BIO 140 PASS_ W13S2 Exam 3 Review 1 ANS

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1. After you add a chemical to cells growing in a test tube, proteins accumulate in the cells’ endoplasmic reticulum (ER). The chemical added prevents movements of proteins from the ER to which organelle? a. Golgi apparatus b. Lysosome c. Mitochondria d. Ribosome After proteins are synthesized in the ER, they move to the golgi. 2. Which of the following correctly matches an organelle with its function? a. Mitochondrion; photosynthesis b. Nucleus; creation of energy (ATP) from sugars c. Lysosome; movement d. Central vacuole; storage Mitochondria are the powerhouse of the cell, nucleus stores DNA, lysosome degrade molecules 3. Which of the following is true of the endoplasmic reticulum? a. The smooth ER is involved in lipid synthesis b. Both the smooth and rough ER are directly involved in protein synthesis c. Functions in the transport of molecules to be endocytosed into the cell d. Rough ER is involved in metabolism and lipid synthesis Smooth ER lacks ribosomes, so it is not involved in protein synthesis like the rough ER 4. Phospholipids create the lipid bilayer of the cell membrane. What is true about their tails? a. Saturated tails increase membrane fluidity through double bonds b. Saturated tails decrease membrane fluidity through lack of double bonds c. Unsaturated tails increase membrane fluidity through lack of double bonds d. Unsaturated tails decrease membrane fluidity through double bonds Saturated fatty acid tails will decrease membrane fluidity through a lack of double bonds that result in a straight structure favoring tight packing. Unsaturated fatty acid tails will increase membrane fluidity through double bonds that result in a kinked structure favoring loose packing. 5. Passive transport allows the movement of molecules across the cell membrane. What is a characteristic of passive transport? a. The input of ATP is required in order to facilitate transportation b. Substances move from areas of high concentration to areas of low concentrations c. Passive transport only refers to the movement of water molecules d. Membrane proteins are always needed in order for it to take place Passive transport is the movement of molecules from high to low concentrations (down a concentration gradient). It is a spontaneous process, so it does not require energy. Passive transport moves many different molecules and is not limited to water. Membrane proteins are not required in simple diffusion but can be used in facilitated diffusion (both are forms of passive transport). 6. What is a similarity between active transport and facilitated diffusion?

a. Both require the input of ATP b. Active transport utilizes proteins and facilitated diffusion does not c. Both require the use of membrane proteins d. Neither require the input of ATP Facilitated diffusion is passive transport and it does not require ATP. Active transport does require ATP. Membrane proteins are needed for transport in both active transport and facilitated diffusion. 7. Red blood cells react to their surrounding environment and can lyse, swell, and shrink. What is most likely to occur if a RBC is placed in a hypertonic solution? a. It will swell b. It will shrink c. No change A hypertonic solution contains more solutes and less water in comparison to the RBC. Water will move from areas of high to low concentrations. Therefore, water will move out of the RBC and shrink. 8. A protein is made on a free ribosome in the cytoplasm, what is a possible destination of this protein? a. Secreted from the cell b. Transmembrane proteins c. Golgi d. Nucleus Proteins made on a free ribosome can end up in the cytoplasm, chloroplast/mitochondria, and the nucleus. Proteins made on the rough ER can end up in the lumen of the endomembrane system (ER, golgi, lysosome, endosome), secreted from the cell (exocytosed), or as a transmembrane protein. 9. The sodium potassium pump functions to pump a. Sodium ions out, potassium ions into the cell b. Sodium ions in, potassium ions out of the cell c. Sodium and potassium ions into the cell d. Sodium and potassium ions out of the cell 10. Why does the sodium potassium pump require ATP to function properly? a. The concentration of sodium and potassium ions is greater outside the cell b. The concentration of sodium and potassium ions is greater inside the cell c. The concentration of sodium is greater inside and potassium is greater outside the cell d. The concentration of sodium is greater outside and potassium is greater inside the cell The sodium potassium pump is a form of active transport and ions move against their concentration gradient. Sodium moves out, so it is greater outside the cell. Potassium moves in, so it is greater inside the cell. 11. Which substance from the light-dependent reactions of photosynthesis is a source of energy for the light-independent reactions? a. ADP b. H 2 O

c. NADPH d. Pyruvic acid In light-dependent reactions NADP+ is the electron acceptor, so NADPH is formed. In the light independent reaction (Calvin Cycle), NADPH and ATP are used to synthesize triose phosphate. 12. What is the purpose of splitting water in PS II of the light dependent reaction? a. Provides e- for PS II and H+ for thylakoid space b. To produce oxygen for animals c. There is no purpose The reaction center will need an electron, so it takes it from H 2 O 13. It is important to create a concentration of H+ in the thylakoid space so that the H+ can diffuse through __ to create ___. a. NADH, NADPH b. Proton pump, protons c. ATP synthase, ATP The photosynthetic electron transport chain occurs across the thylakoid membrane to ultimately produce ATP and NADPH. This can occur because of the creation of the proton gradient. 14. The Calvin cycle is considered light-independent because it can occur in darkness. However, most often the Calvin cycle takes place in sunlight. Which of the following likely explains why? a. The enzymes involved in the Calvin cycle are unable to bind substrates in the dark b. Sunlight is important in activating carbon fixation in the Calvin cycle c. Calvin cycle requires ATP and NADPH, which require sunlight to be produced d. RuBP regeneration requires sunlight in order to occur and continue the Calvin cycle ATP and NADPH are the products of the light-dependent reactions and can be used in the Calvin cycle if ATP and NADPH are not already available for the light-independent reactions. 15. A mutation occurs in the chloroplasts of a lettuce plant, causing its thylakoid membranes to become more permeable to charged ions. How might this mutation affect the Calvin cycle? a. Fewer carbohydrates would be produced by the Calvin cycle b. More carbohydrates would be produced by the Calvin cycle c. There would be no change to the Calvin cycle Less ATP would be produced by the ATP synthase, so less ATP would be available to synthesize triose phosphate (carbohydrates). ATP and NADPH are used to synthesize carbohydrates. 16. T/F: The Calvin cycle can happen at night. a. True b. False The Calvin cycle is a light-independent reaction. 17. What is the name of the enzyme that fixes carbon in photosynthesis?

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a. NADPH reductase b. Carbon Fixase c. Rubisco d. Calvinase Rubisco catalyzes the carboxylation of RuBP by adding CO 2 to RuBP molecules. 18. Which of the following statements about the Calvin cycle is false? a. It binds carbon atoms from CO2 sources into organic compounds b. Releases oxygen as a byproduct c. Occurs within the stroma of the chloroplast d. Carbohydrates are an output Carbon fixation is when CO 2 (inorganic compound) is used to create organic compounds. The Calvin cycle occurs in the stroma. Oxygen is not released as a byproduct. 19. Protons move into the thylakoid due to the a. Concentration gradient in the stroma b. Photosynthesis c. Movement of electrons through the electron transport chain d. CO 2 transfer of electrons 20. The light-dependent reactions of photosynthesis take energy from sunlight and convert it into stored chemical energy. Which compounds are produced in the light-dependent reactions? a. ATP and NADP+ b. ATP and NADPH c. ADP and NADPH d. ADP and NADP+ 21. If oxygen is not present, pyruvate molecules undergo what? a. Fermentation b. Degradation c. Biosynthesis d. Citric acid cycle 22. What are the products of fermentation in plant cells and yeast? a. NAD+, lactate, ATP b. NAD+, ethanol, ATP c. NADH, ethanol, ATP d. NADH, lactate, ATP Plant cells and yeast cells undergo ethanol fermentation, so they will produce ethanol, ATP, and NAD+. No NADH is produced. Animal cells will undergo lactic acid fermentation, so they will produce lactate, ATP, and NAD+. The NAD+ is produced so it can be used in glycolysis. 23. During which metabolic stage is glucose broken down to pyruvate? a. Citric acid cycle b. The electron transport chain c. Glycolysis d. Oxidative phosphorylation

24. Which of the following processes produces the most ATP? a. Glycolysis b. Electron transport chain c. Fermentation d. Citric acid cycle The electron transport chain produces the most ATP through the proton gradient, it is also known as oxidative phosphorylation. 25. Which of the following about the citric acid cycle is the most accurate? a. It is part of both cellular respiration and photosynthesis b. Oxygen and water are produced c. It is the first step in cellular respiration d. Acetyl CoA is the input, while NADH, FADH2, and GTP are products The citric acid cycle is only part of cellular respiration. NADH, FADH2, and GTP are the products, not oxygen and water. Glycolysis is the first step in cellular respiration. 26. NADH and FADH2 are electron carriers that are involved in oxidative phosphorylation, the final step of cellular respiration. Which of the following is true of electron carriers NADH and FADH2? a. FADH2 is a better electron donor than NADH b. All of the electrons that enter the ETC come from NADH and FADH2 c. FADH2 and NADH are single use molecules d. NADH is the oxidized form of NAD+ and FADH2 is the reduced form of FADH NADH is a better electron donor. Once NADH and FADH2 pass through the ETC, they are converted into NAD+ and FAD which can be used in other parts of cellular respiration. NADH is the reduced form of NAD+, FADH2 is the reduced form of FAD. 27. Prior to entering the Citric acid cycle, each pyruvate molecule goes through pyruvate oxidation (pyruvate processing) in the mitochondrial matrix and forms an energy-rich molecule of a. Acetyl CoA b. NAD+ c. More pyruvate d. Oxygen In pyruvate oxidation, pyruvate enters and Acetyl CoA, NADH, and CO 2 is produced. The citric acid cycle follows pyruvate oxidation. 28. The citric acid cycle is halted in a cell, what is the most likely consequence? a. Glycolysis will stop b. Production of pyruvate from glucose will decrease c. Production of NADH and FADH2 from Acetyl CoA will decrease d. Production of ATP will increase Glycolysis will proceed as normal because the input is glucose and it will produce pyruvate. The production of ATP will decrease because the production of Acetyl CoA will decrease if the citric acid cycle is halted. 29. Which of the following best describes what will result when a glucose-fed yeast cell is placed in an anaerobic environment? a. It will produce ATP through fermentation, generating lactic acid

b. It will produce ATP through fermentation, generating ethanol c. Due to lack of oxygen, the yeast cell will be unable to produce ATP d. Due to the presence of oxygen, the yeast cell will produce ATP through the ETC 30. In mitochondria, the rate of ATP synthesis during oxidative phosphorylation is tightly coupled to the movement of electrons through the ETC. When ADP levels rise and the demand for ATP synthesis increases, electron flow through the ETC also increases. Based on the information provided, which of the following best describes an effect of rising ADP levels in mitochondria? a. Fewer protons will be pumped across the inner mitochondrial membrane b. NADH and FADH2 will be oxidized to NAD+ and FAD less rapidly c. The flow of protons through ATP synthase will decrease d. Oxygen consumption will increase The rise in ADP causes more electrons to flow through the ETC. So, more protons will be pumped across the inner mitochondrial membrane and NADH and FADH2 are oxidized (OIL RIG). More ATP is needed, therefore the flow of protons through ATP synthase will increase. If flow through ATP synthase increases, oxygen consumption will increase because it is the final electron acceptor that creates water. 31. What is the purpose of tRNA? a. To bring amino acids to ribosomes b. To form part of the ribosome c. To aid in the transcription of genes d. To bring information from within the nucleus to the cytoplasm tRNA determines the correct amino acid and brings it to the ribosome to complete translation. The anticodon on the tRNA will base pair with a codon on mRNA. 32. A ribosome is made of a large and small subunit. Which of the following will most likely be found in the aminoacyl site of the large ribosomal unit? a. The amino acid free tRNA b. The growing polypeptide chain initiation factors c. The tRNA molecule with the next amino acid to be added to the polypeptide chain d. Initiation factors The large subunit of a ribosome has three sites; the aminoacyl site, peptidyl site, and exit site. The aminoacyl site will have the tRNA molecule with the next amino acid, the peptidyl site will have the growing polypeptide chain, and the exit site is where tRNA leaves the ribosome. 33. If the codon in the mRNA strand is 5’ CAG, what is the anticodon strand sequence? a. 3’ GTC b. 3’ GUC c. 5’ GUC d. 5’ GTC The mRNA is synthesized 5’ to 3’ and it contains codons, while the tNRA is paired to codons in the 3’ to 5’ direction. These are RNA sequences, so “U” is used instead of “T.” 34. What is the main difference between initiation in eukaryotes and prokaryotes? a. Prokaryotes have monocistronic mRNA

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b. Initiation starts at the Shine-Dalgarno sequence for eukaryotes c. Prokaryotes’ mRNA can encode for only one protein d. Initiation for eukaryotes begins at the first AUG Prokaryotes have polycistronic mRNA (more than one gene) and eukaryotes have monocistronic mRNA (one gene codes for a polypeptide). Initiation starts at the 5’ cap for eukaryotes. Initiation starts at the Sine-Dalgarno sequence (Ribosome binding sites, RBS) for prokaryotes. Initiation will begin for eukaryotes at the first AUG, while prokaryotes can start at any AUG. 35. T/F: Translation occurs in the nucleus. a. True b. False Translation occurs in the cytoplasm (free ribosomes and rough ER). 36. The ability of some tRNA to recognize more than one codon because of the flexibility of the third position is known as? a. Mismatch pairing b. Mutations in tRNA c. Wobble d. Complementary pairing Wobble in tRNA allows the tRNA anticodon to pair to multiple codons. 37. Using the codon chart, what is the sequence of amino acids produced? 5’ AUG CCA AGC TCT a. Met - Gly - Ser - Arg b. Met - Gly - Leu - Ser c. Met - Ser - Gly - Gly d. Met - Ser - Arg - Gly 38. Which of the following is true about translation? a. The entire sequence of DNA is used b. DNA polymerase plays an active role c. Incorrect amino acids can be fixed d. A start codon is necessary for translation to being Only necessary parts of DNA will be used. DNA polymerase is not involved in translation. Incorrect amino acids cannot be fixed which is why protein folding with chaperones is important.

BIO 140 PASS_ W13S2 Exam 3 Review 1 ANS

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