Question 1

Chemical bonding between two different atoms always occurs between their

Accepted Answer

A)  Unfilled outer orbital
B)  Nuclei
C)  First shells
D)  Cores
E)  Third shells A

Question 2

In the context of structure and function,explain why lowering the pH of a solution would inhibit an enzyme's activity.

Accepted Answer

The vast majority of enzymes are proteins made up of amino acids held together by peptide bonds.The weak bonds that stabilize secondary,tertiary,and quaternary structure that are responsible for the three-dimensional structure of enzymes are destabilized by alterations in pH,causing denaturation.If an enzyme becomes denatured its active site may adopt a different conformation that will no longer be able to bind to reactants.Therefore,changing the structure of an enzyme disrupts its function.

Question 3

_____ bonds form when electrons are transferred between atoms,whereas _____ bonds involve the sharing of electrons.

Accepted Answer

A)  Covalent; hydrogen
B)  Hydrogen; covalent
C)  Ionic; hydrogen
D)  Covalent; ionic
E)  Ionic; covalent E

Question 4

In terms of chemical structure discuss the similarities and differences between DNA and RNA.

Accepted Answer

The answer of In terms of chemical structure discuss the...

Question 5

Carbon dioxide (CO?)forms as a result of

Accepted Answer

A)  Ionic bonds forming between carbon and oxygen
B)  Two pairs of electrons from the carbon forming double covalent bonds with each oxygen
C)  Single covalent bonds between carbon and oxygen
D)  Hydrogen bonding between carbon and oxygen

Question 6

Name and describe the four levels of protein structure and the chemical bonds involved at each level.Why is protein structure important?

Accepted Answer

The answer of Name and describe the four levels of...

Question 7

Which of the following is a steroid found in animal cell membranes?

Accepted Answer

A)   Glycolipid
B)   Cholesterol
C)  Nucleic acid
D)   Amino acid
E)   Protein

Question 8

The quaternary structure of a protein refers to

Accepted Answer

A)  Its amino acid sequence
B)  The way the protein folds
C)  The links that stabilize the protein
D)  The way protein subunits interact with each other
E)  All of the above

Question 9

Which of the following statements is not true?

Accepted Answer

A)  Oxygen has 2 unpaired electrons in the second shell.
B)  Nitrogen has 7 electrons which occupy the first and second shells.
C)  Hydrogen has an atomic number of 1 and an atomic weight of 2.
D)  Carbon has an atomic number of 6 and an atomic weight of 12.
E)  The third shell must contain 18 electrons to be stable.

Question 10

Which of the following is not synthesized by cells?

Accepted Answer

A)  Carbohydrates
B)  Nucleic acids
C)  Proteins
D)  Lipids
E)  Nalco

Question 11

Water surrounds cations and anions and keeps them dissociated in solution by forming

Accepted Answer

A)  Nonpolar covalent bonds
B)  Tertiary structure
C)  Peptide bonds
D)  Active sites
E)  Spheres of hydration

Question 12

An atom that has donated an electron to form an ionic bond is classified as _____ and is positively charged.

Accepted Answer

A)  A cation
B)  Polar
C)  Nonpolar
D)  A solvent
E)  An anion

Question 13

Some proteins form _____ which stabilizes their folding.

Accepted Answer

A)  Spheres of hydration
B)  Double bonds
C)  Disulfide bridges
D)  Magnetic resonance
E)  Energy of activation

Question 14

Which of the following molecules is not a lipid?

Accepted Answer

A)  Cholesterol
B)  Glycolipid
C)  Steroid
D)  Glycogen
E)  Phospholipid

Question 15

The components of ATP include

Accepted Answer

A)  Adenine, ribose sugar, and three phosphates
B)  Amino acid and three phosphates
C)  Adenine, triglycerols, and one phosphate
D)  Adenine, deoxyribose sugar, and three phosphates

Question 16

A triglyceride contains fatty acids that are _____ and therefore do not dissolve with water.

Accepted Answer

A)  Hydrophilic
B)  Carbohydrates
C)  No lipid groups
D)  Ribose sugars
E)  Hydrophobic

Question 17

DNA differs from RNA in that

Accepted Answer

A)  DNA uses the sugar deoxyribose, whereas RNA uses the sugar ribose
B)  Only DNA has 5-prime to 3-prime direction
C)  DNA uses uracil, whereas RNA uses thymine
D)  DNA is usually found as a single chain, whereas RNA is usually found as a double helix

Question 18

Atomic structure gives an atom

Accepted Answer

A)  Its mass
B)  Its reactivity
C)  Its valence in molecules
D)  All of the above

Question 19

Chlorine has at atomic number of 17.Therefore,which of the following is not correct regarding chlorine?

Accepted Answer

A)  Chlorine has a mass number of 34
B)  Chlorine has 2 electrons in the first shell, 8 electrons in the second shell, and 7 electrons in the third shell
C)  If chlorine accepts an electron, it becomes a chloride cation
D)  Chlorine needs only one electron to fill its outer shell
E)  Atomic chlorine has 17 electrons

Question 20

All 20 amino acids have three common chemical components attached to a central carbon.Which of the following is not attached?

Accepted Answer

A)  Hydrogen
B)  Carboxyl group
C)  Glucose
D)  Amino group

Exam 2: Fundamental Chemistry for Microbiology