Deck 2: The Chemistry of Microbiology

Question 1

All of the following bases are found in RNA molecules EXCEPT

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

Answer 1

D

Question 2

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

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

Answer 2

B

Question 3

Which of the following is an INCORRECT pairing?

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

Answer 3

E

Question 4

A protein is a of amino acids.

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

Question 5

The "backbone" of the DNA molecule is composed of

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

Question 6

Which of the following statements concerning nucleic acids is FALSE?

A) Nucleic acid strands are held together by hydrogen bonds between complementary bases.
B) Some viruses have DNA as their genomes.
C) The nucleic acid polymer is composed of peptide bonds.
D) Not all DNA is double stranded.
E) Cytosine is found in all nucleic acid molecules.

Question 7

Which of the following is found in nucleic acids?

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

Question 8

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

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

Question 9

An acid dissociates in water to release

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

Question 10

Tertiary and quaternary structure of proteins involves bonds.

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

Question 11

An amine group is removed from an amino acid and bonded to a second compound to form a different amino acid. No other molecules are used or produced. What type of reaction is likely to be involved?

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

Question 12

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

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

Question 13

The valence of an atom represents its

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

Question 14

Lipids found in the membranes of all eukaryotic cells are

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

Question 15

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

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

Question 16

Which of the following is an INCORRECT pairing?

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

Question 17

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

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

Question 18

Unstable isotopes can be useful

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

Question 19

Organisms use carbohydrates in all of the following ways EXCEPT

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

Question 20

Decomposition reactions are commonly reactions.

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

Question 21

Which of the following statements about proteins is FALSE?

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

Question 22

A stable atom has in its valence shell.

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

Question 23

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

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

Question 24

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

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

Question 25

Which of the following are examples of pyrimidines?

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

Question 26

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

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

Question 27

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) a buffer; a base
E) an acid; a buffer

Question 28

Compounds that readily dissociate in water are

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

Question 29

Plant cell walls are composed of held together by .

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

Question 30

All of the following are associated with ATP molecules EXCEPT

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

Question 31

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

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

Question 32

Which of the following is a property of water?

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

Question 33

Hydrogen bonds are found in all of the following EXCEPT

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

Question 34

Adenosine triphosphate (ATP) is a

A) polymer.
B) lipid.
C) simple carbohydrate.
D) bilayer.
E) monomer.

Question 35

A polymer composed of simple sugars is a(n)

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

Question 36

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

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

Question 37

Which parts of the atoms interact in a chemical reaction?

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

Question 38

Which of the following types of chemical bonds do carbon atoms generally NOT form?

A) polar covalent bonds
B) ionic bonds
C) hydrogen bonds
D) nonpolar covalent bonds
E) neither ionic nor hydrogen bonds

Question 39

Amylose is a(n) carbohydrate.

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

Question 40

Which of the following is an example of a polysaccharide?

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

Question 41

The sum of all the chemical reactions within an organism is referred to as its (metabolism/physiology).

Question 42

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

Question 43

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

Question 44

The outer ring in Figure 2- 1 represents

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

Question 45

A hydroxyl acts as a base.

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

Question 46

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

Question 47

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

Question 48

Which of the following is NOT a characteristic of phospholipids?

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

Question 49

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

Question 50

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

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

Question 51

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

Question 52

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

Question 53

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

Question 54

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

Question 55

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

Question 56

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

Question 57

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

Question 58

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

Question 59

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

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

Question 60

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

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

Question 61

The electron shells of atoms hold eight electrons each.

Question 62

The long- term chemical energy storage molecules in plants are triglycerides.

Question 63

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 64

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

Question 65

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

Question 66

A molecule composed of carbon and hydrogen is a compound.

Question 67

Hydrogen bonds are stronger then covalent bonds.

Question 68

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

Question 69

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

Question 70

The smallest chemical units of matter are elements.

Question 71

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

Question 72

One of the products of dehydration synthesis reactions is water.

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

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

Question 75

Denaturation of a protein is always permanent.

Question 76

Compare and contrast synthesis reactions with decomposition reactions.