Deck 2: The Chemistry of Microbiology

Question 1

A research microbiologist wants to determine whether a microbe can metabolize a new synthetic organic molecule composed of carbon, hydrogen and oxygen. Which of the following would be useful in tracing the fate of the compound?

A) the 2H isotope
B) the 13C isotope
C) a 13C+ ion.
D) the 14C isotope
E) the 12C isotope

Answer 1

D

Question 2

The outer ring in Figure 2-1 represents

A) a neutron.
B) the nucleus.
C) an electron.
D) an isotope.
E) an electron shell.

Answer 2

E

Question 3

Compounds that readily dissociate in water are

A) ionic.
B) polar.
C) nonpolar.
D) either polar or ionic.
E) never polar or ionic.

Answer 3

D

Question 4

A hydroxyl acts as a base.

A) salt
B) group
C) anion
D) atom
E) cation

Question 5

A stable atom has in its valence shell.

A) 4 electrons
B) 2 neutrons
C) 10 electrons
D) 8 protons
E) 8 electrons

Question 6

Which of the following is a CORRECT pairing of metabolic terms?

A) hydrolysis: decomposition
B) synthesis: exothermic
C) synthesis: catabolism
D) catabolism: endothermic
E) dehydration: decomposition

Question 7

Matter composed of a single type of atom is known as a(n)

A) mineral.
B) electron.
C) molecule.
D) element.
E) compound.

Question 8

The type(s) of bond produced when atoms with somewhat different electronegativities share electrons is/are

A) an ionic bond.
B) a nonpolar covalent bond.
C) a polar covalent bond.
D) a hydrogen bond.
E) both nonpolar covalent and ionic bonds.

Question 9

The reaction described below is consistent with

A) a catabolic reaction.
B) an exchange reaction.
C) a synthesis reaction.
D) a decomposition reaction.
E) both synthesis and decomposition.

Question 10

Which of the following is a property of water?

A) It is a nonpolar molecule.
B) It has a high capacity for heat.
C) It is not a good solvent.
D) It is liquid in a very narrow temperature range.
E) It is not a common reactant in metabolic reactions.

Question 11

The chemical formula of a solid indicates it contains two groups with different electronegativities. This substance is most likely

A) radioactive.
B) a nonpolar molecule.
C) a salt.
D) non-ionic.
E) a mixture.

Question 12

An acid dissociates in water to release

A) hydroxyl groups.
B) anions.
C) cations.
D) hydrogen ions.
E) both anions and hydrogen ions.

Question 13

Which of the following is a particle found in the nucleus of an atom and that has no electrical charge?

A) neutron
B) element
C) electron
D) isotope
E) proton

Question 14

Nucleic acid polymers, proteins, and complex carbohydrates are all produced by

A) dehydration synthesis.
B) exchange reactions.
C) hydrogen bonding.
D) hydrolytic reactions.
E) catabolic reactions.

Question 15

Which parts of the atoms interact in a chemical reaction?

A) ions
B) electrons
C) neutrons
D) isotopes
E) protons

Question 16

You are performing an experiment in your chemistry lab class. The directions advise caution because the reaction is exothermic. Which of the following is the hazard the directions warn about?

A) The reaction may cause the container to become dangerously hot.
B) The reaction will produce a noxious vapor.
C) The reaction will generate enough light to require eye protection.
D) The reaction may cause the container to freeze and break.
E) The reaction will generate radiation.

Question 17

The valence of an atom represents its

A) electronegativity.
B) ability to interact with other atoms.
C) radioactivity.
D) ability to interact with water.
E) ability to attract electrons.

Question 18

Unstable isotopes can be useful

A) in medical diagnosis.
B) in vitamins.
C) in the formation of hydrogen bonds.
D) catalysts.
E) as buffers.

Question 19

The reverse of a dehydration synthesis reaction is a(n) reaction.

A) anabolic
B) endothermic
C) exchange
D) metabolic
E) hydrolysis

Question 20

The type(s) of bonds produced when atoms share electrons equally is/are

A) a hydrogen bond.
B) a nonpolar covalent bond.
C) an ionic bond.
D) a polar covalent bond.
E) both polar covalent and ionic bonds.

Question 21

Proteins contain both acidic and basic R groups, and can therefore function as

A) catalysts.
B) structural macromolecules.
C) energy storage macromolecules.
D) buffers.
E) genetic material.

Question 22

All of the following are components of an amino acid EXCEPT a(n)

A) carboxyl group.
B) pentose group.
C) amino group.
D) R group.
E) α-carbon.

Question 23

Tertiary and quaternary structure of proteins involves bonds.

A) ionic
B) nonpolar covalent
C) polar covalent
D) hydrogen
E) hydrogen, ionic, polar, and nonpolar covalent

Question 24

Which of the following is found in nucleic acids?

A) carboxylic acid
B) purines
C) glycerol
D) R group
E) amino groups

Question 25

A(n) is an arrangement of atoms found in a variety of macromolecules.

A) salt
B) functional group
C) buffer
D) isotope
E) stereoisomer

Question 26

Research suggests taking antacids may make people more susceptible to infection with Vibrio vulnificus by making the stomach environment more tolerable to the bacteria. Based on this information and the name ʺantacid,ʺ which of the following are antacids likely to be?

A) acids
B) non-polar compounds
C) buffers
D) bases
E) either base or buffer

Question 27

All of the following are associated with ATP molecules EXCEPT

A) high-energy bonds.
B) a recyclable energy supply.
C) a long-term energy supply.
D) formation of coenzymes.
E) three phosphate groups.

Question 28

Which of the following lipids has the lowest ratio of hydrogens to carbons?

A) monounsaturated fats
B) polyunsaturated fats
C) saturated fats
D) both saturated and monounsaturated fats
E) Saturated, unsaturated, and polyunsaturated fats have equal ratios of hydrogens to carbons.

Question 29

Hydrogen bonds are found in all of the following EXCEPT

A) in the DNA double helix between nucleotides.
B) between the R groups of amino acids in proteins.
C) in the structure of complex polysaccharides.
D) between water molecules.
E) between phosphates in ATP.

Question 30

Which of the following are examples of pyrimidines?

A) cytosine and guanine
B) cytosine and thymine
C) uracil and adenine
D) thymine and guanine
E) thymine and adenine

Question 31

A macromolecule containing two fatty acids and a phosphate group is a

A) glycerol.
B) wax.
C) phospholipid.
D) steroid.
E) saturated fatty acid.

Question 32

Plant cell walls are composed of held together by .

A) polysaccharides; hydrogen bonds
B) amino acids; peptide bonds
C) fatty acids; polar covalent bonds
D) peptidoglycan; ionic bonds
E) disaccharides; hydrophobic interactions

Question 33

Which of the following is an INCORRECT pairing?

A) secondary structure; β-pleated sheets
B) secondary structure; disulfide bridges
C) primary structure; amino acid sequence
D) tertiary structure; covalent bonds
E) quaternary structure; two or more polypeptides

Question 34

Which of the following is an example of a polysaccharide?

A) glycogen
B) fructose
C) glucose
D) sucrose
E) deoxyribose

Question 35

Which of the following is TRUE of both DNA and RNA?

A) They are highly hydrophobic macromolecules.
B) They contain adenine, cytosine, guanine and thymine.
C) The ʺbackboneʺ is composed of riboses and phosphates.
D) The purines and pyrimidines form hydrogen-bonded pairs.
E) They are usually double-stranded helices.

Question 36

The ʺbackboneʺ of the DNA molecule is composed of

A) pentoses.
B) phosphates.
C) amino acids.
D) alternating phosphates and pentoses.
E) nitrogenous bases.

Question 37

Which of the following is characteristic of proteins?

A) Their secondary structure is composed of β-helices.
B) They have multiple layers of structural organization.
C) They are composed of carbohydrate.
D) They are primarily hydrophobic.
E) They are composed of nucleic acids.

Question 38

Lipids found in the membranes of most eukaryotic cells are

A) phospholipids.
B) waxes.
C) steroids.
D) triglycerides.
E) polyunsaturated fats.

Question 39

Which of the following would NOT normally be found as a component of a cellʹs nucleic acids?

A) cytosine ribonucleotides
B) adenine deoxyribonucleotides
C) adenine ribonucleotides
D) thymine deoxyribonucleotides
E) uracil deoxyribonucleotides

Question 40

Decomposition reactions are commonly reactions.

A) anabolic
B) exchange
C) endothermic
D) exothermic
E) dehydration

Question 41

The phosphorylation of a protein by ATP is a(n) (exchange/transfer/group) reaction

Question 42

The electron shells of atoms hold eight electrons each.

Question 43

A reaction requires water as a reactant and produces heat. What type of reaction is likely to be involved?

A) a decomposition reaction
B) a synthesis reaction
C) a hydrolysis reaction
D) an exchange reaction
E) The answer cannot be determined with the available information.

Question 44

Salts are produced from exchange reactions in which acids and bases neutralize each other.

Question 45

Amylose is a(n) carbohydrate.

A) polymer
B) ionic
C) monomer
D) simple
E) nucleotide

Question 46

Radioactive iodine is sometimes used to treat thyroid cancer. This is an example of the use of (isotopes/elements/radiation) in medical treatment.

Question 47

The smallest chemical units of matter are elements.

Question 48

The side groups of amino acids can interact with each other and with other molecules.

Question 49

Glycolipids are an example of a mixture.

Question 50

Anna is conducting an experiment using a pH indicator that is red at low pH, green at neutral pH, and purple at high pH. She starts with a green solution. When she adds compound X to her solution it turns purple. Then she adds compound Z to the solution and it turns green. She adds more Z and the solution remains green. These observations suggest X is and Z is .

A) a base; a strong acid
B) a base; a buffer
C) a buffer; a base
D) an acid; a base
E) an acid; a buffer

Question 51

A molecule composed of carbon and hydrogen is a compound.

Question 52

An organic molecule with the chemical formula C4H5O1N3 is probably a pyrimidine.

Question 53

Denaturation of a protein is always permanent.

Question 54

DNA is composed of repeating units of sugars, phosphates, and nucleic acids. This is an example of a

A) micelle.
B) polymer.
C) salt.
D) lipid.
E) monomer.

Question 55

Carbon atoms have four valence electrons and typically form polar covalent bonds.

Question 56

Bacterial cell walls are composed of

A) peptides.
B) waxes.
C) peptides and polysaccharides.
D) carbohydrates and waxes.
E) polysaccharides.

Question 57

Neon generally does not react with other atoms because it has (2/4/6/8) electrons in its outer shell.

Question 58

An atom or molecule becomes a(n) (anion/ion/cation) when it loses an electron to a more electronegative molecule.

Question 59

One of the products of dehydration synthesis reactions is water.

Question 60

What functional groups are present in ALL amino acids?

A) amino groups
B) carboxyl groups
C) hydroxyl groups.
D) amino and sulfhydryl groups.
E) amino and carboxyl groups

Question 61

A student is given a compound to identify in an organic chemistry class. The first thing she notices is that it is not soluble in pure water or saline. Analysis of the ratios of atoms indicates the ratio of carbon to hydrogen to oxygen is 1:1.5:0.05. There is no nitrogen. Based on this information, what class of biological macromolecule is the student working with? Justify your answer.

Question 62

Figure 2-2 depicts the (primary/secondary/tertiary) structure of a protein.

Question 63

A fatty acid with two double bonds is a (saturated/monounsaturated/polyunsaturated) fat.

Question 64

A chemical reaction that traps energy within newly formed chemical bonds is an (exothermic/endothermic) reaction.

Question 65

Discuss the importance of hydrogen bonds in the chemistry of the cell.

Question 66

A(n) (catalyst/enzyme/protein) is any molecule that speeds up a chemical reaction.

Question 67

A(n) (indicator/base/buffer) is a substance that maintains the pH even when the amounts of acid and/or base are changing.

Question 68

Max is exploring the properties of various compounds. Some of his explorations involve the use of a pH indicator that is red at low pH, yellow-green at neutral pH, and blue to purple at high pH. He sets up several tubes containing water and the pH indicator and then begins to add some of the compounds he is characterizing in various combinations. His results are shown on the Figure 2.3.
What can Max conclude about his compounds based on these results? Describe the likely events in terms of hydrogen and hydroxyl ions.

Question 69

A(n) (base/acid) is a molecule that binds with hydrogen ions when it is dissolved in water.

Question 70

The (atoms/isotopes/stereoisomers) of an element vary in the number of neutrons in the nucleus.

Question 71

The functional group of a monosaccharide is a(n) (amino/carboxyl/hydroxyl/carbonyl)

Question 72

A chemical reaction in which a water molecule is a reactant is known as a (dehydration/hydrolysis) reaction.

Question 73

Nitrogen is an essential element for living things, as demonstrated by the fact that nearly all fertilizers contain nitrogenous compounds. Discuss why nitrogen is essential.

Question 74

The ʺdouble helixʺ of DNA is the result of (covalent/ionic/hydrogen) bonds.

Question 75

Compare and contrast synthesis reactions with decomposition reactions.

Question 76

The folding of a polypeptide into a three -dimensional shape is its (secondary/tertiary/quaternary) structure.