LS7a PEQ: Week 1-10

A large agricultural chemical company is testing a new experimental pesticide. An unfortunate side effect in plants treated with this new product is a decrease in NADPH production in the chloroplasts. (Interestingly, reduction of NAD+ to NADH in the mitochondria is unaffected.) Given this observation, which of the answer choices would you expect to observe in the chloroplasts of these plants? an increase in 3-phosphoglycerate levels and a decrease in RuBP levels an increase in 3-phosphoglycerate levels and an increase in RuBP levels a decrease in 3-phosphoglycerate levels and an increase in RuBP levels an increase in glyceraldehyde-3-phosphate levels

an increase in 3-phosphoglycerate levels and a decrease in RuBP levels

The horizontal lines indicate the DNA backbones. Which promoter of the template strand would result in an RNA transcript in which the first 12 positions were 5'-CGCAUUUGGCAU-3'? promoter 1 promoter 2 promoter 3 promoter 4

promoter 2

Colchicine is a drug that blocks the assembly of microtubules. If dividing cells are treated with colchicine, at what stage of mitosis would you predict the arrest would occur? prophase late anaphase G1 of interphase metaphase telophase

prophase

An organism's genomic DNA is analyzed and found to contain 22% thymine. What percentage of that organism's DNA is guanine? 78% 22% 28% 56% 44%

28%

A DNA mutation that affects the primary structure of the alpha-globin protein subunit would also affect the primary structure of the beta-globin protein subunit. True False

False

A missense mutation could occur in exon 4: True False

False

ATP synthase will catalyze its reaction more quickly. True False

False

Cells arrested in G2 will contain the same quantity of DNA as cells arrested in G1: True False

False

Changing nucleotide 5 from A to G would result in a missense mutation: False True

False

Consider the haplotype for the bacterial lac operon: I-O+Z+. There is also a plasmid with the haplotype: I+OcZ-. For all of the questions below, assume there is no glucose and no inducer. Functional beta-galactosidase will be produced in this cell: False True

False

Drug A could be working as an allosteric inhibitor at all substrate concentrations: True False

False

Exiting early from G2 would cause the mutant cells to look this way: False True

False

FeS1 would accumulate in its reduced state: True False

False

Gel set C could result from a mutation that causes methylation of the CpG bases in the promoter region of the gene, assuming that WT is not methylated: False True

False

Hemoglobin would be synthesized by a ribosome on the rough ER: True False

False

Individual alpha-helices found in hemoglobin are stabilized by ionic bonds: True False

False

Molecule X could form a hydrogen bond with another Molecule X: True False

False

Molecule X could form an ionic bond with Cl- True False

False

One of the primers failed to bind the cDNA template: False True

False

Reaction B could be coupled to Reaction D: True False

False

Repressor protein will be bound to both operators in this cell: True False

False

The Calvin Cycle will proceed normally. True False

False

The diagram below shows an imaginary eukaryotic gene containing two exons. The exon nucleotides are numbered beginning at the transcription start site and a portion of the intron is not shown to save space. Use this diagram to answer each of the questions below. The polyA tail is added immediately after the stop codon: True False

False

The figure below shows the light-dependent reactions of photosynthesis. Assume that PSII has lost the ability to split water. Determine whether each of the following statements will be true or false based on this scenario. The accessory pigments in PSII will stop transferring energy to each other. True False

False

The polyA signal sequence is in exon 3: False True

False

The same cyclin protein will regulate the transition to S phase and the transition to M phase: True False

False

The stop codon is in exon 4: True False

False

You used PCR to amplify the human insulin gene from a cDNA template. The target sequence for this PCR reaction is approximately 600 base pairs (bp). To confirm that your PCR worked, you run the PCR products on a gel and obtain the results shown below. The left lane contains DNA fragments of known sizes and the right lane contains your PCR products. Use these results to determine whether each of the following statements is true or false. The correct size target sequence was NOT amplified in this reaction: False True

False

Refer to the periodic table. Decide which molecule is held together by ionic bonds: NO CO2 NH3 CH4 KCl

KCl (Elements with nearly empty outer shells can lose their valence electrons, thereby becoming positively charged but still quite stable because the remaining shell of electrons is complete. Conversely, elements with nearly full shells can 'steal' an additional electron to complete their shell. For example, Na would have eleven total electrons, with one of those in its outermost (valence) shell. A highly electronegative atom like Cl, which needs one more electron to complete its outer shell, could 'steal' that electron from Na, becoming a negatively charged ion (Cl-) and leaving Na as a positively charged ion (Na+).)

Lane that shows the results of running Sample #1 and Sample #4 together: Lane E Lane B Lane A Lane D Lane C

Lane B

Lane that shows the results of running Sample #3 only: Lane D Lane E Lane C Lane A Lane B

Lane C

You are running four different DNA samples (#1, #2, #3, #4) on a gel. For each of the questions below, determine which lane on the gel (A-E) shows the results you would predict to observe. Lane that shows the results for running Sample #1 only: Lane D Lane E Lane B Lane A Lane C

Lane D

Which lane contains the DNA fragments produced by digestion of the plasmid with enzymes X and Y and Z? Lane Q Lane K Lane M Lane H Lane L

Lane H

Below on the left is a diagram of double-stranded DNA of a circular plasmid from a bacterial cell. The positions X, Y, and Z are sites where the plasmid DNA is cleaved by restriction enzymes X, Y, and Z, respectively. The numbers are the size in kilobase pairs (kb) of the DNA regions between the restriction sites. On the right is a diagram of an electrophoresis gel. Lane 1 is the ladder, comprised of DNA fragments that range in size from 1-12 kb showing the position of each band size after electrophoresis. The other lanes are DNA bands observed from digestion of the plasmid with one of more of the restriction enzymes. Which lane contains the DNA fragments produced by digestion of the plasmid with enzyme X only? Lane L Lane H Lane M Lane K Lane Q

Lane K

Which lane contains the DNA fragments produced by digestion of the plasmid with enzymes Y and Z? Lane L Lane K Lane M Lane H Lane Q

Lane L

Which lane contains the DNA fragments produced by digestion of the plasmid with enzymes X and Y? Lane L Lane H Lane M Lane K Lane Q

Lane M

Which lane contains the DNA fragments produced by digestion of the plasmid with enzymes X and Z? Lane M Lane Q Lane H Lane K Lane L

Lane Q

The concentration of Waste molecules is ________ inside the cell compared to the outside. Lower About the same Higher

Lower

Unrepaired single-stranded DNA breaks can lead to double-stranded DNA breaks during the next round of replication. Which repair pathway would be most appropriate for repairing double-stranded DNA breaks? DNA proofreading Nonhomologous end joining Mismatch repair Base excision repair

Nonhomologous end joining

The gel diagram shown represents analysis of blood from a victim of a crime and from two suspects. Criminologists created this gel using a single tandem repeat site. Which suspect is definitely innocent? Neither suspect is definitely innocent. suspect 1 Both suspects are definitely innocent. suspect 2

suspect 2

A weapon (W) left behind at a crime scene is typed for a tandem repeat. The DNA from the weapon includes bands from the victim (V) as well as those from the perpetrator. Which of the suspects (A-E) has tandem repeat bands that are consistent with those of the perpetrator? suspect C suspect E suspect D suspect B suspect A

suspect B

The gel diagram shows the bands obtained for a single tandem repeat in evidence obtained at a crime scene (W) and genomic DNA from four suspects (A-E). Which suspect cannot be ruled out as the source of the DNA in the sample? suspect E suspect D suspect A suspect C suspect B

suspect D

If you made a change in the promoter sequence in the DNA that inactivates the promoter, what would happen at the RNA level? Nothing, the RNA would be made as usual. The mutation of the DNA would be carried through to the RNA sequence. The RNA polymerase would not be able to recognize and bind the DNA, so no RNA would be made. The DNA helicase would not be able to recognize and bind the DNA, so the RNA would not be made.

The RNA polymerase would not be able to recognize and bind the DNA, so no RNA would be made.

What would happen to the daughter cells if the G2 phase of the parent cell is shortened? The cells would be larger than normal. The cells would be missing chromosomes. The cells would be smaller than normal. The cells would not undergo cytokinesis.

The cells would be smaller than normal.

What will happen when the Na+ channel is open? There will be net movement of Na+ into the cell through the channel There will be net movement of Na+ out of the cell through the channel There will be no net movement of Na+ through the channel

There will be net movement of Na+ into the cell through the channel

Consider the molecule shown here (Molecule X). The minus sign next to oxygen represents a full negative charge on that atom. Answer the following questions about Molecule X. Molecule X contains at least one nonpolar covalent bond: False True

True

Consider the three sets of gels below. Each set shows an RNA gel and a protein gel for the products of the same gene. For each gel, "WT" indicates the normal wild type products and "Mut" indicates the mutant products. Use these gels to determine whether each of the following statements is true or false. Gel set A could result from a mutation that inhibits the function of the SWI/SNF nucleosome remodeling complex: True False

True

Drug B could be working as an allosteric inhibitor at all substrate concentrations: False True

True

Gel set B could result from a mutation that causes the gene to be targeted by a histone acetyltransferase (HAT), assuming that WT is not targeted by a HAT: True False

True

Hemoglobin is a protein found in the cytosol of red blood cells. In humans, it is coded for by two different genes: HBA and HBB. The HBA gene encodes a protein subunit called alpha-globin and the HBB gene encodes a protein subunit called beta-globin. Each of these subunits binds a heme molecule that binds oxygen. A diagram of human hemoglobin is shown below. Use this information to determine whether each of the following statements is true or false. Hemoglobin has quaternary structure: True False

True

Molecule X could form a hydrogen bond with water: True False

True

Molecule X could form an ionic bond with Na+: True False

True

NADP+ will accumulate in the chloroplast. False True

True

One of the primers was able to bind at two locations in the cDNA template: True False

True

Reaction A should occur at a faster rate than Reaction D: False True

True

Refer to the free energy diagrams below to answer the following questions. You may assume that the y-axis is the same and directly comparable for all four reactions. True False

True

The diagram below shows a gene with four exons. The reading frame that encodes the protein is shaded and begins in exon 1 and ends in exon 3. Use this diagram to determine whether each of the following statements is true or false. The start codon is in exon 1: True False

True

You are studying the cell cycle using fission yeast. A model of the fission yeast cell cycle is shown below. You have observed some mutant cells that are much longer than wild type cells. Use these data to determine whether each of the following statements is true or false. Blocking the transition from G1 to S would cause the mutant cells to look this way: True False

True

In the diagrams below, the horizontal lines represent double-stranded DNA and the numbers are regions within the DNA. The sites labeled W, X, Y, and Z denote the locations of cleavage sites for the restriction enzymes W, X, Y, and Z, respectively. The DNA at the left is located in a bacterial plasmid vector and that on the right is located in chromosomal DNA. Each restriction enzyme produces ends that can pair with the ends of other DNA fragments produced by the same restriction enzyme but not with the ends produced by any of the other enzymes shown. A researcher plans to produce a clone with the genomic DNA inserted into the vector in the orientation 1-4-3-2. Which two enzymes should be used to cleave the vector and the chromosomal DNA to produce complementary ends that will lead to this result? W and X W and Z Y and Z X and Y X and Z W and Y

X and Y

Which one of the choices would most likely contribute to uncontrolled cell proliferation (that is, cancer)? a mutant enzyme needed for microtubule synthesis/polymerization a mutant kinetochore protein that causes reduced microtubule attachment a mutant DNA synthesis mechanism causing blocked chromosome replication a mutant CDK that was active in the absence of its cyclin binding partner a mutant cyclin that cannot bind to its normal CDK binding partner

a mutant CDK that was active in the absence of its cyclin binding partner

Suppose you know the sequence of a region of DNA in an organism, but you want to know the unknown sequences that flank this known sequence. Cleverly, you cleave the DNA with a restriction enzyme at restriction sites outside the known sequence and then use DNA ligase to form a circle as shown in the figure. The dark blue portion of the circles represents double-stranded DNA whose sequence is known, and the light blue portion represents the flanking regions with unknown sequences. The numbered arrows are places where you consider designing PCR primers, with the 3' end of each primer indicated by the arrowhead. Which primers would you use to amplify the light blue region of the circle? 1 and 3 1 and 2 2 and 4 3 and 4 2 and 3 1 and 4

1 and 3

Imagine you are following a particular tRNA, called tRNAQ, through the process of translation in a eukaryote. In what order does tRNAQ go through the steps listed? Note that some steps may be used more than once. 1. The polypeptide is transferred to tRNAQ. 2. tRNAQ binds the A site of the ribosome. 3. tRNAQ binds the P site of the ribosome. 4. The ribosome shifts, with tRNAQ still bound. 5. tRNAQ binds the E site of the ribosome. 2, 1, 4, 3, 4, 5 2, 4, 1, 4, 2, 4, 5 3, 1, 4, 2, 4, 5 3, 4, 1, 4, 2, 4, 5 5, 1, 4, 3, 4, 5

2, 1, 4, 3, 4, 5

The oligonucleotide primers used in the polymerase chain reaction are typically 20-30 nucleotides in length or longer; however, for purposes of this problem, assume that six nucleotides is long enough. You wish to amplify the fragment shown (the raised dots indicate several kilobases of DNA sequence not shown) and decide to design primers corresponding to the regions that are shown in bold. What primer sequences would you use? 5'-ACTTGC-3' and 5'-TGCCAC-3' 5'-ACTTGC-3' and 5'-GTGGCA-3' 5'-GCAAGT-3' and 5'-GTGGCA-3' 5'-GCAAGT-3' and 5'-TGCCAC-3'

5'-ACTTGC-3' and 5'-TGCCAC-3'

In the previous question, what are the first 12 nucleotides in the sequence of the corresponding region of an RNA transcript if the promoter of the template strand in this molecule is located at the position designated 4? 5'-GCAUUGGGCAUA-3' 5'-AUGCCAAAUGCG-3' 5'-CGUAACCCGUAG-3' 5'-CUACGGGUUACG-3' 5'-CGCAUUUGGCAU-3' 5'-UAUGCCCAAUGC-3'

5'-CGUAACCCGUAG-3'

A certain restriction enzyme X cleaves double-stranded DNA at the sequence shown, where the slash indicates where each strand is cleaved. 5'-AA/ATTT-3' 3'-TTTA/AA-5' Note that the cleavage results in a two-base pair single-stranded region at the 5' end that allows the cleaved ends to undergo base pairing. Which of the restriction enzymes that cleave double-stranded DNA (indicated by the slash) would produce overhanging ends able to pair with those produced by enzyme X? 5'-GGA/TCC-3' 3'-CCT/AGG-5' 5'-GG/ATCC-3' 3'-CCTA/GG-5' 5'-AATA/TT-3' 3'-TT/ATAA-5' 5'-GGAT/CC-3' 3'-CCTA/GG-5' 5'-AAA/TTT-3' 3'-TTT/AAA-5'

5'-GG/ATCC-3' 3'-CCTA/GG-5'

A template DNA strand contains the sequence 5'-ATGCTGAC-3'. The corresponding sequence in the RNA transcript is: 5'-TACGACTG-3'. 5'-GTCAGCAT-3'. 5'-UACGACUG-3'. 5'-GUCAGCAU-3'.

5'-GUCAGCAU-3'.

A template DNA strand contains the sequence 3'-ATGCTGAC-5'. The corresponding sequence in the RNA transcript is: 5'-TACGACTG-3'. 5'-GTCAGCAT-3'. 5'-UACGACUG-3'. 5'-GUCAGCAU-3'.

5'-UACGACUG-3'.

What are the first 12 nucleotides in the sequence of the corresponding region of an RNA transcript if the promoter of the template strand in this molecule is located at the position designated 1? 5'-GCAUUGGGCAUA-3' 5'-AUGCCAAAUGCG-3' 5'-CGUAACCCGUAG-3' 5'-CUACGGGUUACG-3' 5'-CGCAUUUGGCAU-3' 5'-UAUGCCCAAUGC-3'

5'-UAUGCCCAAUGC-3'

A double-stranded DNA molecule, only part of which is shown, is being transcribed. If the molecule is transcribed from left to right, one of the nucleotides shown in bold would be the first transcribed in this small molecule. 5′—ATGATCGGATCGATCCAT—3′ 3′—TACTAGCCTAGCTAGGTA—5′ 3′-UACUAGCCUAGCUAGGUA-5′ 3′-AUGAUCGGAUCGAUCCAU-5′ 5′-AUGAUCGGAUCGAUCCAU-3′ 5′-UACUAGCCUAGCUAGGUA-3′

5′-AUGAUCGGAUCGAUCCAU-3′

The product of this gene contains how many amino acids? 1 2 7 9 4 3 5 6 10 or more 8

6

How many hydrogen atoms are present in a hydrocarbon chain of five carbon atoms with two double bonds and two single bonds? 12 10 6 8

8 (Each carbon can have a total of 4 covalent bonds.)

Three carbon atoms are linked by single covalent bond such that those carbon atoms and bonds together form the shape of a V. All of the unshared electrons form covalent bonds with hydrogen. How many hydrogen atoms does this molecule contain? 10 4 6 8 2

8 (Each valence electron not involved in a C-C bond can form a bond with hydrogen.)

Gel pair that could result from a missense mutation in exon 3: A E B C D

A

Which statements are true regarding redox reactions? (Note that in redox reactions, the molecule that "causes" another to gain or lose electrons is referred to as the agent.) Select all that apply. A molecule that has gained H atoms is said to be reduced. Redox reactions may involve the transfer of hydrogen ions (H+). Oxidizing agents accept electrons. If a molecule accepts electrons, it has been reduced. Reducing agents may accept H+ ions. Oxidizing agents may accept H+ ions.

A molecule that has gained H atoms is said to be reduced. Oxidizing agents accept electrons. If a molecule accepts electrons, it has been reduced. Oxidizing agents may accept H+ ions.

If a mutation rendered the signal recognition particle nonfunctional, what would be the most obvious effect on the cell? Proteins destined for the nucleus would remain in the cytosol. No proteins would arrive at their proper destinations within the cell. All proteins normally secreted by the cell would remain partially formed and attached to the endoplasmic reticulum. Translation would not be completed for most proteins. All proteins normally secreted by the cell would remain in the cytosol.

All proteins normally secreted by the cell would remain in the cytosol.

Gel pair that could result from the insertion of 20 bases in exon 2: E A D B C

B

You would like to ligate a fragment you cleaved with the restriction enzyme BamHI into a plasmid you cleaved with a different enzyme. Which of these enzymes' overhangs will be compatible with BamHI-generated fragments? BamHI sequence and cleavage site: 5' G^GATCC 3' (^ indicates cut site) PstI 5' CTGAC^G 3' HpaI 5' GTT^AAC 3' BclI 5' T^GATCA 3' EcoRI 5' G^AATTC 3'

BclI 5' T^GATCA 3'

Where is DNA polymerase found to the left of the dotted line? Both strands Bottom strand Top strand

Both strands

The diagram below represents the replication bubble that has formed at a bidirectional origin of replication. The dotted line shows where replication first began. Use this diagram to answer the questions below. Where does lagging strand synthesis occur to the right of the dotted line? Top strand Both strands Bottom strand

Bottom strand

Which molecule would most likely require a transport protein to cross the plasma membrane of a red blood cell? C6H12O6 O2 H2O CO2

C6H12O6 (Larger, more polar molecules are less able to cross a membrane than smaller, nonpolar molecules.)

Refer to the periodic table. Decide which molecule is held together by nonpolar covalent bonds: CO2 H2O NH3 KCl

CO2 (Elements from nearby families in the periodic table will not have enough difference in electronegativity to result in a polar covalent bond.)

Muscle cells in the mammalian heart are multinucleate, meaning that multiple nuclei are present in the cytoplasm of individual large cells. Predict what is different about the cell cycle in a muscle cell. The G1 and G2 phases are extended. S phase happens twice. Cytokinesis does not occur. M phase is inhibited.

Cytokinesis does not occur.

The diagram below shows a gene with four exons. The reading frame that encodes the protein is shaded and begins in exon 1 and ends in exon 3. Each of the questions below describes a different mutation. Determine which pair of mRNA and protein gels (A-E) you would most likely observe as a consequence of the mutation. On each gel, "Non" is the nonmutant version of the mRNA/protein and "Mut" is the mutated version of the mRNA/protein. Gel pair that could result from a nonsense mutation in exon 2: E B D C A

D

Which of the statements most accurately describes the benefits of the proofreading function of DNA polymerase? DNA polymerase is always present in the nucleus and can repair all mutations when they occur. All DNA mutations can be detected and repaired during DNA replication. DNA polymerase can repair most mutations as they occur during DNA replication. DNA polymerase can be recruited to recently mutated sites to repair mutations.

DNA polymerase can repair most mutations as they occur during DNA replication.

Compared to when the Na+ channel is closed, how will the transport of Waste molecules change when the Na+ channel is open? The rate of Waste transport out of the cell will: Increase Decrease Not change

Decrease

The concentration of ADP in a cell is increasing. Assuming that the cell has plenty of glucose and oxygen available, fatty acid synthesis should Increase Stay the same Decrease

Decrease

The drug you are developing is intended for patients who have enzymatic activity that is too low, so the drug is used to increase enzyme activity. Which drug would be more effective for treatment? Drug A Drug B

Drug A

Which drug causes the enzyme to reach saturation at the lowest substrate concentration? Drug A Drug B

Drug B

A eukaryotic gene is most likely to be transcribed if it is located where? In a region of the genome in which the histones are acetylated In a heterochromatic region of the genome In a region of the genome in which the histones are methylated In a region of the genome in which the histones are unmodified

In a region of the genome in which the histones are acetylated

A plant cell is exposed to a toxin that makes the thylakoid membrane freely permeable to protons. As a result of adding this toxin, the amount of NADPH in the chloroplast would most likely: Increase Decrease Stay the same

Increase

The concentration of ADP in a cell is increasing. Assuming that the cell has plenty of glucose and oxygen available, carbon dioxide (CO2) production by the cell should: Stay the same Decrease Increase

Increase

The concentration of ADP in a cell is increasing. Assuming that the cell has plenty of glucose and oxygen available, phosphofructokinase (PFK) activity should: Stay the same Decrease Increase

Increase

Imagine that a doctor is culturing two types of cells: one from a malignant melanoma and one from a normal skin sample. How would you expect these two cell populations to differ? Malignant melanoma cells would have active telomerases that constantly replenish and lengthen telomeres. Malignant melanoma cells would have telomeres that shorten during successive rounds of replication. Normal skin cells would have active telomerases that constantly replenish and lengthen telomeres. Normal skin cells would have telomeres that do not shorten during successive rounds of replication. Malignant melanoma cells would have inactive telomerases, so their telomeres would shorten during successive rounds of replication.

Malignant melanoma cells would have active telomerases that constantly replenish and lengthen telomeres.

When oxygen is depleted, the citric acid cycle stops. What could we add to the system to restore citric acid cycle activity (other than oxygen)? acetyl-CoA ADP and Pi ethanol and lactic acid NAD+ or FAD

NAD+ or FAD

If the RNA transcript 5′-AUGAUCGGAUCGAUCCAU-3′ resulting from the DNA sequence, 5′—ATGATCGGATCGATCCAT—3′, is present in the mRNA and translated codon by codon from one end to the other, which of the polypeptides would correspond to this part of the mRNA? Use the table shown to answer this question. NH2- Met-Ile-Gly-Ser-Ile-His -COOH . COOH- Met-Ile-Gly-Ser-Ile-His -NH2 NH2- Tyr-Leu-Ala-Arg-Lue-Val -COOH COOH- Tyr-Leu-Ala-Arg-Lue-Val -NH2.

NH2- Met-Ile-Gly-Ser-Ile-His -COOH

Refer to the periodic table. Decide which molecule is held together by polar covalent bonds: NO CH4 NH3 KCl CO2

NH3 (As we move from left to right across a row in the periodic table, electronegativity of each element's atoms becomes stronger. Those elements near the right columns are strong enough that their covalent bonds can be polar if the atom to which they are bonded is significantly less electronegative.)

The diagram below shows a cell with three different membrane transport proteins. The Na+/K+ Pump is a primary active transporter and the Na+/Waste Co-transporter is a secondary active transporter. Arrows show the direction of net movement of molecules through the Pump and Co-transporter. The Na+ Channel can exist in either a closed state (no Na+ can pass through) or an open state (Na+ can pass through). Use this diagram to answer the questions below. The diagram below shows a cell with three different membrane transport proteins. The Na+/K+ Pump is a primary active transporter and the Na+/Waste Co-transporter is a secondary active transporter. Arrows show the direction of net movement of molecules through the Pump and Co-transporter. The Na+ Channel can exist in either a closed state (no Na+ can pass through) or an open state (Na+ can pass through). Use this diagram to answer the questions below. What will happen to the net movement of Waste molecules if the Na+/K+ Pump stops working? Net movement of Waste out of the cell will stop immediately and then Waste will be transported into the cell Net movement of Waste out of the cell will continue indefinitely (nothing will change) Net movement of Waste out of the cell will continue for some time and then Waste will be transported into the cell Net movement of Waste out of the cell will continue for some time and then all net movement of Waste in or out of the cell will stop All net movement of Waste in or out of the cell will stop immediately

Net movement of Waste out of the cell will continue for some time and then all net movement of Waste in or out of the cell will stop

What amino acid does the second codon of this gene's open reading frame encode? Asparagine (Asp) Isoleucine (Ile) Tyrosine (Tyr) Serine (Ser) None of the above

Serine (Ser)

Antinomycin A is a poison that affects the electron transport chain and renders it nonfunctional. In the presence of Antinomycin the Citric Acid Cycle would: Remain the same Speed up Slow down

Slow down

Consider a cell in which one of the proteins involved in DNA replication is altered. This alteration results in an increased occurrence of single-stranded DNA breaks in the newly synthesized DNA. Which protein function is most likely nonfunctional in this situation? The unwinding function of helicase The winding stress relief function of topoisomerase The proofreading function of DNA polymerase The fragment joining function of ligase The strand separation function of single-stranded binding protein (SSB)

The fragment joining function of ligase

Refer to Animation: Fluid Mosaic Model. Although the phospholipid molecules can be in constant lateral movement, they very rarely flip from one side of the bilayer to the other. Which of the answer choices could explain this? The molecular attraction between the fatty acid tails is too strong. The cholesterol keeps the phospholipids on the correct side. The head groups are repelled by the hydrophobic membrane interior. The head groups are too large to fit between the interior fatty acid tails.

The head groups are repelled by the hydrophobic membrane interior. (Head groups are hydrophilic.)

To cells that are defective in primer removal, you add fluorescent ribonucleotides when the cells are undergoing DNA replication. In this case, you observe that one strand glows more than the other not only near the replication fork but also at intervals along its length. Which strand glows in this way and why? The leading strand glows in this way because it is synthesized discontinuously. The lagging strand glows in this way because it is synthesized continuously. The lagging strand glows in this way because its RNA primers are required for each Okazaki fragment and are closely spaced. The leading strand glows in this way because it is synthesized continuously.

The lagging strand glows in this way because its RNA primers are required for each Okazaki fragment and are closely spaced.

Suppose you add fluorescent ribonucleotides to a cell undergoing DNA replication so that the RNA primers used in DNA synthesis glow when viewed with a fluorescent microscope. You notice that, near each replication fork, one strand glows more than the other. Which strand glows more, and why? The leading strand glows more because it is elongated nearest the replication fork. The lagging strand glows more because its RNA primer is nearer the replication fork. The lagging strand glows more because it forms the "trombone loop." The leading strand glows more because it forms the "trombone loop."

The lagging strand glows more because its RNA primer is nearer the replication fork.

Hypothesis: Protein A is a histone acetyltransferase (HAT). This hypothesis is rejected by the results The results do not provide enough information to support or reject this hypothesis This hypothesis is supported by the results

The results do not provide enough information to support or reject this hypothesis

Hypothesis: Protein B represses (decreases) expression of Gene Y. The results do not provide enough information to support or reject this hypothesis This hypothesis is supported by the results This hypothesis is rejected by the results

The results do not provide enough information to support or reject this hypothesis

When carbohydrates are metabolized as cellular fuel, the C-H and C-C bonds of the carbohydrate are oxidized to C=O bonds of carbon dioxide. Oxidation is defined as a loss of electrons, but carbon does not become positively charged in the process. Why, then, is this considered oxidation? The phosphate groups of ATP are ionized and carbons donate those electrons. C=O bonds in CO2 are double bonds, and C-H bonds are single bonds. Electrons in the C=O bonds are higher energy than the electrons in the C-H bonds. The shared electrons in C-O bonds spend less time close to the carbon nucleus than the shared electrons in C-H or C-C bonds.

The shared electrons in C-O bonds spend less time close to the carbon nucleus than the shared electrons in C-H or C-C bonds.

Examine the figure shown, which depicts one stage in the process of translation in a eukaryote. What will happen when the ribosome shifts one codon further on the mRNA, assuming the next codon is not a stop codon? Select all that apply. The tRNA carrying the polypeptide will be in the P site. The tRNA that is in the A site in the figure shown will be ejected from the ribosome. The tRNA that is no longer carrying the polypeptide will be ejected from the ribosome. A new tRNA will bind to the ribosome. The sites of the ribosomes will be relabeled (from left to right) P, A, E.

The tRNA carrying the polypeptide will be in the P site. The tRNA that is no longer carrying the polypeptide will be ejected from the ribosome. A new tRNA will bind to the ribosome.

A beaker contains two solutions of salt dissolved in water. The two solutions have different concentrations of salt (measured by molarity, M) and are separated by a membrane that is permeable to both salt and water. The salt and water will move through the membrane by diffusion. Which statement is true about the diffusion of these solutions? There will be a net movement of water from side A to side B and no movement of salt. There will be a net movement of both salt and water from side B to side A. There will be a net movement of salt from side B to side A and net movement of water from side A to side B. There will be a net movement of salt from side A to side B and no movement of water.

There will be a net movement of salt from side B to side A and net movement of water from side A to side B.

Which of the answer choices could be true if a plant cell is exposed to a toxin that makes the thylakoid membrane freely permeable to protons? Select all that apply. The amount of carbohydrate produced would increase. There would be no ATP produced in the chloroplasts to power photosynthesis in the absence of light energy. There would be no ATP needed to split H2O molecules early in the light-dependent pathway. There would be no ATP available to drive carbohydrate synthesis in the Calvin cycle. ATP generated by the mitochondria would be used to power photosynthesis, so plant cells would not have enough ATP left to supply the many other processes for which they require ATP. The amount of NADPH in the chloroplast would increase.

There would be no ATP available to drive carbohydrate synthesis in the Calvin cycle. The amount of NADPH in the chloroplast would increase.

Kangaroo rats live in the deserts of the southwestern United States. Kangaroo rats have many adaptations to minimize water loss. They obtain a small amount of water from seeds that they eat. However, the rest of the water they obtain is from cellular respiration. This could be true, as water is produced in cellular respiration. This could be true, as water is produced in the citric acid cycle. This cannot be true, as water is actually consumed in cellular respiration. This could be true, as water is produced in glycolysis. This cannot be true, as cellular respiration doesn't really "produce" water.

This could be true, as water is produced in cellular respiration.

Hypothesis: Protein A and Protein B can bind the same piece of DNA at the same time. This hypothesis is supported by the results This hypothesis is rejected by the results The results do not provide enough information to support or reject this hypothesis

This hypothesis is rejected by the results

Hypothesis: Protein B can bind DNA. The results do not provide enough information to support or reject this hypothesis This hypothesis is rejected by the results This hypothesis is supported by the results

This hypothesis is supported by the results

You are studying two proteins (A and B) that you think are involved in regulating the expression of Gene Y. You perform a gel shift (EMSA) assay using a regulatory DNA sequence from Gene Y. Each question below represents a hypothesis that you are testing. For each hypothesis, determine whether it is supported or rejected by the results of your EMSA experiment, or whether the results do not provide enough information. Hypothesis: Protein A can bind DNA. The results do not provide enough information to support or reject this hypothesis This hypothesis is supported by the results This hypothesis is rejected by the results

This hypothesis is supported by the results

Most patients respond well to treatment with the most effective drug (your answer to question 4). However, one unusual patient responds poorly, and her enzymatic activity decreases even further when she takes the drug. From this observation you can conclude that: This patient's substrate concentration is below 100 uM This patient's substrate concentration is over 200 uM This patient has no enzyme for the drug to interact with

This patient's substrate concentration is below 100 uM

Which strand is bound to more RNA primers to the left of the dotted line? Top strand Bottom strand Both strands

Top strand

A nonsense mutation could occur in exon 1: False True

True

Assume the redox potential of cyt-b were to change from +70 to -120. Determine whether each of the following statements is true or false for this scenario. NAD+ would accumulate: False True

True

CRP-cAMP will be bound to both copies of the lac operon in this cell: True False

True

Cells arrested in M will have more condensed DNA than cells arrested in G2: False True

True

Changing nucleotide 13 from C to A would result in a nonsense mutation: False True

True

In the metabolic pathway illustrated, the reactant (substrate A) is converted equally to one of two end products, E or G. Use the diagram of the pathway to answer the question. Letters indicate the substrates and products, and numbers indicate the enzymes. In this pathway, the intermediate, C, is a substrate for both enzyme 3 and enzyme 5 and is converted with equal efficiency to D and F. If end product G inhibits enzyme 5, what would you expect to observe as the amount of G increases in the cell? a decrease in the production of D an increase in the production of C an increase in the production of E an increase in the production of B an increase in the production of G

an increase in the production of E

Assume you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y but not for X. Your strategy should be to: insert the fragments cut with restriction enzyme X directly into the plasmid without cutting the plasmid cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with restriction enzyme Y cut the plasmid with restriction enzyme X and then insert the gene into the plasmid cut the plasmid twice with restriction enzyme Y and ligate the two fragments onto the ends of the DNA fragments cut with restriction enzyme X

cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with restriction enzyme Y

The beaker in the illustration contains two solutions of salt with different concentrations (measured by molarity, M). The two solutions are separated by a membrane that is permeable to water but not to salt. What will occur in this container? diffusion of salt from B to A, but not of water diffusion of water from B to A and of salt from A to B diffusion of both water and salt from B to A diffusion of water from A to B but no diffusion of salt

diffusion of water from A to B but no diffusion of salt

In a metabolic pathway, a series of enzymatic reactions catalyzes the conversion of molecule A to molecule E. Several intermediate steps are involved in which the product of one reaction becomes the substrate for the next. The graph illustrates the changes of free energy that occur at each step in the pathway. Overall, this _____, based on the changes in free energy that take place as A is converted to E. is an anabolic pathway pathway has four endergonic reactionsis a catabolic pathwaypathway has four exergonic reactions

is an anabolic pathway

Which of the reactions would you predict could be coupled to ATP synthesis from ADP + Pi? Select all that apply. creatine phosphate + H2O → creatine + Pi, ΔG - 10.3 kcal/molphosphoenolpyruvate + H2O → pyruvate + Pi, ΔG - 14.8 kcal/molglucose 6-phosphate + H2O → glucose + Pi, ΔG - 3.3 kcal/molglucose 1-phosphate + H2O → glucose + Pi, ΔG - 5.0 kcal/molglutamic acid + NH3 → glutamine, ΔG + 3.4 kcal/mol

kcal/molphosphoenolpyruvate + H2O → pyruvate + Pi, ΔG - 14.8 kcal/molglucose 6-phosphate + H2O → glucose + Pi, ΔG - 3.3

A mutant strain of E. coli is found that produces both β-galactosidase and permease constitutively. Which of the following genotypes could cause this? Select all that apply. lacP- mutation in CRP-cAMP binding site lacI- lacZc and lacYc lacOc

lacI- lacOc

Can it be determined from the data in the table which eukaryotic species has the largest genome? Can it be determined which species has the greatest number of chromosomes? no; no yes; yes no; yes yes; no

no; no

A gene that normally has the sequence CAGAGCCTATTAGGC is replicated as CAGAGCTGACGAGGC. Which of the repair mechanisms would most likely be employed to fix this replication error? base excision repair nucleotide excision repair base excision repair and/or nucleotide excision repair None of the answer options is correct. DNA polymerase proofreading

nucleotide excision repair

Which of the options is circled in this electron micrograph? two double-stranded DNA molecules one double-stranded DNA molecule one single strand of a DNA molecule

one double-stranded DNA molecule

Each DNA parent strand within a replication bubble acts as a template strand that produces: two leading strands or two lagging strands. either a leading strand or a lagging strand. one leading strand and one lagging strand. only leading strands. only lagging strands.

one leading strand and one lagging strand.

As a piece of linear DNA is replicated, the leading strand will have _____ RNA primer(s) and the lagging strand will have _____ RNA primer(s). one; many one; one many; one many; many

one; many

A new experimental pesticide is being tested by a large agricultural chemical company. An unfortunate side effect in plants treated with this new product is a decrease in ATP production in the chloroplasts. (Interestingly, production of ATP in the mitochondria is unaffected.) Which of the answer choices would you expect to be directly affected by the new pesticide? the oxidation of RuBP by rubisco the transport of electrons along the photosynthetic electron transport chain the rate of photorespiration the carboxylation of RuBP by rubisco

the rate of photorespiration

Which of the examples are considered catabolism? Select all that apply. use of fat (triglyceride) stores as a cellular energy source hydrolysis of glycogen (a glucose polymer) during physical activity fat cells growing bigger during times of ample nutrition synthesis of new DNA copies prior to cell division a person losing weight on a calorie restriction diet

use of fat (triglyceride) stores as a cellular energy source hydrolysis of glycogen (a glucose polymer) during physical activity a person losing weight on a calorie restriction diet

Mismatch repair, base excision repair, and nucleotide excision repair are similar in that each: repairs multiple mismatched or damaged bases across a region. repairs a single mismatched base. repairs a short strand of mismatched nucleotides. uses an undamaged segment of DNA as the template to repair a damaged segment of DNA. None of the other answer options is correct.

uses an undamaged segment of DNA as the template to repair a damaged segment of DNA.

The parallel lines shown represent the paired strands of a DNA double helix. If this molecule undergoes one round of replication, which ends are shorter in the daughter molecules than in the parental molecules? w and x w and z w and y y and z y and x

w and z

A strain of E. coli is genetically engineered in which the lacZ and lacY genes are removed and replaced with a gene encoding a fluorescent protein. A copy of the operon in which the protein product fluoresces green is inserted into the chromosome, and a copy in which the protein product fluoresces red is inserted into a plasmid. Both copies carry a wild-type lacO gene, and the cells of the strain have a single copy of the lacI repressor gene. If both fluorescent proteins are expressed, the cells fluoresce yellow (because a combination of red and green fluorescence appears as yellow), and if neither of the fluorescent proteins is expressed, the cells show no fluorescence. If the lacI gene in the genetically engineered fluorescent strain were nonmutant but the lacO sequence on the chromosome mutated to lacOc, how would the cells fluoresce in the presence of inducer? In the absence of inducer? yellow; red yellow; green None of the other answer options is correct. yellow; yellow yellow; no fluorescence

yellow; green

A strain of E. coli is genetically engineered in which the lacZ and lacY genes are removed and replaced with a gene encoding a fluorescent protein. A copy of the operon in which the protein product fluoresces green is inserted into the chromosome, and a copy in which the protein product fluoresces red is inserted into a plasmid. Both copies carry a wild-type lacO gene, and the cells of the strain have a single copy of the lacI repressor gene. If both fluorescent proteins are expressed, the cells fluoresce yellow (because a combination of red and green fluorescence appears as yellow), and if neither of the fluorescent proteins is expressed, the cells show no fluorescence. If the lacI gene in the genetically engineered fluorescent strain were nonmutant but the lacO sequence on the plasmid mutated to lacOc, how would the cells fluoresce in the presence of inducer? In the absence of inducer? yellow; no fluorescence yellow; green yellow; yellow yellow; red None of the other answer options is correct.

yellow; red

A strain of E. coli is genetically engineered in which the lacZ and lacI genes are removed and replaced with a gene encoding a fluorescent protein. A copy of the operon in which the protein product fluoresces green is inserted into the chromosome, and a copy in which the protein product fluoresces red is inserted into a plasmid. Both copies carry a wild-type lacO gene, and the cells of the strain have a single copy of the lacI repressor gene. If both fluorescent proteins are expressed, the cells fluoresce yellow (because a combination of red and green fluorescence appears as yellow), and if neither of the fluorescent proteins is expressed, the cells show no fluorescence. If the lacI gene in the genetically engineered fluorescent strain is mutated to an inactive form (lacI-), the cells would fluoresce _____ in the presence of an inducer and _____ in the absence of an inducer. yellow; red yellow; yellow yellow; no fluorescence yellow; green no fluorescence; no fluorescence

yellow; yellow

In order to analyze how different components of the lac operon work, scientists created special strains of E. coli, called partial diploids. A partial diploid has one full copy of the lac operon in the bacterial chromosome plus another copy of the lac operon in a plasmid. Hence, for the lac operon (and only the lacoperon) the bacterial cell is a diploid. Below is one possible genotype of a partial diploid. The genotype written to the left of the slash (/) is that of the lacoperon in the bacterial chromosome, and the genotype written to the right of the slash is that of the lac operon in the plasmid. I+ P- O+ Z+/ I- P+ O+ Z- For the partial diploid genotype shown here, determine whether functional β-galactosidase is synthesized in the absence and in the presence of lactose. β-galactosidase is produced whether lactose is present or absent. β-galactosidase is produced when lactose is present but is not produced when lactose is absent. β-galactosidase is not produced when lactose is present but is produced when lactose is absent. β-galactosidase is not produced whether lactose is present or absent.

β-galactosidase is not produced whether lactose is present or absent.