Human Biology: Concepts and Current Issues, 5e (Johnson)

Chapter 2

The Chemistry of Living Things

MULTIPLE CHOICE QUESTIONS

1) Which of the following characteristics applies to both living organisms and nonliving things?

A) are made up of matter

B) are made up of cells

C) have the ability to store energy for later use

D) are capable of growth

E) are capable of reproduction

Answer: A

Topic: Sec. 2.0

Skill: Concept review

2) ______is the study of matter and the energy that causes matter to combine, break apart and recombine in everything living and non-living.

A) Physics

B) Biology

C) Chemistry

D) Geology

Answer: C

Topic: Sec. 2.0

Skill: Terms you should know

3) ______is the capacity to do workthe capacity to cause some change in matter.

A) Molecule

B) Energy

C) Atom

D) Matter

Answer: B

Topic: Sec. 2.2

Skill: Terms you should know

4) A mad scientist has ripped apart an atom and collected all the subatomic particles located in the nucleus of the atom. Which of the following has he collected?

A) electrons

B) neutrons and electrons

C) protons

D) protons and neutrons

E) electrons and protons

Answer: D

Topic: Sec. 2.1

Skill: Apply what you know

5) Which of the following is true regarding the structure of the atom?

A) Neutrons carry a negative charge.

B) All electrons are located at the same distance from the nucleus.

C) The nucleus is composed of equal numbers of positively charged particles and negatively charged particles.

D) Most of the mass of an atom is due to its protons and neutrons.

E) In small elements, such as carbon, electrons have a positive charge; in larger elements, such as barium, electrons have a negative charge.

Answer: D

Topic: Sec. 2.1

Skill: Concept review

6) Isotopes of an element have the same atomic number as the more common atoms but different atomic mass because

A) isotopes contain more protons than the more common atoms.

B) isotopes contain more electrons than the more common atoms.

C) isotopes contain more neutrons than the more common atoms.

D) isotopes absorb water from the surrounding environment.

Answer: C

Topic: Sec. 2.1

Skill: Concept review

7) The total number of protons and neutrons in an atom can best be determined from which of the following?

A) subscript number following the chemical symbol

B) the chemical symbol

C) atomic number

D) atomic mass

E) the charge on the atom

Answer: D

Topic: Sec. 2.1

Skill: Concept review

8) Isotopes of an element have the same ______, but different ______.

A) atomic mass, atomic numbers

B) number of electron shells, numbers of protons

C) atomic number, atomic masses

D) number of neutrons, numbers of protons

E) name, chemical symbols

Answer: C

Topic: Sec. 2.1

Skill: Concept review

9) Radioisotopes have a number of uses in science and medicine. These uses include all of the following EXCEPT

A) locating damaged heart tissue.

B) dating fossils.

C) providing the power supply in heart pacemakers.

D) treating cancer.

E) curing diabetes.

Answer: E

Topic: Sec. 2.1

Skill: Concept review

10) Oxygen has an atomic number of 8 and an atomic mass of 16. Therefore, oxygen has ______electrons and ______neutrons.

A) 16, 8

B) 8, 16

C) 6, 10

D) 16, 16

E) 8, 8

Answer: E

Topic: Sec. 2.1

Skill: Concept review

11) Which of the following is true regarding electrons, shells, and energy?

A) As an electron moves to a shell further from the nucleus, it loses energy.

B) Electrons are located in shells around the nucleus.

C) In order for an electron to move closer to the nucleus, it must absorb energy.

D) Electrons are attracted to each other because they have the same charge.

E) The innermost electron shell has the most potential energy.

Answer: B

Topic: Sec. 2.2

Skill: Concept review

12) Which of the following is NOT a molecule?

A) NaCl

B) CO2

C) C

D) H2

E) H2O

Answer: C

Topic: Sec. 2.2

Skill: Concept review

13) A molecule of water forms when one oxygen binds with two hydrogen atoms, completely filling the outershell of the hydrogens and oxygen. The type of bond linking the atoms together is

A) disulfide.

B) ionic.

C) covalent.

D) hydrogen.

E) polar.

Answer: C

Topic: Sec. 2.2

Skill: Concept review

14) Ions in body fluids of a human are referred to as

A) isotopes.

B) electrolytes.

C) osmolytes.

D) atoms.

Answer: B

Topic: Sec. 2.2

Skill: Apply what you know

15) Which of the following is true regarding water?

A) Water molecules are attracted to each other by ionic bonds.

B) The oxygen side of the water molecule is partially positive.

C) Each molecule of water consists of two atoms of hydrogen and one atom of oxygen covalently bonded to each other.

D) Electrons are shared equally between the atoms of water.

E) Water is a type of ion.

Answer: C

Topic: Sec. 2.2

Skill: Concept review

16) Which of the following is true concerning hydrogen bonds?

A) The bonds break when water enters a vapor state and remain broken as long as water molecules remain in the gas phase.

B) Hydrogen bonds hold strands of DNA together.

C) They are weak bonds that form between water molecules in liquid form.

D) All of the above are correct.

Answer: D

Topic: Sec. 2.2

Skill: Concept review

17) The essential elements of life that make up humans and other organisms on Earth include all of the following EXCEPT

A) carbon.

B) magnesium.

C) nitrogen.

D) hydrogen.

E) phosphorus.

Answer: B

Topic: Sec. 2.2

Skill: Concept review

18) Which of the following is NOT a property of water?

A) holds heat energy

B) composed of polar molecules

C) consists of molecules attracted to each other by covalent bonds

D) biological solvent for polar molecules

E) liquid at room temperature

Answer: C

Topic: Sec. 2.3

Skill: Concept review

19) Water is an excellent solvent for biological systems because

A) it can maintain a relatively stable temperature for chemical reactions to occur.

B) the polar nature of water prevents reassociation of ions once dissolved.

C) water is a semi-solid at body temperature preventing it from flowing freely through the human body.

D) Both A and B are correct.

Answer: D

Topic: Sec. 2.3

Skill: Concept review

20) A solution with a pH of 6 has ______times as many hydrogen ions as a solution with a pH of 7.

A) 100,000

B) 100

C) 10,000

D) 10

E) 1,000

Answer: D

Topic: Sec. 2.4

Skill: Concept review

21) A student measuring the pH of the water in a fish tank found it to have a pH of 8. Which of the following statements is true regarding that solution?

A) The water is more alkaline than a solution with a pH of 10.

B) The water does not contain hydrogen ions.

C) The water is alkaline.

D) The water contains equal numbers of hydrogen ions and hydroxyl ions.

E) The water is highly acidic.

Answer: C

Topic: Sec. 2.4

Skill: Concept review

22) Body fluids in humans have a high buffering capacity because

A) it is the natural result of water as a solvent.

B) shifts in blood pH are required to maintain homeostasis.

C) it promotes hydrogen bonding between water molecules in biological fluids.

D) even modest shifts in pH can severely alter the physiology of cells.

Answer: D

Topic: Sec. 2.4

Skill: Concept review

23) Which of the following is NOT true regarding carbon?

A) is found in organic molecules

B) is most stable when its outermost shell is filled with seven electrons

C) can form molecules that branch in many directions

D) is capable of forming strong covalent bonds with other elements

E) is an ideal structural component of living systems

Answer: B

Topic: Sec. 2.5

Skill: Concept review

24) Which of the following is NOT true regarding macromolecules?

A) Cells use macromolecules to signal other cells.

B) An example of a macromolecule is a protein.

C) Cells produce macromolecules by the process of hydrolysis.

D) The subunits needed to make macromolecules important to the human body result from the digestion of food.

E) Cells use certain macromolecules to store energy.

Answer: C

Topic: Sec. 2.5

Skill: Terms you should know

25) Hydrolysis reactions are important in biological systems

A) due to their role in the breakdown of food molecules during digestion.

B) since these reactions are associated with recycling of materials and elimination of substances from the body.

C) because they promote the release of energy when covalent bonds are broken.

D) All of the above are correct.

Answer: D

Topic: Sec. 2.5

Skill: Concept review

26) Carbohydrates are characterized by

A) possessing a carbon backbone that is hydrated.

B) releasing energy when their peptide bonds are broken.

C) being indigestible by most organisms.

D) being composed of carbon, hydrogen, and nitrogen.

Answer: A

Topic: Sec. 2.5

Skill: Terms you should know

27) Which of the following is a monosaccharide that is a very important source of energy for cells?

A) glucose

B) cellulose

C) starch

D) ribose

E) deoxyribose

Answer: A

Topic: Sec. 2.6

Skill: Concept review

28) Which of the following is an oligosaccharide?

A) starch

B) maltose

C) DNA

D) glucose

E) ribose

Answer: B

Topic: Sec. 2.6

Skill: Terms you should know

29) Sucrose is an oligosaccharide made up of which of the following sugars?

A) deoxyribose and ribose

B) glucose and fructose

C) maltose and glucose

D) glucose and glucose

E) starch and glycogen

Answer: B

Topic: Sec. 2.6

Skill: Concept review

30) Lipids are important to biological systems because

A) all lipids are very soluble in water.

B) they are solid at body temperature so they stabilize membranes.

C) some lipid types are potentially large sources of energy to perform cellular work.

D) most help to buffer aqueous solutions in the body.

Answer: C

Topic: Sec. 2.7

Skill: Concept review

31) Which of the following molecules is stored in adipose tissue and serves as an important source of energy for the human body?

A) triglycerides

B) glucose

C) glycogen

D) steroids

E) phospholipids

Answer: A

Topic: Sec. 2.7

Skill: Concept review

32) All of the following are types of lipids EXCEPT

A) cholesterol.

B) steroids.

C) maltose.

D) triglycerides.

Answer: C

Topic: Sec. 2.7

Skill: Terms you should know

33) The most important physical characteristic of lipids with regard to living organisms is that they

A) are hydrophobic.

B) are typically a form of waste product that is difficult to eliminate.

C) are more dense than water.

D) are very large and therefore difficult to store.

E) dissolve easily in water.

Answer: A

Topic: Sec. 2.7

Skill: Concept review

34) Pancreatic cells make insulin, which is a type of protein. These cells use ______in order to synthesize insulin by the process of ______.

A) nucleotides, condensation.

B) monosaccharides, dehydration synthesis.

C) amino acids, dehydration synthesis.

D) fatty acids and glycerol, hydrolysis.

E) oligosaccharides, hydrolysis.

Answer: C

Topic: Sec. 2.8

Skill: Apply what you know

35) Each amino acid is composed of a central carbon that forms covalent bonds with four other atoms/molecules. These atoms/molecules include all but a(n)

A) A group.

B) amino group.

C) R group.

D) carboxyl group.

E) hydrogen atom.

Answer: A

Topic: Sec. 2.8

Skill: Concept review

36) Disulfide bonds are most characteristic of which of the following levels of protein structure?

A) secondary

B) tertiary

C) primary

D) quaternary

E) none of the above

Answer: B

Topic: Sec. 2.8

Skill: Terms you should know

37) Which of the following is NOT a function of a protein?

A) stores genetic material

B) acts as a catalyst

C) provides structural support

D) forms part of the cell membrane

E) aids in muscle contraction

Answer: A

Topic: Sec. 2.8

Skill: Concept review

38) All of the following are linked to protein folding EXCEPT

A) the primary structure of a protein.

B) when a protein becomes denatured, its shape is changed.

C) normal transport of chloride across a cell membrane.

D) chaperone proteins.

E) weak hydrogen bonds that form between amino acids in a protein chain.

Answer: A

Topic: Sec. 2.8

Skill: Apply what you know

39) Which of the following is true regarding enzymes?

A) Enzymes convert products into reactants.

B) Enzymes slow the rate of chemical reactions in living systems.

C) Enzyme function is not affected by changes in temperature or pH.

D) Enzymes are consumed in a chemical reaction, so an organism must constantly replace these enzymes.

E) Each enzyme catalyzes one specific reaction or group of reactions.

Answer: E

Topic: Sec. 2.8

Skill: Concept review

40) All of the following are needed to synthesis a new strand of DNA EXCEPT

A) lipids.

B) carbohydrates.

C) nucleotides.

D) "old" DNA strand.

Answer: A

Topic: Sec. 2.9

Skill: Concept review

41) DNA differs from RNA in that DNA

A) contains cytosine.

B) contains deoxyribose.

C) is single stranded.

D) is made up of nucleotides.

E) contains phosphates.

Answer: B

Topic: Sec. 2.9

Skill: Terms you should know

42) A research student is analyzing the nucleic acid of a virus. He finds that the nucleic acid contains thymine. From this it can be concluded that the nucleic acid

A) is a strand of DNA.

B) contains glucose.

C) is actually a protein.

D) is double stranded.

E) contains ribose.

Answer: D

Topic: Sec. 2.9

Skill: Apply what you know

43) Which of the following is NOT true regarding nucleotides?

A) There are four different DNA nucleotides.

B) RNA nucleotides are assembled into RNA by the process of dehydration synthesis.

C) DNA nucleotides contain deoxyribose; RNA nucleotides contain sucrose.

D) Nucleotides are bonded together by covalent bonds between the sugars and the phosphates.

E) An RNA nucleotide could be made up of ribose, a phosphate, and cytosine.

Answer: C

Topic: Sec. 2.9

Skill: Concept review

44) Which of the following occurs when a phosphate is removed from an ATP molecule?

A) Energy is added to the ATP molecule to form ATP4.

B) Chemical reactions stop in a cell due to lack of an energy source.

C) Oxygen produced in the reaction causes the molecule to explode.

D) Energy is released for cell work.

E) Fat is converted to protein.

Answer: D

Topic: Sec. 2.10

Skill: Concept review

45) Which of the following is NOT true regarding antioxidants?

A) Fresh fruits and vegetables contain a high level of antioxidants.

B) Observational studies have led to the conclusion that antioxidants may be associated

with a lower risk of cardiovascular death.

C) Research indicates that antioxidants are most likely the cause of early aging.

D) Antioxidants prevent the formation of free radicals which oxidize other molecules.

E) Vitamin C and beta-carotene are examples of antioxidants.

Answer: C

Topic: Current Issue

Skill: Concept review

TRUE/FALSE QUESTIONS

1) Electrons are smaller than protons, negatively charged, and orbit the nucleus.

Answer: True

Topic: Sec. 2.1

Skill: Terms you should know

2) All matter is made up of atoms.

Answer: False

Topic: Sec. 2.1

Skill: Concept review

3) If the number of protons in an atom equals the number of electrons in the atom, the atom is electrically neutral.

Answer: True

Topic: Sec. 2.1

Skill: Concept review

4) Atoms with either more or fewer neutrons than the usual number for an element are referred to as isotopes.

Answer: True

Topic: Sec. 2.1

Skill: Terms you should know

5) Potential energy is energy that has not been used yet, but has the potential to do work.

Answer: True

Topic: Sec. 2.2

Skill: Terms you should know

6) When water is released from a dam, potential energy is converted to kinetic energy.

Answer: True

Topic: Sec. 2.2

Skill: Concept review

Figure 2.1 shows water molecules in close proximity to one another. Use this figure to answer the following questions.

Figure 2.1

7) The type of bond indicated by the dotted lines is a covalent bond.

Answer: False

Topic: Sec. 2.2

Skill: Concept review

8) The difference between water molecules in liquid water versus water molecules in ice is the number and the stability of hydrogen bonds.

Answer: True

Topic: Sec. 2.2

Skill: Concept review

9) During intense exercise, you produce a lot of heat energy yet your body temperature rise only in small increments. This temperature stability is because water in body fluids releases the heat very quickly.

Answer: False

Topic: Sec. 2.3

Skill: Apply what you know

10) One of the most important buffer pairs in blood is carbonic acid and bicarbonate because they regulate the pH of blood by absorbing and releasing hydrogen ions as needed.

Answer: True

Topic: Sec. 2.4

Skill: Concept review

11) The more buffers present in a body fluid, the less stable the pH will be.

Answer: False

Topic: Sec. 2.4

Skill: Concept review

12) Because carbon requires four additional electrons to fill its outermost shell, it has a natural tendency to form four covalent bonds with other atoms, making it an ideal element for forming structures in living cells.

Answer: True

Topic: Sec. 2.5

Skill: Concept review

Use Figure 2.2 to answer the following questions.

Figure 2.2

13) The figure above shows a triglyceride that contains unsaturated fatty acids.

Answer: False

Topic: Sec. 2.7

Skill: Concept review

14) The diagram shows a triglyceride with fatty acid tails representing a fat that is liquid at room temperature.

Answer: False

Topic: Sec. 2.7

Skill: Concept review

15) If the pH of your blood is lowered significantly, many proteins will not be able to fold correctly. The result will be a change in protein function.

Answer: True

Topic: Sec. 2.8

Skill: Concept review

MATCHING QUESTIONS

Match each of the following descriptions to the appropriate term.

1) a component of an atom that carries a negative charge
Topic: Sec. 2.1
Skill: Terms you should know / A) molecules
2) the smallest unit of matter that can take part in a chemical reaction
Topic: Sec. 2.1
Skill: Terms you should know / B) matter
3) anything that has mass and occupies space
Topic: Sec. 2.1
Skill: Terms you should know / C) atom
4) formed by chemical reactions between atoms
Topic: Sec. 2.2
Skill: Terms you should know / D) amino acids
5) different forms of the same element that differ in their atomic mass
Topic: Sec. 2.1
Skill: Terms you should know / E) lipids
6) steroids, triglycerides
Topic: Sec. 2.7
Skill: Terms you should know / F) molecule
7) matter that cannot be broken down
Topic: Sec. 2.1
Skill: Terms you should know / G) nucleic acids
8) DNA, RNA
Topic: Sec. 2.9
Skill: Terms you should know / H) carbohydrates
9) water, sodium chloride, carbon dioxide
Topic: Sec. 2.2
Skill: Terms you should know / I) elements
10) alanine, glycine, cysteine
Topic: Sec. 2.8
Skill: Terms you should know / J) electron
11) glucose, cellulose, glycogen
Topic: Sec. 2.6
Skill: Terms you should know / K) isotope

1) J2) C3) B4) F5) K6) E