Sample Exam #1 PDF

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Sample Exam for Bio 101/Zoo 101 taught by Sharon Thoma...

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Sample Exam 1 1. From the choices below, which level of biological organization is the least complex AND shows the emergent property of life? a. molecules b. cells c. organisms d. ecosystems e. organelles 2. Consider the following: two adjacent water molecules, α-helices, a globular protein, and two complementary strands of DNA. Which of the following describes a way that all of these molecules/structures are held together/are stabilized? a. phosphodiester bonds b. ionic bonds c. hydrophobic interactions d. polar covalent bonds e. hydrogen bonds 3. Diatoms (Kingdom Protista) may be extremely abundant in both freshwater and marine ecosystems; it is estimated that 20% to 25% of all organic carbon fixation (photosynthesis) on the planet is carried out by diatoms. Diatoms can convert light energy to chemical energy because they have ______, and they can convert the energy of the food they consume to the energy of ATP because they have __________. a. mitochondria; mitochondria b. chloroplasts; peroxisomes c. mitochondria; chloroplasts d. chloroplasts; chloroplasts (because they are photosynthetic, they don’t have mitochondria) e. chloroplasts; mitochondria 4. Lactose is a molecule composed of two monosaccharides, galactose and glucose. Cellulose is composed of many glucose monomers bound together. The structures of lactose and cellulose are shown below. Which of the following statements regarding these molecules is NOT true? a. lactose is a disaccharide and cellulose is a polysaccharide b. lactose can be hydrolyzed by an organism for quick energy, cellulose is a structural molecule c. ruminant animals, such as cows, can derive nutrients from cellulose because they have commensalistic methanogens that can hydrolyze the molecule d. lactose is produced by animals; cellulose is found in the cell walls of all eukaryotes e. lactose and cellulose are both built by dehydration synthesis reactions 5. In the elongation phase of translation, what type of bond is formed to join two amino acids? (1 point) a. ionic bond b. amino bond c. peptide bond d. hydrogen bond e. disulfide bond

6. Which of the statements regarding enzymes is NOT true? a. enzymes are proteins that function as catalysts; they speed up the rate of a chemical reaction b. a single enzyme can often react with a number of different substrates c. enzymes can be used many times for a specific reaction d. enzymes must be folded in their correct tertiary structure to be able to work e. enzymes can be denatured by shifting away from their optimal temperature or pH Use this information to help answer questions 7 – 15. Aromatase is an enzyme involved in the production of estrogen (shown below) and is abundant in estrogen-producing cells in adrenal glands, ovaries, placenta, testicles, fat tissue, and the brain. 7. Cells that express aromatase (and thus produce estrogen) are likely to be abundant in (1 point) a. rough endoplasmic reticulum b. Golgi c. lysosomes d. smooth endoplasmic reticulum e. microtubules 8. Estrogen can move in and out of cells without the help of any proteins. The movement of estrogen across your cell membranes can best be described as a. against a concentration gradient b. simple diffusion c. facilitated diffusion d. Active transport e. a and d are both correct 9. The tertiary structure of aromatase is shown to the right. Which of the following is the main type of secondary structure seen within this protein? (1 point) a. alpha-helices b. double helices c. beta-pleated sheets d. phosphodiester bond e. none of the above 10. The amino acids threonine and valine are shown to the right. Where in the tertiary structure of aromatase (a soluble protein), would you find threonine and valine? a. threonine would be in the interior of the protein due to hydrophobic interactions and valine would be on the exterior, forming hydrogen bonds with water b. valine would be in the interior of the protein due to hydrophobic interactions and threonine would be on the exterior, forming hydrogen bonds with water c. both would be on the interior of the protein due to hydrophobic interactions d. both would be on the exterior of the protein because of hydrophilic interactions e. e. the nature of the R group has no effect on the tertiary structure of a protein 11. Aromatase consists of 503 amino acids. If one amino acid in aromatase is changed to another, which of the following is true? a. there was a nonsense mutation b. the primary structure would be changed, but that will never impact tertiary structure or function c. this would sometimes change the primary structure of a protein, always affect the

tertiary structure, and never alter its function d. this would always change the primary structure and always alter the function of the protein e. this would always alter the primary structure of a protein, and sometimes affect its tertiary structure and function Shown below is the beginning of the gene encoding aromatase from American alligator (Alligator mississippiensis). The sequence provided contains the start codon. 5’ Promoter - TTGGAAAAGATGATTCTGGAAACCTTGAATCCAATGCAT----3’ 3’ Promoter- AACCTTTTCTACTAAGACCTTTGGAACTTAGGTTACGTA---5’ 12. What is the mRNA that would be produced from this segment? a. 5’-UUGGAAAAGAUGAUUCUGGAAACCUUGAAUCCAAUGCAU- 3’ b. 3’-AACCUUUUCUACUAAGACCUUUGGAACUUAGGUUACGUA- 5’ c. 3’-UUGGAAAAGAUGAUACUGGAAACCUUGAAUCCAAUGCAU- 5’ d. 5’-AACCUUUUCUACUAAGACCUUUGGAACUUAGGUUACGUA- 3’ e. 5’-AACCTTTTCTACTAAGACCTTTGGAACTTAGGTTACGTA- 3’ 13. What are the first four amino acids that will be present in the aromatase protein? a. NH3-Asn-Glu-Lys-Met…-COOH b. NH3-Leu-Glu-Lys-Met…-COOH c. NH3- Met-Ile-Leu-Glu… -COOH d. NH3-Met-His-Trp-Ile…-COOH e. It is impossible to tell as the genetic code is redundant 14. The tRNA with an anticodon AGC would be charged with which amino acid? a. Thr b. Arg c. Ser d. Cys e. Ala 15. Aromatase deficiency is a rare human disorder. Affected females do not produce estrogen, and at puberty fail to develop secondary sexual characteristics and exhibit progressive virilization (development of male physical characteristics). In one case of aromatase deficiency, a mutation was found that changed a single base from GA in exon 9 of the gene. Which of the following best describes this mutation? a. base pair substitution; missense b. base pair substitution; nonsense c. insertion; frameshift d. thymine dimer e. none of the above, since the mutation is in an exon, it will always be spliced out 16. The triglyceride (or fat) molecule shown below has _____ UNSATURATED fatty acid(s)? Consuming this fat in one’s diet (as opposed to consuming only saturated fats) would tend to decrease levels of ______ in the blood. a. one; LDL b. one; HDL c. two; LDL d. two: HDL e. three; LDL 17. The two molecules depicted above are classified as lipids because

a. they are both largely hydrophilic b. they are both largely hydrophobic c. they have lots of non-polar C-H bonds d. a and c are both correct e. B and c are both correct 18. Which of the following statements about biological membranes is NOT true? a. hydrophilic tails of phospholipids face towards each other; hydrophobic heads face out b. phospholipids can move laterally in their half of the bilayer c. all plasma membrane proteins have a signal peptide directing them to the endomembrane system d. the carbohydrate group attached to glycoproteins faces the outside of the cell e. they are selectively permeable 19. Desaturases have been found in many organisms, including yeast (a fungus), Arabidopsis thaliana (a plants), corn borer (an insect), and carp (a fish). The primary structure of the desaturase enzyme is very similar in all of these organisms. Based on this information, which of the following statements is ACCURATE? a. fungi, plants, insects, and fish can all increase membrane fluidity at low temperatures by removing cholesterol from their membrane b. the genes for desaturase in yeast, A. thaliana, the corn borer, and carp must share some similarity c. fungi, plants, and animals share an evolutionary relationship d. a, b, and c are all correct e. b and c are both correct 20. Compared to a cell in the core of its body, the cell membranes on the paw of a polar bear would most likely have an increased concentration of which of the following? a. phospholipids with unsaturated fatty acids b. phospholipids with saturated fatty acids c. cholesterol d. a and c are both correct e. b and c are both correct 21. Water balance in the brain is important to prevent high intracranial pressure that could ultimately lead to stroke and death. Water can move OUT of specific brain cells and move QUICKLY because a. the specific brain cells with rapid water movement have abundant aquaporins in their plasma membranes b. the fluid surrounding the brain cells is hypertonic to the cytosol of the cells c. the fluid surrounding the brain cells is hypotonic to the cytosol of the cells d. a and b are both correct e. a and c are both correct Use the following choices, a-e, to determine the type of membrane transport that best describes items 22-26. Each choice may be used once, more than once, or not at all. Each question has only one best answer. (1 point each) a. Pinocytosis b. Facilitated diffusion c. Active Transport d. Phagocytosis e. Exocytosis 22. The cystic fibrosis transmembrane regulator (CFTR) pumps chloride ions across cell membranes against the concentration gradient. CFTR requires ATP for function.

- C. Active Transport 23. The molecule folate is needed for proper mammalian nerve cell growth. Folate moves into cells through a carrier protein, down its concentration gradient. - B. Facilitated Diffusion 24. Small particles suspended in extracellular fluid are brought into the cell through an invagination of the cell membrane, the resulting vesicle can fuse with a lysosome. - A. Pinocytosis 25. Humans can have immune system disorders in which neutrophils fail to engulf invading bacteria. Individuals with these disorders have a defect in this process. - D. Phagocytosis 26. 26. Serotonin is a neurotransmitter made by certain nerve cells. Serotonin is a protein and is released by the cells that make it by ______. - E. Exocytosis Use the following information to answer information to answer questions 27-29. Iron is essential for hemoglobin to perform its job of carrying oxygen through the bloodstream and producing energy. Iron is transported in your blood complexed to a protein called transferrin. The transferrin/iron complex binds to transferrin receptors located in the plasma membrane and is drawn into the cell in a small vesicle. The cell uses the iron bound to the transferrin and the receptor is recycled back to the plasma membrane. 27. The mechanism by which iron gets from your blood into your cells is best described as (1 point) a. phagocytosis b. alternative splicing c. hydrolysis d. receptor-mediated endocytosis e. pinocytosis 28. The inability to bring iron into the cell with the transferrin/transferrin receptor system results in an intracellular iron deficiency. Which of the following mutations could lead to this iron deficiency? a. a nonsense mutation in the transferrin gene b. a missense mutation in the transferrin receptor gene that results in mis-folding of the protein c. a frameshift mutation in the transferrin gene d. a, b, and c are all correct e. b and c are both correct 29. An individual with a novel form of iron deficiency is tested, and it’s found that her transferrin receptor proteins lack an ER signal peptide. How does this explain symptoms? a. the transferrin receptor ends up in the lysosome and can’t bind transferrin/iron complexes b. the transferrin receptor ends up in the plasma membrane, but without the ER signal peptide it can’t bind transferrin/iron complexes c. the transferrin receptor ends up in the cytosol, can’t fold correctly, and can’t bind transferrin/iron complexes d. the transferrin receptor is secreted from the cell, and can’t bring transferrin/iron complexes back into the cell e. it does not; if the transferrin receptor is mis-localized, the iron will be moved into

the cell by pinocytosis 30. How are membrane receptors and enzymes similar? They both a. are transmembrane proteins b. require ATP hydrolysis to function c. supply energy for the cell d. act as biological catalysts e. bind to molecules of a particular shape 31. The figure to the right shows the movement of glucose from the outside of a cell to the inside of the cell. How can you distinguish that this movement is via carrier proteins rather than channel proteins? a. the proteins are transmembrane proteins b. no ATP is required c. movement is down the concentration gradient d. one molecule at a time is being moved across the membrane e. none of the above 32. Which of the following helps other proteins fold? (1 point) a. apolipoproteins b. histones c. chaperones d. glycoproteins e. axolotls 33. Shawn and Gus are looking at a picture of Naegleria, a single celled protist that can cause a rare, but severe brain infection in humans. Shawn argues that it is prokaryotic. Gus correctly points out that the organism is clearly not prokaryotic because a. it has a cell wall b. it is unicellular c. it contains a nucleus and histones d. it has a plasma membrane e. it has ribosomes 34. Natronobacterium gregoryi is classified in Domain Archaea and lives in environments with a high concentration of salts. N. gregoryi is a. a prokaryotic thermophile b. a eukaryotic halophile c. a eukaryotic methanogen d. multicellular e. a prokaryotic halophile 35. Your microbiome a. is identical to the microbiome of the person sitting next to you b. includes many important commensals c. can be changed by antibiotic use and by what we eat d. a, b, and c are all correct e. b and c are both correct 36. Using model organisms, what have we learned about the role of bacteria in our gut? a. that obesity and leanness are correlated with different microbiomes b. that our gut microbiome impacts our mental health c. that bacteria residing in the gut may shape development

d. they are unimportant e. a, b, and c are all correct 37. The human stomach microbiome consists of hundreds of species of bacteria. Helicobacter pylori (Hp) is a bacterial species that is associated with stomach cancer. The microbiome of individuals with stomach cancer was compared with that of healthy individuals, and it was found that the stomach microbiome of the cancer patients was dominated by Hp. A researcher decides to evaluate the microbiome of people at risk for stomach cancer and to treat them with a “stomach microbiome transplant” using the microbiome of a healthy individual. Why would the researcher reasonably conclude that such a transplant might help prevent stomach cancer? The transplanted bacteria a. could convert Hp from a pathogen to a commensal b. could create a stomach environment that is not favorable for Hp survival, essentially out-competing Hp c. could act as an anti-quorum sensing drug d. would produce broad spectrum antibiotics that would selectively kill Hp e. this type of idea – doing a microbiome transplant is impossible and could never help in any situation 38. Bacterial quorum sensing would be best described as a. a. the use of receptors that bind to a signal molecule called a “quorum” b. a system of communication that depends on cell density c. the ability to grow bacteria in extreme conditions d. the tendency for bacteria to die in the presence of an antibiotic e. a situation where bacteria sense the presence of danger and run away 39. Jeroen Raes, a microbiologist at the Catholic University of Leuven in Belgium, and his colleagues studied 1054 Belgians they had recruited to determine “a normal microbiome.” Some in the group—173 in total—had been diagnosed with depression, and the team compared their microbiomes with those of other participants. Two kinds of microbes, Coprococcus and Dialister, were missing from the microbiomes of the depressed subjects, but not from those without depression. How can the bacteria of the microbiome (or the lack of those microbes) influence mental health? a. the gut-brain axis allows for bi-directional communication between gut microbes and the brain b. some gut bacteria can produce neurotransmitters c. some bacteria can produce molecules that impact our ability to make neurotransmitters d. a, b, and c are all correct e. a and b are both correct 40. Which of the following points supports the theory that mitochondria were once freeliving prokaryotic cells? a. mitochondria have ribosomes that resemble prokaryotic ribosomes b. both mitochondrial membranes resemble prokaryotic membranes c. mitochondria have linear chromosomes d. a, b, and c are all correct e. a and b are both correct 41. The nuclear lamina is an array of intermediate filaments that line the inner side of the nuclear membrane. If a chemical treatment destroyed intermediate filaments, what would

you expect to be the most likely immediate consequence? a. no nucleosomes would form in the nucleus and nuclear pores would be closed b. ribosomes would not be produced and protein synthesis would cease c. the shape of the nucleus would be changed and DNA would be disorganized d. the chromosomes would immediately lose their telomeres and fuse together e. vesicles would not be transported correctly through the endomembrane system Use this information to answer questions 42-43. Heparan N-sulfatase is a lysosomal enzyme that hydrolyzes large carbohydrates called glycosaminoglycans (GAGs). 42. What is the path that heparan N-sulfatase takes to get to the lysosome? a. rough ER transport vesicles Golgi apparatus transport vesicles lysosome b. b. rough ER transport vesicles Golgi apparatus transport vesicles plasma membrane lysosome c. c. cytosol lysosome d. d. rough ER transport vesicles peroxisomes transport vesicles lysosome e. e. rough ER transport vesicles trans Golgi cis Golgi exocytosis endocytosis lysosome 43. 43. Which of the enzyme activity curves below was most likely generated from heparan N-sulfatase? (1 point) a. curve A b. curve B c. curve C d. curves A or B e. curves A, B, or C 44. How does the lysosome maintain a pH that is so different from the cytosol? (1 point) a. proton pumps transport H+ out of the lysosome b. proton pumps transport H+ into the lysosome c. lysosomal enzymes break down molecules to generate excess OHd. H+ diffuses into the lysosome e. H+ diffuses out of the lysosome 45. How does the molecule shown to the right energize cellular processes? By (1 point) a. inserting itself into a mitochondrion b. acting as an enzyme c. by transfer of a phosphate group to another molecule d. magic e. by donating its hydroxyl groups 46. How does the enzyme catalase get targeted to its correct cellular location? a. mitochondrial targeting signal b. peroxisomal targeting signal c. nuclear export signal d. chloroplast targeting signal e. ER signal peptide 47. Which of the following statements comparing prokaryotic and eukaryotic DNA replication is NOT accurate? a. both eukaryotic and prokaryotic DNA polymerases build off RNA primers b. eukaryotic DNA replication requires multiple origins of replication; prokaryotic DNA replication uses a single origin of replication to replicate the entire genome

c. eukaryotic DNA replication occurs in the nucleus; prokaryotic DNA replication occurs in the nucleoid region d. eukaryotic and prokaryotic DNA replication use different sets of polymerases e. the chromosome(s) shortens each time DNA is replicated in both eukaryotes and prokaryotes 48. Okazaki fragments have to be formed during DNA replication because a. DNA polymerase can only build new strands in the 5’ 3’ direction and the template strands are only available as the replication bubble expands b. the leading strands must be built pointing away from the replication fork c. the cell lacks enough DNA ligase for bonding Okazaki fragments together if they were produced from both parental strands d. newly formed DNA tends to break into fragments due to the strain of unwinding the double helix e. by having one leading strand and one lagging strand the cell can limit the amount of DNA polymerase used for chromosomal replication 49. Which of the following enzymes/proteins is NOT correctly paired with its function? a. DNA polymerase III – starting with 3’-OH on primer, builds ...