Cell Physiology Unit 1 and 2 Exams

If hydrolysis of 1 mole of ATP (ATP + H20 → ADP + Pi) produces a free energy change of -30.1 kJ/mole, which of the following reactions can be productively coupled to 2 moles of ATP hydrolysis. A+B→C+D, deltaG= −30 kJ/mol A+B→C+D, deltaG= −60 kJ/mol A+B→C+D, deltaG= 90 kJ/mol A+B→C+D, deltaG= 60 kJ/m

A+B→C+D, deltaG= 60 kJ/m

(Q033) Which of the following statements about Illumina sequencing is FALSE? a) The nucleoside triphosphates that are used have a fluorescent marker. b) The nucleoside triphosphates that are used have a 3´ chemical group that will terminate DNA synthesis. c) The termination of DNA synthesis by the nucleoside triphosphates that are used is reversible. d) Both normal and modified nucleoside triphosphates are used to synthesize DNA.

Both normal and modified nucleoside triphosphates are used to synthesize DNA.

In chloroplasts, photosystems II and I coordinate to produce NADPH and ATP. NADPH is produced using the electrons generated at the reaction center by splitting water and via ferredoxin. How is ATP produced? Similar to NADPH, electrons transferred to the mobile carrier plastoquinone is used to power ATP synthesis. By using light energy to create a high-energy phosphate bond in the reaction center, using a special pair of chlorophyll subunits. By fixing CO2 via the Calvin cycle where ATP is a byproduct. By generating a H+ gradient across the thylakoid membrane to power an ATP synthase enzyme.

By generating a H+ gradient across the thylakoid membrane to power an ATP synthase enzyme.

Cells need to transport materials or cargo from one region of the cell to another. Which of the following acts as a cellular highway networkthat can be used to transport molecular cargo? Motor proteins Cytoskeleton Golgi apparatus Cilia and flagella

Cytoskeleton

For studying enzyme kinetics, rate (V) of a biochemical reaction is plotted against a range of substrate concentrations [S]. How is the Michaelis-Menten constant (Km) of an enzyme-catalyzed reaction calculated? Km is calculated as the slope of the linear regression. Km is the [S] at which V=0.5 Vmax, on a non-linear curve fit. Km equals V at which [S] is at 50% Km equal [S] at Vmax

Km is the [S] at which V=0.5 Vmax, on a non-linear curve fit.

(Q011) DNA ligase is an enzyme used when making recombinant DNA molecules in the lab. In what normal cellular process is DNA ligase involved? a) none; it is only found in virally infected cells b) transcription c) transformation d) DNA replication

DNA replication

(Q019) Which diagram accurately represents the directionality of DNA strands at one side of a replication fork?

Diagram D

(Q023) Which of the following statements is TRUE? a) Disulfide bonds are formed by the cross-linking of methionine residues. b) Disulfide bonds are formed mainly in proteins that are retained within the cytosol. c) Disulfide bonds stabilize but do not change a protein's final conformation. d) Disulfide bonds are more common for intracellular proteins, compared to extracellular proteins.

Disulfide bonds stabilize but do not change a protein's final conformation.

Which of the following is NOT an accurate category for active transport pumps? ATP-driven pump Light-driven pump Mechanically-gated pump Gradient-driven pump

Mechanically-gated pump

(Q039) Both glycoproteins and proteoglycans contribute to the carbohydrate layer on the surface of the cell. Which of the following statements about glycoproteins is FALSE? a) They can be secreted into the extracellular environment. b) They have only one transmembrane domain. c) They have long carbohydrate chains. d) They are recognized by lectins.

They have long carbohydrate chains.

(Q025) K+ leak channels are found in the plasma membrane. These channels open and close in an unregulated, random fashion. What do they accomplish in a resting cell? a) They set the K+ concentration gradient to zero. b) They set the membrane potential to zero. c) They disrupt the resting membrane potential. d) They keep the electrochemical gradient for K+ at zero.

They keep the electrochemical gradient for K+ at zero.

Where do the electrons from the electron-transfer chain end up? They are recycled NADH regeneration They help ATP synthase function for the production of ATP They are recycled into dehydrogenase reactions of glycolysis They participate in the final production of water using oxygen.

They participate in the final production of water using oxygen.

Which of the following is a type of membrane protein organization (i.e. the way in which the protein associates with the membrane) rather than a membrane protein function? Anchor proteins Transmembrane proteins Receptor proteins Transporter proteins

Transmembrane proteins

FISH is a type of in situ hybridization used for targeting nucleic acids in cells using fluorescence.' True False

True

(Q039) An SNP found in the conserved sequence of the regulatory region of a gene is likely to a) affect protein folding. b) affect when and where the gene is expressed. c) be a new mutation. d) be found in plants as well as humans.

affect when and where the gene is expressed.

(Q029) HIV is a human retrovirus that integrates into the host cell's genome and will eventually replicate, produce viral proteins, and ultimately escape from the host cell. Which of the following proteins is not encoded in the HIV genome? a) reverse transcriptase b) envelope protein c) RNA polymerase d) capsid protein

RNA polymerase

(Q025) How are most eukaryotic transcription regulators able to affect transcription when their binding sites are far from the promoter? a) by binding to their binding site and sliding to the site of RNA polymerase assembly b) by looping out the intervening DNA between their binding site and the promoter c) by unwinding the DNA between their binding site and the promoter d) by attracting RNA polymerase and modifying it before it can bind to the promoter

by looping out the intervening DNA between their binding site and the promoter

(Q013) Membranes undergo spontaneous rearrangement if torn. Which of the following would happen if a cell membrane underwent a large tear? a b c d

c

(Q004) Mistakes in replicating the DNA of a cell before division a) have no consequence on the cell's survival. b) always lead to reduced survival of the cell. c) lead to increased survival of the cell. d) can have positive, negative, or neutral effects.

can have positive, negative, or neutral effects.

(Q029) Choose the phrase that best completes this sentence: Microtubules __________ and are required to pull duplicated chromosomes to opposite poles of dividing cells. a) generate contractile forces b) are intermediate in thickness c) can rapidly reorganize d) are found in especially large numbers in muscle cells

can rapidly reorganize

Which of the following types of cells is likely to have a higher number of mitochondria? epithelial cells white blood cells cardiac muscle cells neurons

cardiac muscle cells

What is the function of kinase enzymes? catalyzes the oxidation of a molecule by removing a hydrogen atom plus an electron catalyzes the addition of a phosphate group to molecules catalyzes the rearrangement of bonds within a single molecule catalyzes the shifting of a chemical group from one position to another within a molecule

catalyzes the addition of a phosphate group to molecules

Other than sugars, fatty acids and amino acids can also be used as a source of energy. Identify the stage (process or metabolite) which is NOT one where amino acid metabolism can merge with cellular respiration. citric acid cycle glycolysis pyruvate acetyl-CoA

glycolysis

(Q005) Which of the following is not a good example of a housekeeping protein? a) DNA repair enzymes b) histones c) ATP synthase d) hemoglobin

hemoglobin

(Q010) Disulfide bonds stabilize protein shape outside the cell by a) covalent bonds between cysteines. b) noncovalent bonds between charged side chains. c) hydrophobic interactions within the lipid bilayer. d) hydrogen bonds with water molecules.

covalent bonds between cysteines.

(Q002) DNA replication is considered semiconservative because a) after many rounds of DNA replication, the original DNA double helix is still intact. b) each daughter DNA molecule consists of two new strands copied from the parent DNA molecule. c) each daughter DNA molecule consists of one strand from the parent DNA molecule and one new strand. d) new DNA strands must be copied from a DNA template.

each daughter DNA molecule consists of one strand from the parent DNA molecule and one new strand.

Membrane based-systems use which of the following conditions to drive the synthesis of ATP. glucose-Na+ symports chemiosmotic coupling electrochemical proton gradient voltage-gated ion channels

electrochemical proton gradient

(Q024) The cell constantly exchanges materials by bringing nutrients in from the external environment and shuttling unwanted by-products back out. Which term describes the process by which external materials are captured inside transport vesicles and brought into the cell? a) degradation b) exocytosis c) phagocytosis d) endocytosis

endocytosis

Which of the following movements within the phospholipid bilayer occur only rarely? lateral diffusion flexion rotation flip-flop

flip-flop

What type of protein structure is observed in highly variable regions within an antibody's antigen recognition domain? ⍺ helices β sheets coiled-coils loops

loops

(Q027) Methylation and acetylation are common changes made to histone H3, and the specific combination of these changes is sometimes referred to as the "histone code." Which of the following patterns will probably lead to gene silencing?a) lysine 9 methylation b) lysine 4 methylation and lysine 9 acetylation c) lysine 14 acetylation d) lysine 9 acetylation and lysine 14 acetylation

lysine 9 methylation

For acetyl CoA to enter the citric acid, what substrate must it first react with? citrate (citric acid) citrate synthase oxaloacetate pyruvate

oxaloacetate

phosphofructose phosphorylase phosphofructokinase fructose 1,6-bisphosphate dehydrogenase aldolase

phosphofructokinase

(Q006) The DNA from two different species can often be distinguished by a difference in the a) ratio of A + T to G + C. b) ratio of A + G to C + T. c) ratio of sugar to phosphate. d) presence of bases other than A, G, C, and T.

ratio of A + T to G + C.

(Q014) The sigma subunit of bacterial RNA polymerase a) contains the catalytic activity of the polymerase. b) remains part of the polymerase throughout transcription. c) recognizes promoter sites in the DNA. d) recognizes transcription termination sites in the DNA.

recognizes promoter sites in the DNA.

(Q011) The main function of the nucleus is to a) provide energy for the cell. b) allow cells to segregate their chromosomes. c) make proteins using the genetic material. d) house the DNA in a separate cell compartment.

house the DNA in a separate cell compartment.

(Q025) The pH of an aqueous solution is an indication of the concentration of available protons. However, you should not expect to find lone protons in solution; rather, the proton is added to a water molecule to form a/an __________ ion. a) hydroxide b) ammonium c) chloride d) hydronium

hydronium

(Q017) Two or three α helices can sometimes wrap around each other to form coiled-coils. The stable wrapping of one helix around another is typically driven by __________ interactions. a) hydrophilic b) hydrophobic c) van der Waals d) ionic

hydrophobic

(Q035) Which of the following statements about iPS cells is FALSE? a) iPS cells can be made by adding a combination of transcription regulators to a fibroblast. b) iPS cells made from mouse cells can differentiate into almost any human cell type. c) Stimulation by extracellular signal molecules causes iPS cells to differentiate. d) A cell that is dedifferentiated to become an iPS cell will undergo changes to its gene expression profile.

iPS cells made from mouse cells can differentiate into almost any human cell type.

(Q048) The long noncoding RNA Xist a) is important for the formation of highly condensed heterochromatin on the X chromosome. b) binds to foreign RNAs in the cell to promote their destruction. c) catalyzes miRNA maturation. d) acts with the RTS complex to bind to complementary RNA molecules.

is important for the formation of highly condensed heterochromatin on the X chromosome.

(Q002) The central dogma provides a framework for thinking about how genetic information is copied and used to produce structural and catalytic components of the cell. From the choices below, select the order of biochemical processes that best correlates with the tenets of the central dogma. a) replication, transcription, translation b) replication, translation, transcription c) translation, transcription, replication d) translation, replication, transcription

replication, transcription, translation

(Q021) Carbon atoms can form double bonds with other carbon atoms, nitrogen atoms, and oxygen atoms. Double bonds can have important consequences for biological molecules because they are __________ compared to single covalent bonds. a) long b) rigid with respect to rotation c) weak d) unstable

rigid with respect to rotation

From the image below, identify the type of assembly (boxed and highlighted in pink) produced during detergent-based solubilization of membrane proteins. water-soluble complexes of transmembrane protein and detergent detergent monomers detergent micelle lipid-detergent micelle

s detergent micelle

(Q020) DNA polymerases are processive, which means that they remain tightly associated with the template strand while moving rapidly and adding nucleotides to the growing daughter strand. Which piece of the replication machinery accounts for this characteristic? a) helicase b) sliding clamp c) single-strand binding protein d) primase

sliding clamp

(Q009) Compared to eukaryotes, prokaryotic organisms are a) more abundant and more widespread on Earth. b) less abundant and less widespread on Earth. c) more abundant and less widespread on Earth. d) less abundant and more widespread on Earth.

more abundant and more widespread on Earth.

Which of the following is not a part of the phosphatidylcholine chemical structure? Question options: Ketone Glycerol Choline Phosphate

Ketone

(Q029) If proteins A and B have complementary surfaces, they may interact to form the dimeric complex AB. Which of the following is the correct way to calculate the equilibrium constant for the association between A and B? a) kon/koff = K b) K = [A][B]/[AB] c) K = [AB]/[A][B] d) (A) and (C)

(A) and (C)

(Q021) Nucleosomes are formed when DNA wraps __________ times around the histone octamer in a __________ coil. a) 2.0; right-handed b) 2.5; left-handed c) 1.7; left-handed d) 1.3; right-hande

1.7; left-handed

The ΔG° for the reaction X + Y → XY is -1000 cal/mol. What is the ΔG at 25°C (298 K) starting with 0.01 M of each X, Y, and XY. Value of R is 1.987 cal/(degree・mol). Use the formula: ΔG = ΔG° + RT ln K, where K is the dissociation constant. 3727 cal/mol 1727 cal/mol 2727 cal/mol -1002.95 cal/mol

1727 cal/mol

NaCl molecular weight is 180 g/mol. To make a 1 L solution of 100 mM NaCl, how much salt must we weigh? [Hint: 1 M = 1 mol/L] 1.8 g 18 g 18 mg 1.8 mg

18 g

At what position of the sugar within a nucleotide can we observe a difference when comparing DNA and RNA? 2' Carbon 3' Carbon 4' Carbon 5' Carbon

2' Carbon

(Q043) The enzyme ribulose bisphosphate carboxylase (Rubisco) normally adds carbon dioxide to ribulose 1,5-bisphosphate. However, it will also catalyze a competing reaction in which O2 is added to ribulose 1,5-bisphosphate to form 3-phosphoglycerate and phosphoglycolate. Assume that phosphoglycolate is a compound that cannot be used in any further reactions. If O2 and CO2 have the same affinity for Rubisco, which of the following is the lowest ratio of CO2 to O2 at which a net synthesis of sugar can occur? a) 1:3 b) 1:2 c) 3:1 d) 2:1

3:1

(Q005) Figure 7-3 shows a ribose sugar. The part of the ribose sugar where a new ribonucleotide will attach in an RNA molecule is pointed to by arrow

4.

(Q044) Because there are four different monomer building blocks that can be used to assemble RNA polymers, the number of possible sequence combinations that can be created for an RNA molecule made of 100 nucleotides is a) 100^4. b) 4^100. c) 4 ? 100. d) 100/4.

4100

Question 521 / 1 point (Q009) You are interested in a single-stranded DNA molecule that contains the following sequence:5´- . . . . .GATTGCAT. . . . -3´a. Which molecule will hybridize to your sequence of interest? a) 5´-GATTGCAT-3´ b) 5´-TACGTTAG-3´ c) 5´-CTAACGTA-3´ d) 5´-ATGCAATC-3´

5´-ATGCAATC-3´

(Q035) Motor proteins use the energy in ATP to transport organelles, rearrange elements of the cytoskeleton during cell migration, and move chromosomes during cell division. Which of the following mechanisms is sufficient to ensure the unidirectional movement of a motor protein along its substrate? a) A conformational change is coupled to the release of a phosphate (Pi). b) The substrate on which the motor moves has a conformational polarity. c) A conformational change is coupled to the binding of ADP. d) A conformational change is coupled to ATP hydrolysis

A conformational change is coupled to ATP hydrolysis.

(Q004) Fully folded proteins typically have polar side chains on their surfaces, where electrostatic attractions and hydrogen bonds can form between the polar group on the amino acid and the polar molecules in the solvent. In contrast, some proteins have a polar side chain in their hydrophobic interior. Which of the following would NOT occur to help accommodate an internal, polar side chain? a) A hydrogen bond forms between two polar side chains. b) A hydrogen bond forms between a polar side chain and the protein backbone. c) A hydrogen bond forms between a polar side chain and an aromatic side chain. d) Hydrogen bonds form between polar side chains and a buried water molecule

A hydrogen bond forms between a polar side chain and an aromatic side chain.

(Q004) Fully folded proteins typically have polar side chains on their surfaces, where electrostatic attractions and hydrogen bonds can form between the polar group on the amino acid and the polar molecules in the solvent. In contrast, some proteins have a polar side chain in their hydrophobic interior. Which of the following would NOT occur to help accommodate an internal, polar side chain? a) A hydrogen bond forms between two polar side chains. b) A hydrogen bond forms between a polar side chain and the protein backbone. c) A hydrogen bond forms between a polar side chain and an aromatic side chain. d) Hydrogen bonds form between polar side chains and a buried water molecule.

A hydrogen bond forms between a polar side chain and an aromatic side chain.

If a phospholipid within a lipid bilayer of a membrane has a double-bond in the fatty acid chain, what effect may this have on the membrane? A kink is produced on the hydrophobic tail, and may lead to increased rigidity in the membrane. A kink is produced on the hydrophilic tail, and may lead to increased rigidity in the membrane. A kink is produced on the hydrophobic tail, and may lead to increased fluidity in the membrane. A kink is produced on the hydrophillic tail, and may lead to increased fluidity in the membrane.

A kink is produced on the hydrophobic tail, and may lead to increased fluidity in the membrane.

(Q001) Which of the following statements is FALSE? a) A mutation that arises in a mother's somatic cell often causes a disease in her daughter. b) All mutations in an asexually reproducing single-celled organism are passed on to the progeny. c) In an evolutionary sense, somatic cells exist only to help propagate germ-line cells. d) A mutation is passed on to offspring only if it is present in the germ lin

A mutation that arises in a mother's somatic cell often causes a disease in her daughter.

(Q008) Which of the following changes is least likely to arise from a point mutation in a regulatory region of a gene? a) A mutation that changes the time in an organism's life during which a protein is expressed. b) A mutation that eliminates the production of a protein in a specific cell type. c) A mutation that changes the subcellular localization of a protein. d) A mutation that increases the level of protein production in a cell.

A mutation that changes the subcellular localization of a protein.

(Q002) Your friend works in a lab that is studying why a particular mutant strain of Drosophila grows an eye on its wing. Your friend discovers that this mutant strain of Drosophila is expressing a transcription factor incorrectly. In the mutant Drosophila, this transcription factor, which is normally expressed in the primordial eye tissue, is now misexpressed in the primordial wing tissue, thus turning on transcription of the set of genes required to produce an eye in the wing primordial tissue. If this hypothesis is true, which of the following types of genetic change would most likely lead to this situation? a) A mutation within the transcription factor gene that leads to a premature stop codon after the third amino acid. b) A mutation within the transcription factor gene that leads to a substitution of a positively charged amino acid for a negatively charged amino acid. c) A mutation within an upstream enhancer of the gene. d) A mutation in the TATA box of the gene.

A mutation within an upstream enhancer of the gene.

(Q041) Activated carriers are small molecules that can diffuse rapidly and be used to drive biosynthetic reactions in the cell. Their energy is stored in a readily transferable form such as high-energy electrons or chemical groups. Which of the molecules below donates a chemical group rather than electrons? a) FADH2 b) NADH c) NADPH d) ATP

ATP

Which of the following statements is true about active transport? Select ALL that apply. Active transport moves solutes against its concentration gradient Active transport occurs only on the plasma membrane. Active transport proteins are typically classified as "pumps" Active transport moves solutes in the same direction as the electrochemical gradient. Active transport requires energy

Active transport moves solutes against its concentration gradient Active transport occurs only on the plasma membrane. Active transport proteins are typically classified as "pumps" Active transport moves solutes in the same direction as the electrochemical gradient. Active transport requires energy

Why is it advantageous for cells to oxidize sugars in a stepwise manner, rather than direct burning of sugars as non-living systems (like 🔥 wood in a campfire)? Select ALL that apply (no partial credit for this one). All free energy is released as heat in direct burning, and cells cannot withstand the heat. Furthermore, cells cannot store this energy to power cellular reactions that occur over time in a variety of sub-cellular locations. A large amount of activation energy is required in direct burning (such as lighting a match). Cells cannot overcome this energy-barrier. In stepwise reactions, enzymes can lower the small activation energy associated with each step. The net yield of energy released per sugar molecular is much higher when released in small packets rather than all at once. Cells use enzymes to facilitate maximizing energy yield using the same amount of starting material. While most current life forms use the stepwise process of cellular respiration to release small packets of energy, some organisms like archaeological thrive in extreme conditions by using direct-burning of sugars for energy. Most cells cannot survive the heat generated and have evolved to oxidize sugars at low temperature, but thermophilic archaea can.

All free energy is released as heat in direct burning, and cells cannot withstand the heat. Furthermore, cells cannot store this energy to power cellular reactions that occur over time in a variety of sub-cellular locations. A large amount of activation energy is required in direct burning (such as lighting a match). Cells cannot overcome this energy-barrier. In stepwise reactions, enzymes can lower the small activation energy associated with each step.

Which of the following is NOT a function of the glycocalyx (carbohydrate layer coating the outer surface of the plasma membrane)? Protects the cell surface from mechanical damage. Makes the cell surface slimy allowing motile cells to squeeze through narrow spaces. Allows epithelial cells to attach to the basal lamina. Prevents blood cells from sticking to one another and to walls of blood vessel

Allows epithelial cells to attach to the basal lamina.

Which of the following is not a result of splitting of a glucose molecule during glycolysis? Pyruvate ATP CO2 NADH

CO2

What is the main difference between a channel protein and a transporter? Channel proteins remain embedded in the membrane, wherever transported carry cargo in and out to the cell passing through the cell membrane. Channel proteins discriminate between solutes mainly based on size and charge, while transporters require solutes to fit into specific binding sites. Channels proteins engage in active transport whereas transporters engage in passive transport. Channel proteins always undergo large conformational changes whereas transporters undergo little or no conformational changes during membrane transport.

Channel proteins discriminate between solutes mainly based on size and charge, while transporters require solutes to fit into specific binding sites.

(Q028) Enhancers can act over long stretches of DNA, but are specific about which genes they affect. How do eukaryotic cells prevent these transcription regulators from looping in the wrong direction and inappropriately turning on the transcription of a neighboring gene? a) The cell uses histone acetyltransferase to prevent enhancer binding to the DNA. b) The cell will group neighboring genes into operons so that they are transcribed as a single unit, regulated by a single enhancer. c) Chromosome loop-forming proteins arrange the DNA into topological associated domains such that individual genes and their associated enhancer binding regions are in proximity. d) There is no mechanism to prevent inappropriate enhancer action on neighboring genes. The cells will degrade inappropriately produced mRNA molecules.

Chromosome loop-forming proteins arrange the DNA into topological associated domains such that individual genes and their associated enhancer binding regions are in proximity.

How does electron affinity change as the mitochondrial electron transfer chain proceeds from the first to the last membrane-embedded protein complex? X-axis: direction of electron flow Y-axis: redox potential (mV) Electron affinity is directly proportional to redox potential. It decreases along the direction of electron flow in the above graph. Electron affinity is directly proportional to redox potential. It increases along the direction of electron flow in the above graph. Electron affinity is inversely proportional to redox potential. It increases along the direction of electron flow in the above graph. Electron affinity is inversely proportional to redox potential. It decreases along the direction of electron flow in the above graph.

Electron affinity is directly proportional to redox potential. It increases along the direction of electron flow in the above graph.

Under steady-state conditions, the resting membrane potential of a cell is not equal to zero. In animal cells, this number ranges from -20 to -200 mV. Which of the following options best explains this phenomena? The exterior of the cell has a greater negative charge compared to the interior. This is true despite the fact that the interior of the cell is rich monovalent cations such as sodium and potassium, which effectively balance out the negative charges on nucleic acids. The exterior of the cell is rich in negatively charged chloride ions. The resting potential of the cell membrane is negative because positively charged sodium ions are abundant outside which negatively charged potassium ions are abundant inside the cell. Even in unstimulated conditions, the interior of the cell is more negatively charged than the exterior. The interior has a relative negative charge mainly due to higher concentration of sodium (and calcium) ions outside, compared to potassium ions inside the cell. This is because in unstimulated (resting) cells, the movement of cations and anions across the cell membrane is NOT perfectly balanced.

Even in unstimulated conditions, the interior of the cell is more negatively charged than the exterior. The interior has a relative negative charge mainly due to higher concentration of sodium (and calcium) ions outside, compared to potassium ions inside the cell.

Free energy change value is an indicator of the speed of a biochemical reaction. True False

FAlse

Free energy change value is an indicator of the speed of a biochemical reaction. True False

False

siRNAs are less accurate compared to miRNAs because they typically engage in partial base-pairing with the target sequence. True False

False

(Q021) Which of the following statements about RNA splicing is FALSE? a) Conventional introns are not found in bacterial genes. b) For a gene to function properly, every exon must be removed from the primary transcript in the same fashion on every mRNA molecule produced from the same gene. c) Small RNA molecules in the nucleus perform the splicing reactions necessary for the removal of introns. d) Splicing occurs after the 5´ cap has been added to the end of the primary transcript.

For a gene to function properly, every exon must be removed from the primary transcript in the same fashion on every mRNA molecule produced from the same gene.

Which of the following is not a product of photosynthetic light reactions? Question options: NADPH Glucose O2 ATP

Glucose

Telomeres are characterized by which type of chromatin? Heterochromatin Euchromatin Both Heterochromatin and Euchromatin Protein Coding Genes

Heterochromatin

(Q030) Why are dideoxyribonucleoside triphosphates used during DNA sequencing? a) They cannot be incorporated into DNA by DNA polymerase. b) They are incorporated into DNA particularly well by DNA polymerases from thermophilic bacteria. c) Incorporation of a dideoxyribonucleoside triphosphate leads to the termination of replication for that strand. d) Dideoxyribonucleoside triphosphates are more stable than deoxyribonucleoside triphosphates.

Incorporation of a dideoxyribonucleoside triphosphate leads to the termination of replication for that strand.

How did Francis Crick originally describe the Central Dogma of Molecular Biology? DNA → RNA → Protein RNA molecules must have evolved first. Information once passed on to proteins, cannot flow back. DNA → mRNA → Protein

Information once passed on to proteins, cannot flow back.

(Q019) How does methylation of histone tails affect the accessibility of DNA? a) It relaxes the chromatin to make DNA more accessible. b) It compacts the chromatin to make DNA less accessible. c) Histone methylation has no effect on chromatin. d) It can have different effects depending on the location.

It can have different effects depending on the location.

The spliceosome complex is an RNA-protein complex involved in mRNA splicing. Which of the following statements describes the spliceosome accurately. It is made up of 6 snRNAs named U1-U6 along with spliceosomal proteins. It operates in the cytoplasm. It is found only in prokaryotes such as bacteria and archaea. It is made up of self-splicing lncRNAs.

It is made up of 6 snRNAs named U1-U6 along with spliceosomal proteins.

How does the presence of an unsaturated fatty acid chain within the phospholipid bilayer affect the cell membrane? It makes the cell membrane more rigid. It prevents channel proteins from being embedded within the membrane. It prevents the formation of a kink within the phospholipid bilayer. It makes the cell membrane more fluid.

It makes the cell membrane more fluid.

(Q017) Which of the following statements about the newly synthesized strand of a human chromosome is TRUE? a) It was synthesized from a single origin solely by continuous DNA synthesis. b) It was synthesized from a single origin by a mixture of continuous and discontinuous DNA synthesis. c) It was synthesized from multiple origins solely by discontinuous DNA synthesis. d) It was synthesized from multiple origins by a mixture of continuous and discontinuous DNA synthesis.

It was synthesized from multiple origins by a mixture of continuous and discontinuous DNA synthesis.

(Q024) The equilibrium constant (K) for the reaction Y→X can be expressed with respect to the concentrations of the reactant and product molecules. Which of the expressions below shows the correct relationship between K, [Y], and [X]? a) K = [Y]/[X] b) K = [Y] * [X] c) K = [X]/[Y] d) K = [X] - [Y]

K = [X]/[Y]

(Q026) Which of the following statements about mobile genetic elements is TRUE? a) Mobile genetic elements can sometimes rearrange the DNA sequences of the genome in which they are embedded by accidentally excising neighboring chromosomal regions and reinserting these sequences into different places within the genome. b) DNA-only transposons do not code for proteins but instead rely on transposases found in cells that are infected by viruses. c) The two major families of transposable sequences found in the human genome are DNA-only transposons that move by replicative transposition. d) During replicative transposition, the donor DNA will no longer have the mobile genetic element embedded in its sequence when transposition is complete

Mobile genetic elements can sometimes rearrange the DNA sequences of the genome in which they are embedded by accidentally excising neighboring chromosomal regions and reinserting these sequences into different places within the genome.

Where do the electrons for the electron-transport chain come from? NADH carried two high-energy electrons in the form of a C-H bond produced during sugar oxidation. When NADH is converted to NAD+, initially an unstable hydride ion (H-) is produced. This is quickly converted to an H+ ion and this conversion produces to free electrons. Each time NAD+ is produced from NADH, a single electron is released in order to balance the chemical reaction. Similarly which FADH2 is converted to FAD+, two electrons are released to balance the net charge. ATP contains a high-energy phosphate bond. Each time ATP is converted to ADP, it releases a negatively charged PO43- ion. The extra electrons from this phosphate ion is transferred during electron transport. Electrons are directly produced at multiple stages during glycolysis and citric acid cycle, each time a H+ ion is produced.

NADH carried two high-energy electrons in the form of a C-H bond produced during sugar oxidation. When NADH is converted to NAD+, initially an unstable hydride ion (H-) is produced. This is quickly converted to an H+ ion and this conversion produces to free electrons.

(Q024) NADH and FADH2 carry high-energy electrons that are used to power the production of ATP in the mitochondria. These cofactors are generated during glycolysis, the citric acid cycle, and the fatty acid oxidation cycle. Which molecule below can produce the most ATP? Explain your answer. NADH from glycolysis b) FADH2 from the fatty acid cycle c) NADH from the citric acid cycle d) FADH2 from the citric acid cycl

NADH from the citric acid cycle

Which of the following pumps is an antiport? Na+-driven glucose pump Bacteriorhodopsin Na+-K+ pump Na+-H+ exchanger

Na+-H+ exchanger

Which of the following accompanies the transfer of an electron-pair along transport proteins embedded on the inner mitochondrial membrane? One H+ is pumped from the matrix to the inter-membrane space One Ca2+ is pumped from the matrix to the inter-membrane space One H+ is pumped from the inter-membrane space to the matrix One Ca2+ is pumped from the inter-membrane space to the matrix

One H+ is pumped from the matrix to the inter-membrane space

(Q016) There are several reasons why the primase used to make the RNA primer for DNA replication is not suitable for gene transcription. Which of the statements below is NOT one of those reasons? a) Primase initiates RNA synthesis on a single-stranded DNA template. b) Primase can initiate RNA synthesis without the need for a base-paired primer. c) Primase synthesizes only RNAs of about 5-20 nucleotides in length. d) The RNA synthesized by primase remains base-paired to the DNA templat

Primase can initiate RNA synthesis without the need for a base-paired primer.

Which products of glycolysis would accumulate in the cytosol in the absence of oxygen in cells that cannot do fermentation? Select ALL that apply (no partial credit for this Q). Pyruvate NADH NAD+ Ethanol

Pyruvate NADH

Q010) Which of the following statements is FALSE? a) RNA polymerase can start making a new RNA molecule without a primer; DNA polymerase cannot. b) RNA polymerase does not proofread its work; DNA polymerase does. c) RNA polymerase catalyzes the linkage of ribonucleotides while DNA polymerase catalyzes the linkage of deoxyribonucleotides. d) RNA polymerase adds bases in a 3´-to-5´ direction; DNA polymerase adds bases in a 5´-to-3´ direction.

RNA polymerase adds bases in a 3´-to-5´ direction; DNA polymerase adds bases in a 5´-to-3´ direction.

(Q045) Ribozymes are known to catalyze which of the following reactions in cells? a) DNA synthesis b) transcription c) RNA splicing d) protein hydrolysis

RNA splicing

(Q033) Which of the following statements about retroviruses is FALSE? a) Retroviruses are packaged with a few molecules of reverse transcriptase in each virus particle. b) Retroviruses use the host-genome integrase enzyme to create the provirus. c) The production of viral RNAs can occur long after the initial infection of the host cell by the retrovirus. d) Viral RNAs are translated by host-cell ribosomes to produce the proteins required for the production of viral particles

Retroviruses use the host-genome integrase enzyme to create the provirus.

Which of the following is NOT bound by a phospholipid bilayer? Ribosomes Mitochondria Peroxisomes Golgi apparatus

Ribosomes

Which of the following scientists were excluded from the recipients of the Nobel Prize in Chemistry for solving the structure of DNA. James Watson Francis Crick Rosalind Franklin Maurice Wilkins

Rosalind Franklin

Which of the following solutes is likely to have the highest rate of crossing a lipid bilayer, assuming that membrane has no embedded membrane proteins? Steroid hormone Sodium ion Water Glucose

Steroid hormone

(Q011) What do you predict would happen if you replace the Lac operator DNA from the Lac operon with the DNA from the operator region from the tryptophan operon? a) The presence of lactose will not cause allosteric changes to the Lac repressor. b) The Lac operon will not be transcribed when tryptophan levels are high. c) The lack of glucose will no longer allow CAP binding to the DNA. d) RNA polymerase will only bind to the Lac promoter when lactose is present.

The Lac operon will not be transcribed when tryptophan levels are high.

Which of the following statements is true about Na+-K+ pumps? The Na+-K+ pump reverses the resting membrane potential making the inside of the cell positively charged relative to the outside. The Na+-K+ pump transports 3 potassium ions into the cell for every 2 sodium ions pumped out of the cell. The Na+-K+ pump is an ATPase that is powered by the hydrolysis of ATP. The Na+-K+ pump transports sodium against its electrochemical gradient, while moving potassium along the direction of its concentration gradient.

The Na+-K+ pump is an ATPase that is powered by the hydrolysis of ATP.

(Q026) The ribosome is important for catalyzing the formation of peptide bonds. Which of the following statements is TRUE? a) The number of rRNA molecules that make up a ribosome greatly exceeds the number of protein molecules found in the ribosome. b) The large subunit of the ribosome is important for binding to the mRNA. c) The catalytic site for peptide bond formation is formed primarily from an rRNA. d) Once the large and small subunits of the ribosome assemble, they will not separate from each other until degraded by the proteasome.

The catalytic site for peptide bond formation is formed primarily from an rRNA.

(Q019) Shown below is the ATP hydrolysis cycle of a motor protein. What sentence BEST describes the state of the motor protein in "C"? a) The hydrolysis of ATP to ADP caused a conformational change in the protein. b) The binding of ADP and inorganic phosphate displaced ATP. c) The release of ADP led to a forward shift of the protein along the filament. d) The binding of ATP activated the protein for movement.

The hydrolysis of ATP to ADP caused a conformational change in the protein.

Which of the following most accurately describes allosteric inhibition of enzyme function? The inhibitor binds directly at the enzyme active site. The inhibitor binds to the enzyme at a location distant from the active site and alters the structure of the active site. The inhibitor binds directly to the substrate, blocking it from interacting with the enzyme active site. The inhibitor binds to the enzyme-substrate complex, speeding up the dissociation of the complex into free enzyme and free substrate.

The inhibitor binds to the enzyme at a location distant from the active site and alters the structure of the active site.

Damage to membrane phospholipid bilayer is quickly repaired, a valuable attribute for a cell and its membrane-bound organelles. Which of the following best explains the driving forces behind this phenomenon? Glycolipids line the external layer of the cell membrane prevents high-impact collisions with the lipid bilayer, therefore membrane damage is a rare phenomenon. The ER, which is the site of membrane synthesis, responds instantaneously to membrane damage delivering new phospholipids in the form of a membrane-bound vesicle. The vesicle fuses into the damaged bilayer restoring membrane integrity. Membranes whether its is plasma membrane or intracellular membranes contain embedded transmembrane proteins. Some transmembrane proteins are enzymatic, and specifically respond to damaged bilayer structure to synthesize new phospholipids to replace damaged ones. Cholesterol is embedded within the lipid bilayer makes the membrane rigid. Membrane damage is therefore a rare phenomenon. Damaged portions of the bilayer are quickly sealed by new cholesterol molecules inserting themselves in place of non-viable phospholipids. The membrane bilayer is amphipathic, and self-sealing due to the opposing forces of hydrophobic tails and hydrophilic heads of phospholipids. This promotes rearrangement of phospholipids in response not membrane damage, until the lowest energetic state is reached.

The membrane bilayer is amphipathic, and self-sealing due to the opposing forces of hydrophobic tails and hydrophilic heads of phospholipids. This promotes rearrangement of phospholipids in response not membrane damage, until the lowest energetic state is reached.

What effect does the addition of extra pyruvate have on the rate at which the Kreb's cycle operates? The rate at which the Kreb's cycle operates remains constant. The rate at which the Kreb's cycle operates is decreases dramatically. The rate at which the Kreb's cycle operates is increased dramatically. Additionally of pyruvate affects the rate of glycolysis but not Kreb's cycle.

The rate at which the Kreb's cycle operates is increased dramatically.

In step 2 of the citric acid cycle, the enzyme aconitase generates isocitrate from citrate. Which of the following statements about this reaction is TRUE? a) There is a substantial free-energy difference between the reactants and products of this reaction. b) The unbonded electrons from hydroxide ions provide energy for this reaction. c) The aconitase enzyme functions as a mutase in this reaction. d) The reaction sequence first generates one molecule of water and then consumes one molecule of water.

The reaction sequence first generates one molecule of water and then consumes one molecule of water.

(Q008) Which of the following statements correctly explains what it means for DNA replication to be bidirectional? a) The replication fork can open or close, depending on the conditions. b) The DNA replication machinery can move in either direction on the template strand. c) Replication-fork movement can switch directions when the fork converges on another replication fork. d) The replication forks formed at the origin move in opposite directions.

The replication forks formed at the origin move in opposite directions.

(Q024) Which of the following limits the use of PCR to detect and isolate genes? a) The sequence at the beginning and end of the DNA to be amplified must be known. b) It also produces large numbers of copies of sequences beyond the 5´ or 3´ end of the desired sequence. c) It cannot be used to amplify cDNAs or mRNAs. d) It will amplify only sequences present in multiple copies in the DNA sample

The sequence at the beginning and end of the DNA to be amplified must be known.

(Q011) Which one of the following is the main reason that a typical eukaryotic gene is able to respond to a far greater variety of regulatory signals than a typical prokaryotic gene or operon? a) Eukaryotes have three types of RNA polymerase. b) Eukaryotic RNA polymerases require general transcription factors. c) The transcription of a eukaryotic gene can be influenced by proteins that bind far from the promoter. d) Prokaryotic genes are packaged into nucleosomes.

The transcription of a eukaryotic gene can be influenced by proteins that bind far from the promoter.

The sodium pump and the calcium pump have similarities amino acid sequences as well as three-dimensional protein structures. Which of the following conclusions of these two pumps are accurate? The calcium pump must also be able to transport a second ion (like potassium) in the opposite direction. The two pumps are interchangeable for sodium and calcium ions. The toxic inhibitor of the sodium pump, Ouabain (arrow poison) also inhibits the calcium pump. The two pumps likely share a common evolutionary origin.

The two pumps likely share a common evolutionary origin.

If the formation of NADH and ATP during step 6 and 7 of glycolysis are energetically unfavorable, how do these reactions occur at all? These reactions are coupled with breakage of high-energy hydride bonds. These reactions are made spontaneous by the enzymes pyruvate dehydrogenase and hexokinase, respectively These reactions are coupled with energetically favorable C-H bond oxidation and high-energy phosphate bond breakage. These reactions are made spontaneous by the enzymes glyceraldehyde 3-phosphate dehydrogenase and phopshoglycerate kinase, respectively.

These reactions are coupled with energetically favorable C-H bond oxidation and high-energy phosphate bond breakage.

(Q009) Which of the following is FALSE about molecular chaperones? a) They assist polypeptide folding by helping the folding process follow the most energetically favorable pathway. b) They can isolate proteins from other components of the cells until folding is complete. c) They can interact with unfolded polypeptides in a way that changes the final fold of the protein. d) They help streamline the protein-folding process by making it a more efficient and reliable process inside the cell.

They can interact with unfolded polypeptides in a way that changes the final fold of the protein.

(Q014) DNA can be introduced into bacteria by a mechanism called a) transcription. b) ligation. c) replication. d) transformation

Transformation

(Q007) Which of the following statements is FALSE? a) A new RNA molecule can begin to be synthesized from a gene before the previous RNA molecule's synthesis is completed. b) If two genes are to be expressed in a cell, these two genes can be transcribed with different efficiencies. c) RNA polymerase is responsible for both unwinding the DNA helix and catalyzing the formation of the phosphodiester bonds between nucleotides. d) Unlike DNA, RNA uses a uracil base and a deoxyribose sugar.

Unlike DNA, RNA uses a uracil base and a deoxyribose sugar.

Which of the following best describes how membrane transport affects signaling at a nerve terminal? When an electrical impulse arrives at a nerve terminal, it opens voltage-gated Ca2+ channels on the nerve cell membrane, allowing flow of calcium ions into the terminal. Increased calcium ion concentration stimulates a whole synaptic vesicle to be released into synaptic cleft. In the synaptic cleft, the vesicle fuses with the postsynaptic cell, allowing the neurotransmitter chemical signal to bind to the receptor. When an action potential arrives at a nerve terminal, it opens voltage-gated Ca2+ channels on the nerve cell membrane, allowing flow of calcium ions into the terminal. Increased calcium ion concentration stimulates a synaptic vesicle containing neurotransmitters to fuse with the cell membrane releasing the neurotransmitters into the synaptic cleft. Electrical signal is converted to a secreted chemical signal. When an action potential arrives at a nerve terminal, it activates ATP-driven Ca2+ pumps on the nerve cell membrane, releasing calcium ions into the terminal. Increased calcium ion concentration stimulates a synaptic vesicle containing neurotransmitters to fuse with the cell membrane releasing the neurotransmitters into the synaptic cleft. Electrical signal is converted to a secreted chemical signal. When an action potential arrives at a nerve terminal, it activates ATP-driven Ca2+ pumps on the nerve cell membrane, releasing calcium ions into the terminal. Increased calcium ion concentration stimulates a whole synaptic vesicle to be released into synaptic cleft. In the synaptic cleft, the vesicle fuses with the postsynaptic cell, allowing the neurotransmitter chemical signal to bind to the receptor

When an action potential arrives at a nerve terminal, it opens voltage-gated Ca2+ channels on the nerve cell membrane, allowing flow of calcium ions into the terminal. Increased calcium ion concentration stimulates a synaptic vesicle containing neurotransmitters to fuse with the cell membrane releasing the neurotransmitters into the synaptic cleft. Electrical signal is converted to a secreted chemical signal.

Antibodies have a characteristic Y-shaped structure and contain two sets of heavy and light chains. Are the heavy and light chains covalently linked to each other? Are the heavy and light chains part of the same polypeptide sequence? No - heavy and light chains are not covalently linked. They are composed of 2 distinct polypeptide sequences, not 1. Yes - heavy and light chains are covalently linked via disulphide bonds. However, they are composed of 2 distinct polypeptide sequences, not 1. Yes - heavy and light chains are covalently linked via peptide bonds. Therefore they are composed of a single polypeptide sequence. No - heavy and light chains are not covalently linked. However, they are part of a single polypeptide sequence.

Yes - heavy and light chains are covalently linked via disulphide bonds. However, they are composed of 2 distinct polypeptide sequences, not 1.

(Q026) You want to design a set of PCR primers to amplify a portion of a gene from a cDNA library. Which of the following concerns about PCR primer design is the most legitimate? a) You must be careful when designing your primers to take into account which DNA strand was transcribed in mRNA and make sure both primers are complementary to the mRNA. b) You must be certain not to include any DNA sequences in your primer that are upstream (5´) of the AUG start codon. c) You must make sure that all the DNA sequences in your primer lie within an exon, and do not span two exons. d) You must be certain that all the DNA sequences in your primer are not located downstream (3´) of the polyadenylation signal

You must be certain that all the DNA sequences in your primer are not located downstream (3´) of the polyadenylation signal

(Q007) During respiration, energy is retrieved from the high-energy bonds found in certain organic molecules. Which of the following, in addition to energy, are the ultimate products of respiration? a) CO2; H2O b) CH3; H2O c) CH2OH; O2 d) CO2; O2

a CO2; H2O

(Q027) The repair of mismatched base pairs or damaged nucleotides in a DNA strand requires a multistep process. Which choice below describes the known sequence of events in this process? a) DNA damage is recognized, the newly synthesized strand is identified by an existing nick in the backbone, a segment of the new strand is removed by repair proteins, the gap is filled by DNA polymerase, and the strand is sealed by DNA ligase. b) DNA repair polymerase simultaneously removes bases ahead of it and polymerizes the correct sequence behind it as it moves along the template. DNA ligase seals the nicks in the repaired strand. c) DNA damage is recognized, the newly synthesized strand is identified by an existing nick in the backbone, a segment of the new strand is removed by an exonuclease, and the gap is repaired by DNA ligase. d) A nick in the DNA is recognized, DNA repair proteins switch out the wrong base and insert the correct base, and DNA ligase seals the nick

a. DNA damage is recognized, the newly synthesized strand is identified by an existing nick in the backbone, a segment of the new strand is removed by repair proteins, the gap is filled by DNA polymerase, and the strand is sealed by DNA ligase.

RNA polymerase is less efficient compared to DNA polymerase. This is due to critical differences in structural features and related functions. Which of the following statements is FALSE when comparing DNA and RNA polymerases. a. RNA polymerase can backtrack on the DNA template, and therefore has proofreading capacity. This is what makes RNA polymerase slower than DNA polymerase, which lacks proofreading function. b. RNA polymerase has intrinsic helices function due to a wedge shaped leading edge. DNA polymerase requires a dedicated helices enzyme. c. DNA polymerase is more processive compared to RNA polymerase, due to the presence of a DNA clamp. d. DNA polymerases can only extend an existing free 3' end. RNA polymerases can add nucleotides in the absence of a primer.

a. RNA polymerase can backtrack on the DNA template, and therefore has proofreading capacity. This is what makes RNA polymerase slower than DNA polymerase, which lacks proofreading function.

(Q041) Activated carriers are small molecules that can diffuse rapidly and be used to drive biosynthetic reactions in the cell. Their energy is stored in a readily transferable form such as high-energy electrons or chemical groups. Which of the molecules below donates a chemical group rather than electrons? a) FADH2 b) NADH c) NADPH d) ATP

atp

(Q002) Which of the following statements about restriction nucleases is FALSE? a) A reproducible set of DNA fragments will be produced every time a restriction nuclease digests a known piece of DNA. b) Restriction nucleases recognize specific sequences on single-stranded DNA. c) Some bacteria use restriction nucleases as protection from foreign DNA. d) Some restriction nucleases cut in a staggered fashion, leaving short, single-stranded regions of DNA at the ends of the cut molecule

b. Restriction nucleases recognize specific sequences on single-stranded DNA.

How does termination of translation take place? The stop codon is recognized at the E-site by a release factor protein The stop codon is recognized at the A-site by a release factor protein The stop codon is recognized at the A-site by the terminator t-RNA The stop codon is recognized at the E-site by the terminator t-RNA

b. The stop codon is recognized at the A-site by a release factor protein

(Q004) The consistent diameter of the DNA double helix arises because of which property? a) base pairing of pyrimidines with purines b) the use of deoxyribose sugar with a 3′ -OH c) phosphodiester linkages having a consistent bond length d) the antiparallel nature of the two strands of DNA

base pairing of pyrimidines with purines

Q004) The human genome encodes about 21,000 protein-coding genes. Approximately how many such genes does the typical differentiated human cell express at any one time? a) 21,000—all of them b) between 18,900 and 21,000—at least 90% of the genes c) between 5000 and 15,000 d) less than 2100

between 5000 and 15,000

(Q009) The tryptophan operator a) is an allosteric protein. b) binds to the tryptophan repressor when the repressor is bound to tryptophan. c) is required for production of the mRNA encoded by the tryptophan operon. d) is important for the production of the tryptophan repressor.

binds to the tryptophan repressor when the repressor is bound to tryptophan.

label X (the second mobile carrier in the mitochondria used during electron transport chain): plastoquinone cytochrome c ferredoxin ubiquinone

cytochrome c

(Q023) Telomeres serve as caps protecting the ends of linear chromosomes. Which of the following is FALSE regarding the replication of telomeric sequences? a) The lagging-strand telomeres are not completely replicated by DNA polymerase. b) Telomeres are made of repeating sequences. c) Additional repeated sequences are added to the template strand. d) The leading strand doubles back on itself to form a primer for the lagging strand

d) The leading strand doubles back on itself to form a primer for the lagging strand

Which proteins are likely to act as gene activators? a) G b) H c) J d) both H and J

d) both H and J

(Q019) A chemical reaction is defined as spontaneous if there is a net loss of free energy during the reaction process. However, spontaneous reactions do not always occur rapidly. Favorable biological reactions require __________ to selectively speed up reactions and meet the demands of the cell. a) heat b) ATP c) ions d) enzymes

enzymes

(Q031) Which of the following monomer building blocks is necessary to assemble selectively permeable boundaries around and inside cells? a) sugars b) fatty acids c) amino acids d) nucleotides

fatty acids

Which of the following accurately describes the state of the voltage-gated Na+ channel at condition C. Y-axis denoted membrane potential in mV (marked -40, 0 and 40), and X-axis represents time in milliseconds. open inactivated closed resting

inactivated

Where does this reaction take place? mitochondrial inter-membrane space mitochondrial matrix inner mitochondrial membrane cytosol

mitochondrial matrix

(Q017) Which of the following organelles has both an outer and an inner membrane? a) endoplasmic reticulum b) mitochondrion c) lysosome d) peroxisome

mitochondrion

Which of the following organelles has both an outer and an inner membrane? a) endoplasmic reticulum b) mitochondrion c) lysosome d) peroxisome

mitochondrion

The enzyme ___ catalyzes the transfer of random phospholipids from one monolayer to another.

scramblase

(Q027) Antibody production is an indispensable part of our immune response, but it is not the only defense our bodies have. Which of the following is observed during an infection that is NOT a result of antibody-antigen interactions? a) B cell proliferation b) aggregation of viral particles c) systemic temperature increase d) antibody secretion

systemic temperature increase

(Q008) Which of the following is found only in eukaryotic genomes, and NOT in prokaryotic genomes? a) telomeres b) deoxyribose sugar c) packaging proteins d) chromosomes

telomeres

(Q034) The graph in Figure 3-34 illustrates the relationship between reaction rates and substrate concentration for an enzyme-catalyzed reaction. What does the Kmvalue indicate with respect to enzyme-substrate interactions? a) the maximum rate of catalysis b) the number of enzyme active sites c) the enzyme-substrate binding affinity d) the equilibrium rate of catalysis

the enzyme-substrate binding affinity

(Q037) Nonhomologous end joining can result in all but which of the following? a) the recovery of lost nucleotides on a damaged DNA strand b) the interruption of gene expression c) loss of nucleotides at the site of repair d) translocations of DNA fragments to an entirely different chromosome

the recovery of lost nucleotides on a damaged DNA strand

(Q018) Which of the following factors DO NOT influence the length of a covalent bond? a) the tendency of atoms to fill the outer electron shells b) the attractive forces between negatively charged electrons and positively charged nuclei c) the repulsive forces between the positively charged nuclei d) the minimization of repulsive forces between the two nuclei by the cloud of shared electrons

the tendency of atoms to fill the outer electron shells

(Q022) Which of the following regions of the genome is the LEAST likely to be conserved over evolutionary time? a) the upstream regulatory region of a gene that encodes the region conferring tissue specificity b) the upstream regulatory region of a gene that binds to RNA polymerase c) the portion of the genome that codes for proteins d) the portion of the genome that codes for RNAs that are not translated into protein

the upstream regulatory region of a gene that encodes the region conferring tissue specificity

(Q036) Select the option that best completes the following statement: Nonhomologous end joining is a process by which a double-stranded DNA end is joined a) to a similar stretch of sequence on the complementary chromosome. b) after repairing any mismatches. c) to the nearest available double-stranded DNA end. d) after filling in any lost nucleotides, helping to maintain the integrity of the DNA sequence.

to the nearest available double-stranded DNA end.

(Q014) The process of sorting human chromosome pairs by size and morphology is called karyotyping. A modern method employed for karyotyping is called chromosome painting. How are individual chromosomes "painted"? a) with a laser b) using fluorescent antibodies c) using fluorescent DNA molecules d) using green fluorescent protein

using fluorescent DNA molecules

(Q032) Viruses reproduce inside a host cell because a) viruses package DNA from the host-cell genome into the virus particle. b) viruses need host-cell reverse transcriptase to convert its RNA into DNA. c) viruses use host-cell ribosomes to produce viral coat proteins. d) all viruses must insert their genomes into the host-cell genome in order to be replicated.

viruses use host-cell ribosomes to produce viral coat proteins.

The Cas9 enzyme used in the CRISPR system a) was created by scientists by modifying restriction enzymes. b) was discovered in bacteria as part of a mechanism to protect themselves from foreign DNA. c) was found as part of a natural mechanism used by plants to protect themselves from viruses. d) was found in cultured mouse embryonic stem (ES) cells.

was discovered in bacteria as part of a mechanism to protect themselves from foreign DNA.

(Q010) Cell biologists employ targeted fluorescent dyes or modified fluorescent proteins in both standard fluorescence microscopy and confocal microscopy to observe specific details in the cell. Even though fluorescence permits better visualization, the resolving power is essentially the same as that of a standard light microscope because the resolving power of a fluorescent microscope is still limited by the __________ of visible light. a) absorption b) intensity c) filtering d) wavelength

wavelength

(Q023) For the reaction Y→X at standard conditions with [Y] = 1 M and [X] = 1 M, ΔG is initially a large negative number. As the reaction proceeds, [Y] decreases and [X] increases until the system reaches equilibrium. How do the values of ΔG and ΔG° change as the reaction equilibrates? a) ΔG becomes less negative and ΔG° stays the same. b) ΔG becomes positive and ΔG° becomes positive. c) ΔG stays the same and ΔG° becomes less negative. d) ΔG reaches zero and ΔG° becomes more negative.

ΔG becomes less negative and ΔG° stays the same.

Which of the following is the least likely type of transmembrane polypeptide/protein? Question options: ⍺-helical polypeptide multiple amphipathic ⍺-helices β-sheet polypeptide β-barrel protein

β-sheet polypeptide