EPOB 1210, Dr. Schmidt

Choose the best answer to each question.

1. What does the energy that vaporizes water do?
A) oxidizes the water
B) reduces (adds electrons to) the water molecules
C) decreases the pH of water
D) increases the kinetic energy of water molecules and breaks hydrogen bonds between them
E) decreases the density of water and lowers the kinetic energy of vaporized molecules

2. Which of the following descriptions best fits a nucleotide?
A) a nitrogen base and a phosphate group
B) a nitrogen base and a five-carbon sugar
C) a nitrogen base, a phosphate group, and a five-carbon sugar
D) a five-carbon sugar and adenine or uracil
E) a five-carbon sugar and a purine

3. The partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule. What is this attraction called?
A) a covalent bond
B) a hydrogen bond
C) an ionic bond
D) a hydration shell
E) a hydrophobic bond

4. A solution with a pH of 3 has how many more H ions than a solution with a pH of 6?
A) 2 times more
B) 10 times more
C) 100 times more
D) 300 times more
E) 1000 times more

5. Which of the statements regarding enzymes is false?
A) Enzymes are proteins that function as catalysts.
B) Enzymes display specificity for substrate molecules to which they attach.
C) Enzymes provide activation energy for the reactions they catalyze.
D) The activity of enzymes can be regulated by factors in their immediate environment.
E) An enzyme may be used many times over for a specific reaction.

6. The atomic number of carbon is 6. 14C is heavier than 12C because 14C has
A) six protons.
B) six neutrons.
C) eight protons.
D) eight neutrons.

7. An atomic form of an element containing different numbers of neutrons is
A) an isotope.
B) an ion.
C) a polar atom.
D) an isomer.

8. A chemical reaction that has a positive delta G is correctly described as
A) endergonic.
B) exergonic.
C) enthalpic.
D) exothermic.

9. Ice floats on water because it is a crystalline structure held together by
A) ionic bonds only.
B) hydrogen bonds with high kinetic energy.
C) hydrogen bonds with low kinetic energy.
D) both ionic and covalent bonds.

10. Which of the following is a carbonyl group?
A) -OH
B) -C=O
C) -COOH
D) -NH2
E) -SH

11. Why are hydrocarbons not soluble in water?
A) They are hydrophilic.
B) The C-H bond is nonpolar.
C) They ionize.
D) They are large molecules.
E) They are lighter than water.

12. Which of the following is true of stereoisomers?
A) They have variations in arrangement around a double bond.
B) They have an asymmetric carbon that makes them mirror images.
C) They have the same chemical properties.
D) They have different molecular formulas.

13. Which of the following is basic, can accept H+ and can become positively charged.
A) -OH
B) -C=O
C) -COOH
D) -NH2

14. How many electron pairs does carbon share in order to complete its valence shell?
A) 1 B) 2 C) 3 D) 4 E) 5

15. Which two functional groups are always found in amino acids?
A) amine and sulfhydryl
B) carbonyl and carboxyl
C) carboxyl and amine
D) alcohol and aldehyde
E) ketone and amine

16. A compound contains hydroxyl groups as its predominate functional group. Which of the following statements is true concerning this compound?
A) It is probably a lipid.
B) It should dissolve in water.
C) It should dissolve in a non-polar solvent.
D) It won't form hydrogen bonds with water.
E) It is hydrophobic.

17. How does an enzyme catalyze a reaction?
A) by supplying the energy to speed up a reaction
B) by lowering the energy of activation of a reaction
C) by lowering the deltaG of a reaction
D) by increasing the amount of free energy of a reaction

18. Why is ATP an important molecule in metabolism?
A) It has high energy sulfate bonds.
B) Its phosphate bonds are easily made and broken.
C) Its hydrolysis is endergonic.
D) It is extremely stable and not reactive.

19. Which of the following is part of the first law of thermodynamics?
A) Energy cannot be created or destroyed.
B) The entropy of the universe is decreasing.
C) The entropy of the universe is constant.
D) Kinetic energy is stored energy.
E) Energy cannot be transferred or transformed.

20. Whenever energy is transformed, there is always an increase
A) in the free energy of the system.
B) in the free energy of the universe.
C) in the entropy of the system.
D) in the entropy of the universe.
E) in the enthalpy of the universe.

21. Which of the following endergonic reactions could be coupled to the reaction:
ATP --> ADP + Pi (deltaG = -7.3 Kcal)?
A) X + Pi --> XP (deltaG = +9 Kcal)
B) Y + Pi --> YP (deltaG = +8 Kcal)
C) E + Pi --> EP (deltaG = +5 Kcal)
D) All of the above

22. What is the general metabolic process of breaking down large molecules into smaller ones called?
A) catalysis
B) metabolism
C) anabolism
D) condensation
E) catabolism

23. ATP generally energizes a cellular process by
A) releasing heat upon hydrolysis.
B) acting as a catalyst.
C) direct chemical transfer of a phosphate group.
D) releasing ribose electrons to drive reactions.
E) emitting light flashes.

24. Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about ammonia (NH3)?
A) Each hydrogen atom has a partial positive charge.
B) The nitrogen atom has a strong positive charge.
C) Each hydrogen atom has a slight negative charge.
D) The nitrogen atom has a partial positive charge.
E) There are covalent bonds between the hydrogen atoms.

25. According to the second law of thermodynamics
A) the entropy of the universe is constantly increasing.
B) for every action there is an equal and opposite reaction.
C) every energy transfer requires activation energy from the environment.
D) the total amount of energy in the universe is conserved or constant.
E) energy can be transferred or transformed, but it can be neither created or destroyed.

26. Correct statements regarding ATP include:
I. ATP (adenosine triphosphate) serves as the main energy shuttle in cells
II. ATP drives endergonic reaction in the cell by the transfer of a phosphate group to specific reactants
III. The regeneration of ATP from ADP and phosphate is an endergonic reaction.
A) I only
B) II only
C) III only
D) I and III only
E) I, II and III

27. All of the following statements regarding enzymes are true EXCEPT
A) Enzymes are carbohydrates that function as agents that change the rate of reaction without being consumed in the reaction.
B) Enzymes allow molecules to react in metabolism by lowering activation energies.
C) Each type of enzyme has a uniquely shaped active site, that gives it specificity.
D) Enzymes are very sensitive to environmental conditions that influence the weak chemical bonds responsible for their three-dimensional structure.

28. Which of the following contain amino sugars and D-amino acids?
A) Chitin B) Peptidoglycan C) Cellulose D) A and B
E) All of the above

29. A measure of the average kinetic energy of the molecules in a body of matter is.
A) calorie
B) temperature
C) heat of vaporization
D) buffer
E) mole

30. Polymers of polysaccharides, fats, and proteins are all synthesized from monomers by
A) connecting monosaccharides together.
B) the addition of water to each monomer.
C) the removal of water (condensation synthesis).
D) ionic bonding of the monomers.
E) the formation of disulfide bridges between monomers.

31. Genes are made of
A) rRNA
B) Deoxyribonucleic acid
C) phospholipids
D) tRNA
E) polypeptides

32. Amino acids with carboxyl groups in their R groups would be expected to be
A) polar and basic
B) nonpolar and acidic
C) polar and acidic
D) basic and uncharged
E) all of the above

33. Which of the following is true both of starch and of cellulose?
A) They are both polymers of glucose.
B) They are geometric isomers of each other.
C) They can both be digested by humans.
D) They are both used for energy storage in plants.
E) They are both structural components of the plant cell wall.

34. Which of the following is true of an amino acid and starch?
A) Both contain nitrogen.
B) Both contain oxygen.
C) Both are polymers of repeating monomers.
D) Both are hydrophobic.
E) Both are found in proteins.

35. The molecular mass of glucose is 180 daltons. A one-molar solution of glucose, consists which of the following?
A) 100g of glucose in a liter of water.
B) 180 grams of glucose in a gallon of solution.
C) 180 grams of glucose in 100 grams of water.
D) 180 daltons of glucose in one liter of solution.
E) 180 grams of glucose in one liter of solution.

36. Large organic molecules are usually assembled by polymerization of repeating
monomers such as nucleotides or amino acids. Which of the following is an exception to the above statement?
A) a steroid
B) a contractile protein
C) DNA
D) an enzyme

37. At a temperature of 70 degrees C, enzymes from human cells would be expected to
A) grow
B) catalyze reactions faster than at body temperature
C) denature
D) increase the activation energy of a reaction
E) triglycerate

38. What maintains the secondary structure of a protein?
A) peptide bonds
B) hydrogen bonds
C) disulfide bridges
D) ionic bonds
E) electrostatic charges

39. Which of the following is true concerning saturated fats?
A) They have double bonds between the carbon atoms of the fatty acids.
B) They have a higher ratio of hydrogen to carbon than unsaturated fats.
C) They are usually liquid at room temperature.
D) They are usually produced by plants.
E) All of the above are true.

40. Which bonds form the primary structure of a protein?
A) peptide bonds
B) hydrogen bonds
C) disulfide bonds
D) Only a and c are correct.
E) a, b and c are correct.

41. The alpha helix and the beta pleated sheet are both common forms found in which level of structure of proteins?
A) primary
B) secondary
C) tertiary
D) quaternary
E) Both a and d are correct.

42. In the double helix structure of nucleic acid, cytosine hydrogen bonds to
A) deoxyribose (D)
B) ribose (U)
C) adenine (A)
D) thymine (T)
E) guanine (G)

43. An example of the tertiary structure of a protein is the
A) bonding together of several polypeptide chains by weak bonds.
B) order in which amino acids are joined in a peptide chain.
C) bonding of two amino acids together to form a dipeptide.
D) twisting of a peptide chain into an alpha helix.
E) folding of the alpha helix into a knot-like structure

44. The element nitrogen (N) is present in all of the following EXCEPT
A) proteins.
B) nucleic acids.
C) amino acids.
D) DNA.
E) lipids.

45. Which of the following would yield the most energy per gram when oxidized?
A) starch
B) glycogen
C) fat
D) protein

46. The atomic number of the noble gas neon is 10 and it
A) has 8 electrons in the outer electron shell.
B) is inert.
C) has an atomic mass of 10.
D) Only a and b are correct.
E) a, b and c are correct.

47. Which of the following is a trace element that is essential to humans?
A) nitrogen B) oxygen C) iodine D) carbon

48. Which of the following results from a transfer of electron(s) between atoms.
A) nonpolar covalent molecule
B) polar covalent bond
C) ionic bond
D) hydrogen bond
E) hydrophobic interaction

49. Which four elements make up approximately 96% of living matter?
A) carbon, hydrogen, nitrogen, and oxygen
B) carbon, sulfur, phosphorus, and hydrogen
C) oxygen, hydrogen, calcium, sodium
D) carbon, sodium, chlorine, magnesium
E) carbon, oxygen, sulfur, calcium

50. The number of additional electrons needed to complete the valence shell of hydrogen is (atomic number = 1)
A) 1 B) 2 C) 3 D) 4 E) 5