Deck 2: The Chemistry of Microbiology

Question 1

Which of the following is a property of water?

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

Answer 1

A

Question 2

Unstable isotopes can be useful

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

Answer 2

B

Question 3

Organisms use carbohydrates in all of the following ways EXCEPT

A) as a component of cell walls.
B) as a long-term energy source.
C) as a short-term energy source.
D) to keep membranes flexible at low temperatures.
E) as a building block of DNA and RNA molecules.

Answer 3

D

Question 4

A weak acid may function as a

A) transfer group.
B) buffer.
C) hydroxyl donor.
D) cation.
E) salt.

Question 5

The number of ________ of an element determines its atomic number.

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

Question 6

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

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

Question 7

The atomic mass of this stable isotope atom (Figure 2.1) is

A) 4.
B) 6.
C) 10.
D) 12.
E) cannot be determined from the available information

Question 8

Which of the following is NOT a characteristic of phospholipids?

A) they are found in cellular membranes.
B) they can form micelles and bilayers.
C) they contain fatty acids that associate with water.
D) they contain a hydrophilic phosphate "head."
E) they contain two fatty acids and a phosphate functional group.

Question 9

An acid dissociates in water to release

A) hydrogen ion(s).
B) cation(s).
C) hydroxyl group(s).
D) anion(s).
E) both anions and hydrogen ions.

Question 10

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

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

Question 11

Which of the following is an atomic particle that has no electrical charge?

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

Question 12

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

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

Question 13

The carbon atoms in organic compounds typically form ________ with other atoms.

A) nonpolar covalent bonds
B) polar covalent bonds
C) ionic bonds
D) hydrogen bonds
E) either ionic or hydrogen bonds

Question 14

Nucleic acids, proteins, and complex carbohydrates are all produced by

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

Question 15

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

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

Question 16

The chemical formula of the oxygen we require is O₂. It is

A) a compound.
B) an isotope.
C) an element.
D) a molecule.
E) both an element and a molecule.

Question 17

A stable atom has ________ in its valence shell.

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

Question 18

Which of the following is NOT a characteristic of saturated fats?

A) they are usually solid at room temperature.
B) they contain at least one double bond.
C) they are found in animals.
D) their fatty acids pack tightly together.
E) they are a form of stored energy.

Question 19

Which of the following is an incorrect pairing?

A) electrolytes; anions
B) synthesis; endothermic
C) hydrolysis; hydrogen bonds
D) catabolism; exothermic
E) dehydration; anabolism

Question 20

Which parts of the atoms interact in a chemical reaction?

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

Question 21

All amino acids contain what functional group(s)?

A) aldehyde
B) amino
C) ester
D) carboxyl
E) both amino and carboxyl

Question 22

Cell walls containing ________ provide the best protection from drying.

A) polysaccharides
B) triglycerides
C) waxes
D) peptidoglycan
E) sterols

Question 23

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

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

Question 24

Which of the following statements about proteins is FALSE?

A) They are composed of amino acids.
B) They have multiple levels of structural organization.
C) They can be hydrophobic, hydrophilic, or both.
D) Their primary function is energy storage.
E) They are formed by dehydration synthesis reactions.

Question 25

Which of the following would NOT normally be found as a component of a cell's nucleic acids?

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

Question 26

A(n) ________ is a compound that dissolves into anions and cations in water.

A) acid
B) buffer
C) base
D) salt
E) catalyst

Question 27

Synthesis reactions are commonly ________ reactions.

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

Question 28

Which of the following is an accurate description of ATP?

A) ATP is a form of long term energy storage.
B) ATP is a compound formed of ionic bonds.
C) ATP does not readily react with other cellular macromolecules.
D) ATP serves as a recyclable energy for cells.
E) ATP is a structural component of DNA.

Question 29

Which of the following is an incorrect pairing?

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

Question 30

Lipids found in the cytoplasmic membranes of all eukaryotic cells are

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

Question 31

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

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

Question 32

Which of the following is NOT characteristic of RNA?

A) It is a helical polymer.
B) It is usually double-stranded.
C) Its "backbone" is composed of pentoses and phosphates.
D) It contains both purines and pyrimidines.
E) It can function as a catalyst.

Question 33

Which of the following is an example of a polysaccharide?

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

Question 34

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

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

Question 35

A protein is a ________ of amino acids.

A) monomer
B) polymer
C) bilayer
D) solution
E) decomposition product

Question 36

Hydrogen bonds are found in all of the following EXCEPT

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

Question 37

Tertiary and quaternary structure of proteins involves ________ bonds.

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

Question 38

Which of the following is found in nucleic acids?

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

Question 39

All of the following bases are found in RNA molecules EXCEPT

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

Question 40

The double-strands of DNA result from the formation of ________ between the bases.

A) covalent bonds
B) peptide bonds
C) ionic bonds
D) hydrogen bonds
E) α−1,4 bonds

Question 41

Which of the following is an organic compound?

A) adenine
B) carbon dioxide
C) molecular oxygen
D) sodium chloride
E) water

Question 42

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

Question 43

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

Question 44

A molecule composed of carbon and hydrogen is a compound.

Question 45

Cell surface markers composed of both carbohydrate and lipid molecules are known as (glycoproteins/glycolipids/LPS).

Question 46

The electron shells of atoms hold eight electrons each.

Question 47

Hydrogen bonds are stronger than covalent bonds.

Question 48

A nucleotide with a single cyclic ring structure is a pyrimidine.

Question 49

A(n) (nonpolar/polar/ionic/hydrogen) bond is one in which electrons are shared equally between atoms.

Question 50

The smallest chemical units of matter are elements.

Question 51

Which of the following is found in RNA but not DNA?

A) adenine
B) cytosine
C) deoxyribose
D) guanine
E) uracil

Question 52

Dehydration synthesis is a common feature of polymer production in cells.

Question 53

Denaturation of a protein is always permanent.

Question 54

The valence of an atom is determined by the total number of electrons it contains.

Question 55

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

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

Question 56

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

A) an endothermic reaction
B) a dehydration reaction
C) an exchange reaction
D) a synthesis reaction
E) The answer cannot be determined from the available information.

Question 57

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

Question 58

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, the solution remains green. These observations suggest X is ________ and Z is ________.

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

Question 59

An unbranched polymer composed of simple sugars is a(n)

A) protein.
B) triglyceride.
C) starch.
D) glycoprotein.
E) amino acid.

Question 60

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

Question 61

The monomer of a nucleic acid is called a (nucleoside/nucleotide/base).

Question 62

When a base dissolves in water it releases a(n) (electron/cation/hydrogen ion).

Question 63

A saturated fatty acid contains (no/one/multiple) double bonds.

Question 64

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

Question 65

A nitrogenous base composed of two rings is a (purine/pyrimidine/ribose).

Question 66

Jim adds an acid to a solution, but finds the pH has not changed afterward. This suggests the solution contains a(n) (anion/buffer/salt).

Question 67

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

Question 68

The isotopes of an element vary in the number of (electrons/neutrons/protons) in the atom.

Question 69

Figure 2.2 depicts the (primary/secondary/tertiary) structure of a protein.

Question 70

Consider the structure of thymine, shown on the left in Figure 2.3 above, and compare to the structure of pyrimidine X on the right. What would be the impact if X is incorporated into the structure of a DNA strand in place of thymine?

Question 71

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

Question 72

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

Question 73

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 (L, M, and N) he is characterizing in various combinations. His results are shown on the following table.

What can Max conclude about his compounds based on these results? Describe the likely events in terms of hydrogen and hydroxyl ions.

Question 74

Describe the chemical properties of phospholipids that account for their behavior in water.

Question 75

The DNA double helix is held together by (covalent/ionic/hydrogen) bonds.

Question 76

Compare and contrast synthesis reactions with decomposition reactions.