reverse reactions are always equal.
D. All of the above.
E. None of the above.

Back 36

B

Front 37

In the reaction A+B AB, the equilibrium constant K is large if
A. kon>>koff
B. [A][B]<<[AB]
C. kon<<koff
D. A&B
E. B&C

Back 37

D

Front 38

Suppose for a simple reaction YX that ΔG °= 15 kcal/mol and [Y] = 1 mol and [X] = e10 mol. What is the approximate free-energy change, ΔG, for the reaction?
(Hint: ΔG=ΔG° + 0.6*ln(K) )
A. 16 kcal/mol
B. 11 kcal/mol
C. 21 kcal/mol
D. 5 kcal/mol
E. 1.1 kcal/mol

Back 38

C

Front 39

Which of the following is an important carrier of electrons?
A. ATP
B. NADPH
C. GTP
D. ADP
E. DNA

Back 39

B

Front 40

ATP synthesis involves ______ and is energetically _______.
A. hydrolysis; favorable
B. phosphorylation; favorable
C. hydrolysis; unfavorable
D. phosphorylation; unfavorable
E. None of the above

Back 40

D

Front 41

For ATP hydrolysis at standard conditions, ΔG° = -7 kcal/mol, however ATP hydrolysis within a cell yields between 11 and 13 kcal/mol of usable energy (i.e. ΔG ≈ -12 kcal/mol), this value takes into account the standard free energy and also:
A. The concentration of ATP in a cell
B. The concentration of ADP in a cell
C. The concentration of Pi in a cell
D. A and B
E. All of the above

Back 41

E

Front 42

In a reaction A+BAB, which of the following is true?
A. The disassociation rate=koff[AB].
B. The association rate=kon[A][B].
C. The equilibrium constant=K= koff/kon
D. A&B
E. A,B,&C

Back 42

D

Front 43

What is the most widely used activated carrier molecule?
A. ATP
B. NADPH
C. GTP
D. ADP
E. DNA

Back 43

A

Front 44

Condensation reactions are all energetically favorable.
A. True
B. False

Back 44

B

Front 45

Polysaccharides, nucleic acids, and proteins are all macromolecules that require the energy harnessed from ATP hydrolysis to assemble.
A. True
B. False

Back 45

B

Front 46

Amino acids with _______side chains reside on the ______ of a properly folded protein in aqueous solution.
A. nonpolar; outside
B. nonpolar; inside
C. polar; inside
D. polar; outside
E. acidic; outside
F. acidic; inside

Back 46

B or D

Front 47

Molecular chaperones are proteins that bind to partly folded amino acid chains and help them fold to a conformation that minimizes the _______.
A. Entropy
B. Enthalpy
C. Gibbs free energy
D. Overall charge
E. All of the above

Back 47

C

Front 48

Protein aggregation is responsible for a number of diseases such as
A. Alzheimer’s disease
B. Huntington’s disease
C. Prion diseases
D. A&C
E. All of the above

Back 48

E

Front 49

All of the information for a protein’s conformation resides in its _________.
A. Primary structure
B. Secondary structure
C. Tertiary structure
D. DNA sequence

Back 49

A

Front 50

Antibodies are made up of two ____ chains and two______ chains held together with ______ bonds.
A. Light ; dark; hydrogen
B. Light; dark; disulfide
C. Heavy; light; hydrogen
D. Heavy; light; disulfide
E. Heavy; light; non-covalent
F. Light; dark; non-covalent

Back 50

D

Front 51

Monoclonal antibodies are made by fusing _______ with _________.
A. Antibody-secreting B cell; Mouse epithelial cell
B. Antibody-secreting B cell; Mouse B cell
C. Mouse epithelial cell; tumor cell
D. Mouse epithelial cell; B cell
E. None of the above

Back 51

E

Front 52

In SDS-PAGE, which of the following is true?
A. Separate Di Sulfate (SDS) masks a polypeptide’s intrinsic charge by forming a protein-SDS complex that is positively charged.
B. Sodium Dodecyl Sulfate (SDS) masks a polypeptide’s intrinsic charge by forming a protein-SDS complex that is positively charged.
C. An oxidizing agent like mercaptoethanol is used to break any disulfide bonds.
D. A reducing agent like SDS is used to break any disulfide bonds.
E. None of the above.

Back 52

E

Front 53

In gel-filtration chromatography, proteins are separated by ______ and ______ proteins wash out of the columns first.
A. Size; large
B. Charge; polar
C. Size; small
D. Charge; nonpolar
E. All of the above

Back 53

A

Front 54

______ tags proteins for destruction and ________ influences protein localization.
A. Phosphoylation; ubiquitylation
B. Acetylation; ubiquitylation
C. Phosphorylation; acetylation
D. Ubiquitylation; acetylation
E. Ubiquitylation; phosphorylation

Back 54

E

Front 55

What does the term “protein domain” refer to?
A. The functional activity of a protein
B. A region in the cell containing the maximum number of alpha helices and beta sheets
C. A segment of a protein that can fold independently into its own three-dimensional structure
D. The region where an antibody can bind the protein
E. All of the above

Back 55

C

Front 56

The binding of a ligand to another protein is very specific and relies on many strong, _______ bonds.
A. covalent
B. disulfide
C. non-covalent
D. all of the above
E. none of the above

Back 56

C

Front 57

In two-dimensional polyacrylamide-gel electrophoresis, proteins are separated by
A. osmolarity and size
B. osmolarity and charge
C. charge and antibody affinity
D. size and antibody affinity
E. none of the above

Back 57

E

Front 58

________ phosphorylate, ________ dephosphorylate, and both either decrease or increase the protein’s activity, depending on the site of phosphorylation and the _______.
A. Kinases; phosphatases; hydrophobicity
B. Phosphatases; kinases; hydrophobicity
C. Phosphatases; kinases; Gibbs free energy
D. Kinases; phosphatases; Gibbs free energy
E. Phosphatases; kinases; protein structure
F. Kinases; phosphatases; protein structure

Back 58

F

Front 59

Which of the following is NOT a technique that can be used to determine the precise three-dimensional structure of a protein?
A. X-ray crystallography
B. NMR spectroscopy
C. Scanning electron microscopy
D. None of the above

Back 59

C

Front 60

_____ is a protein that contains ______, a nonprotein portion essential for its function.
A. Retinal; rhodopsin
B. Hemoglobin; heme
C. Insulin; heme
D. A & B
E. None of the above

Back 60

B

Front 61

In the DNA double helix, ______pairs with adenine, _____ pairs with cytosine, and the bond between them is ______.
A. thymine; guanine; covalent
B. thymine; guanine; hydrogen
C. guanine; thymine; covalent
D. guanine; thymine; hydrogen
E. none of the above

Back 61

B

Front 62

Gene expression and chromosome replication occur in M phase.
A. True
B. False

Back 62

B

Front 63

The ______ is a DNA sequence element that attaches duplicated chromosomes to the mitotic spindle and the ______caps each chromosome end.
A. centromere; telomere
B. telomere; centromere
C. centromere; centromere
D. telomere; telomere

Back 63

A

Front 64

In a _____, DNA wraps around a protein core of eight ________ molecules.
A. histone; nucleosome
B. chromosome; nucleosome
C. nucleosome; histone
D. chromosome; histone

Back 64

C

Front 65

Histone tail modifications confer meanings (such as gene silencing, heterochromatin formation, or gene expression) on the stretch of chromatin on which they occur.
A. True
B. False

Back 65

A

Front 66

DNA is synthesized in the ____ to ____ direction.
A. 7’ to 5’
B. 1’ to 5’
C. 3’ to 5
D. None of the above

Back 66

D

Front 67

When there are errors in DNA synthesis, repairs must be made. They occur in the following order:
A. Excision, resynthesis, ligation
B. Resynthesis, ligation, excision
C. Ligation, excision, resynthesis
D. Resyntheis, excision, ligation

Back 67

A

Front 68

If left uncorrected, DNA errors lead to
A. an extra chromosome
B. mutations
C. a new amino acid
D. DNA errors are always corrected
E. All of the above

Back 68

B

Front 69

Homologous recombination repairs double strand breaks by
A. using RNA primers as templates for the broken strand
B. using an adjacent chromosome as a template for the broken strand
C. unraveling an adjacent nucleosome and using its DNA as a template for the broken strand
D. using the homologous strand as a template for the broken strand
E. none of the above

Back 69

D

Front 70

Viruses are essentially genes that enter a cell and hijack the cell’s machinery to express their genes to make proteins and replicate their chromosomes.
A. True
B. False

Back 70

A

Front 71

In females, gene expression on one of the two X chromosomes is permanently inactivated by:
A. Histone modification
B. Condensing the chromosome into heterochromatin
C. Nuclease DNA digestion
D. Gene silencing proteins
E. none of the above

Back 71

B

Front 72

Consider the process that a cell uses to replicate its double-stranded DNA to make copies for daughter cells. Which statement describes the DNA in daughter cells?
A. The double helices in each daughter cell consist of one parental strand and one newly made strand.
B. The two strands of the double helices in both daughter cells consist of segments of new and parental DNA
C. The double helix in one daughter cell consists of two strands that were originally in the parent cell, while the double helix in the other daughter cell consists of two newly made strands.
D. The two strands of the double helices in both daughter cells consist of segments that were originally in the parental cell.
E. None of the above

Back 72

A

Front 73

At the leading strand the DNA is synthesized ______________, and at the lagging strand the DNA is synthesized ________________.
A. continuously; discontinuously
B. discontinuously; continuously
C. continuously; continuously
D. discontinuously; discontinuously
E. none of the above

Back 73

A

Front 74

Okazaki fragments make up for the fact that DNA can only be replicated in the 3’ to 5’ direction.
A. True
B. False

Back 74

B

Front 75

In a retrovirus, RNA is synthesized using DNA as a template.
A. True
B. False

Back 75

B

Front 76

The _____ is a region on ______ that tells the _____ polymerase where to start transcription.
A. primer; DNA; RNA
B. primer; RNA; DNA
C. primer; DNA; DNA
D. promoter; DNA; RNA
E. promoter; RNA; DNA

Back 76

D

Front 77

Which of the following serve as adaptors between mRNA and amino acids during protein synthesis
A. miRNAs
B. tRNAs
C. rRNAs
D. mRNAs
E. all of the above

Back 77

B

Front 78

Bacterial RNA polymerase requires transcription factors to initiate transcription in vitro.
A. True
B. False

Back 78

B

Front 79

Which molecules are largely responsible for RNA splicing?
A. Proteins and RNA molecules
B. Proteins
C. RNA molecules
D. smURFs
E. None of the above

Back 79

C

Front 80

The protein-manufacturing machine of _______ is the _____ , which moves along _____, captures complementary ______ , and holds them together in order to covalently link the attached amino acids and build a protein chain.
A. transcription, ribosome, tRNA, mRNA
B. transcription, ribosome, mRNA, tRNA
C. translation, ribosome, mRNA, tRNA
D. translation, ribosome, tRNA, mRNA
E. translation, mitochondria, tRNA, mRNA

Back 80

C

Front 81

A single prokaryotic mRNA molecule can encode several different proteins.
A. True
B. False

Back 81

A

Front 82

Which of the following is not a way to control gene expression?
A. Translation control
B. RNA processing control
C. mRNA degradation control
D. transcriptional control
E. None of the above

Back 82

E

Front 83

_____ bind to ______ and turn genes off.
A. Repressor proteins; promoter regions
B. Repressor proteins; operators
C. Repressor proteins; ATG start sequences
D. TATAs; promoter regions
E. TATAs; promoter regions

Back 83

B

Front 84

How does the chromatin-remodeling complex recruited to the promoter region of genes help make DNA more accessible to proteins?
A. It removes histones from the nucleosomes.
B. It remodels nucleosomes.
C. It removes nucleosomes from the histones.
D. It remodels histones.
E. None of the above

Back 84

B

Front 85

When the concentration of tryptophan in E. coli is high, what do you expect to happen?
A. The tryptophan operon is transcribed
B. The tryptophan operon is not transcribed
C. The tryptophan repressor binds tryptophan
D. The tryptophan repressor does not bind DNA
E. B and C
F. B, C, and D

Back 85

E

Front 86

DNA methylation patterns cannot be inherited.
A. True
B. False

Back 86

B

Front 87

The lac operon is controlled by two signals, glucose and lactose levels. The lac operon is turned on when:
A. Glucose is present and galactose is present
B. Glucose is present and lactose is absent
C. Glucose is absent and lactose is absent
D. Glucose is absent and lactose is present

Back 87

D

Front 88

Proteins are marked for degradation via the proteasome pathway by the covalent attachment of:
A. Methyl group
B. Ubiquitin group
C. Phosphate group
D. Protease group

Back 88

B

Front 89

Which of the following mutational changes would be most harmful to an organism?
A. Deletion of three consecutive nucleotides in the middle of the coding sequence
B. Removal of a single nucleotide near the beginning of the coding sequence
C. Removal of a single nucleotide near the end of the coding sequence
D. Substitution of one nucleotide for another in the middle of the coding sequence

Back 89

B

Front 90

The bonds that form between the anti-codon of a tRNA molecule and the three nucleotides of a codon in mRNA are:
A. Covalent bonds formed by GTP hydrolysis
B. Hydrogen bonds that form when the tRNA is at the A-site
C. Broken by the translocation of the ribosome along the mRNA
D. A and C
E. B and C

Back 90

E

Front 91

When is an mRNA molecule ready to be exported into the cytosol?
A. When it has bound poly-A-binding proteins
B. When it has a bound cap-binding complex
C. When it has bound initiation factors for protein synthesis
D. A and B
E. A and C

Back 91

D

Front 92

Which statements are true in general regarding long-lived mRNA?
A. They produce proteins whose levels change rapidly in response to signals.
B. They can be translated only once.
C. They produce proteins made at high levels.
D. A and B
E. A and C

Back 92

C

Front 93

For DNA with the following sequence,
5’ a t t t a a c g g g c 3’
What is the expected RNA transcript sequence?
A. a u u u a a c g g g u
B. u a a a u u g c c g g
C. g c c g a a u u u a
D. g c c c g u u a a a u
E. None of the above

Back 93

D

Front 94

When does protein translation terminate?
A. A release factor binds to the stop codon UAA at the A-site on a ribosome
B. A water molecule is added to the peptidyl-tRNA
C. The amino end of the polypeptide is freed from its attachment to a tRNA
D. A and B
E. All of the above

Back 94

D

Front 95

You are a graduate student studying the role of the protein Klp61f in Drosophila cells. You add double-stranded RNA of Klp61f to your cells and a Western blot confirms that you have successfully knocked down the level of the protein. What is responsible for the decrease in protein level?
A. The protein was degraded by proteasomes.
B. The mRNA was degraded.
C. Transcription was inhibited.
D. All of the above.
E. None of the above.

Back 95

B

Front 96

The absence or presence of guanine in bacteria affects protein translation through the use of a riboswitch. What does the presence of such a riboswitch suggest?
A. Post-translational controls are inferior to self-regulating mRNAs.
B. Short sequences of RNA change their conformations in response to sugars.
C. An RNA world may have existed on Earth before modern cells appeared.
D. The poly-AAA tail is not as important as previously thought.
E. None of the above.

Back 96

C

Front 97

The tryptophan repressor regulates transcription by:
A. Binding and inactivating RNA polymerase in the presence of tryptophan
B. Binding and inactivating RNA polymerase in the absence of tryptophan
C. Competitive binding of the promoter region of the DNA in the absence of tryptophan
D. Competitive binding of the promoter region of the DNA in the presence of tryptophan
E. Binding the enhancer region and preventing RNA polymerase from binding

Back 97

D

Front 98

The reason that multiple, different cell types exist in a multicellular organism yet each cell has the same DNA (with the exception of gametes) is:
A. Gene expression is regulated at the RNA level.
B. The statement is untrue. The DNA is different in different cells because of homologous recombination.
C. The statement is untrue. The DNA is different in different cells because of heritable mutations.
D. Gene expression is regulated at the protein level. E. A and D

Back 98

E

Front 99

The glucocorticoid receptor completes the combination of transcription regulators needed to activate a set of genes in liver cells. Analogously, how do bacteria coordinate expression of sets of genes?
A. Post-translational controls
B. Self-regulating mRNAs
C. Clustering the genes together in an operon under the control of a single promoter.
D. Clustering the genes together in an operon under the control of a single ribosome.
E. Clustering the genes together in a promoter under the control of a single operator.

Back 99

C

Front 100

The assembly of general transcription factors to a eucaryotic promoter begins at what site in a promoter?
A. The TATA box
B. The ATAT
C. The GAGA box
D. The AGAG box
E. None of the above

Back 100

A

Front 101

Which one is true for mutation within a gene?
A. It can alter the activity or stability of a protein
B. It can change the location of a protein in the cell
C. It can affect protein-protein interactions
D. A and C
E. All of the above

Back 101

E

Front 102

What is the overall mutation frequency in E. Coli?
A. 0.1 nucleotide change per 108 nucleotide pairs per cell generation
B. 1 nucleotide change per 108 nucleotide pairs per cell generation
C. 10 nucleotide change per 108 nucleotide pairs per cell generation
D. 0.1 nucleotide change per 109 nucleotide pairs per cell generation
E. 0.1 nucleotide change per 1010 nucleotide pairs per cell generation

Back 102

A

Front 103

Nucleotide point mutations that lead to no change in the amino acid sequence of any protein are known as silent, selectively neutral mutations and they steadily accumulate in the genome of a species over evolutionary time.
A. True
B. False

Back 103

A

Front 104

It is thought that gene duplications are generated by an error in what process?
A. DNA replication and pair
B. Transcription
C. Homologous recombination
D. The replication of chromosome ends

Back 104

C

Front 105

Which structures in eucaryotic genes are thought to have facilitated the ability to duplicate a protein domain of a gene without damaging it in the recombination process?
A. Exons
B. Introns
C. Promoters
D. Regulatory regions

Back 105

B

Front 106

Which of the following are true concerning the human genome?
A. The human genome sequence refers to the complete nucleotide sequence of the DNA contained in 22 chromosomes
B. The human genome contains approximately 3.2 x 109 nucleotide pairs
C. Contains approximately 25000 genes
D. B & C
E. All of the above

Back 106

D

Front 107

Almost every gene in the genome of vertebrates exists in single version.
A. True
B. False

Back 107

B

Front 108

Which one is not a major division under the tree of life?
A. Archaea
B. Bacteria
C. Eucaryotes
D. Yeast

Back 108

D

Front 109

If two distantly related organisms have regions of conserved synteny, what does this mean?
A. The genes examined in the two species are present in the same order as in their most recent common ancestor.
B. The genes examined in the two species are identical in sequence to each other.
C. The genes examined in the two species are on different chromosomes, but in their last common ancestor, the genes were on the same chromosome.

Back 109

A

Front 110

Gel electrophoresis separates DNA based on ________ whereby ____________________________.
A. Fragment size; the larger the molecule the faster the migration
B. Fragment size; the smaller the molecule the faster the migration
C. Fragment sequence; the higher G/C content the faster the migration
D. Fragment sequence; the higher A/T content the faster the migration
E. None of the above is correct

Back 110

B

Front 111

Which of the following statements regarding restriction nucleases (restriction enzymes) is NOT true?
A. Restriction nucleases provide a bacterial defense mechanism against foreign DNA
B. Restriction nucleases typically recognize and cleave palindromic sequences
C. All restriction nucleases generate sticky ends
D. A longer restriction nuclease target sequence is less likely to occur by random chance
E. All of the above are true

Back 111

C

Front 112

Southern blotting is used to detect specific DNA fragments by:
A. A radioactive DNA probe binding to denatured DNA on the nitrocellulose paper and visualized by autoradiography
B. A radioactive DNA probe binding to denatured DNA within the agarose gel and visualized by autoradiography
C. A radioactive DNA probe binding to denatured DNA within the agarose gel and visualized by fluorescence
D. A radioactive DNA probe binding to denatured DNA on the nitrocellulose paper and visualized by fluorescence
E. None of the above

Back 112

A

Front 113

Given the following phylogenetic tree, the arrow points in the direction of:
A. Time before present (increasing), Percentage nucleotide substitution (increasing)
B. Time before present (decreasing), Percentage nucleotide substitution (increasing)
C. Time before present (increasing), Percentage nucleotide substitution (decreasing)
D. Time before present (decreasing), Percentage nucleotide substitution (decreasing)

Back 113

A

Front 114

Which of the following is not true concerning the single nucleotide polymorphisms (SNPs)?
A. Most of the genetic variation in the human genome takes the form of SNPs.
B. Most, but not all, SNPs in the human genome occur in regions where they affect the function of a gene.
C. SNPs are sequences in the genome that differ by a single nucleotide pair between one portion of the population and another.
D. All of the above are true

Back 114

B

Front 115

Which of the following is not required for the synthesis of cDNA?
A. Messenger RNA
B. RNA polymerase
C. DNA polymerase
D. Reverse transcriptase
E. Poly-T oligonucleotide primer
F. All of the above are required

Back 115

B

Front 116

What is the chance (approximately) to cleave DNA with an enzyme that has 6 nucleotide pairs?
A. 1 in 256
B. 1 in 1024
C. 1 in 4096
D. 1 in 16384
E. 1 in 65536

Back 116

C

Front 117

Which of the following is required when combining two DNA fragments produced by the restriction nuclease EcoRI?
A. Ligase
B. ATP
C. Polymerase
D. A&B
E. All of the above are required

Back 117

D

Front 118

C in cDNA stands for:
A. Complex
B. Clone
C. Complementary
D. Complete
E. None of the above

Back 118

C

Front 119

Genomic DNA clones and cDNA clones derived from the same region of DNA are the same.
A. True
B. False

Back 119

B

Front 120

Recombinant DNA techniques make it possible to obtain _____________________.
A. gene from protein
B. protein from gene
C. gene from protein and protein from gene

Back 120

C

Front 121

What is true about green fluorescent protein (GFP) tagging?
A. In many cases, the GFP gene is inserted in the middle of the gene that encodes protein of interest
B. GFP fusion protein often changes the behavior of the original protein
C. Original gene expression can be monitored by tracking fluorescence intensity
D. All of the above are true

Back 121

C

Front 122

In the dideoxy method of sequencing DNA, if the ratio of dATP to ddATP is increased:
A. The strand polymerization terminates less frequently
B. The strand polymerization terminates more frequently
C. These conditions are favorable for determining short nucleotide sequences
D. A & C
E. B & C

Back 122

A

Front 123

What is not true about shotgun sequencing?
A. It is often combined with a BAC-based, clone by clone sequencing approach
B. It requires multiple copies of the genome
C. It is the best method for sequencing big genomes
D. It requires random fragmentation of DNA and these fragments are sequenced
E. All of the above are true

Back 123

C

Front 124

To determine which parts of a polypeptide chain are critical for protein folding, one would do ____________ to alter one or few amino acids.
A. Gene knockout
B. Site-directed mutagenesis
C. In situ hybridization
D. Expression vectors
E. None of the above

Back 124

B

Front 125

The correct sequence of steps in polymerase chain reaction (PCR) is ____________________, and, assuming you start with one double-stranded DNA molecule, after N cycles the number of double-stranded DNA molecules is ______.
A. Denaturation → Primer hybridization → DNA synthesis; N2
B. Denaturation → Primer hybridization → DNA synthesis; 2N
C. Denaturation → DNA synthesis → Primer hybridization; N2
D. Denaturation → DNA synthesis → Primer hybridization; 2N
E. None of the above

Back 125

B

Front 126

The plasma membrane is involved in:
A. Cell motility
B. Export and import of molecules
C. Cell division
D. A & B
E. All of the above

Back 126

D

Front 127

Inside the cell, all organelles have the same residential proteins in the internal membranes enclosing them.
A. True
B. False

Back 127

B

Front 128

Which of the following is not true about hydrophilic molecules?
A. They can form favorable interactions with water. B. Water molecules form cage-like structures around them.
C. Acetone is an example of hydrophilic molecule.
D. B & C
E. All of the above are true

Back 128

B

Front 129

Phospholipids can move within a membrane bilayer. Which of the following types of movement is least likely to occur?
A. Lipid lateral diffusion (diffusion within a monolayer)
B. Lipid rotation (rotation about an axis normal to the bilayer)
C. Lipid flip-flop (moving from one monolayer to the other)
D. Lipid flexion (changing the lipid tilt angle)
E. All of the above are equally likely to occur

Back 129

C

Front 130

The plasma membrane is about _____ nm thick.
A. 1
B. 5
C. 10
D. 15
E. 20

Back 130

B

Front 131

___________ hydrocarbons contain only single bonds while ___________ hydrocarbons contain one or more double bonds.
A. Saturated; amphipathic
B. Unsaturated; amphipathic
C. Saturated; unsaturated
D. Unsaturated; saturated

Back 131

C

Front 132

Which of the following is not true about membrane proteins?
A. Membrane proteins constitute about 25% of the mass of most plasma membrane in animal cells.
B. Peripheral membrane proteins can be removed by detergents, while more gentle extraction procedures are required to release integral membrane proteins from the membrane.
C. Membrane proteins have functional classes like transporters, anchors, receptors and enzymes.
D. A & B
E. A & C
F. All of the above are true

Back 132

D

Front 133

Which of the following is not an integral membrane protein?
A. A transmembrane protein with a single pass transmembrane a-helix
B. A transmembrane protein with several transmembrane a-helicies
C. A protein attached to the membrane through non-covalent interactions with other membrane proteins
D. A lipid linked protein anchored to the outer leaflet of the bilayer
E. A monolayer associated protein tucked into the inner leaflet of the bilayer

Back 133

C

Front 134

Lipid bilayers are highly impermeable to:
A. O2
B. Na+
C. Cl-
D. H2O
E. A & D
F. B & C
G. Lipid bilayers are impermeable to all of the above
H. Lipid bilayers are permeable to all of the above

Back 134

F

Front 135

Which of the following is not a mechanism for restricting the movement of proteins in the membrane?
A. Tethering proteins to the cell cortex
B. Tethering proteins to the extracellular matrix
C. Tethering proteins to the surface of another cell D. Coating proteins with carbohydrates
E. Using barriers such as tight junctions

Back 135

D

Front 136

Given the results for two plasma membranes (PM-I and PM-II) from fluorescence recovery after photobleaching (FRAP) shown to the right, which of the following statements is correct?
A. PM-I is more fluid than PM-II
B. PM-I may contain a higher percentage of lipids with unsaturated hydrocarbon tails
C. PM-I may contain more cholesterol than PM-II
D. A and B
E. All of the above are correct

Back 136

D

Front 137

Inside of a cell:
A. Is more positive than outside of the cell
B. Is more negative than outside of the cell
C. Has no electrical potential difference between outside of the cell

Back 137

B

Front 138

Facilitated diffusion through a transporter is an example of passive transport.
A. True
B. False

Back 138

A

Front 139

Channels form hydrophilic pores across the membrane through which specific solutes can diffuse. A. True
B. False

Back 139

A

Front 140

Which term describes a coupled transporter that moves both solutes in opposite directions across a membrane?
A. Antiport
B. Symport
C. Uniport

Back 140

A

Front 141

Which of the following is the fastest way for an ion to pass through cell membrane?
A. Simple diffusion through the membrane
B. Passive transport through a channel
C. Passive transport through a transporter
D. Active transport through a transporter

Back 141

B

Front 142

Which one is true about Na+-K+ pump?
A. Active import Na+ and export of K+ : Energy source is Na+ gradient
B. Active export Na+ and import of K+ : Energy source is Na+ gradient
C. Active export Na+ and import of K+ : Energy source is ATP hydrolysis
D. Active import Na+ and export of K+ : Energy source is ATP hydrolysis

Back 142

C

Front 143

Which of the following statements is not true regarding the Nernst equation?
A. The Nernst equation can be used to calculate the resting potential of a membrane.
B. The Nernst equation takes the electrical gradient into account.
C. The Nernst equation takes the chemical gradient into account.
D. The Nernst equation does not depend in the charge of the ion.
E. All of the above are true

Back 143

D

Front 144

What is the order of current measured during ion channel activity?
A. Milliampere
B. Microampere
C. Nanoampere
D. Picoampere
E. Femtoampere

Back 144

D

Front 145

How would the membrane potential relax back to the initial resting value (-60mV) after initial depolarizing stimulus if there had been no voltage-gated ion channels in the plasma membrane?
A. The membrane potential would past 0 and reaches +40mV before it returns to its initial resting value
B. The membrane potential would past 0 but would not reach +40mV before it returns to its initial resting value
C. The membrane potential would return to its initial resting potential without increasing any further
D. None of the above

Back 145

C

Front 146

The action potential travels in one direction because:
A. The K+ leak channels allow K+ to flow out, restoring the membrane to the resting potential.
B. The Na+-K+ pump restores the concentration of Na+ and K+ to their original levels.
C. Voltage-gated Na+ channels spend less time in the open conformation when the membrane returns to the resting potential.
D. Voltage-gated Na+ channels adopt a transitionary inactive conformation after being opened.
E. Depolarization of the membrane causes voltage-gated K+ channels to open.

Back 146

D

Front 147

__________ signal is converted into a __________ signal at synapse, and __________ signal is converted into a __________ signal at nerve terminal.
A. Chemical; electrical; electrical; chemical
B. Electrical; chemical; chemical; electrical
C. Mechanical; electrical; electrical; mechanical
D. Electrical; mechanical; mechanical; electrical
E. None of the above

Back 147

A

Front 148

Which of the following statements is true about the concentration of calcium ions in the cells?
A. Calcium levels are kept same in the cytosol compared to outside of the cell
B. Calcium levels are kept low in the cytosol compared to outside of the cell
C. Calcium levels are kept high in the cytosol compared to outside of the cell

Back 148

B

Front 149

Voltage-gated ion channels are major targets for the drugs used to treat insomnia, anxiety, depression, and schizophrenia.
A. True
B. False

Back 149

B

Front 150

Which of the following statements is true about neurotransmitters?
A. Neurotransmitters are packed in membrane enclosed vesicles and they are released from the nerve ending by exocytosis.
B. Excitatory and inhibitory neurotransmitters bind to different receptors.
C. Ion channels activated by excitatory neurotransmitters allow the passage of Na+ and Ca2+.
D. All of the above are true
E. All of the above are false

Back 150

D

Front 151

Catabolism is a very efficient process, 90% of the energy that could be created from the oxidation of glucose or fatty acids is used to drive the production of ATP.
A. True
B. False

Back 151

B

Front 152

Per molecule of glucose, the net production of glycolysis is:
A. Two molecules of NADH
B. Four molecules of ATP
C. Two molecules of pyruvate
D. A & C
E. B & C
F. A, B & C

Back 152

D

Front 153

Which of the following statements is not true?
A. Fermentation yields less energy than complete oxidation.
B. Usefulness of fermentation is limited because the end products are toxic to the producer.
C. Anaerobic respiration differs from fermentation in that it uses an oxygen as a final electron acceptor.
D. A & B
E. B & C

Back 153

C

Front 154

When fatty acids are oxidized to acetyl CoA, each cycle of reaction removes how many carbon atoms from the fatty acid molecule?
A. 1
B. 2
C. 3
D. 4

Back 154

2

Front 155

Which of the following statements is not true about pyruvate dehydrogenase complex?
A. It contains three different enzymes.
B. It converts acetyl CoA to pyruvate.
C. The reactions are carried out in the cytoplasm.
D. A & C
E. B & C

Back 155

E

Front 156

When nutrients are plentiful, animals store glucose as _________ while plants store glucose as _________.
A. starch : glycogen
B. glycogen : starch
C. starch : glucosamine
D. glucosamine : starch

Back 156

B

Front 157

ATP synthase allows the flow of ______ down it electrochemical gradient, driving the production of ATP from ADP.
A. Ca2+
B. Na+
C. K+
D. Cl-
E. H+

Back 157

E

Front 158

How many types of activated carrier molecules are produced by the citric acid cycle?
A. 1
B. 2
C. 3
D. 4
E. 5

Back 158

C

Front 159

The citric acid cycle converts the carbon atoms in the acetyl CoA to which of the following?
A. CO2
B. C2H2
C. C2H4
D. CH3OH
E. C6H5O73-
F. C3H4O3

Back 159

A

Front 160

NADH donates its electrons to the electron transport chain and becomes NAD+. Which of the following statements regarding the conversion of NADH to NAD+ is not true?
A. Electrons are donated from NADH via oxidation
B. A hydride ion, having a negative charge, is donated from methylene group within NADH
C. Upon donating the hydride ion, NADH forms a temporary, unstable isomer before rearranging its bonds such that positive charge is transferred from carbon to a nitrogen forming NAD+
D. The hydride ion is made up of hydrogen atom and two extra electrons, with the two electrons being donated to the electron transport chain
E. FADH2 carries its electrons in a similar way
F. All of the above are true

Back 160

D

Front 161

NADH and FADH2 transport the electrons they have gained to the electron transport chain which is located in __________.
A. the inner cell membrane
B. the inner nuclear membrane
C. the outer nuclear membrane
D. the inner membrane of mitochondria
E. the outer membrane of mitochondria

Back 161

D

Front 162

Synthesizing glucose from pyruvate is called __________, while the reverse is called __________.
A. glycogen synthase : glycogen phosphorylase
B. glycogen phosphorylase : glycogen synthase
C. glycolysis : gluconeogenesis
D. gluconeogenesis : glycolysis

Back 162

D

Front 163

Which one of the following is not an essential requirement for cells to harness energy?
A. Pump protein
B. ATP synthase
C. High energy electrons
D. H+ ions
E. All are essential

Back 163

E

Front 164

Quinones are electron carriers in the electron transport chain that can function with being tightly bound to a protein.
A. True
B. False

Back 164

B

Front 165

Identify the correct path for an electron through the electron transport chain:
I. Cytochrome b-c1 complex
II. Oxygen
III. NADH dehydrogenase complex
IV. Cytochrome oxidase complex
V. NADH
VI. Ubiquinone
VII. Cytochrome C
A. III, V, VII, I, VI, IV, II
B. III, V, VI, I, VII, IV, II
C. III, V, VII, IV, VI, I, II
D. V, III, VI, I, VII, IV, II
E. V, III, VI, IV, VII, I, II
F. None of the above

Back 165

D

Front 166

Ubiquinone has redox potential of +30mV while cytochrome c has a redox potential of +230mV. In the electron transport chain, electrons flow from:
A. Ubiquinone to cytochrome c
B. Cytochrome c to ubiquinone

Back 166

A

Front 167

Chlorophyll molecules absorb which color of light strongly?
A. UV light
B. Blue light
C. Green light
D. Yellow light
E. Red light
F. Infrared light

Back 167

E

Front 168

dentify the correct path of an electron during the photosynthetic electron transport chain in the thylakoid membrane.
I. Cytochrome b6-f complex
II. Photosystem II
III. NADPH
IV. Ferredoxin-NADP reductase
V. Photosystem I
VI. H2O
VII. Plastoquinone
A. VI, I, V, II, VII, IV, III
B. VI, II, VII, V, I, IV, III
C. VI, II, VII, I, V, IV, III
D. III, I, V, II, VII, IV, VI
E. III, II, VII, V, I, IV, VI
F. III, II, VII, I, V, IV, VI

Back 168

C

Front 169

Redox potential does not change along the mitochondrial electron transport chain.
A. True
B. False

Back 169

B

Front 170

Which of the following is found in chloroplast but not in mitochondrion?
A. Matrix
B. Cristae
C. Stroma
D. Thylakoid membrane
E. A & B
F. C & D

Back 170

F

Front 171

In photosynthesis, what drives ATP synthesis by ATP synthase?
A. Phosphorylation of ATP synthase
B. Absorption of a photon of light by an adjacent chlorophyll molecule
C. Proton gradient across thylakoid membrane
D. Transfer of high energy electrons to ATP synthase

Back 171

C

Front 172

During electron transport chain, protons flow ______________________ however within the mitochondria, it is energetically favorable for protons to flow ______________________.
A. matrix → intermembrane space; matrix → intermembrane space
B. intermembrane space → matrix; matrix → intermembrane space
C. matrix → intermembrane space; intermembrane space → matrix
D. intermembrane space → matrix; intermembrane space → matrix

Back 172

C

Front 173

Photosynthesis generates ATP and NADPH which cannot be exported directly to the cytosol. How do cells then provide energy to the rest of the cell?
A. ATP is dephosphorylated to become ADP, this reaction provides energy for transporting NADPH out of the chloroplast
B. ATP synthase transports the molecules out of the chloroplast into the cytosol
C. ATP and NADPH are used to make sugars that can be exported, called carbon fixation
D. Ubiquinone transports the molecules into the intermembrane space where they can penetrate the outer membrane

Back 173

C

Front 174

If needed, a mitochondrion can divide into two mitochondria or it can combine with another mitochondrion.
A. True
B. False

Back 174

A

Front 175

The reason why electrons can be extracted easier from H2S than from H2O is because H2S has a much lower redox potential.
A. True
B. False

Back 175

B

Front 176

Proteins are selectively transferred from __________, to the compartments in which they are used. This process is a called protein __________.
A. Endoplasmic reticulum : transfer
B. Nucleus : transfer
C. Cytosol : transfer
D. Endoplasmic reticulum : sorting
E. Nucleus : sorting
F. Cytosol : sorting

Back 176

F

Front 177

Which of the following is not a membrane-enclosed organelle in eukaryotic cell?
A. Endoplasmic reticulum
B. Golgi apparatus
C. Mitochondria
D. Nucleus
E. All of the above are membrane-enclosed

Back 177

E

Front 178

Rough endoplasmic reticulum lacks ribosomes.
A. True
B. False

Back 178

B

Front 179

In which organelle does modification, sorting and packaging of proteins and lipids for secretion take place?
A. Endosomes
B. Peroxisomes
C. Lysosomes
D. Golgi apparatus
E. Mitochondria

Back 179

D

Front 180

Which of the following membrane-enclosed organelle occupy the largest volume in a liver cell?
A. Nucleus
B. Cytosol
C. Endoplasmic reticulum
D. Golgi apparatus

Back 180

B

Front 181

In which transport mechanism steps imported proteins usually remain unfolded?
A. Transport through nuclear pores
B. Transport across membranes
C. Transport by vesicles
D. A & C

Back 181

B

Front 182

Which of the following statement is false?
A. Nuclear transport receptors bind to the nuclear localization signal on newly synthesized proteins destined for the nucleus
B. Nuclear transport receptors help direct the new protein to a nuclear pore by interacting with the tentacle like fibrils that extend from the rim of the pore
C. Nuclear transport receptors grab onto repeated amino acid sequences within the tangle of nuclear pore proteins, pulling themselves from one to the next, to carry their cargo protein into the nucleus
D. Nuclear transport receptor is returned to the cytosol via the nuclear pore for degradation
E. All of the above are true

Back 182

D

Front 183

In the Ran-GTP/GDP nuclear transport system, which of the following statement is not true?
A. The nuclear localization signal is located on the cargo protein destined for nucleus
B. Hydrolysis of GTP results in Ran-GDP dissociation from the nuclear transport receptor
C. Binding of Ran-GTP to the nuclear transport receptor occurs in the cytosol
D. Hydrolysis of GTP occurs in the cytosol
E. All of the above are true

Back 183

C

Front 184

Attaching Green Fluorescent Protein (GFP) to a protein of interest is a popular method to study localization, either cytosolic or nuclear, of that protein within a cell. Which of the following is true for this method?
A. GFP sequence itself does not contain a nuclear localization signal
B. GFP alone is small enough to diffuse freely through nuclear pores
C. GFP alone is large enough to require active localization into the membrane
D. A & B
E. A & C

Back 184

D

Front 185

In the process of translocating a polypeptide across the membrane of the endoplasmic reticulum, a stop transfer halts the process. What eventually becomes of the stop transfer sequence?
A. It forms beta–barrel membrane-spanning segment of the protein
B. It forms alpha–helical membrane-spanning segment of the protein
C. It is cleaved from the protein
D. It is translocated into the lumen of the endoplasmic reticulum

Back 185

B

Front 186

COP-coated vesicles transport molecules between plasma membrane and endosomes.
A. True
B. False

Back 186

B

Front 187

Identify the correct order for directing transport vesicles to their target membrane
I. Cargo is delivered into the target membrane
II. v-SNARE on the vesicle binds to t-SNARE on target membrane
III. Tethering protein on the target membrane binds to Rab protein in the vesicle
IV. Vesicle fuses to the target membrane
A. III -> II -> IV -> I
B. II -> III -> IV -> I
C. II -> III -> I -> IV
D. III -> II -> I -> IV

Back 187

A

Front 188

Which type of protein binds to improperly folded or improperly assembled proteins in the ER, holding them there until proper folding occurs?
A. SNARE proteins
B. Tethering proteins
C. Rab proteins
D. Chaperone proteins
E. Antibody proteins

Back 188

D

Front 189

Proteins entering cis Golgi network can do the following?
A. They are sorted according to whether they are destined for lysosomes or for the cell surface
B. They can either move backward through the Golgi stack or be sent to plasma membrane
C. They can either move onward through the Golgi stack or be sent to ER
D. A & B
E. All of the above

Back 189

C

Front 190

Receptors internalized by endocytosis can take 3 different paths following endocytosis. Which of the following is not one of them?
A. The receptor is returned to the same plasma membrane domain from which it came
B. The receptor to a lysosome where it is degraded C. The receptor travels to the nucleus and becomes a nuclear receptor
D. The receptor proceeds to a different domain of the plasma membrane

Back 190

C

Front 191

What is the function of a signal-recognition particle (SRP)?
A. Slows down protein synthesis in the ribosome
B. Binds to the translocation channel to aid in protein transport into endoplasmic reticulum (ER)
C. Binds to an SRP receptor on ER, thereby connecting ribosomes synthesizing ER protein to ER
D. A & B
E. A & C

Back 191

E

Front 192

________ cells produce hormones which are secreted ________________.
A. Endocrine; locally through the extracellular fluid
B. Paracrine; locally through the extracellular fluid C. Endocrine; into the blood stream
D. Paracrine; into the blood stream

Back 192

C

Front 193

Nitric Oxide (NO) acts only on the neighboring cells (as local mediator in paracrine signaling) because:
A. It is rapidly washed away by the blood stream
B. It is rapidly converted to nitrates and nitrites in the extracellular fluid
C. It is rapidly converted to nitrates and nitrites in the target cell
D. The amount produced is so little by the signaling cell

Back 193

B

Front 194

Which of the following is not one of the basic classes for cell surface receptors?
A. Ion-channel-coupled receptors
B. G-protein-coupled receptor
C. Phospholipid-coupled receptor
D. Enzyme-coupled receptor

Back 194

C

Front 195

A rise in Ca+2 in a cell can lead to …
A. An egg to start development
B. Muscle contraction
C. Secretion of protein
D. All of the above
E. None of the above

Back 195

D

Front 196

Which of the following statements about inositol phospholipid signaling pathway is not true?
A. Inositol phospholipid pathway is activated by GPCRs which activate the phospholipid C, a signaling molecule which also happens to be a phospholipid
B. Phosholipase C cleaves the sugar-phosphate head off inositol phospholipid to generate IP3,and dicylglycerol (DAG)
C. DAG remains embedded in the plasma membrane where it recruits protein kinase C (PKC)
D. IP3 is released into the cytosol where it binds to open and opens Ca+2 channels in the ER membrane
E. Binding of DAG to PKC requires cytosolic Ca+2
F. All of the above are true

Back 196

A

Front 197

Put the following receptor tyrosine kinase events in order.
I. Ras protein GDP-GTP exchange
II. Signaling proteins bind phosphor-tyrosines
III. Active Ras protein
IV. Receptor trans-phoshorylation
V. Ligand binding and receptor dimerization
A. V, IV, II, I, III
B. V, I, II, IV, III
C. II, IV, V, III, I
D. II, I, V, IV, III
E. None of the above

Back 197

A

Front 198

Ras protein triggers a phosphorylation cascade of three protein kinases that transfer a signal from the plasma membrane to the nucleus, which can lead to cell differentiation and cell proliferation. This cascade is called __________.
A. PKA
B. CaM kinase
C. MAP kinase
D. PKC

Back 198

C

Front 199

How does IP3 function in the inositol phospholipid pathway?
A. It directly activated protein kinase C
B. It activates phospholipase C
C. It binds to and opens Ca+2 channels that are embedded in the ER membrane, releasing Ca+2 into cytosol
D. It punches

Back 199

C

Front 200

Mutant Ras genes, which are found in approximately _____ of cancers, code for Ras proteins that are _________.
A. 30% : constitutively inactive
B. 30% : constitutively active
C. 70% : constitutively inactive
D. 70% : constitutively active

Back 200

B

Front 201

The cytoplasm of a eukaryotic cell is supported and spatially organized by three types of protein filaments with same mechanical properties and formed from identical protein subunits.
A. True
B. False

Back 201

B

Front 202

Put the following components of the cytoskeleton in order of decreasing diameter.
A. Microtubules > Actin filaments > Intermediate filaments
B. Actin filaments > Intermediate filaments > Microtubules
C. Microtubules > Intermediate filaments > Actin filaments
D. Intermediate filaments > Actin filaments > Microtubules
E. None of the above

Back 202

C

Front 203

Intermediate filament (IF), Microtubules (MT), or Actin filament (AF).
A. … structures have an outer diameter of 25 nm
B. … have a helical primary structure
C. … are highly concentrated in the cortex
D. … are the most rigid of the three types of protein filaments
E. … can span the cytoplasm from one cell-cell junction to another to distribute
mechanical stresses in epithelial tissue
F. ...typically have one end attached to a centrosome

Back 203

A MT
B AF
C AF
D IF
E IF
F MT

Front 204

Intermediate filaments are elongated fibrous proteins, each composed of an N-terminal globular tail, a C-terminal globular head and a central elongated rod domain.
A. True
B. False

Back 204

B

Front 205

Which of the following is not true regarding microtubules (MT)?
A. MT  molecules are arranged in a circle of 13 molecules with a hollow center
B. MT play a role in organizing the cell, guiding intracellular transport of vesicles, cell organelles and other components
C. MT are constructed from heterodimeric -tubulin molecules
D. All of the above are true

Back 205

D

Front 206

In a centrosome, which structures serve as nucleation sites for the formation of microtubules?
A. -tubulin dimers
B. - and -tubulin monomers
C. -tubulin rings
D. Tubulin protofilaments

Back 206

C

Front 207

Taxol, a drug used both as a cancer chemotherapy as well as in coating stents to prevent restenosis (recurrent narrowing of the coronary artery), is a mitotic inhibitor that works by:
A. Binding to free tubulin molecules and preventing polymerization
B. Binding to microtubules and preventing polymerization
C. Binding to free tubulin and preventing de-polymerization
D. Binding to microtubules and preventing de-polymerization
E. None of the above

Back 207

D

Front 208

Which of the following statements is not true?
A. Cilia are longer than flagella and are designed to propel a whole cell
B. Cilia move fluid over the surface of a cell generating a current
C. Cilia and flagella have similar internal structures which differ from cytoplasmic microtubules
D. All of the above are true

Back 208

A

Front 209

A sarcomere is about _____ nm long.
A. 2.5
B. 25
C. 250
D. 2500
E. None of the above

Back 209

D

Front 210

In a sarcomere actin filaments (thin filaments) are centrally positioned whereas myosin filaments (thick filaments) extend inward from each end of sarcomere and overlap the ends of actin filaments.
A. True
B. False

Back 210

B

Front 211

The membrane of the Golgi apparatus is pulled toward the cell center by interacting with the motor protein:
A. Dyneins that pull toward the plus end
B. Dyneins that pull toward the minus end
C. Kinesins that pull toward the minus end
D. Kinesins that pull toward the plus end
E. None of the above

Back 211

B

Front 212

Which organelle sequesters Ca2+ inside muscle fibers?
A. Golgi apparatus
B. Mitochondria
C. Nucleus
D. The sarcoplasmic reticulum
E. Lysosomes

Back 212

D

Front 213

Which of the following eukaryotic cell type divide the fastest?
A. Mammalian fibroblast in culture
B. Yeast cell
C. Human liver cell
D. Early frog embryo cell
E. Mammalian intestinal epithelial cell

Back 213

D

Front 214

Below is the order of events of muscle contraction in terms of the actin-myosin interaction. Put the following transitional energetic events of muscle contraction in order.
I. ATP hydrolysis to ADP + Pi
II. Binding of ATP to myosin head
III. Myosin head releases ADP
IV. Myosin head releases Pi
A. II  I  III  IV
B. III  I  II  IV
C. II  I  IV  III
D. IV  II  I  III
E. III  II  I  IV

Back 214

A

Front 215

Which is the correct order of the cell cycle?
A. S  G1  M  G2  S …
B. G1  M  G2  S  G1 …
C. S  G1  G2  M  S …
D. G1  S  M  G2  G1 …
E. None of the above

Back 215

E

Front 216

Given the cell cycle profile of proliferating,
asynchronous cells as measured by flow cytometry,
which of the following statements is NOT true?
A. Stage I is the longest stage in the cell cycle
B. Inhibition of DNA synthesis would cause cells to accumulate in stage II
C. Inhibition of mitosis would cause cells to
accumulate in stage III
D. All of the above are true

Back 216

B

Front 217

Which of the following statement is not true about cyclin dependent protein kinases (Cdks)?
A. The activity of Cdks is regulated by cyclin degradation
B. Distinct Cdks associate with different cyclins to trigger the different event of the cell cycle
C. Cell cycle depends on Cdks
D. Cdk activity and cyclin concentration are highest during mitosis
E. All of the above are true

Back 217

E

Front 218

If the cell is at Cytokinesis, what are the names of the phases just before and after this phase?
A. Telophase - Interphase
B. Prometaphase - Anaphase
C. Metaphase - Telophase
D. Prophase - Telophase
E. None of the above

Back 218

A

Front 219

What function do kinetochores perform?
A. They complete the cell separation in cytokinases B. They attach the spindle microtubules to condensed chromosomes
C. They break down the nuclear envelope during prometaphase
D. They bind to cyclin D to advance the cell into S phase

Back 219

B

Front 220

Which of the following is not true?
A. Mitogens stimulate cell division
B. Survival factors suppress apoptosis
C. Growth factors stimulate an increase in cell size and mass
D. All of the above are true
E. None of the above are true

Back 220

D

Front 221

1. The SNP sites of the human genome was sequenced and analyzed in a research project for a number of individuals. For the vast majority of the sites, the relative frequencies of the different variants were not changed in the relative frequencies of different variants as these humans aged. Rarely, however, a particular variant at one position was found to decrease in frequency progressively for people over 50 years old. Which of the possible explanations would explain this phenomenon?
A. The nucleotide in that SNP at that position is unstable, and mutates with age.
B. Those people born more than 50 years ago came from a population that tended to lack the disappearing SNP variant.
C. The SNP variant alters an important gene product in a way that shortens the human life span, or is linked to a neighboring allele that has this effect.
D. None of the above.

Back 221

C

Front 222

2. What is the difference between a malignant and benign tumor?
A. A malignant tumor invades and colonizes other tissues, while a benign tumor does not.
B. A malignant tumor proliferates in defiance of normal constraints, while a benign tumor does not. C. A benign tumor can be treated while a malignant tumor cannot be treated.
D. A malignant tumor can be treated while a benign tumor cannot be treated.
E. Both A and B.

Back 222

A

Front 223

3. Which epithelial cell junctions serve to seal neighboring cells together so that water-soluble molecules cannot easily leak between them?
A. Adherens junctions
B. Tight junctions
C. Gap junctions
D. Desmosomes
E. All of the above

Back 223

B

Front 224

4. Which of the following is NOT an advantage of sexual reproduction?
A. Reshuffling genes through sexual reproduction can help a species survive in an unpredictably variable environment.
B. Through sexual reproduction, a set of parents can produce a large number of identical offspring.
C. Sexual reproduction can speed the elimination of deleterious alleles from a population (e.g., males who succeed in mating allow the best collections of genes to be passed on).
D. All of the above are advantages of sexual reproduction

Back 224

B

Front 225

5. What are the two defining characteristics of a stem cell?
A. Stem cells can divide indefinitely
B. Stem cells are less prone than normal cells to kill themselves by apoptosis.
C. Stem cells can give rise to other specialized cell types of the human body
D. A and C
E. A and B
F. None of the above

Back 225

D

Front 226

6. Gelatin is primarily composed of collagen that has a remarkable tensile strength characteristic. However, it is also the basic ingredient of Jello but Jello has no tensile strength. Why is that?
A. Jello has added preservatives that may disrupt the mechanical strengths of the collagen of the Jello gel.
B. The gelatin in Jello is boiled and then cooled which causes the collagen fiber to denature and then solidify into a gel.
C. The gelatin (collagen) in Jello is outside its native environment causing lower tensile strength.
D. All of the above.

Back 226

B

Front 227

7. Which of the following is NOT a step in sexual reproduction of a diploid organism?
A. Haploid gametes
B. Haploid zygote
C. Diploid zygote
D. Mitosis
E. Meiosis

Back 227

B

Front 228

8. What are key behaviors of cancer cells that distinguish them from normal cells?
A. They are independent from other signals from other cells needed for their growth, survival, and division causing them to proliferative indefinitely. B. Cancer cells are less prone than normal cells to kill themselves by apoptosis.
C. Most cancer cells are genetically stable with an increased mutation rate.
D. Both normal and cancer cells can proliferate indefinitely but cancer cells tend to live longer giving a tendency to forming tumors.
E. All of the above.

Back 228

B

Front 229

9. Which of the following is NOT a key factor in maintaining cellular organization of tissues?
A. Cell Communication
B. Cell DNA Repair Machinery
C. Cell Memory
D. Selective Cell-Cell Adhesion
E. None of the above

Back 229

B

Front 230

10. Which of the following is the term for a variant of a gene?
A. Mutant
B. Dominant negative
C. Allele
D. Homologues
E. Sister genes

Back 230

C

Front 231

11. Which type of epithelial cell junction allows ions and small molecules to pass from cell to cell?
A. Tight Junction
B. Gap Junction
C. Cytoskeleton-linked junctions
D. Adherens Junction
E. None of the above

Back 231

B

Front 232

12. Which type of epithelial cell junction binds eptheilial cells robustly to one another and to the basal lamina?
A. Tight junction
B. Gap Junction
C. Cytoskeleton-linked junctions
D. Adherens Junctions
E. None of the above

Back 232

C

Front 233

13. Meiosis generates _______________________ cells, and mitosis generates ____________________ cells.
A. Four identical; two identical
B. Two non-identical; two identical
C. Four non-identical; two non-identical
D. Two identical; two non-identical
E. None of the above

Back 233

E

Front 234

14. What is the average frequency by which any two human differ in their nucleotide sequence?
A. 0.001%
B. 0.01%
C. 0.1%
D. 1%

Back 234

C

Front 235

15. How many possible different haploid gametes can there be for an organism with 2 chromosomes?
A. 1
B. 2
C. 4
D. 23

Back 235

C