FREE Chapter 2 Chemical Principles

Microbiology: An Introduction, 12e (Tortora)

Chapter 2   Chemical Principles

2.1   Multiple Choice Questions

1) Which of the following statements about the atom C is FALSE?

A) It has 6 protons in its nucleus.

B) It has 12 neutrons in its nucleus.

C) It has 6 electrons orbiting the nucleus.

D) Its atomic number is 6.

E) Its atomic weight is 12.

Answer:  B

Section:  2.1

Bloom’s Taxonomy:  Comprehension

Learning Outcome:  2.1

Global Outcome:  2

2) Table 2.1

O C H

Using the information in Table 2.1, calculate the molecular weight of ethanol, C2H5OH.

A) 96

B) 46

C) 34

D) 33

E) The answer cannot be determined.

Answer:  B

Section:  2.1

Bloom’s Taxonomy:  Application

Learning Outcome:  2.1

Global Outcome:  2

3) Antacids neutralize acid by the following reaction. Identify the salt in the following equation:

Mg(OH)2 + 2HCl → MgCl2 + H2O

A) Mg(OH)2

B) HCl

C) MgCl2

D) H2O

E) None of the answers is correct.

Answer:  C

Section:  2.4

Bloom’s Taxonomy:  Comprehension

Learning Outcome:  2.5

4) Which of the following statements is FALSE?

A) Salts readily dissolve in water.

B) Water molecules are formed by hydrolysis.

C) Water freezes from the top down.

D) Water is formed as a part of a dehydration synthesis reaction.

E) Water is a polar molecule.

Answer:  B

Section:  2.4

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.4

5) Which of the following is the type of bond holding K+ and I ions in KI?

A) ionic bond

B) covalent bond

C) hydrogen bond

Answer:  A

Section:  2.2

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.2

6) Which of the following is the type of bond between molecules of water in a beaker of water?

A) ionic bond

B) covalent bond

C) hydrogen bond

Answer:  C

Section:  2.2

Bloom’s Taxonomy:  Comprehension

Learning Outcome:  2.2

Global Outcome:  7

7) What is the type of bond holding hydrogen and oxygen atoms together in a single H2O molecule?

A) ionic bond

B) covalent bond

C) hydrogen bond

Answer:  B

Section:  2.2

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.2

8) Identify the following reaction:  Glucose + Fructose → Sucrose + Water

A) dehydration synthesis reaction

B) hydrolysis reaction

C) exchange reaction

D) reversible reaction

E) ionic reaction

Answer:  A

Section:  2.5

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.7

9) Identify the following reaction: Lactose + H2O → Glucose + Galactose

A) dehydration synthesis reaction

B) hydrolysis reaction

C) exchange reaction

D) reversible reaction

E) ionic reaction

Answer:  B

Section:  2.5

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.7

10) Identify the following reaction: HCl + NaHCO3 → NaCl + H2CO3

A) dehydration synthesis reaction

B) hydrolysis reaction

C) exchange reaction

D) reversible reaction

E) ionic reaction

Answer:  C

Section:  2.3

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.7

Global Outcome:  2

11) Identify the following reaction: NH4OH NH3 + H2O

A) dehydration synthesis reaction

B) hydrolysis reaction

C) exchange reaction

D) reversible reaction

E) ionic reaction

Answer:  D

Section:  2.3

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.7

Global Outcome:  2

12) Which type of molecule contains the alcohol glycerol?

A) carbohydrate

B) phospholipids

C) DNA

D) protein

Answer:  B

Section:  2.5

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.9

13) Which type of molecule is composed of (CH2O) units?

A) carbohydrate

B) lipid

C) nucleic acid

D) protein

Answer:  A

Section:  2.5

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.8

14) Which type of molecule contains -NH2 (amino) groups?

A) carbohydrate

B) triglycerides

C) nucleic acid

D) protein

Answer:  D

Section:  2.5

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.10

15) Which type of molecule NEVER contains a phosphate group?

A) triglycerides

B) phospholipid

C) nucleic acid

D) ATP

Answer:  A

Section:  2.5

Bloom’s Taxonomy:  Comprehension

Learning Outcome:  2.9

16) Based upon the valence numbers of the elements magnesium (2) and hydrogen (1), predict how many covalent bonds would form between these atoms to achieve the full complement of electrons in their outermost energy shells.

A) one

B) two

C) three

D) four

Answer:  B

Section:  2.2

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.2

Global Outcome:  2

17) Table 2.1

O C H

Using the information in Table 2.1, calculate the number of moles in 92 grams of ethanol,

C2H5OH.

A) 1

B) 2

C) 3

D) 4

E) The answer cannot be determined.

Answer:  B

Section:  2.2

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.2

Global Outcome:  4

18) Which of the following statements regarding protein structure is FALSE?

A) The primary structure is formed by covalent bonding between amino acid subunits.

B) Secondary structures are formed only from hydrogen bonds.

C) Tertiary structures are formed only from covalent bonds.

D) Quaternary structures involved multiple polypeptides.

Answer:  C

Section:  2.5

Bloom’s Taxonomy:  Comprehension

Learning Outcome:  2.10

19) Which of the following pairs is mismatched?

A) NaOH Na+ + OH — base

B) HF H+ + F — acid

C) MgSO4 Mg2+ + SO42- — salt

D) KH2PO4 K+ + H2PO4 — acid

E) H2SO4 2H+ + SO42- — acid

Answer:  D

Section:  2.3

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.3

Global Outcome:  2

20) Table 2.2

NaOH Na+ + OH — base

HF H+ + F – acid

MgSO4 Mg2+ + SO42- — salt

KH2PO4 K+ + H2PO4 — acid

H2SO4 2H+ + SO42- — salt

Which of the following statements about the reactions in Table 2.2 is FALSE?

A) They are exchange reactions.

B) They are ionization reactions.

C) They occur when the reactants are dissolved in water.

D) They are dissociation reactions.

E) They are reversible reactions.

Answer:  A

Section:  2.3

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.3

Global Outcome:  2

21) What is the type of weak bond between the hydrogen of one molecule and the nitrogen of another

molecule, where the two don’t actively share an electron?

A) ionic bond

B) covalent bond

C) hydrogen bond

D) disulfide bond

E) hydrophobic bond

Answer:  C

Section:  2.3

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.2

Global Outcome:  7

22) What is the type of strong chemical bond between carbon, hydrogen, and oxygen atoms in a single organic molecule?

A) ionic bond

B) covalent bond

C) hydrogen bond

Answer:  B

Section:  2.3

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.2

Global Outcome:  7

23) What is the type of bond between ions in salt?

A) ionic bond

B) covalent bond

C) hydrogen bond

Answer:  A

Section:  2.3

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.2

Global Outcome:  7

24) A scientist wants to perform a test that will indicate whether a nucleic acid sample is composed of RNA or DNA. Testing for the presence of which of the following is most appropriate in this situation?

A) phosphate

B) nitrogen

C) guanine

D) uracil

E) thymine

Answer:  D

Section:  2.5

Bloom’s Taxonomy:  Comprehension

Learning Outcome:  2.11

Global Outcome:  2

25) Structurally, ATP is most like which type of molecule?

A) carbohydrate

B) lipid

C) protein

D) nucleic acid

Answer:  D

Section:  2.5

Bloom’s Taxonomy:  Comprehension

Learning Outcome:  2.12

26) What do genes consist of?

A) carbohydrates

B) lipids

C) proteins

D) nucleic acids

Answer:  D

Section:  2.5

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.11

Global Outcome:  7

27) Which molecule is composed of a chain of amino acids?

A) carbohydrate

B) lipid

C) protein

D) nucleic acid

Answer:  C

Section:  2.5

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.10

28) Which are the primary molecules making up plasma membranes in cells?

A) carbohydrates

B) lipids

C) proteins

D) nucleic acids

Answer:  B

Section:  2.5

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.9

Global Outcome:  7

29) The antimicrobial drug imidazole inhibits sterol synthesis. This would most likely interfere with

A) bacterial cell walls.

B) fungal cell walls.

C) eukaryotic plasma membranes.

D) prokaryotic plasma membranes.

E) genes.

Answer:  C

Section:  2.5

Bloom’s Taxonomy:  Analysis

ASMcue Outcome:  3.4

Learning Outcome:  2.9

Global Outcome:  2

Figure 2.1

30) In Figure 2.1, which is an alcohol?

A) a

B) b

C) c

D) d

E) e

Answer:  C

Section:  2.5

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.7

Global Outcome:  3

31) Which compound in Figure 2.1 is an ester?

A) a

B) b

C) c

D) d

E) e

Answer:  D

Section:  2.5

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.7

Global Outcome:  3

32) Which compound in Figure 2.1 is an organic acid?

A) a

B) b

C) c

D) d

E) e

Answer:  A

Section:  2.5

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.6

Global Outcome:  3

33) Most amino acids found in cells demonstrate what type of chirality?

A) L-isomers

B) D-isomers

C) C-isomers

D) B-isomers

E) A-isomers

Answer:  A

Section:  2.5

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.10

34) Figure 2.3

What kind of bond is at the arrow in Figure 2.3?

A) disulfide bridge

B) double covalent bond

C) hydrogen bond

D) ionic bond

E) peptide bond

Answer:  E

Section:  2.5

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.10

Global Outcome:  3

35) An E. coli culture that has been growing at 37°C is moved to 25°C. Which of the following changes must be made in its plasma membrane to help it cope with the decrease in temperature?

A) The number of phosphate groups must increase.

B) The viscosity must increase.

C) The number of saturated chains must increase.

D) The number of unsaturated chains must increase.

E) No changes are necessary.

Answer:  D

Section:  2.5

Bloom’s Taxonomy:  Comprehension

Learning Outcome:  2.9

36) Radioisotopes are frequently used to label molecules in a cell. The fate of atoms and molecules in a cell can then be followed. Assume Saccharomyces cerevisiae is grown in a nutrient medium containing the radioisotope 35S. After a 48-hour incubation, the 35S would most likely be found in the S. cerevisiae’s

A) carbohydrates.

B) nucleic acids.

C) water.

D) lipids.

E) proteins.

Answer:  E

Section:  2.5

Bloom’s Taxonomy:  Comprehension

Learning Outcome:  2.10

Global Outcome:  2

37) Radioisotopes are frequently used to label molecules in a cell. The fate of atoms and molecules in a cell can then be followed. Assume Saccharomyces cerevisiae is grown in a nutrient medium containing the radioisotope 32P. After a 48-hour incubation, the majority of the 32P would be found in the S. cerevisiae’s

A) plasma membrane.

B) cell wall.

C) water.

D) proteins.

E) carbohydrates.

Answer:  A

Section:  2.5

Bloom’s Taxonomy:  Comprehension

Learning Outcome:  2.9

Global Outcome:  2

38) Starch, dextran, glycogen, and cellulose are polymers of

A) amino acids.

B) glucose.

C) fatty acids.

D) nucleic acids.

E) acids.

Answer:  B

Section:  2.5

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.8

39) Which of the following is a base?

A) C2H5OCOOH → H+ + C2H5OCOO

B) C2H5OH

C) NaOH → Na+ + OH

D) H2O → H+ + OH

E) H2CO

Answer:  C

Section:  2.4

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.6

Global Outcome:  2

40) Two glucose molecules are combined to make a maltose molecule. What is the chemical formula for maltose?

A) C3H6O3

B) C6H12O6

C) C12H24O12

D) C12H22O11

E) C12H23O10

Answer:  D

Section:  2.5

Bloom’s Taxonomy:  Comprehension

Learning Outcome:  2.8

Global Outcome:  3

41) If an amino acid contained a hydrocarbon (a group of multiple carbons and hydrogens linked together) as its side group, in which of the following categories could it be appropriately designated?

A) hydrophilic

B) polar

C) nonpolar

D) basic

E) acidic

Answer:  C

Section:  2.5

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.10

Global Outcome:  2

2.2   True/False Questions

1) Elements only achieve the full complement of electrons in outermost energy cells by donating away or sharing electrons.

Answer:  FALSE

Section:  2.1

Bloom’s Taxonomy:  Comprehension

Learning Outcome:  2.1

2) Covalent bonds are always shared equally.

Answer:  FALSE

Section:  2.1

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.2

Global Outcome:  7

3) Individual covalent bonds are stronger than individual ionic bonds.

Answer:  TRUE

Section:  2.1

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.2

4) All chemical reactions are, in theory, reversible.

Answer:  TRUE

Section:  2.3

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.3

5) The formation of ADP from ATP can be defined as a hydrolytic reaction.

Answer:  TRUE

Section:  2.3

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.12

6) The density of liquid water is greater than the density of ice.

Answer:  TRUE

Section:  2.4

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.4

7) A basic solution is expected to contain more hydrogen ions than hydroxyl ions.

Answer:  FALSE

Section:  2.4

Bloom’s Taxonomy:  Comprehension

Learning Outcome:  2.5

Global Outcome:  7

8) All forms of life function optimally at a pH of 7.

Answer:  FALSE

Section:  2.4

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.5

9) There are some forms of life on Earth that can survive without water.

Answer:  FALSE

Section:  2.4

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.4

Global Outcome:  2

10)  Any compound that contains carbon is considered to be strictly organic.

Answer:  FALSE

Section:  2.4

Bloom’s Taxonomy:  Knowledge

Learning Outcome:  2.6

Global Outcome:  2

2.3   Essay Questions

1) Describe how the properties of phospholipids make these molecules well suited for plasma membranes.

Section:  2.5

Bloom’s Taxonomy:  Synthesis

Learning Outcome:  2.9

Global Outcome:  8

2) Figure 2.5

Use Figure 2.5 to answer the following. Starch, cellulose, dextran, and glycogen are polysaccharides. How are they similar? To what are their different properties due? Why can’t an enzyme that hydrolyzes starch degrade cellulose?

Section:  2.5

Bloom’s Taxonomy:  Synthesis

Learning Outcome:  2.8

Global Outcome:  8

3) Compare a molecule of a nucleotide to ATP. Could a cell simply insert ATP into DNA without altering it? Explain.

Section:  2.5

Bloom’s Taxonomy:  Synthesis

Learning Outcome:  2.12

Global Outcome:  8

4) A scientist claims that when a protein is denatured, it can be expected that its secondary structure will more likely be retained when compared to all other levels of protein structure structures. Do you agree? Explain.

Section:  2.5

Bloom’s Taxonomy:  Evaluation

Learning Outcome:  2.10

Global Outcome:  8

5) A bacterium that grows at a temperature of 37°C transports both glucose and NaCl into its cytoplasm.  Which is most easily dissolved in the cytoplasm? Explain how the bonds of these molecules impact disassociation rate.

Section:  2.5

Bloom’s Taxonomy:  Analysis

Learning Outcome:  2.6

Global Outcome:  8