The Chemistry Of Life Exam Questions Chapter 2

Biology: The Essentials, 3e (Hoefnagels)

Chapter 2 The Chemistry of Life

1) The most abundant bulk elements that make up the vast majority of living organisms are

A) carbon, hydrogen, oxygen, and calcium.

B) carbon, oxygen, iron, and chlorine.

C) carbon, hydrogen, iron, and calcium.

D) carbon, hydrogen, oxygen, and nitrogen.

E) carbon, oxygen, sulfur, and calcium.

2) The atomic number of an atom or element is the number of

A) neutrons in the nucleus.

B) electrons in the nucleus.

C) protons in the nucleus.

D) neutrons in the orbitals.

E) protons in the orbitals.

3) An ion could be 

A) an atom that has gained electrons.

B) an atom that has a positive charge.

C) an atom that has lost electrons.

D) an atom that has a negative charge.

E) All answers are correct.

4) If you were told to sort cards into boxes after a lab on elements, you would put into a slot labelled "Mass Number" any card with text that included the total number of

A) protons, neutrons, and electrons of an atom.

B) protons and electrons of an atom.

C) protons and neutrons of an atom.

D) neutrons and electrons of an atom.

E) protons of an atom.

5) Isotopes of the same element are different from one another in that

A) they have a different number of protons.

B) they have a different number of neutrons.

C) they have a different number of electrons.

D) they are a different element.

E) only one of the isotopes is matter.

6) For most atoms, the outermost electron shell would be full if it contained

A) one electron.

B) four electrons.

C) eight electrons.

D) sixteen electrons.

7) If an atom exists in nature with a valence shell that is full, then it is

A) highly reactive.

B) chemically unstable.

C) highly likely to combine with other atoms.

D) found only in a gas form.

E) inert.

8) In a covalent bond

A) atoms share electrons.

B) atoms of opposite charges attract each other.

C) atoms share protons.

D) atoms share neutrons.

E) atoms are repelled by each other.

9) An ionic bond is a bond in which

A) atoms share electrons.

B) atoms share protons.

C) atoms of opposite charges attract each other.

D) atoms share neutrons.

E) atoms are repelled by each other.

10) Which statement about a bond between sodium and chlorine is incorrect?

A) Na is the chemical symbol for sodium.

B) Chlorine donates an electron.

C) Chlorine becomes negatively charged.

D) Sodium becomes positively charged.

E) The bond that is formed is a strong bond.

11) In the example of ionic bond formation between sodium and chlorine

A) Na is the chemical symbol for chlorine.

B) sodium accepts an electron.

C) chlorine accepts an electron.

D) chlorine becomes positively charged.

E) both sodium and chlorine accept electrons.

12) If a covalent bond is polar

A) electrons are not shared by atoms.

B) protons are shared by atoms.

C) it will not form in living organisms.

D) the electronegativity of atoms is unequal in their pull on electrons.

E) the bond is weak in strength.

13) A hydrogen bond

A) is generally a strong bond.

B) does not occur in living organisms.

C) does not require electron transfer.

D) forms between atoms having the same electronegativity.

E) is a specialized type of covalent bond.

14) Evaporation is

A) the conversion of a liquid into a vapor.

B) the conversion of a solid into a vapor.

C) the conversion of a vapor into a liquid.

D) the conversion of a vapor into a solid.

E) All answers are correct.

15) A friend who is not taking your Biology course fills a cup with ice and then a drink. The friend asks you why the ice in the cup is floating, and you are able to say that 

A) the molecules are closer together in ice than in liquid water.

B) the molecules are farther apart in ice than in liquid water.

C) ice is denser than liquid water.

D) convection currents caused by temperature differences push upwards on the ice.

E) water vapor is less dense than liquid water.

16) In a chemical equation

A) the reactants are on the right of the yields arrow.

B) reactants and products are on both sides of the yields arrow.

C) the products are on the left of the yields arrow.

D) the reactants are on the left of the yields arrow.

E) the number of atoms of each element may differ on the two sides of the yields arrow.

17) An acid

A) has a value above 7 on the pH scale.

B) is a chemical that takes hydrogen ions from a solution.

C) has a value of 7 on the pH scale.

D) is a chemical that adds hydrogen ions to a solution.

E) All answers are correct.

18) A base

A) has a value of 7 on the pH scale.

B) is a chemical that adds hydrogen ions to a solution.

C) is a chemical that absorbs hydrogen ions from a solution.

D) has a value below 7 on the pH scale.

19) A substance with a pH of 2 is

A) neutral.

B) a weak acid.

C) a weak base.

D) a strong base.

E) a strong acid.

20) As part of an exam, you are given a powder to analyze. When you perform various tests, you find that it contains a single chemical that changes the pH of neutral water to a pH of 6. You would conclude that the chemical is a

A) weak acid.

B) neutral.

C) weak base.

D) strong acid.

E) strong base.

21) A substance with a pH of 7 is

A) a weak acid.

B) a weak base.

C) neutral.

D) a strong acid.

E) a strong base.

22) As part of a lab exam, you are given a vial of orange crystals. When you add them to pure, neutral pH water, the pH changes to 13. Other tests show that the crystals consist of a single chemical. You could conclude the chemical is 

A) a weak acid.

B) a weak base.

C) neutral.

D) a strong acid.

E) a strong base.

23) Organic molecules are defined as chemical compounds that contain

A) hydrophilic solutions.

B) isotopes of carbon.

C) ionically bonded atoms.

D) strong hydrogen bonds.

E) carbon and hydrogen.

24) The four major groups of organic compounds are

A) fats, waxes, carbohydrates, and amino acids.

B) carbohydrates, lipids, steroids, and monosaccharides.

C) lipids, fats, waxes, and steroids.

D) carbohydrates, lipids, proteins, and nucleic acids.

E) carbohydrates, proteins, amino acids, and nucleic acids.

25) You are asked to help prepare a lab and need to label some beakers. In one, you are told, there are sugars polymerizing into a large polymer, so you prepare a label that mentions 

A) hydrolysis.

B) reproduction.

C) dehydration synthesis.

D) translation.

E) transcription.

26) A process by which cells break polymers down into smaller units is

A) hydrolysis.

B) dehydration synthesis.

C) reproduction.

D) hydrolysis and dehydration synthesis.

E) unrelated to chemical bonds.

27) Imagine that you are in a study session, and your group is taking a practice quiz that members grade for one another. For the question, "A cook decides to cook only using monomers, so what chemicals could the cook use?" you would mark correct if the paper you are grading has the answer as 

A) cellulose and sucrose.

B) lactose and sucrose.

C) glucose and fructose.

D) glucose and cellulose.

E) None of the answers are correct.

28) You are asked to help solve a murder, and a note from the murderer taunting the police says that the crime was committed using a lipid. What molecule could you exclude from your search?

A) a triglyceride

B) a phospholipid

C) a wax

D) a sterol

E) a starch molecule

29) The primary building block (monomer) of proteins is

A) a glucose molecule.

B) a fatty acid.

C) a nucleotide.

D) an amino acid.

E) four interconnected rings.

30) If asked to build a model of an amino acid, you would need parts to represent 

A) three R groups and a glycerol.

B) nitrogen, carbon, and an R group.

C) multiple saccharide rings.

D) carbon and phosphorus monomers.

E) carbon and phosphorus.

31) As part of a lab practical, you need to attach labels about chemical models. For the bond between amino acids, you would add a label describing that it is 

A) an ionic bond in proteins.

B) a covalent bond in carbohydrates.

C) a covalent bond in proteins.

D) an ionic bond in carbohydrates.

E) a hydrogen bond in nucleic acids.

32) The primary building block (monomer) of nucleic acids is

A) a nucleotide.

B) a glucose molecule.

C) a fatty acid.

D) an amino acid.

E) four interconnected carbon rings.

33) Water is best described as which of the following?

A) an ion

B) a nonpolar molecule

C) an atom

D) a polar molecule

E) an element

34) You encounter a new compound that is bright purple and smells of violets. It sticks to surfaces in a way similar to water and can replace water in the running of living cells. You might expect that this new molecule will make 

A) covalent bonds.

B) ionic bonds.

C) hydrogen bonds.

D) hydrophobic bonds.

E) peptide bonds.

35) Within a single molecule of water, ________ bonds form between oxygen and hydrogen.

A) ionic

B) covalent

C) hydrogen

D) hydrophobic

E) nuclear

36) What do a lemon, a toaster oven, and sand grains have in common?

A) All are composed of matter and energy.

B) All are alive.

C) All are composed of organic molecules.

D) All are acidic.

E) All are basic.

37) You can painlessly wade into a pool, but doing a belly flop off of the high diving board hurts because of

A) water's higher density compared to the air.

B) adhesion of your molecules with the water molecules.

C) water's high boiling point.

D) a neutral pH.

E) cohesion of the water molecules.

Scientists use carbon dating to determine the age of fossils. 14C is a rare isotope of carbon that has a half life of 5730 years and decays into 14N. By measuring the amount of 14C remaining in a fossil, scientists can estimate when the organism died to within 60,000 years. The atomic numbers of C is 6 and of N is 7.

38) The most common isotope of carbon is 12C. 14C has ____ than 12C.

A) more protons

B) more neutrons

C) fewer neutrons

D) fewer protons

E) more electrons

39) 14C and 14N have the same

A) atomic number.

B) number of protons.

C) mass number.

D) number of neutrons.

E) number of electrons.

40) What is an example of matter?4615

A) oxygen gas

B) energy

C) light

D) heat

E) None of the answers are correct.

41) Hydrogen, nitrogen, carbon, and oxygen account for 96% of the human body. These elements are

A) also the main elements in organic molecules.

B) rare in nonhuman organisms.

C) rare on Earth.

D) always bonded by hydrogen bonds.

E) All answers are correct.

42) The polymers with the most complex and diverse three-dimensional structures are

A) saturated fats.

B) unsaturated fats.

C) proteins.

D) waxes.

E) carbohydrates.

43) Water is a compound.

44) Proteins are compounds because they are polymers.

45) Two hydrogen atoms and an oxygen atom bonded together form

A) a molecule, but not a compound.

B) a compound, but not a molecule.

C) a molecule and a compound.

D) an atom and a molecule.

E) an atom, but not a molecule or compound.

46) Polymers are made of monomers, and both are kinds of compounds.

47) Carbon is a compound.

48) The four most abundant elements needed by the human body are carbon, hydrogen, oxygen, and nitrogen. Because these are needed in large amounts to support our cells, these are referred to as

A) bulk elements.

B) trace elements.

C) isotopes.

D) buffers.

E) essential elements.

49) If a molecule is added to a glass of water, and is easily dissolved by the water, the added molecule is described as hydrophilic.

50) Blood is closely maintained at a pH of 7.4. A patient whose blood pH drops below 7.35 is suffering from metabolic acidosis and can go into a coma. What happens to the concentration of H+ ions in a patient with a blood pH of 6.4?

A) H+ concentration is decreased 10-fold.

B) H+ concentration is decreased 2-fold.

C) H+ concentration is increased 2-fold.

D) H+ concentration is decreased 4-fold.

E) H+ concentration is increased 10-fold.

51) The four nitrogen bases found in RNA are

A) adenine, thymine, guanine, and uracil.

B) adenine, cytosine, guanine, and uracil.

C) adenine, thymine, cytosine, and uracil.

D) thymine, cytosine, guanine, and uracil.

E) None of the answer choices is correct.

52) Saturated fats have long, straight tails of fatty acids, whereas unsaturated fats from vegetables have kinks in their tails due to double bonds. These kinks prevent the fats from packing together as tightly. Hydrogenated vegetable oils, or trans fats, have hydrogens added back to the double bonds and thus behave like

A) unsaturated fats.

B) waxes.

C) carbohydrates.

D) proteins.

E) saturated fats.

53) Which of these pairs does not correctly match a carbohydrate with its function?

A) Glycogen is the storage form of energy in animals.

B) Starch is the storage form of energy in plants.

C) Cellulose provides structural support for human hair.

D) Chitin provides an exoskeleton for insects.

54) Proteins store the genetic information of the cell and transmit it to the next generation.

55) If a carbohydrate polymer contains only two monomer units, such as sucrose made from glucose and fructose, it is called a(n)

A) disaccharide.

B) polysaccharide.

C) monosaccharide.

D) oligosaccharide.

E) complex carbohydrate.

56) Tawny crazy ants survive a fire ant's sting by having a

A) venom that detoxifies the fire ant venom.

B) more potent venom than the fire ant venom.

C) hard carapace that protects the crazy ants. 

D) lipid that coats their skin.

57) In the experiment investigating tawny crazy ants and fire ants, the control group included

A) tawny crazy ants with open venom glands.

B) tawny crazy ants with plugged venom glands.

C) fire ants with open venom glands.

D) fire ants with plugged venom glands.

58) How does the formic acid in the venom of the tawny crazy ants protect them from the fire ant venom?

A) It deactivates enzymes in the fire ant venom.

B) It raises the pH which crystallizes the fire ant venom.

C) It melts the lipids in the fire ant venom.

D) It turns the polysaccharides in the fire ant venom into monosaccharides.