BIOL 213 FINAL EXAM BANK:

BIOL 213 FINAL EXAM BANK: EXAM 1: EXAM 1 HW: 1. If phosphorus-32 has an atomic number of15, how many neutrons does it usually have? - 17 2. The seed of a desert plant may be dormant for many years without growing, but is still considered to be alive because it? - Possesses heritable information 3. A “rogue” scientist is featured in many movies, but actual scientific discovery and advancement is done as a community, involving lots of dedicated scientists. Once a hypothesis has been supported in many ways and is accepted by the scientific community as fact, it now considered a? - Theory 4. Your pet chameleon changes color depending on its environment. You think this is because it can respond to how much heat it absorbs from whatever it is sitting on. In scientific terms, your thoughts are a(n)? - Hypothesis 5. The atomic weight of carbon is 12.011. Its mass number is 12.000. Why are these two values slightly different? - Atomic weight is the average of the mass numbers of a representative sample of the element, including all its isotopes. 6. Which of the following statements about the atom is true? - In an atom with a neutral charge, the number of electrons is equal to the number of protons. 7. Which component of an atom does not significantly add to its mass? - Electron 8. Nitrogen, oxygen, hydrogen, and carbon make up approximately how much of the living mass on earth? - 99% 9. Which of the following is the most basic structural and physiological unit of all living organisms? - Cell 10. H2SO4 can ionize completely to yield two H+ ions and one SO42- ion. H2SO4 is therefore a - Strong acid 11. The ability of an atom to combine with other atoms is determined by the atom's - Valence electron shell Contact: 12. All of the following are nonpolar except for - NaCl 13. Two characteristics of water make it different from most other compounds: Its solid state is _______ its liquid state, and it takes up _______ heat as it changes to its gaseous state. - less dense than; large amounts of 14. The two covalent bonds in a water molecule are polar because - oxygen is more electronegative than hydrogen. 15. Carbonic acid and sodium bicarbonate act as buffers in the blood. When a small amount of acid is added to this buffer, the H+ ions are used up as they combine with the bicarbonate ions. When this happens, the pH of the blood - Does not change 16. A covalent bond is formed by the sharing of _______ between atoms, whereas an ionic bond is formed by the _______. - electrons; transfer of electrons from one atom to another 17. To determine the number of molecules in a teaspoon of sugar you have to know - the weight and molecular weight of the sugar, and Avogadro's number. 18. Oxygen forms _______ covalent bond(s), carbon forms _______, and hydrogen forms _______ - Two;four;one 19. Which of the following compounds containing 1H, 12C, and/or 16O has the greatest number of molecules in a sample with a mass of 2 grams? - Water (H20) 20. Aldehydes and ketones are very similar in that they both contain? Selected Answer: a carbonyl group (C=O). 21. During the formation of a peptide linkage, a(n) _______ is formed. - molecule of water 22. In condensation reactions, the atoms that make up a water molecule are derived from? - both reactants. 23. All of the following amino acids have an optical isomer except for? - glycine. 24. If all of the cysteine residues of a protein were changed to threonine, then? - the protein would lose disulfide bond formation, which would affect its tertiary structure. 25. Amino and carboxyl functional groups tend to form bases and acids by gaining or losing? - a proton. 26. Each amino acid has a unique _______ group. - “R”. 27. What do polysaccharides, polypeptides, and polynucleotides have in common? - They are broken down in hydrolysis reactions 28. Leucine and valine have side chains that do not interact with water; therefore, they? - are nonpolar. 29. An essential functional group involved in cellular energy transfer is the _______ group. - phosphate. 30. What is the difference between α-glucose and β-glucose? - They differ in the placement of their OH and H groups. 31. Which of the following are true of starch and glycogen, which are both polysaccharides. Starch is _______, whereas glycogen _______. - an energy storage compound of plants; an energy storage molecule of animals. 32. A β pleated sheet organization in a polypeptide chain is an example of _______ structure. - Secondary 33. The primary structure of a folded protein is determined by? - the sequence of its amino acids 34. A molecule with the formula C15H30O15 is a - Carbohydrate 35. Researchers find that removing an enzyme from a neutral pH environment and placing it in an acidic pH environment causes a loss of activity. However, when the enzyme is returned to its original neutral pH, its activity has doubled from its original state. What is one possible explanation for this observation? - The enzyme has refolded differently due to an absence of chaperones, and now the active site is more available to the substrate. 36. Glucose and fructose both have the formula C6H12O6, but the atoms in these two compounds are arranged differently. Glucose and fructose are therefore? - isomers. 37. A type of protein that functions by helping other proteins fold correctly is called a - Chaperone 38. Peptide chains have a(n) _______ and a(n) _______ end. - N terminus; C terminus. 39. The magnesium chelatase protein has quaternary structure. This means that magnesium chelatase - is composed of multiple peptide subunits 40. Which of the following statements about fatty acids molecules is true? - They are composed of hydrocarbon tails and a carboxyl group 41. Nucleotides in RNA are connected to one another in the polynucleotide chain by _______ bonds between _______. - phosphodiester; a sugar and a phosphate group. 42. Miller and Urey’s 1954 hot chemistry experiment was based on the assumption that Earth’s early atmosphere contained water (H2O) vapor, methane, hydrogen, and ammonia. Subsequent research showed that volcanoes released carbon dioxide (CO2), hydrogen sulfide (H2S), and sulfur dioxide (SO2) around 4 billion years ago. This discovery suggests that? - Earth’s early environment included these gases as well. 43. If you chew a cracker long enough, it eventually tastes sweet. This is because the amylase enzyme in your saliva is? - breaking down the starch into monosaccharides 44. Which of the following statements concerning genetic information in most cells is true? - The flow of information in a cell is from DNA to RNA to protein. 45. Lipids play an important role in a number of functions. Which of the following is not one of those functions? - Storing of genetic information 46. Ribose and deoxyribose are both found in nucleic acids. The difference between ribose and deoxyribose is that? - both a and b are true 47. A nucleotide contains a pentose sugar, a phosphate group, and a(n)? - nitrogen-containing base. 48. Which of the following is least likely to dissolve in water? - a lipid 49. A molecule that has an important role in limiting what gets into and out of cells is? - phospholipid. EXAM 1 ONLINE RESOURCE: 1. The simplest level of biological organization at which something can considered “Life” is? a. atoms b. molecules c. cells d. tissues e. ecosystems 2. The main purpose of any single experiment is to a. explain an observation. b. prove unambiguously that a particular hypothesis is correct. c. give know-it-all college professors something to do. d. answer as many key questions as possible. e. test a prediction that is based on a hypothesis. 3. Metabolism is a. the consumption of energy only. b. the release of energy only. c.. the exchange of nutrients and waste products with the environment. d. the production of heat by chemical reactions. e. all conversions of matter and energy taking place in an organism 4. The part of the atom that carries a positive charge is the a. proton. b. electron. c. neutron. d. megatron. e. nucleus. 5. The atomic number of an element is the same as the number of _______ in each atom. a. neutrons b. Protons c. protons plus electrons d. neutrons plus protons e. neutrons plus electrons 6. An atom with additional neutrons has a larger atomic mass and can undergo radioactive decay. They are known as? a. chaperones b. isotopes. c. variants d. isoforms e. none of the above are correct 7. The element Nitrogen is found in the second row of the periodic table and has an atomic number of 7. How many electrons must Nitrogen gain in order for its valence shell to be full? a. 0 b. 2 c. 3 d. 7 e. 8 8. Which of the following bonds is formed when atoms share electrons unequally? a. non-polar covalent b. polar covalent c. cationic d. anionic e. van der waals force 9. Which of the following are special properties of water? a. It has a high (large) heat capacity. b. Its molecules form hydrogen bonds with themselves and solutes. c. It dissolves all four classes of biological molecules (nucleic acids, proteins, lipids, and carbohydrates). d. Answers A and B are correct e. All of the above are correct. 10. How would you make 1 liter of an aqueous solution with a 0.5 M concentration of a compound that has a molecular weight of 200 daltons (grams)? a. Add 0.20 grams of the compound to 1000 ml of water. b. Add 200 grams of the compound to 1000 ml of water. c. Measure out 200 grams of the compound and add water until the volume equals 1000 ml. d. Measure out 100 grams of the compound and add water until the volume equals 1000 ml. e. Measure out 0.5 grams of the compound and add water until the volume equals 1000 ml. 11. Assuming you have made the solution preceding question correctly, how many molecules of the compound are in the 1 liter of solution? a. 0.5 b. 100 c. 3.011 x 1023 d. 200 e. cannot be determined from information given 12. A soft drink may have an H+ concentration of 10–3 mol/L. The pH of this drink is? a. 0.001. b. –3. c. 0. d. 3. e. 1,000 13. Carbonic acid and sodium bicarbonate act as buffers in the blood. When a small amount of acid is added to this buffer, more H+ ions combine with the bicarbonate ions. When this happens, the pH of the blood? a. becomes significantly more basic. b. becomes significantly more acidic. c. does not significantly change. d. Answers A and B are correct. e. All of the above are correct. 14. Which of the following functional groups is a weak acid? a. carboxyl b. amino. c. hydroxyl. d. phosphate. e. ketone. 15. Which statements regarding a 2-carbon molecule with an amino functional group is/are TRUE? a. It is a weak acid b. It is a weak base. c. It is non-charged and non-polar. d. It will be hydrophobic e. All of the above are true. 16. Which of the following is a correct monomer/polymer pairing? a. Monosaccharide/phospholipid b. Amino acid/protein c. Triglyceride/cellulose d. Nucleotide/steroid e. Monosaccharide/DNA 17. During a condensation reaction in which two monosaccharides are joined to form a disaccharide, a(n) ___?____ bond is formed. a. glyosidic bond b. peptide bond c. phosphodiester bond d. answers A and B are correct e. all of above are correct 18. Which of the following can have enzymatic activity? a. RNA. b. proteins. c. carbohydrates d. answer A and B are correct e. all of the above are correct 19. Which of the following amino acid(s) is unique in that it does NOT contain a central chiral carbon? a. Glycine b. Tyrosine c. Lysine d. Cysteine e. Threonine 20. Which of the following amino acids is non-polar and non-charged? a. Cysteine b. Tyrosine c. Lysine d. Valine e. Threonine 21. Which of the following elements is not normally found in any of the 20 amino acids? a. carbon b. nitrogen c. sulfur d. phosphorus (phosphate) e. hydrogen 22. Which of the following statements about proteins is/are FALSE? a. They possess peptide bonds between amino acids. b. They can form structural components of the cell. c. They can be enzymes. d. They can be signaling molecules (hormones) such as insulin. e. They can be genetic material. 23. The “C” terminus of a polypeptide is? a. The first amino acid in a polypeptide. b. The last amino acid in a polypeptide. c. An amino acid with a free “R” group. d. An amino acid with a free amino group. e. None of the above are correct. 24. The sequence of amino acids incorporated into a polypeptide is which level of protein structure/folding? a. primary b. Secondary c. tertiary d. quaternary. e. none of the above are correct. 25. The formation of alpha-helices and beta-sheets in proteins is primarily stabilized by? a. ionic bonds b. covalent bonds c. hydrogen bonds d. disulfide bonds e. hydrophobic interactions 26. A type of protein that functions by helping other proteins fold correctly is called a a. foldzyme. b. renaturing protein. c. chaperone protein. d. hemoglobin. e. denaturing protein 27. L-amino acids and D-amino acids differ from each other in what manner? a. they are enantiomers of each other b. L-amino acids are biologically active, D-amino acids are not c. D-amino acids are more hydrophobic than L-amino acids d. answers A and B are correct e. all of the above are correct 28. Which of the following has the molecular formula of C6H12O6? a. an amino acid. b. monosaccharide. c. triglyceride. d. a fatty acid. e. none of the above 29. The difference between α- and β-glucose is a. in the number of covalent bonds present. b. in the arrangement of OH and H atoms attached to the carbon at position 1. c. in the type of R group attached to the terminal carbon. d. that α-glucose is polar, whereas β-glucose is nonpolar. e. that α-glucose is a pentose, whereas β-glucose is a hexose 30. A phospholipid contains which of the following? a. glycerol. b. a polar head group c. 2 fatty acid sides chains d. answers A and B are correct e. all of the above are correct 31. Polyunsaturated triglycerides differ from saturated triglycerides in that they? a. have a lower melting temperature b. have more carbon to carbon double bonds. c. are more often found in animal fats than in plant oils. d. answers A and B are both correct e. all of the above are correct 32. Which statement(s) regarding purines and pyrimidines is/are TRUE? a. Purines only have single bonds in their structure, whereas pyrimidines have both single and double bonds in their structure. b. Pyrimidines are found in RNA only; while purines are found in DNA only. c. Purines consist of hydrogen, carbon, oxygen, and nitrogen, whereas pyrimidines have phosphorus, hydrogen, carbon, oxygen, and nitrogen. d. Purines include the bases of guanine and cytosine; pyrimidines include the bases of adenine and thymine. e. Purine bases are double-ring structures, whereas pyrimidine bases are single-ring structures. 33. Which of the following would NOT be found in DNA? a. ribose. b. phosphate c. Cytosine d. Guanine e. thymine 34. What is attached to the 3´-carbon of deoxyribose in DNA? a. Adenine b. Phosphate c. Hydroxyl d. Thymine e. Hydrogen 35. What is the nucleotide sequence of the complementary strand of the DNA molecule:5’- T T A C G C T-3’? a. 5’-T T A C G C T-3’ b. 3’-A A T G C G A-5’ c. 3’-G G C A T A G-5’ d. 5’-C C G T T A T-3’ e. 3’-A G C G T A A-5’ 36. A guanine/cytosine base paring in DNA is held together with which type of bonds? a. peptide b. van der waals c. hydrogen d. ionic e. glycosidic 37. The central dogma of molecular biology states that a. the information flow in a cell is from DNA to a protein to RNA. b. the information flow between DNA, RNA, and a protein is reversible. c. the information flow in a cell is from DNA to RNA to protein. d. the information flow in a cell is from protein to RNA to DNA. e. the genetic code is ambiguous. 38. All life we can imagine needs? a. oxygen b. water. c. carbon dioxide d. sunlight e. methane 39. Examination of meteorites suggests that a. biological molecules are not limited to Earth. b. early cellular life was commonly obliterated by meteorite impact. c. comets brought Earth most of its water. d. meteorites brought life to Earth. e. meteorites are responsible for Earth’s magnetic field. 40. Which of the following have been demonstrated experimentally? a. RNA-like molecules can self-replicate, elongate, and mutate b. Basic metabolic reactions can occur spontaneously if energy, chemical substrates, and inorganic catalysts are present c. Complex organic molecules can originate from inorganic ones if heat and electricity are applied d. Answers A and B are correct e. All of the above are correct EXAM 1 actual test: 1. The "N" terminus of a polypeptide is? 1.The first amino acid in a polypeptide. The last amino acid in a polypeptide. An amino acid with a free "R" group. An amino acid with a free carboxyl group. None of the above are correct. 2. Glucose and fructose both have the formula C6H1206, but the atoms in these two compounds are arranged differently. Glucose and fructose are therefore? pentoses. tural isomers. Stereosaccharides. isotopes. polysaccharides. 3. The formation of alpha-helices and beta-sheets is which level of protein structure? - Secondary 4. How many molecules of a solute are in 1 liter of a 1M solution? - 6.022 x 10^23 5. Which of the following is correct regarding thymine? - It is one of 4 nitrogenous bases found in DNA. 6. A common health concern in humans is the condition atherosclerosis, in which triglycerides accumulate on the walls of arteries. A diet rich in which of the following is thought to contribute to this condition? - Saturated fat 7. Which of the following functional groups is easily transferred from one molecule to another and is known as the energy currency of living cells? - Phosphate 8. Which of the following amino acids is unique in that it contains an atom of sulfur and forms disulfide bridges in proteins? - Cysteine 9. How would you make 1 liter of an aqueous solution with 1M concentration of a compound that has a molecular weight of 200 daltons [grams]? - Measure out 200 grams of that compound and add water until the volume equals 1000 ml. 10. Carbon-12 is the most abundant isotope of carbon on Earth.Carbon-13 makes up about 1 percent of Earth’s carbon atoms. Which of the following is true? - Carbon-13 has more neutrons than carbon 12. 11. The Miller Urey experiment showed that in an environment with conditions similar to those of primitive Earth, which of the following could occur? - Inorganic molecules could react to form organic molecules. 12. The element oxygen is found in the second row of the periodic table and has an atomic number of 8. How many electrons must oxygen gain in order for its valence shell to be full? - 2. 13. Which of following bond is formed when atoms share electrons equally? - Non-polar covalent 14. The hard shell of insects is made of chitin. Chitin is mostly which of the following? - Carbohydrate 15. Which of the following has a ribose, phosphate and nitrogenous base? - Nucleotide. 16. As a protein folds into its tertiary structure it is potentially stabilized by? - Ionic bonds, 17. In 1969, scientists shaved off pieces of the Murchison meteorite and found both D- and L-isomers of 10 amino acids, as well as purines, pyrimidines, and sugars. This indicates that? - Basic chemical building blocks of life can form extra terrestrially, The meteorite war not contaminated by Earth’s materials, and If appropriate conditions exist [such as temperature and liquid water], cellular life similar to that on earth could form on other planets. 18. Which of the following amino acids is hydrophilic and ionic [charged]? - Lysine 19. The most likely source of Earths atmospheric oxygen was? - Photosynthesis by ancient cyanobacteria [blue-green algae] 20. A type of protein that functions by helping other proteins fold correctly is called a - Chaperone 21. Which of the following elements is found in only 2 of the 20 amino amino acids? - Sulfur 22. What id attached to the 5’ -carbon of deoxyribose in DNA? - Phosphate 23. L-amino acids and D-amino acids differ from each other in what manner? - They are enantiomers of each other 24. The atomic weight or mass of an element is the same as the number of ___ in each atom? - Neutrons plus protons 25. Which of the following statements about living organisms on earth is False? - All living organisms move within their environment - Living organism possess DNA as the genetic material - All living organisms require a source of energy - ALL Living organisms interact with or influence the environment in which they live - Living populations evolve over time 26. Which of the following would not be found in DNA? - Uracil 27. Whats up doc? Eating carrots is considered good for your eyesight as they are rich in the light absorbing molecule vitamin A which is derived from beta-carotene. Beta-carotene is derived from which of the following? - Protein 28. During a condensation reaction in which two amino acids are joined to form a dipeptide, what kind of a bond if formed? - Peptide bond 29. Signaling molecules (hormones) in humans are derived from? - Proteins and lipids 30. Glycogen is an energy storage molecule in human muscle and liver tissue. Glycogen is a ? - Polysaccharide 31. Which of the following is a correct monomer/polymer pairing? - Nucleotide/nucleic acid. 32. Which of the following represents the correct order of the levels of complexity at which life is studied, from most inclusive to least inclusive [most complex to simplest] - Population, organism, organ system, organ, tissue,and cell. 33. After overserving that fish live in clean water but not in polluted water, researchers state that ‘polluted water kills fish’. This statement is an example of a[n]? - Hypothesis 34. Carbonic acid and sodium bicarbonate act as buffers in the blood. When a small amount of acid is added to this buffer, the H+ ions are used up as they combine with the bicarbonate anions. When this happens, the pH of the blood? - Does not significantly change. 35. The element Neon is found in the last column of the second row of the periodic table. It’s a noble gas with an atomic number of 10. Which of the following statements about Neon is/are TRUE? - Its 1s electron orbital is full, its 2s electron orbital is full, its 2p orbitals are all full. 36. The tendency of. Atoms to attract electrons is known as? - Electronegativity. 37. Life on Earth arose approximately how many years ago? - 3.5 to 4 billion. 38. Which of the following are special properties of water? - It has a high[large] heat capacity & Its molecules form hydrogen bonds with themselves and solutes. EXAM 1 practice exam: 1. Which represents the correct order of biological organization (from simplest to most complex)? a. cells, molecules, atoms, organ systems, tissues, organism b. molecules, atoms, cells, tissues, organ systems, organism c. organism, organ systems, tissues, cells, molecules, atoms d. atoms, molecules, cells, tissues, organ systems, organism e. atoms, molecules, organ systems, tissues, cells, organism 2. Which of the following is/are features of scientific hypotheses? a. They are based on observations. b. They make predictions. c. They can be tested by experimentation. d. Answers A and B are correct. e. All of the above are correct 3. The part of the atom that carries a positive charge is the a. proton. b. electron. c. neutron. d. innermost shell. e. nucleus. 4. Which of the following elements is NOT common in living things? a. Nitrogen b. Phosphorus c. Flourine d. Carbon e. All of the above 5. The atomic number of an element is the same as the number of _______ in each atom. a. neutrons b. protons c. protons plus electrons d. neutrons plus protons e. neutrons plus electrons 6. Phosphorus has an atomic number of 15 and an atomic weight of 30.974. From this information it can be determined that this element? a. has isotopes. b. usually has 31 neutrons. c. carries a positive charge. d. answers A and B are correct e. all of the above are correct 7. Which of the following is directly involved in forming bonds between atoms? a. the atom’s protons. b. The atom’s nucleus. c. the atom’s neutrons d. valence electrons e. pH. 8. Which of the following is the correct order (in decreasing order) for the relative strengths of chemical bonds? a. van der Waals forces, covalent, ionic, hydrogen b. Ionic, covalent, hydrogen, van der Waals forces c. Covalent, ionic, hydrogen, van der Waals forces d. Hydrogen, covalent, van der Waals forces, ionic e. Ionic, covalent, van der Waals forces, hydrogen 9. The tendency of atoms to attract electrons when it occurs as part of a compound is? a. hydrophobic interactions b. van der waals forces c. electronegativity d. ionic bonds e. radioactivity 10. Ethanol is composed primarily of two carbon atoms and a hydroxyl functional group. Therefore, one would expect ethanol to be? a. hydrophobic. b. hydrophilic. c. a base. d. an acid. e. a buffer. 11. Lithium and fluorine are most likely to form which kind of bond? a. van der Waals interaction b. Hydrogen bond c. Hydrophobic interaction d. Ionic bond e. Covalent bond 12. Which of the following are special properties of water? a. Water has a high (large) heat capacity. b. Water’s solid state is less dense than its liquid state. c. Water molecules form hydrogen bonds between themselves and with solutes. d. Answers A and B are correct e. All of the above are correct 13. Which contains more molecules, a mole of glucose or a mole of fructose? a. a mole of glucose b. a mole of fructose c. both contain the same number of molecules. d. inadequate information is provided. e. it depends on the pH of the system. 14. To determine the number of molecules in a teaspoon of sugar you have to know a. Avogadros number (6.022 x 1023 molecules/mole). b. the weight of the sugar. c. the molecular weight of the sugar. d. answers A and B are correct e. all of the above are correct 15. How would you make 1 liter of an aqueous solution with a 0.50 M concentration of a compound that has a molecular weight of 200 daltons (grams)? a. Add 0.50 grams of the compound to 1000 ml of water. b. Add 500 grams of the compound to 1000 ml of water. c. Measure out 100 grams of the compound and add water until the volume equals 1000 ml. d. Measure out 50 grams of the compound and add water until the volume equals 1000 ml. e. Measure out 5 grams of the compound and add water until the volume equals 1000 ml. 16. Two samples of rainwater have H+ concentrations of 10–4 mol/L (Sample A) and 10–6 mol/L (sample B) respectively. Which of the following statements is/are FALSE? a. the pH of Sample A is 4 b. the pH of Sample B is 6 c. Sample A is more acidic than Sample B d. Sample A is more basic than Sample B e. Sample A has 100 times more H+ in solution than Sample B 17. Carbonic acid and sodium bicarbonate act as buffers in the blood. When a small amount of acid is added to this buffer, the H+ ions are used up as they combine with the bicarbonate ions. When this happens, the bicarbonate ion is described as a? a. weak (conjugate) basic. b. weak (conjugate) acid. c. hydrogen chelator d. cation e. all of the above are correct 18. When hydrochloric acid (HCL) is added to water, it ionizes, releasing Cl– and H+ ions. The resulting solution is a. acidic. b. basic. c. anionic. d. molar. e. a buffer. 19. Which of the following functional groups is frequently transferred from one molecule to another and is considered the “energy currency” of living cells? a. carboxyl b. amino. c. hydroxyl. d. phosphate. e. ketone. 20. Molecules containing a large number of amino groups are? a. basic. b. acidic. c. involved in reactions forming more simple molecules. d. nonpolar and non-charged. e. highly insoluble in water. 21. Which of the following is a correct monomer/polymer pairing? a. Monosaccharide/triglyceride b. Amino acid/protein c. Triglyceride/cellulose d. Nucleotide/polysaccharide e. Monosaccharide/protein 22. During the formation of a peptide linkage, a(n) _______ is formed. a. molecule of water b. covalent bond c. disulfide bond d. answers A and B are correct e. all of above are correct 23. Enzymes are usually a. DNA. b. lipids. c. proteins. d. carbohydrates. e. amino acids. 24. Which of the following amino acid(s) would be described as non-polar and hydrophobic? a. Leucine b. Aspartic acid c. Serine d. Arginine e. Tyrosine 25. Which of the following amino acid(s) would be described as electrically charged (ionic)? a. Leucine b. Arginine c. Methionine d. Cysteine e. Threonine 26. Which of the following is NOT found in every amino acid? a. carbon b. nitrogen c. sulfur d. oxygen e. hydrogen 27. Which of the following general statements about proteins is FALSE? a. Some function as enzymes. b. The can form structural components of the cell. c. They possess peptide linkages between amino acids. d. They are highly insoluble in water. e. They are necessary for immune function in humans (antibodies). 28. The amino acid Cysteine may be involved in what unique bond? a. peptide bond b. disulfide bond c. hydrophobic interactions d. glycosidic bond e. phosphodiester bond 29. The “C” terminus of a polypeptide is? a. the first amino acid b. the last amino acid c. an amino acid with a free amino group d. an amino acid with a free carboxyl group e. answers B and D are both correct 30. The tertiary shape of a folded protein is influenced by a. the sequence of its amino acids. b. hydrogen bonds c. hydrophobic interactions d. ionic interactions between R-groups. e. all of the above are correct. 31. The amino acids of the protein keratin are arranged in a helix. This secondary structure is stabilized primarily by a. covalent bonds. b. peptide bonds. c. glycosidic linkages. d. hydrogen bonds. e. polar bonds. 32. The protein hemoglobin has four separate polypeptide subunits and a heme group. This level of protein structure (or folding) is known as? a. primary. b. secondary. c. tertiary d. quaternary e. none of the above are correct 33. Which of the following levels of protein structure is stabilized entirely by covalent bonds? a. Primary b. Secondary c. Tertiary d. Quaternary e. none of the above 34. Which of the following environmental factors influences protein folding a. pH b. temperature c. molecular chaperones d. concentrations of other polar molecules. e. all of the above 35. L-amino acids and D-amino acids differ from each other in what manner? a. they are enantiomers of each other b. L-amino acids are biologically active, D-amino acids are not c. D-amino acids are more hydrophobic than L-amino acids d. answers A and B are correct e. all of the above are correct 36. Three monomers of glucose (C6H12O6) are bonded together by condensation (dehydration) reactions to form an oligosaccharide. The new molecular formula is? a. C6H10O5 b. C18H32O16 c. C18H36O18 d. C16H32O16 e. C12H24O12 37. Which of the following has the molecular formula of C6H12O6? a. sucrose. b. an amino acid. c. fructose. d. a fatty acid. e. none of the above 38. The difference between α- and β-glucose is a. in the placement of OH and H atoms or stereoisomerism. b. in the number of covalent bonds present c. in the type of R group attached to the terminal carbon. d. that α-glucose is polar, whereas β-glucose is nonpolar. e. that α-glucose is a pentose, whereas β-glucose is a hexose. 39. An abundant energy storage molecule in plants is? a. steroids. b. starch. c. RNA. d. amino acids. e. cellulose. 40. A phospholipid contains which of the following? a. fatty acids. b. a polar head group c. glycerol d. answers A and B are correct e. all of the above are correct 41. You have two samples of triglycerides. Sample A has more carbon to carbon double bonds than found in Sample B. Which of the following statements is FALSE? a. Sample A has a lower melting point. b. Sample B is more saturated than Sample A. c. Sample A is more unsaturated than Sample B. d. Sample B contains more phospholipid than sample A e. Both samples contain fatty acids and glycerol. 42. Which statement about cholesterol is FALSE? a. It is a lipid-derived molecule b. It is soluble in water c. It is required for animal cell membranes to function properly d. It is related to the sterol class of hormone molecules in humans e. Elevated cholesterol levels contribute to atherosclerosis and heart disease in humans. 43. The bases of nucleic acids are purines or pyrimidines. Purines and pyrimidines are distinguished by the fact that a. purines include the bases of guanine and adenine; pyrimidines include the bases of cytosine and thymine. b. pyrimidines are found in RNA; purines are found in DNA. c. purines consist of hydrogen, carbon, oxygen, and nitrogen, whereas pyrimidines have phosphorus, hydrogen, carbon, oxygen, and nitrogen. d. purines only have single bonds in their structure, whereas pyrimidines have both single and double bonds in their structure. e. purines are single-ring structures, whereas pyrimidines are double-ring structures. 44. Ribose and deoxyribose are both found in nucleic acids. The difference between ribose and deoxyribose is that a. ribose has one less oxygen molecule than deoxyribose has. b. ribose is a pentose sugar, whereas deoxyribose is a hexose sugar. c. deoxyribose is found in DNA, whereas ribose is found in RNA. d. Both a and b e. Both a and c 45. Which of the following is not a difference between DNA and RNA? a. DNA has thymine, whereas RNA has uracil. b. Nucleotides in DNA are linked by phosphodiester bonds but RNA uses glycosidic bonds c. DNA has deoxyribose sugar, whereas RNA has ribose sugar. d. DNA usually has two polynucleotide strands, whereas RNA usually has one strand. e. In DNA, A pairs with T, whereas in RNA, A pairs with U. 46. What is attached to the 3´-carbon of deoxyribose in DNA? a. Adenine b. Phosphate c. Hydroxyl d. Thymine e. Hydrogen 47. What is the nucleotide sequence of the complementary strand of the DNA molecule: T T A C G C T? a. T T A C G C T b. A A T G C G A c. G G C A T A G d. C C G T T A T e. A G C G T A A 48. The two strands of the DNA double helix are held to each other by which type of bond(s)? a. peptide b. ionic c. van der waals d. hydrogen e. glycosidic 49. The central dogma of molecular biology states that a. the information flow in a cell is from DNA to RNA to protein. b. the information flow between DNA, RNA, and a protein is reversible. c. the information flow in a cell is from DNA to a protein to RNA. d. the information flow in a cell is from protein to RNA to DNA. e. the genetic code is ambiguous. 50. A prerequisite for life on Earth or any other planet is a. an energy source. b. water. c. genetic material. d. answers A and B are correct e. all of the above are correct Exam 2: Homework questions: 1.Which of the following statements are TRUE about the nuclear envelope? - Supported by a cytoskeletal network known as the nuclear lamina. - contains pores for the passage of large molecules. - Double membrane - contains chromosomal DNA od eukaryotic cells. 1a. Which of the following statements are FALSE about the nuclear envelope? - Consists of cellulose 2.The nuclear genetic material of a eukaryotic cell consist of DNA associated with protein. This material is called? - Chromatin 2a. Correct matched structure-function - Ribosomes: protein synthesis - SER: sterol synthesis - Golgi: protein modification and sorting. - Nuclear lamina: dna replication and nuclear structure. 3.A prokaryote cell does not have a nucleus, or complex cytoskeleton. 4. Ribosomes are not visible under a light microscope, but they can be seen with an electron microscope because? - electron microscopes have more resolving and magnifying power than light microscopes. 5. A technique for studying the different organelles of a cell involves lysing the cell and separating all its individual components using centrifugation. This technique is known as? - cell fractionation 6. Fluorescent microscopy is used to see ‘tagged membrane proteins and lipids in an intact, living cell. 7. Prokaryotes has ….? 8.Which of the following is TRUE about plastids. 9.An individual who cannot produce 1 or more hydrolytic enzymes found in lysosomes suffers from TaySachs disease. 10. mitochondria is the site of aerobic respiration 11.An organic material foreign the cell (alcohol) will end up being modified/ destroyed in 12.Lysosomes contain digestive/hydrolytic enzymes. 13.Components of endomembrane system: plasma membrane, golgi body, nuclear envelope, ER, lysosomes. 14.Thylakoids of chloroplast have light reaction occurring in them that produce NADH & ATP. 15. The polymer peptidoglycan is important in the cell walls of bacteria. 16. Microfilaments and microtubules have a polarity [negative and positive]] 18. TRUE statements about eukaryotic flagella. - Has 9+2 array of dimers. - made up of tubulin - requires a molecular protein called dynein. - motion requires hydrolysis of karge amounts of ATP and ADP 20. The extracellular matrix of animal cells is holds cells together, contains collagen and interacts with the internal cytoskeleton. 34. The cellular receptor protein kinase receptors autophosphorylates itself when it interacts with its signal. 35. The release of the neurotransmitters cause cations to flow across the target cell membrane leading to membrane depolarization [an action potential]. What type of receptor is most likely responsible for this effect? - Ligand gates channels 36. The abnormal ras oncoprotein causes the development of bladder cancer. What is the function of the normal ras protein? - G protein 37. Which type of cellular receptor has 7 transmembrane helices as part of its protein structure? - G protein coupled receptors 38. The benefits of many steps involved in the protein kinase cascades. - Multiple signals intersect. - amplification of the signal - information can be communicated to multiple compartments within the cell. - variation in the response form one cell type to another 39. Which of the following statements is/are FALSE? - Inositol triphosphate is generated by the cleavage [hydrolysis] of cholesterol. 39. True statements: - Protein kinase C can phosphorylate a wide variety of proteins. - inositol triphosphate can open an ion channel, releasing calcium into the cytoplasm. - Diacyl glycerol and inositol triphosphate are formed through the action of a phospholipid. - inositol triphosphate can act as a second messenger. 40. Which statement about IP3, DAG, cAMP, Ca2+ and NO is FALSE? - They are made [released] in response to protein kinase receptor signaling exclusively 41. True statements about IP3, DAG, cAMP, Ca2+ and NO - they can easily pass through gap junctions from cell to cell. - They are required for indirect signal transduction. - they can rapidly diffuse through the cytosol of the cell. - they are examples of secondary signaling molecules. 42. Which of the following is directly involved in hydrolysis of GTP to GDP in response to a cell signal? - G proteins 43. Autocrine signals affects the same cell type that made it. 44. In thermodynamic terms, water held back by a dam represents _______ energy. - potential. 45. How does the second law of thermodynamics apply to living organisms? - Living organisms require a constant input of energy to maintain complex structures and order. 46. The first law of thermodynamics states that the total energy in the universe is? - constant 47. Which of the following statements about the exergonic hydrolysis of maltose to glucose is true? - The reaction releases free energy 48. Which of the following affects the rate of a reaction? - The activation energy 49. What is the correct order in which the following molecules would be produced if phosphate ions were removed from ATP one at a time? - ATP, ADP, AMP, adenosine 50. When ADP gains a phosphate to form ATP, - energy is required. 51. Which of the following will not increase the rate of conversion of substrate A to product B in the presence of enzyme C? - The addition of substrate D, that can compete with A for binding on the active site. 52. Many enzymes require ATP and ADP for a reaction to occur. These molecules temporarily bind to and then are released from the substrate before participating in other reactions. ATP and ADP are thus considered? - coenzymes. 53. Competitive inhibitors of enzymes work by? - fitting into the active site 54. The addition of the competitive inhibitor mevinolin slows the reaction HMG-CoA → mevalonate, which is catalyzed by the enzyme HMG-CoA reductase. In order to overcome the effects of mevinolin and increase the rate of the reaction you would? - add more HMG-CoA 55. Enzymes are highly sensitive to pH and temperature because? - pH and temperature affect their three-dimensional structure and side-chain chemistry 56. The enzyme a-amylase increases the rate at which starch is broken down into smaller oligosaccharides by _______ of the reaction? - lowering the activation energy. 57. An active site is the? - part of the enzyme that binds with a substrate. 58. The inhibition of enzyme activity by noncompetitive inhibitors can be reduced by? - increasing the concentration of allosteric enzyme. 59. In the presence of alcohol dehydrogenase, the rate of reduction of acetaldehyde to ethanol increases as the concentration of acetaldehyde is increased. Eventually, the rate of the reaction reaches a maximum, at which point further increases in the concentration of acetaldehyde have no effect. Why? - All the alcohol dehydrogenase is converting acetaldehyde molecules, the reaction is saturated. 60. End products of biosynthetic pathways often act to block the initial step in that pathway. This phenomenon is called? - feedback inhibition 61. Which of the following statements about metabolic pathways is true? - Each pathway is regulated by specific enzymes 62. In the first reaction of glycolysis, glucose receives a phosphate group from ATP. This reaction is? - endergonic. 63. When a molecule loses an electron, it becomes? - Oxidized 64. In most cells on earth, glucose catabolism begins with? - Glycolysis 65. Which of the following statements about metabolic pathways is true? - Each pathway is regulated by specific enzymes 66. Glycolysis converts glucose into pyruvate, ATP, and NADH. The process requires? - 10 enzyme-catalyzed reactions, with each reaction dependent on the products of the previous reaction to proceed 67. Manipulating the biochemical process that is used by brown fat, rather than by white fat, could be a mechanism for inducing weight loss in adults. This is because? - when brown fat molecules are catabolized, the stored energy is released as heat rather than as chemical energy. 68. NAD+[NADH]? - is a key electron carrier in redox reactions. 69. The end result of glycolysis includes the? - formation of two molecules of pyruvate 70. The end product of glycolysis is? - all of the above are correct. 71. More free energy is harvested during the citric acid cycle than during glycolysis, but only one mole of ATP is produced for each mole of acetyl CoA that enters the cycle. Most of the remaining free energy released during the citric acid cycle is? - used to reduce electron carriers 72. The fermentation process in vertebrate muscle cells produces? - lactic acid 73. Which of the following is/are produced during the citric acid cycle? - NADH and FADH2 74. Animals breathe in air containing O2 and breathe out air with less O2 and more CO2. The CO2 primarily comes from? - the citric acid cycle 75. Pyruvate oxidation (the intermediate step) generates? 76. In the conversion of pyruvate to acetyl CoA, hydrogen atoms are transferred to NAD+. The conversion of pyruvate to acetyl CoA is an example of? - a redox reaction 77. H2O is a by-product of cellular respiration. The H2O is produced as a result of the? - reduction of O2 at the end of the electron transport chain 78. The source of electrons for the electron transport chain is? 79. Rotenone is a potent inhibitor of mitochondrial complex I. If you were to treat isolated mitochondria with rotenone, what would you expect to happen to ATP production by oxidative phosphorylation? - ATP production and electron transport would decrease 80. In the absence of O2, cells capable of fermentation? - can oxidize NADH to produce NAD+. 81. In noncyclic electron transport, electrons from _______ replenish chlorophyll molecules that have given up electrons? - water. 82. Which of the following occurs during the light-independent (dark) reactions of photosynthesis? - CO2 is converted into sugars 83. Which of the following biological groups is dependent on photosynthesis for its survival? 84. Why is the absorption spectrum of chlorophyll a not identical to the action spectrum of photosynthesis? - Accessory pigments contribute energy to drive photosynthesis. 85. If a plant has plenty of NADPH available but is running low on ATP, how does the plant make up the ATP deficit during the daylight hours? - It uses cyclic photophosphorylation. 86. Both the light reactions and light-independent reactions of photosynthesis? - occur in the chloroplast 87. The wavelength of X rays is shorter than the wavelength of infrared waves. Based on this information, which of the following is true? - X rays have more energy per photon than infrared waves have. 88. In the first phase of photosynthesis, a series of reactions stores light energy in ATP and NADPH formation . These reactions are referred to as? - light reactions 89. During CO2 fixation, CO2 combines with? - 1,5-ribulose bisphosphate (RuBP) 90. Plants are green because? - chlorophylls do not absorb green light EXAM 2 PRACTICE EXAM: 1. Which of the following represents kinetic energy? a. The flow of hydrogen ions (H+) through ATP synthase and the phosphorylation of ADP to form ATP b. A concentration gradient across a membrane c. An electric charge imbalance across a membrane d. Both A and B e. All of the above 2. The sum total of all the anabolic and catabolic reactions in a living cell is called its a. energetics. b. activity. c. metabolism. d. entropy. e. respiration. 3 Which term most precisely describes the cellular process of making higher energy molecules out of lower energy ones? a. catalysis b. metabolism c. anabolism d. condensation e. catabolism 4. How does the first law of thermodynamics apply to organisms? a. As energy transformations occur, free energy is transferred from one form to another, it is neither created nor destroyed. b. To maintain order, life requires a balance of energy. c. The potential energy of ATP is converted to kinetic energy such as muscle contractions but also releases heat. d. Reactions occur only with a release of energy. e. It does not apply to organisms; the complexity of organisms contradicts the first law. 5. During photosynthesis, plants capture only about 5% of the energy available in sunlight and convert it into the potential energy found in glucose. This inefficiency in energy transfer is an example of? a. negative free energy (-G). b. chemical equilibrium. c. the first law of thermodynamics. d. the second law of thermodynamics. e. a spontaneous reaction. 6. In any system, the total energy includes usable and unusable energy. The usable energy is referred to as a. free energy. b. entropy. c. heat. d. thermodynamics. e. equilibrium. 7. If ΔG of a chemical reaction is positive, you can conclude that it… a. releases energy. b. is endergonic. c. is exergonic. d. will not reach equilibrium. e. increases the disorder in the system. 8 The mathematical expression for the free change in free energy of a system is G=H-T S. Which of the following is (are) correct? a. S is the change in entropy b. H is the change in free energy c. G is a change in the enthalpy d. T is the temperature e. Answers A and D are correct 9. Which of the following statements about enzymes is false? a. An enzyme changes shape when it binds to a substrate. b. Enzymes lower the activation energy. c. Enzymes can only catalyze a certain number of reactions before they are completely consumed. d. An enzyme may orient substrates, induce strain, or temporarily add chemical groups. e. Most enzymes are much larger than their substrates. 10. The hydrolysis of sucrose to glucose and fructose is exergonic. However, if sucrose is dissolved in water and the solution is kept overnight at room temperature, there is no detectable conversion to glucose and fructose. Why? a. The change in free energy of the reaction is positive. b. Room temperature does not achieve the necessary energy of activation for the reaction to occur. c. The change in free energy of the reaction is negative. d. This is a condensation reaction. e. The free energy of the products is higher than the free energy of the reactants. 11. In some cases, a substrate–enzyme complex is stabilized by a. hydrogen bonds. b. covalent bonds. c. ionic attractions. d. hydrophobic interactions. e. all of the above 12. Which of the following could denature an enzyme? a. high temperature b. changes in pH. c. an allosteric regulator d. answers A and B are correct e. all of the above are correct 13. Why is ATP an important molecule in metabolism? a Its hydrolysis provides an input of free energy for endergonic reactions. b Its terminal phosphate groups ionize easily, releasing free energy. c It transfers (couples) free energy between exergonic and endergonic reactions. d Answers A and B are correct e. All of the above are correct 14. Many enzymes require NAD+ and NADH for a reaction to occur. They temporarily bind to and then release from the substrate to participate in other reactions. NAD+ and NADH are considered a. a side chain. b. a coupled reaction c. coenzymes d. a prosthetic group. e. cofactors. 15. Four atoms of ferrous Iron (Fe) are required for hemoglobin protein to efficiently carry oxygen in the human bloodstream. The iron most likely functions as a(n) a cofactor necessary for enzyme activity b noncompetitive inhibitor of the enzyme. c. allosteric activator of the enzyme. d. competitive inhibitor of the enzyme. e. coenzyme necessary for moving hydrogen ions from one pathway to another. 16. How do competitive and noncompetitive enzyme inhibitors differ? a. They function at different pH values. b. Competitive inhibitors have a higher energy of activation than noncompetitive inhibitors have. c. Competitive inhibitors bind to the active site, whereas noncompetitive inhibitors change the shape of the active site. d. Noncompetitive enzyme inhibitors contain magnesium, whereas competitive inhibitors contain iron. e. Noncompetitive enzyme inhibitors are reversible, whereas competitive inhibitors are irreversible. 17. An allosteric inhibitor a. decreases the concentration of the enzyme. b. changes the shape of a substrate. c. increases the concentration of a product. d. changes the shape of an enzyme (the shape of its active site). e. increases the concentration of an enzyme–substrate complex 18. The process that involves an end product acting as an inhibitor of an earlier step in a metabolic pathway is called a. feedback inhibition. b. feedback activation. c. positive feedback. d. concerted activation. e. competitive inhibition. 19. When organisms move from one environment to another, they sometimes synthesize variations of existing enzymes, which are called a. coenzymes. b. isozymes. c. abzymes. d. effectors. e. activators. 20. Consider the pathway below, if product F is an allosteric inhibitor of enzyme 3, what will be the result as F accumulates? a. The concentration of product C will decrease. b. The concentration of reactants A and B will increase. c. The concentration of product E will increase because more of F is converted back to E. d. The concentration of product D will increase. e. The concentration of products E and F will both increase. 21. You are studying a new species. It lives in freshwater hot springs where the water temperature averages 50°C to 60°C. You determine that it has a surface enzyme that catalyzes a reaction leading to its protective coating, and you decide to study this enzyme in the laboratory. Under what conditions would you most likely find optimal activity of this enzyme? a. 0°C b. 37°C c. 55°C d. 95°C e. 105°C 22. Which of the following statements about metabolic pathways is false? a. The product of one reaction becomes the reactant for the next reaction. b. They are a series of enzyme-catalyzed reactions. c. Many are compartmentalized in eukaryotes. d. Many are highly conserved even between organisms in different domains of life e. Almost all are catabolic. 23. When NADH gives two electrons to complex I of the respiratory electron transport system, NADH is a. reduced. b. oxidized. c. phosphorylated. d. aerobic. e. hydrolyzed. 24 When electrons move closer to a more electronegative atom, what happens? a. Free energy is released. b. Free energy is consumed. c. Atoms are ionized. d. Atoms become chemically inert or “noble”. e. A and C are correct. 25. In all cells, glucose catabolism begins with a. the citric acid cycle b. fermentation. c. pyruvate oxidation to acetyl CoA. d. glycolysis. e. chemosmosis. 26. NAD+ a. is a key electron carrier in redox reactions. b. is an amino acid class of biological molecule. c. requires oxygen to function. d. answer A and B are correct. e. all of the above are correct 27. Which of the following processes occurs during aerobic respiration? a. Pyruvate oxidation to acetyl-CoA b. The citric acid cycle c. Fermentation d. Answers A and B are correct e. All of the above 28. Which of the following is an intermediate of the citric acid cycle? a. pyruvate. b. glucose-6-phosphate c. oxaloacetate d. phosphoenol pyruvate e. 3-phosphoglyceric acid 29. Substrate-level phosphorylation is the enzymatic transfer of a phosphate from an organic molecule to? a. another enzyme. b. ADP c. ATP. d. NAD+ e. a carbohydrate. 30. The pyruvate dehydrogenase complex (pyruvate oxidation) generates a. CO2 b. NADH + H+ from NAD+. c. glucose-6-phosphate d. answer A and B are correct e. all of the above are correct 31. Which of the following is produced/generated during the citric acid cycle? a. NADH and FADH2 b. 3-phosphoglycerate c. Lactic acid d. Pyruvate e. Glucose-6-phosphate 32. Animals breathe in air containing oxygen and breathe out air with less oxygen and more carbon dioxide. The carbon dioxide comes from a. pyruvate oxidation to acetyl-CoA. b. the citric acid cycle. c. glycolysis. d. answers A and B are correct e. All of the above are correct 33. You have a friend who lost 7 kg (about 15 pounds) of fat on a diet. How did that matter leave their body? a Chemical energy was converted to heat and then released. b Most was converted to muscle and muscle weighs less than fat. c Most was converted to ATP, which weighs much less than fat. d. Most was released as CO2 and H2O. e. Most was converted to feces and eliminated from the body. 34. During aerobic respiration in the eukaryotic cell, H+ ions accumulate where? a. nucleus. b. endoplasmic reticulum c. mitochondrial intermembrane space. d. mitochondrial matrix e. cytosol. 35. Which of the following statements about the respiratory electron transport chain is FALSE? a. Electrons are received from NADH and FADH2. b. Electrons are passed from donor to recipient carrier molecules in a series of oxidation– reduction reactions. c. In humans, the terminal electron acceptor is pyruvate. d. Most of the enzymes are part of the inner mitochondrial membrane. e. It contains Cytochromes and Ubiquinone (Coenzyme Q). 36. Human infants and hibernating animals have specialized “brown fat” cells that produce a protein called Thermogenin. This protein releases the H+ ion gradient created by the respiratory electron transfer chain. Which of the following statements regarding “brown fat” cells is/are TRUE? a. Oxygen would no longer be reduced to water during respiration. b. No ATP would be made. c. The citric acid cycle would eventually stop functioning as all available NAD+ became reduced. d. The cells would generate large amounts of heat. e. Hibernating animals increasingly rely on fermentation pathways for energy 37. The component of aerobic respiration that produces the most ATP per mole of glucose is a. glycolysis b. the citric acid cycle. c. the electron transport chain and oxidative phosphorylation. d. lactic acid fermentation. e. alcoholic fermentation. 38. Which of the following statements regarding the formation of lactate by human cells is/are TRUE a. it is an example of fermentation. b. it recycles NAD+ from NADH c. it produces CO2 d. answer A and B are true e. all of the above are true 39. Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose-6- phosphate to fructose-1,6-bisphosphate, an early step of glycolysis. An increased accumulation of citrate (an allosteric regulator of PFK) would be expected to… a inhibit the enzyme and slow the rates of glycolysis and the citric acid cycle. b activate the enzyme and slow the rates of glycolysis and the citric acid cycle. c. inhibit the enzyme and thus increase the rates of glycolysis and the citric acid cycle. d. activate the enzyme and increase the rates of glycolysis and the citric acid cycle. e. citrate would have no effect on the rates of glycolysis and the citric acid cycle. 40. Which hormone is deficient (absent) in humans with Type I (juvenile) diabetes? a. oxaloacetate b. insulin c. thyroxin d. peptidase e. glucose levelase 41. Which of the following are benefits of exercise in humans? a. improves LDL to HDL ratio b. uses calories c. increases bone mass and muscle tone d. answers A and B are correct e. all of the above are correct 42. Plants are green because a. plants do not possess green pigment. b. chlorophylls absorb blue and orange-red wavelengths of light and reflect green light. c. energized chlorophyll a emits green light. d. chloroplasts hydrolyze ATP to produce green light. e. chlorophylls absorb green light. 43. The main photosynthetic pigments in plants are _______ and _______. a. chlorophyll a; chlorophyll b b. chlorophyll x; chlorophyll y c. retinal pigment; accessory pigment d. caratonoids and phycobilins e. None of the above 44. Accessory pigments a. play no role in photosynthesis. b. transfer energy from chlorophyll to the electron transport chain. c. absorb only the red wavelengths. d. allow plants to absorb visible light of varying wavelengths. e. transfer electrons to NADP. 45. Which of the following gives up electrons during noncyclic photophosphorylation (light dependent reactions)? a. CO2 b. water (H2O) c. ATP d. O2 gas e. None of the above 46. The net energy outcome of noncyclic photophosphorylation (light dependent reactions) is a. ATP. b. ATP and NADH. c. NADPH. d. ATP and NADPH. e. sugar. 47. Which of the following occurs during the light-independent (dark or calvin-benson) reactions of photosynthesis? a. ATP and NADPH are recycled back to ADP and NADP+. b. CO2 is converted into organic molecules (glyceraldehydes-3-phosphate). c. Water is converted into hydrogen and oxygen. d. Answers A and B are correct e. All of the above are correct 48. Where would you find photosytem II in a green plant? a. the stroma of a chloroplast b. the thylakoid membrane of a chloroplast c. the cytoplasmic membrane d. the cytosol e. the mitochondrial inner membrane 49. If you were to grow a green plant in a lighted chamber in the presence of radioactive carbon dioxide for several minutes only, which of the following types of compounds in the plant would be radioactive? a. Only sugars b. Amino acids and proteins c. Oils and membrane lipids d. Calvin cycle intermediates e. All of the above 50. During sunny dry days, photorespiration may occur in plants. During photorespiration, the enzyme rubisco uses _______ as a substrate. a. O2 b. CO2 c. glyceraldehyde 3-phosphate d. 3-phosphoglycerate e. NADPH EXAM 2 ONLINE RESOURCE: 1. Which of the following represents potential energy? a. Chemical bonds in an organic molecule b. A concentration gradient across a membrane c. An electric charge imbalance across a membrane d. Both a and b e. All of the above 2 Which term most precisely describes the cellular process in which higher energy molecules are converted to lower energy ones with the release of energy? a. catalysis b. metabolism c. anabolism d. evaporation e. catabolism 3. During photosynthesis, plants use light energy to synthesize glucose from carbon dioxide. However, plants do not use up energy during photosynthesis; they merely convert it from light energy to chemical energy. This process is an illustration of a. increasing entropy. b. chemical equilibrium. c. the first law of thermodynamics. d. the second law of thermodynamics. e. a spontaneous reaction. 4. In any system, the total energy includes usable and unusable energy. The usable energy is referred to as a. free energy. b. entropy. c. heat. d. thermodynamics. e. equilibrium. 5. If ΔG of a chemical reaction is negative, you can conclude that it… a. is explosive. b. is endergonic. c. is exergonic. d. will not reach equilibrium. e. increases the disorder in the system 6. The mathematical expression for the free change in free energy of a system is G=H-T S. Which of the following is (are) correct? a. S is the change in entropy b. H is the change in enthalpy c. G is a change in the free energy d. T is the temperature e. All of the above are correct 7. Which of the following statements about enzymes is false? a. Enzymes increase the free energy released by a reaction. b. Enzymes lower the activation energy. c. Enzymes are not consumed or permanently modified by the reaction. d. An enzyme may orient substrates, induce strain, or temporarily add chemical groups. e. Most enzymes are much larger than their substrates 8. The hydrolysis of sucrose to glucose and fructose is exergonic. However, if sucrose is dissolved in water and the solution is kept overnight at room temperature, there is no detectable conversion to glucose and fructose. Why? a. The change in free energy of the reaction is positive. b. The reaction will not occur in water c. The change in free energy of the reaction is negative. d. Room temperature does not achieve the necessary energy of activation for the reaction to occur. e. The free energy of the products is higher than the free energy of the reactants. 9. Organisms can usually withstand temperatures only a few degrees warmer than their optimal temperature. When this high temperature is exceeded, which of the following begins to happen? a. The energy of activation necessary for reactions to proceed cannot be achieved b. The hydrogen bonds of enzymes break causing denaturation and loss of enzyme function. c. Enzymatic reactions accelerate and metabolism can no longer be controlled. d. The covalent bonds of proteins break down causing denaturation and loss of protein function e. Membrane integrity is lost as the covalent bonds in phospholipids break down. 10. Which of the following molecules stores/transfers chemical energy in the form of multiple phosphate groups? a NADH b FADH2 c NADPH d ATP e. pyruvate 11. The enzyme complex hemoglobin requires the additional organic molecule porphyrin in order to function. Porphyrin is part of the quaternary structure of the enzyme complex. Porphyrin would be considered which of the following? a. a side chain. b. a coupled reaction c. a prosthetic group d. coenzyme e. cofactors. 12. Which of the following statements about competitive enzyme inhibitors is/are TRUE? a. They are slightly different functional versions of the same enzyme. b. They have a higher energy of activation than the normal substrate. c. They block the active site, preventing the substrate from entering. d. They are always irreversible e. They can activate or inhibit enzyme activity 13. An allosteric regulator a. interacts with an enzyme at a different site than the active site. b. enables the reaction to occur at a maximum rate even when the concentration of substrate is very low. c. increases the rate at which an enzyme can catalyze a reaction d. answers a and b are correct. e. all of the above are correct 14. The process that involves an end product acting as an inhibitor of an earlier step in a metabolic pathway is called a. feedback activation. b. feedback inhibition. c. positive feedback. d. concerted activation. e. noncompetitive inhibition. 15. You fill two containers with identical amounts of reactants A and B and enzymes 1–4. In the reactions shown below, if product F inhibits enzyme 1, what will be the final result if you add extra product F to the second container? a. The concentration of product C will increase compared to the first container. b. The concentration of reactants A and B will increase relative to the first container. c. The concentration of reactant B will increase in the second container because more of C is converted back to B. d. The concentration of products E and F will both increase in the second container. e. The concentration of product D will increase relative to the first container. 16. The deadly nerve agent DIPF interacts with the active site of the enzyme acetylcholine esterase, permanently modifying it so that it no longer functions. DIPF is a? a. reversible, competitive inhibitor b. reversible, non-competitive inhibitor c. irreversible, competitive inhibitor d. reversible, non-co