BZE_PracticeTest_forFinal_F23 (1)

Practice Test 3 (for Final Exam ): Biology BZE Fall 23 QNS 1-32 Ch. 3, 4, 5, 7, 8, 9 & 10 QNS 33-70 Genetics Ch. 16 & 17 1. Which of the following is not formed by a condensation (dehydration) reaction? a. The disaccharide sucrose b. Triglycerides c. DNA d. The primary structure of a polypeptide e. The secondary structure of a polypeptide 2. If a polypeptide chain becomes arranged in a complex folded conformation as a result of R-group interaction, this describes the molecules’ _______________. a. tertiary structure b. quaternary structure c. primary structure d. secondary structure e. all of the above 3. In a covalent bond: (basic recall from Chem NYA) a. electrons are donated by the more electronegative atom b. electrons are donated by the more electropositive atom c. valence electrons are shared d. the cation bonds to the anion e. valence electrons are donated by the anion to the cation 4. Water has a high heat capacity because: a. it has a lot of calories b. it has a high surface tension c. it has a lot of hydrogen bonds d. it is liquid e. a and b 5. Which of the following kinds of bonds requires the least energy to break? a. Hydrophobic interactions b. Covalent bonds c. Hydrogen-bonds d. Ionic bonds e. All of the above bonds are of equal strength 6. The formation of ice during colder weather helps to moderate the seasonal transition to Winter. This is mainly because: a. the formation of hydrogen bonds releases heat b. the formation of hydrogen bonds absorbs heat c. there is less evaporative cooling of lakes d. ice melts each autumn afternoon e. ice is warmer than the winter air 7. Which of the following statements is false ? a. Monosaccharides usually have a formula which is a multiple of (CH 2 O) b. Triglycerides are not normally found as cell membrane components. c. Adenine and Guanine are classified as pyrimidine bases. d. All amino acids contain at least one nitrogen in their chemical formula. 1

e. Fatty acids with one or more carbon double-bonds are classified as unsaturated. 8. Ribosomes : a. are always associated with the E.R. b. are found only in eukaryotic cells c. contain DNA d. make steroids and some lipids e. are composed of ribosomal RNA (rRNA) and proteins 9. Both mitochondria and chloroplasts have the ability to replicate independently of the rest of the cell. Which of the following would you therefore expect to be found as a component of these organelles? Recall from NYA a. Nucleolus b. DNA (circular) c. Rough Endoplasmic reticulum d. Golgi complex e. Chlorophylls and Photosystems 10. A polysome (poly-ribosomal complex) is: a. an aggregate of lysosomes b. an aggregate of liposomes (phospholipid vesicles) c. a structure involved in DNA replication d. a structure involved in protein synthesis (translation) 11. Which of the following statements is TRUE: a. in the double-helix, CG base pairs form 2 H-bonds, and AT base pairs 3 H-bonds b. whenever nucleic acid strands are complementary, they associate in parallel conformation (5’ ends match and 3’ ends match) c. RNA can sometimes form short double-helical segments running in anti-parallel directions (like in the DNA helix) d. DNA has the sugar deoxyribose, which is ribose deoxygenated at carbon-3 e. RNA-polymerases can sometimes make an RNA transcript without using a DNA template strand 12. Which of the following is NOT true of facilitated diffusion? a. It requires a carrier protein b. It is a mechanism that can be saturated c. It can occur against a concentration gradient d. It can be inhibited by competitive inhibitors e. All of the above are true 13. If a red blood cell is placed in a hypertonic sugar solution: a. no visible change will occur b. water will move out causing lysis of the cell c. water will move in causing lysis of the cell d. water will move out causing crenation of the cell e. water will move in causing crenation of the cell 14. Membrane phospholipids: a. are entirely hydrophilic b. allow passage of large, polar molecules through the membrane bilayer c. are joined to each other by polar covalent bonds d. are entirely hydrophobic e. are not free to transpose from one side of the membrane to the other 2

21. The most important function of the redox reactions of the electron transport chain is to: a. supply oxygen for cellular respiration b. generate electrons for use in the Krebs’ cycle c. supply energy for the oxidative phosphorylation of ADP + Pi d. store energy in electron transport carriers such as cytochromes e. all of the above 22. The electron transport chain consists of a series of complexes (ex. cytochrome proteins which are alternately oxidized and reduced with the passage of electrons). The ultimate (final) acceptor of these electrons in mitochondria is: a. NAD + b. CO 2 c. Complex IV d. O 2 e. H 2 O 23. Poisons like cyanide or rotenone, which bind to carriers in the inner mitochondrial membrane, cause a decrease in ATP synthesis by : a. directly inhibiting the reactions that occur inside the matrix compartment b. carrying protons (H+) across mitochondrial membranes through phospholipid bilayers c. inhibiting ATP-synthase or “knob enzyme” directly (which prevents the formation of ATP) d. interfering with electron transfer and preventing the formation of the pH gradient e. these poisons affect two of the above processes in mitochondria 24. The chemiosmotic hypothesis suggests that the ATP formed during cellular respiration results from the presence of a gradient across the inner mitochondrial membrane. The gradient is of which of the following types? a. Electron b. pH c. NADH d. ADP e. Water 25. In glycolysis, as phosphoenolpyruvic acid (PEP) is converted to pyruvic acid, ADP is converted to ATP. The utilisation of a phosphorylated compound, such as PEP, in the production of ATP is called: a. respiration b. substrate-level phosphorylation c. oxidative phosphorylation d. fermentation e. cyclic photophosphorylation 26. When oxygen is not available in animal cells, the end result of hexose breakdown is production of: a. CO 2 b. alcohol and CO 2 c. pyruvic acid d. lactic acid e. triose (G3P) 27. The production of ATP associated with the flow of electrons along the mitochondrial electron transport chain is called: a. cyclic phosphorylation b. substrate phosphorylation c. reductive phosphorylation 4

d. oxidative phosphorylation e. photophosphorylation 28. When one molecule of glucose is degraded to CO 2 and H 2 O in a typical eukaryotic cell: a. there is a net production of 6 ATP molecules by substrate-level phosphorylation b. a total of 36 molecules of ATP are synthesized c. 10 molecules of NADH are generated in the mitochondria d. more than 75% of the free energy change of the reaction is recovered as the high energy phosphate bonds of ATP e. all of the above 29. Photosynthesis consists of two processes, a light-dependent phase and a series of light- independent (dark) reactions. The “dark” reactions refer to the: a. production of ATP and NADPH b. consumption of O 2 c. incorporation of CO 2 and evolution of O 2 d. evolution of O 2 e. incorporation of CO 2 into reduced carbon compounds 30. Photosystems I and II are required for: a. CO 2 production b. CO 2 oxidation c. transfer of electrons from the Electron Transport System to oxygen d. reduction of NADP + e. cyclic photophosphorylation 31. When water acts as an electron donor, noncyclic (linear) phosphorylation results in the production of: a. O 2 b. ATP and NADPH c. ATP, NADPH and O 2 d. ATP e. NADPH 32. The pigments most commonly associated with chloroplasts, such as chlorophyll and carotene, are found in membranous structures, called thylakoids, which are arranged in closely packed stacks, the grana . These stacks represent: a. the site of chloroplast protein synthesis b. the site of synthesis of the circular chloroplast DNA c. the site of O 2 evolution and photophosphorylation d. the site of G3P and glucose synthesis e. all of the above 5

d. attachment of amino acids to tRNAs e. both c and d are correct 39. Which of the following is not characteristic of prokaryotic transcription and translation: a. RNA polymerase b. promoter sequences on DNA c. snRNA (small nuclear RNA) d. rRNA (ribosomal RNA) e. tRNAs and activating enzymes 40. Which of the following experiments proved semiconservative DNA replication? a. Griffith’s experiment on bacteria (transforming the R strain into the S strain) b. Hershey and Chase’s expt. Using two radio-isotopes (P32 and S35) c. the discovery of the double helical structure of DNA (Watson, Crick and Franklin) d. the expt. by Meselson and Stahl using heavy DNA (N15) in E. Coli e. Chargaff’s rule of nitrogen bases (purines always equal pyrimidines in DNA) 41. Which of the following is TRUE of eukaryotic transcription and translation: a. introns and transcribed and translated b. introns are transcribed by RNA polymerase but removed before translation c. the final mRNA product contains only exons, and has a cap sequence on the 5’ side and a poly-A tail on the 3’ end of the molecule d. exons only are transcribed by RNA polymerase e. b and c above 42. What part of a eukaryotic gene initiates binding of the active RNA-polymerase enzyme? a. intron d. promoter b. start AUG codon e. spliceosome c. exon (coding segments) 43. Which component initiates binding of ribosomal subunits at the start of translation? a. intron b. start AUG codon c. exon (coding segments) d. promoter e. spliceosome 44. If a cell was given a modified tRNA carrying the wrong amino acid, then: a. nothing would happen as it would not enter into ribosomes b. the modified tRNA would get into ribosomes but the anticodon would not match the codon c. nothing would happen as an enzyme would rapidly hydrolyse it d. mutations would be introduced in proteins (with possible harmful effects) e. mutations would occur in the DNA (with possible harmful effects) 45. Which of the following mutations in a gene would most likely be very harmful to an organism? a. a base substitution in DNA on the third position of a coding triplet b. a base-insertion in the trailer region of the last exon (after the stop codon) c. a base-deletion in the leader region of the first exon (before the start AUG) d. a base-insertion in the middle of an intron (between two exons) e. a base-deletion in the first exon after the start AUG 46. An intron region is _________________. a. found in pre-mRNA only until it is processed b. removed from an mRNA molecule before translation c. a region that does not code for anything 7

d. a region that separates coding regions e. all of the above -The following figure illustrates a replication fork in bacteria (nothing else is shown). A-E represent the protein machinery carrying out specific activities. i – vi represent the ends of the DNA backbone (either 3’ or 5’). Answer the following TWO questions that refer to the figure above. 47. Look carefully, which roman labels represent the 5’ ends of the DNA molecules shown? A) ii, iii, and v only. B) vi only. C) v and vi only. D) i, iv, and vi only. 48. Helicase is represented by ____ while DNA polymerase removing a primer is shown by ____ . A) B; E. B) A; C. C) A; D. D) B; D. E) D; E. 49. In sickle-cell hemoglobin, a glutamic acid has been replaced by a valine in both of the beta-chains. The disease is therefore the result of : a. a deletion mutation d. a frameshift mutation b. a substitution mutation e. two of the above could cause sickle cell anemia c. an insertion mutation 50. Joining nucleotides together is an endergonic process. How is DNA synthesis accomplished? A) DNA polymerase provides the source of energy. B) Nucleoside triphosphates (dATP, dGTP, dTTP, and dCTP) are used as "activated" reactants in the process. C) Synthesizing DNA starting from an RNA primer does not require energy. D) The process is endergonic but does not require activation energy. 8

56. If there were 5 different nucleotides in DNA instead of only 4, and if the codons were the same size, how many different possible codons would there be? a. 5 d. 125 b. 15 e. 250 c. 25 57. Replication of the lagging strand during DNA synthesis is achieved by a. the unwinding enzyme (helicase) b. replication forks c. base pairing d. formation of short DNA fragments (Okazaki fragments) which must later be joined together e. a special DNA polymerase enzyme which can work backwards (i.e. in the 3' to 5' direction) 58. RNA is composed of a chain of nucleotides. Nucleotides themselves are made up of three molecular components. Which of these components could be removed from a nucleotide that is part of the RNA chain without breaking the chain? a. amino acid b. phosphate c. fatty acid d. nitrogenous base e. pentose sugar 59. Aminoacyl-tRNA synthases (activating enzymes) link _________ to ______________, a process that requires the hydrolysis of ________ (and releases pyrophosphate PPi). a. amino acids; tRNA; ATP b. codons; anticodons; ATP c. mRNA; tRNA; GTP d. mRNA; tRNA; ATP 60. Which of the following isotope labels did Hershey and Chase use to distinguish between protein and DNA? a. 14 C and 15 N b. 18 O and 13 C c. 32 P and 35 S d. 15 N and 3 H e. 35 S and 14 C 61. Which of the following statements about DNA replication is TRUE ? a. The leading strand is synthesized in the 3’ to 5’ direction. b. Only one of the strands of the original DNA is used as a template. c. DNA polymerase joins the Okazaki fragments together. d. DNA helicase is the enzyme that catalyzes the addition of nucleotides to the new DNA strand. e. The energy for polymerization is provided by the hydrolysis of pyrophosphate groups from nucleoside triphosphates 62. Which of the following components is required for the initiation of protein synthesis in a cell? a. a tRNA molecule with methionine (met) attached b. a small ribosomal subunit c. a molecule of mRNA d. a large ribosomal subunit e. all of the above 10

63. Which of the following is TRUE of eukaryotic transcription and translation: a. introns and transcribed and translated b. introns are transcribed by RNA polymerase but removed before translation c. the final mRNA product contains only exons, and has a cap sequence on the 5’ side and a poly-A tail on the 3’ end of the molecule d. exons only are transcribed by RNA polymerase e. b and c above 64. In cells, nucleotides may function as a. building blocks for DNA b. membrane components c. coenzymes ex. NAD+ d. enzymes e. a and c above 65. A tRNA molecule: a. can attach to only one of the 20 different amino acids used in protein synthesis b. is shaped roughly like a ‘clover leaf’ folded into a three dimensional “L” c. has some portions being folded due to base-pair formation d. possesses an anticodon responsible for “recognizing” a codon e. all of the above Match the following descriptions with the correct letter . One choice per question . Structure Description A. exon 66. a proton pump operates here _____ B. surface of rough ER. 67. codes for proteins _____ C. promoter 68. RNA-polymerase binds here _____ D. thylakoid membrane 69. ribosomes are made here _____ E. nucleolus 70. ribosomes making export proteins are attached here _____ 11

Cell communication - Describe the briefly the mode of action of G-coupled protein receptors : (ex. epinephrine or glucagon hormone receptor) Make sure to mention the role of GTP and cyclic AMP (cAMP) in signal transduction: Additional Practice MC questions (mixed topics) 1. Which of the following elements is/are found in all nucleic acids but not in triglycerides or carbohydrates? a. calcium b. phosphorus c. sulfur d. nitrogen e. two of the above are found in nucleic acids but not in triglycerides or carbohydrates 2. glucose + glucose  maltose + water The above reaction : a. is a dehydration reaction (condensation) b. is a hydrolysis reaction c. represents a catabolic (degradation) reaction d. results in breakdown of a glycosidic linkage e. all of the above are true of this reaction, except one statement 3. The tertiary structure of a protein is stabilized by: a. disulfur bridges (between cysteine amino acids) b. hydrophobic interactions and ionic bonds c. hydrogen-bonds (H-bonds) between polar R-groups d. d. all the above types of bonds are part of tertiary protein structure e. only a and b above 4. Which of the following is NOT true of facilitated diffusion? a. It requires a channel or carrier protein in the membrane b. It is a mechanism that can be affected by defective genes c. It can occur against a concentration gradient (against the concentration difference) d. It can be affected by inhibitor molecules (which bind to the transport protein and block it) e. It moves polar solutes across the membrane without any ATP expenditure 13

5. Which of the following would be expected from the fluid mosaic model of the membrane ? a. the passage of polar solutes through the hydrophobic interior of the bilayer b. the lateral movement of phospholipids within their half of the bilayer (lateral diffusion) c. the presence of peripheral membrane proteins embedded deep inside the bilayer (transmembrane) d. the movement of phospholipids from one side of the membrane to the other side (flip-flop) e. the increase in membrane fluidity as the number of trans double-bonds increases 6. If an animal cell is immersed in a hypertonic solution, then: a. the cell will crenate because it has a lower solute concentration than the outside medium b. the cell will crenate because it has a higher solute concentration than the outside medium c. the cell will lyse because it has a lower solute concentration than the outside medium d. the cell will lyse because it has a higher solute concentration than the outside medium 7. Which of the following processes require ATP as energy source? 1. engulfing a large food particle into the cell (ex. phagocytosis) 2. transport of Na+ by primary active transport 3. transport of Na+ by facilitated diffusion (through a channel protein) 4 osmosis a. 1 and 2 b. 2 and 4 c. 1 and 3 d. 1, 2 and 4 e. all of the above require ATP energy 8. All the following statements are true EXCEPT : a. glycolysis occurs in virtually all life forms on earth, it produces only a net 2 ATP per glucose b. the enzymes of glycolysis are always found in the cell cytoplasm, not enclosed within organelles c. glycolysis does not release any CO2 gas or require oxygen gas to proceed d. glycolysis requires glucose and NADH to proceed, but not oxygen gas e. glycolysis makes ATP exclusively by substrate-level phosphorylation, it does not make any use of chemiosmosis (such as in oxidative phosphorylation) 9. Which of the following concerning the reaction below is TRUE : 6 CO2 + 6 H2O  C6H12O6 + 6 O2 a. CO2 is oxidized b. CO2 acts as the reducing agent. c. H2O acts as the oxidizing agent. d. H2O is reduced. e. H2O acts as the reducing agent 10. Once PSII (P680) has been oxidized in the light-reactions, which of the following molecules reduces it back ____________ . Also, as a second part to the question, where do the electrons in this form of transport end ( in which molecule are the electrons found after these light-reactions ) _____________. a. water……………… oxygen gas b. oxygen gas……….. NADP+ c. G3P (triose)……… NADPH d. water……………… NADPH 14

16. The Calvin cycle uses six ATP molecules for the net production of one 3-carbon sugar from three molecules of RuBP and three molecules of carbon dioxide. Yet the Calvin cycle requires nine ATP molecules to function. Explain? a. Three additional ATP molecules are used to produce the C3 sugar (G3P). b. Three additional ATP molecules are used to phosphorylate CO2 for the next cycle. c. Three additional ATP molecules are used to regenerate 3 RuBP (from 5 G3P). d. Three additional ATP molecules are used to reduce 6 NADP+ to 6 NADPH. e. Three additional ATP molecules are used to prevent photorespiration 17. From your knowledge of macromolecules, which of the following experiments demonstrates that nucleic acid is the genetic material, NOT protein? a. Griffith’s experiment on bacteria, transforming the R strain into the S strain (encapsulated) b. Hershey and Chase’s experiment using bacteriophage and two radioisotopes (P32 and S35) c. the discovery of the double helix structure of DNA (Watson, Crick and Rosalind Franklin) d. the experiment by Meselson and Stahl using heavy DNA (Nitrogen-15) in dividing E. Coli e. Chargaff’s rule of nitrogen bases (purines always equal pyrimidines in DNA) 18. Which of the following statements about photosynthesis and respiration is FALSE ? a. Photosynthesis involves reduction whereas respiration involves oxidation of carbon. b. Photosynthesis is a plant process whereas respiration is an animal process. c. Both photosynthesis and respiration involve proton pump(s). d. Both photosynthesis and respiration involve electron transport complexes. e. In eukaryotes photosynthesis and respiration take place in membrane-bound organelles. 19. Which of the following occur(s) only in linear (noncyclic) electron flow in photosynthesis? a. oxidation of water (photolysis) b. formation of ATP from ADP + Pi c. reduction and oxidation of electron transport proteins (in thylakoids) d. reduction and oxidation of Photosystem I (P700) e. formation of a proton (H+) gradient across the thylakoid membrane 20. Consider the reaction that converts Pyruvic acid into Acetyl-CoA: Answer True or False for each of the following: - This reaction occurs in the cell cytoplasm (cytosol) ______ - This reaction produces ATP directly by substrate-level phosphorylation _____ - The reaction involves decarboxylation of pyruvate _____ - acetyl-CoA is more oxidized than pyruvate ______ - This reaction occurs just before the citric acid cycle in the matrix _____ - This reaction occurs whether oxygen is present or not _____ 16

- The reaction involves reduction of NAD+ and oxidation of pyruvate _____ Question. The table provided shows all the codons & the amino acids they code for: Use this information as needed to answer the following questions: a. What are the two anticodons for the amino acid tyrosine (abbreviated Tyr )? _________________________________ b. What is the series of amino acids that the template DNA triplets: 3’ G ATTGACCCCAA 5’ would produce if transcribed and translated ? Use abbreviations . c. What would be the resulting sequence of amino acids if a mutation resulted in a T being inserted after the G in the first triplet of the sequence in b. above: between G and A ? ( name also this type of mutation ) End. 17