BISC-220 Practice Exam 1 [ANSWER KEY] PDF

Name: _______________________________ Lab Instructor:_________________________ Spring 2025 BISC-220 Practice Exam 1 [ANSWER KEY] Lecturer: Rita Barakat, PhD NOTE: The following answer key corresponds to the practice exam posted on Brightspace, which is also last spring’s first exam. PLEASE READ ALL THE INSTRUCTIONS ON THIS PAGE CAREFULLY. 1. Write in your name and your lab instructor’s name on this exam sheet. 2. DO NOT start until instructed. 3. Make sure you have a total of 14 pages. 4. Continuing on the exam after the time is up will result in a zero for the exam. Instructions for filling in the Blue Scantron Answer Sheet (must use #2 pencil): 1. NAME – bubble in your last name, bubble in an empty bubble for a space, bubble in your first name 2. IDENTIFICATION NUMBER – your USC ID # 3. Columns K & L: last two digits of your LECTURE section: a. 13028: 8:00 am Tuesday/ Thursday b. 13022: 9:30 am Tuesday/ Thursday 4. Columns O & P: last two digits of your LAB section (for example 62 for 13162) 5. Bubble in your answers with a #2 pencil on SIDE 1. Be sure to fill in the entire circle. Fully erase all mistakes. 6. When you are done turn in the entire exam with the Blue Scantron Answer Sheet (inserted between your exam pages) to the instructor. TOTAL : ________/ 150 Instructions: Read each question carefully and choose the most correct answer. 1. Why is it not possible for a large polar or ionic molecule to directly cross the cell membrane? a. These molecules are too large to fit through the miniscule pores created by the fatty acid tails in the middle of the membrane. b. These molecules are not miscible, or “mixable” with the hydrophobic medial layer of the membrane. c. These molecules are likely to react with other molecules embedded within the membrane. d. These molecules are not capable of moving fast enough to cross the cell membrane without the use of energy on the part of the cell. e. None of the above. 2. If you were to dissolve 30 mg of NaCl in water, the compound would ionize and _________ would become a cation while _________ would become an anion. a. sodium; water b. chloride; water c. sodium; chloride d. chloride; sodium e. water; chloride 3. All of the following statements about bulk transport in cells are true except: a. Endo- and exocytosis are examples of bulk transport. b. Forms of bulk transport do not require any energy expenditure. c. In eukaryotic cells, the endomembrane system plays an important role in bulk transport, and endocytosis specifically. d. Bulk transport can include the endo- or exocytosis of solid or liquid materials that are not otherwise able to cross the cell membrane. e. All of the above are true statements about bulk transport 4. In a plant cell, one would expect transcription to take place in the ___________ and translation to take place at the ___________. a. nucleolus; ribosome b. nucleus; ribosome c. nucleolus; endoplasmic reticulum d. nucleus; endoplasmic reticulum e. nucleus; Golgi apparatus BISC-220 Practice Exam 1 [ANSWER KEY], 2 5. You and your lab partner are attempting to visualize an onion root tip cell as it is dividing under a standard light microscope. You review the steps for achieving optimal Koehler Illumination, then begin by setting the objective lens to the lowest magnification. You place the microscope slide on the stage, secure it with the clips and turn on the lamp, but you find it difficult to bring the image into focus. What is most likely the problem with your microscope calibration? a. The objective lens may be scratched or otherwise damaged, preventing the image from coming into focus. b. The ocular lens may not be positioned over the specimen. c. You did not lower the stage completely before adjusting the height using the coarse adjustment knobs. d. You should always begin at the highest magnification setting on the objective lens. e. The specimen is likely damaged and is thus not possible to visualize. 6. ____________ are relatively weak intermolecular bonds that are formed due to electrostatic forces. a. Polar covalent bonds b. Nonpolar covalent bonds c. Hydrogen bonds d. Ionic bonds e. Peptide bonds 7. Hexokinase is an enzyme that catalyzes the first reaction of glycolysis, which takes place in the cytoplasm of all cells (prokaryotic and eukaryotic). Where specifically would you expect this enzyme to be synthesized in a eukaryotic cell? a. In the nucleus b. At a ribosome c. At a ribosome floating freely in the cytoplasm d. At a ribosome embedded in the rough endoplasmic reticulum e. Close to the cell membrane 8. Which of the four major macromolecules are most essential for cell respiration, and are typically utilized as an “immediate energy source” by cells? a. Lipids b. Proteins c. Carbohydrates d. Nucleic Acids e. Enzymes BISC-220 Practice Exam 1 [ANSWER KEY], 3 9. Which of the following statements about valence shells is/ are true? a. The innermost valence shell of all atoms (except Hydrogen and Helium) is considered to be “full” if it contains 2 electrons. b. The outermost valence shell of all atoms (except Hydrogen and Helium) is considered to be “full” if it contains 8 electrons. c. The innermost valence shell of all atoms (except Hydrogen and Helium) is considered to be “full” if it contains 8 electrons d. Both a and b e. Both b and c 10.Long-term carbohydrate energy storage in animals typically requires converting glucose into which of the following polysaccharides? a. Amylose b. Amylopectin c. Glycogen d. Cellulose e. Triglycerides 11.You would expect a plasma membrane that is enriched with saturated fatty acid tails to be more ________. a. fluid b. dynamic c. viscous d. flexible e. permeable 12.Which of the following molecules is the monomer for proteins? a. b. correct answer c. d. e. None of the above BISC-220 Practice Exam 1 [ANSWER KEY], 4 13.You are performing a digestion assay on an unknown carbohydrate isolated from a plant cell. You attempt to digest the carbohydrate with a solution containing the enzyme pepsin, which is found in the human stomach and aids in chemical digestion. You find that over time, this carbohydrate is broken down into its monomeric units (glucose). Which of the following is most likely the type of carbohydrate isolated? a. Glycogen b. Cellulose c. Starch d. a or c e. b or c 14.Which of the following is an example of an unsaturated cis fatty acid in our diet? a. Poultry b. Whole grains c. Avocado oil d. Butter e. French fries 15.Dopamine signaling via D2-type receptors, which are GPCRs (as with D1-type receptors), results in ________ of Adenylyl Cyclase, leading to a net ________ in movement. a. excitation; increase b. excitation; decrease c. inhibition; decrease d. inhibition; increase e. modulation; decrease 16.Hemoglobin is an example of a protein that has achieved a __________ level of folding structure. a. primary b. secondary c. tertiary d. quaternary e. heme BISC-220 Practice Exam 1 [ANSWER KEY], 5 17.In order for neurotransmitters to be transported from the cell body of a neuron (where they are synthesized) to the axon terminal (where they are released into the synapse), they must be transported by a special polarized intracellular motor protein known as _________, which carries the neurotransmitters in pre-packaged synaptic vesicles. a. kinesin b. myosin c. actin d. microtubules e. intermediate filaments 18.The products in an ATP hydrolysis reaction are __________ and __________. a. AMP; ADP b. ribose sugar; inorganic phosphate c. ADP; inorganic phosphate d. nucleotide; inorganic phosphate e. nitrogenous base; inorganic phosphate 19.At which level of protein structure would you expect disulfide bonds to form? a. Primary b. Secondary c. Tertiary d. Quaternary e. None of the above 20.An enzyme that binds a single substrate and produces two or more products is typically considered a(n) __________ enzyme. a. anabolic b. catabolic c. catalytic d. kinase e. phosphorylase 21.All of the following are biochemically accurate differences between DNA and RNA except: a. DNA contains the nitrogenous base Uracil where RNA contains the nitrogenous base Thymine b. DNA contains the nitrogenous base Thymine where RNA contains the nitrogenous base Uracil c. DNA is (almost always) double-stranded, whereas RNA is (almost always) single-stranded d. DNA lacks an oxygen on the ribose sugar in the phosphodiester backbone, whereas RNA contains this additional sugar e. All of the above are biochemically accurate differences between DNA and RNA BISC-220 Practice Exam 1 [ANSWER KEY], 6 22.All of the following elements are considered to be essential for life on Earth, and are the most abundant elements in most living things, except: a. Hydrogen b. Oxygen c. Sulfur d. Potassium e. Nitrogen 23.You are interested in studying the distribution of a specific membrane protein that is embedded on the outer (extracellular) surface of the plasma membrane in myofibrils (structures found in skeletal muscle cells). Which of the following microscopy techniques would be most appropriate to use for this kind of research? a. Scanning Electron Microscopy (SEM) b. Transmission Electron Microscopy (TEM) c. Fluorescent Microscopy d. Light Microscopy e. X-ray Crystallography 24.All of the following kingdoms are within the domain Eukarya except: a. Protista b. Fungi c. Archaea d. Animalia e. Plantae 25.Which of the following statements about prokaryotic cells is false? a. Some prokaryotic cells may have a cell wall, though this cell wall does not typically consist of cellulose. b. Prokaryotic cells contain circular DNA, in addition to small loops of DNA accumulated through reproduction called plasmids. c. An entire prokaryotic organism consists of a single (prokaryotic) cell. d. Prokaryotic cells may contain some membrane-bound organelles, such as vesicles. e. Prokaryotic cells may have flagella or cilia to aid in whole-cell motility and responding to their environment. 26.In the lac operon, the ________ will bind most strongly to the control region of the operon when the concentration of lactose within the cell is ________. a. repressor; low b. repressor; high c. enhancer; low d. enhancer; high e. transcription factor; low BISC-220 Practice Exam 1 [ANSWER KEY], 7 Questions 27 - 32 pertain to the figure shown below. 27.Which of the structures in this diagram are considered part of the endomembrane system? a. 8, 5, 4 and 3 b. 9, 5, 4 and 3 c. 6, 5, 4 and 3 d. 1, 5, 3 and 6 e. 4, 5, 6 and 9 28.The structure labeled 11 is the location of cellular respiration in animal and plant cells, which means that it is the _________. a. ribosome b. nucleus c. mitochondria d. chloroplast e. Golgi Apparatus 29.Which organelle or structure plays an important role in intracellular motility, specifically during cell division? a. 9 b. 1 c. 7 d. 6 e. 10 BISC-220 Practice Exam 1 [ANSWER KEY], 8 30.Proteins that are destined to remain within the cell, such as enzymes or transcription factors, are most likely to be synthesized at a ribosome in which structure/ location? a. 10 b. 5 c. 4 d. 3 e. 6 31.The structure labeled 2 is found in all cells, including prokaryotes. It is the location where the concentration of genetic material (DNA) is most dense, and is known as the _________. a. nucleus b. nucleolus c. nucleosome d. cytoplasm e. ribosome 32.Which of the following structures is/ are not membrane-bound? a. 3 b. 7 c. 9 d. b and c e. a, b and c 33.For both, G-protein Coupled Receptors and Receptor Tyrosine Kinases, the N-terminus of the protein is typically located on/ in the ________, whereas the C-terminus is typically located on/ in the ________. a. intracellular side; extracellular side b. extracellular side; intracellular side c. cell membrane, extracellular side d. cell membrane; intracellular side e. extracellular side; cell membrane 34.Which of the following types of RNA participate(s) in translation in prokaryotes and eukaryotes? a. messenger RNA (mRNA) b. transfer RNA (tRNA) c. ribosomal RNA (rRNA) d. a and b only e. a, b and c BISC-220 Practice Exam 1 [ANSWER KEY], 9 35.Estradiol is a steroid hormone secreted by the ovaries in biological females. Because steroid hormones are considered to be lipids, which of the following transport mechanisms is most likely to occur when small amounts of estradiol are present outside of a cell? a. Simple diffusion of estradiol into the cell b. Facilitated diffusion of estradiol into the cell c. Cotransport of estradiol and another chemical into the cell d. Bulk transport of estradiol into the cell e. Receptor-mediated endocytosis of estradiol into the cell 36.An increase in the number of free-floating ______ in a solution will result in a(n) _______ in the pH, making the solution more acidic. a. H+ ; decrease b. H+ ; increase c. OH- ; decrease d. OH- ; increase e. H ; decrease 37.Which of the following shows the trans geometric isomer of pentene? b. a. d. c. correct answer e. None of the above BISC-220 Practice Exam 1 [ANSWER KEY], 10 38.In 2007, a Sacramento radio station sponsored a “water drinking contest” which resulted in the death of a 29-year old, otherwise healthy woman (this unfortunately happened again in 2022). The woman’s cause of death was listed as “water intoxication”. At the cellular level, what are the consequences of consuming too much water in too short of a period of time? a. Excessive water consumption results in a hypotonic extracellular environment, causing cells to shrivel due to water loss. b. Excessive water consumption results in a hypertonic extracellular environment, causing cells to shrivel due to water loss. c. Excessive water consumption results in a hypotonic extracellular environment, causing cells to burst due to rapid influx of water into the cell. d. Excessive water consumption results in a hypertonic extracellular environment, causing cells to burst due to rapid influx of water into the cell. e. Excessive water consumption leads to uncontrolled swelling of the plasma membrane, specifically in red blood cells. 39.Which of the following statements is/ are true about cotransporters but not protein pumps? a. They require energy in the form of ATP to function. b. They require energy in the form of favorable entropy from the movement of one molecule along its concentration gradient to function. c. They can transport two or more molecules at a time in the same or opposite directions. d. Both a and c e. Both b and c 40.You are conducting a dialysis experiment in order to determine the relative size of an unidentified molecule isolated from an animal cell. You begin by dissolving the unidentified molecule in an aqueous solution, then load this solution into your dialysis tubing. After tying both ends of the tubing, you record its initial mass (18.2 g) and then place it in another aqueous solution containing 12 mM KCl (the dialysate, in this case). After 20 minutes, you remove the dialysis tubing and record its final mass (22.4 g). Based on this final mass, what can you conclude about the results of this experiment? a. The unidentified molecule was not small enough to migrate through the pores of the dialysis tubing. b. The Potassium and Chloride ions diffused into the dialysis tubing, increasing its mass. c. There was most likely a net movement of molecules out of the dialysis tubing. d. There was most likely a net movement of molecules into the dialysis tubing. e. There was most likely a net movement of water into the dialysis tubing. BISC-220 Practice Exam 1 [ANSWER KEY], 11 41.All of the following statements are true about protein channels except: a. Many protein channels exhibit various forms of gating that influence their conformation, such as voltage-gating, ligand-gating or tension-gating mechanisms. b. All channel proteins are considered to be integral proteins. c. Channel proteins are typically only selective for certain molecules based on the size of the channel pore. d. Channel proteins are most often necessary in cases where a molecule is polar or has a formal charge and thus, cannot freely cross the phospholipid bilayer. e. All of the above are true about protein channels. 42.You are studying a protein channel that is known to flux (or allow for the movement of) Chloride ions along their concentration gradient. What type of amino acids would you expect to find in the inner lining of the channel pore? a. Negatively-charged amino acids b. Positively-charged amino acids c. Polar amino acids d. a or c e. b or c 43.Transcription factors are ________ that bind to the ________ regions of DNA to facilitate transcription of specific genes. a. carbohydrates; promoter b. proteins; promoter c. carbohydrates; enhancer d. proteins; enhancer e. nucleic acids; promoter 44.In the mammalian endocrine system, it is common for the cells in individual glands to require self-regulation as a means for maintaining intracellular homeostasis. Which of the following chemical signaling mechanisms most likely underlies this homeostatic regulation? a. Autocrine signaling b. Paracrine signaling c. Endocrine signaling d. Neuroendocrine signaling e. G-protein Coupled Receptor (GPCR) signaling BISC-220 Practice Exam 1 [ANSWER KEY], 12 45.Which of the following is/ are an example(s) of metabotropic signaling? a. Glutamate binding to an NMDA receptor on a postsynaptic neuron, triggering an influx of Sodium and Calcium ions into the postsynaptic neuron. b. Light stimulating rhodopsin, which triggers the activation of a G-protein that phosphorylates Adenylyl Cyclase. c. Epidermal Growth Factor (EGF) binding to its receptor, which stimulates the secondary messengers RAS And PI3K to promote cell growth. d. b and c e. a, b and c 46.Ionotropic signaling mechanisms, such as those that rely on protein channels to facilitate the diffusion of ions across the cell membrane, are typically ________ than metabotropic signaling mechanisms. a. faster b. slower c. more common d. less common e. None of the above 47.In the majority of G-protein Coupled Receptor (GPCR) signaling cascades, the final result of the chemical message relayed is ________________. a. a change in the concentration of a specific protein within a cell b. a change in gene expression c. a change in enzymatic activity within the cell d. a change in the number of vesicles docked at the cell membrane e. digestion of incoming chemicals at the lysosome 48.When a G-protein becomes activated, there is an exchange of _______ for _______ which aids in the dissociation of the G-protein domains. a. ATP; ADP b. ATP; GTP c. GTP; GDP d. GDP; GTP e. ADP; ATP BISC-220 Practice Exam 1 [ANSWER KEY], 13 49.You are working in a research laboratory that studies the potential role of a newly-isolated receptor protein in endocrine signaling. Your team has performed a protein crystallography experiment and determined that the receptor protein structure consists of seven transmembrane domains, with the N-terminus localized to the extracellular side and the C-terminus localized to the intracellular side. Based on this information about the receptor’s structure, you and your labmates conclude that the receptor is most likely a(n) _____________. a. Receptor Tyrosine Kinase (RTK) b. Insulin Receptor c. Dopamine Receptor d. G-protein Coupled Receptor (GPCR) e. Piezo channel 50.Which of the following occurs immediately after the individual domains of a Receptor Tyrosine Kinase bind their respective ligands? a. A G-protein on the intracellular side of the cell membrane exchanges GDP for GTP to become activated b. A secondary messenger such as Adenylyl Cyclase is activated through phosphorylation c. The intracellular regions of the Receptor Tyrosine Kinase are phosphorylated d. The intracellular domains of the Receptor Tyrosine Kinase phosphorylate a secondary messenger to relay the chemical signal e. Ions or other molecules are transported across the cell membrane Exam Issues or Errors: Please note any issues or errors with the exam (including, but not limited to: illegible text or images, ambiguity in the wording of the question, or typos) in this section. Please indicate the question number so that we can most effectively address the issue. BISC-220 Practice Exam 1 [ANSWER KEY], 14

BISC-220 Practice Exam 1 [ANSWER KEY] PDF

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