Chapter 2

Question 1

If the side chains of amino acids contain the ammonium ion, they readily form ions that:

A.	are described as acidic amino acids.
B.	give positive electric charges to the amino acid AND are described as basic amino acids.
C.	give positive electric charges to the amino acid.
D.	react with lipids to form lipoproteins.
E.	are described as basic amino acids.

Answer 1

B. give positive electric charges to the amino acid AND are described as basic amino acids.

Question 2

If the side chains of amino acids contain carboxyl (-COOH) groups, they:

A.	contribute a positive charge to the amino acid at pH 10. 
B.	contribute a negative charge to the amino acid at pH 10. 
C.	are considered acidic amino acids. 
D.	contribute a negative charge to the amino acid at pH 10 AND are considered acidic amino acids. 
E.	have no effect on the charge of the amino acid at pH 10.

Answer 2

D. contribute a negative charge to the amino acid at pH 10 AND are considered acidic amino acids.

Question 3

Which is true of carbohydrates?

A.	They may be part of the structure of bacteria.
B.	They may serve as a source of food.
C.	They contain carbon, hydrogen, and oxygen in a 1:2:1 ratio.
D.	They may be bonded to proteins to form glycoproteins.
E.	All of the choices are correct.

Answer 3

E. All of the choices are correct.

Question 4

The atomic number for an atom of a specific element is equal to (Check all that apply)

A.	the number of electrons in a single atom of that element.
B.	the number of electrons plus neutrons in a single atom of that element.
C.	the number of protons in a single atom of that element.
D.	the number of neutrons and protons in a single atom of that element.

Answer 4

B. the number of electrons plus neutrons in a single atom of that element.
C. the number of protons in a single atom of that element.
D. the number of neutrons and protons in a single atom of that element.

Question 5

Phospholipids are non-polar molecules.

True
False

Answer 5

False

Question 6

Unsaturated fats have lower melting points than saturated fats.

True
False

Answer 6

False

Question 7

The atom, as a whole, is uncharged because:

A.	the number of protons equals the number of electrons.
B.	neutrons neutralize the charges.
C.	the number of protons equals the number of neutrons.
D.	the number of electrons equals the number of neutrons.

Answer 7

A. the number of protons equals the number of electrons.

Question 8

Atoms that gain electrons are now
	A.	negatively charged.
	B.	lighter.
	C.	neutral.
	D.	positively charged.

Answer 8

A. negatively charged.

Question 9

If you placed the molecule in a vertical orientation, then from top to bottom, the two parallel strands of DNA are both orientedin the same, 5′ to 3′, direction.

True
False

Answer 9

True

Question 10

Amino acids in proteins are linked to one another by peptide bonds between the:

A.	carboxyl group of one amino acid and the amino group of another.
B.	carbon atoms of two adjacent amino acids.
C.	methyl group of one amino acid and a side group of another amino acid.
D.	nitrogen atom and carboxyl ion.

Answer 10

A. carboxyl group of one amino acid and the amino group of another.

Question 11

Which shows the incorrect complementary base pairing?
	A.	A:T
	B.	A:U
	C.	G:C
	D.	A:T, G:C, AND A:U
	E.	G:T

Answer 11

E. G:T

Question 12

In addition to investigations with bacteria that led to him being considered the Father of Microbiology, Pasteur also:

A.	found that some molecules can exist as stereoisomers.
B.	discovered polarized light.
C.	found that some molecules can exist as stereoisomers AND separated organic acids using a microscope.
D.	created aspartame.
E.	separated organic acids using a microscope.

Answer 12

C. found that some molecules can exist as stereoisomers AND separated organic acids using a microscope.

Question 13

As DNA is always double-stranded, RNA is always single-stranded.

True
False

Answer 13

False

Question 14

Lipids, like nucleic acids and proteins, are made of strings of similar subunits.

True
False

Answer 14

False

Question 15

The most important molecule(s) in the world is(are)

A.	water. 
B.	protein. 
C.	nucleic acids. 
D.	carbohydrates.

Answer 15

A. water.

Question 16

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

	A.	Uracil
	B.	Adenine
	C.	Thymine
	D.	Ribose
	E.	Ribose AND Uracil

Answer 16

E. Ribose AND Uracil

Question 17

The sugars found in nucleic acids consist of

A.	5 carbon atoms.
B.	3 carbon atoms.
C.	9 carbon atoms.
D.	7 carbon atoms.

Answer 17

A. 5 carbon atoms.

Question 18

The N terminal in a protein:

A.	is the end characterized by a free amino group.
B.	refers to that area of a protein that is bound to another protein.
C.	is the end characterized by a free carboxyl group.
D.	is typically found in the middle of a protein.

Answer 18

A. is the end characterized by a free amino group.

Question 19

What type of bonding holds one strand of DNA to the complementary strand of DNA?

A.	Disulfide
B.	Hydrogen
C.	Ionic
D.	Covalent

Answer 19

B. Hydrogen

Question 20

Which determines the chemical and physical properties of an atom of an element?

A.	Atomic weight
B.	Neutron
C.	Atomic number
D.	Electron

Answer 20

C. Atomic number

Question 21

Water-soluble substances easily pass through the phospholipid bilayer of a cell membrane.

True
False

Answer 21

False

Question 22

Which is true of nucleotides?

A.	They are the building blocks of DNA.
B.	They carry chemical energy in their bonds.
C.	They are part of certain enzymes.
D.	They serve as specific signaling molecules.
E.	All of the choices are true.

Answer 22

E. All of the choices are true.

Question 23

The end of the nucleic acid chain that grows by adding more nucleotides is always the:

A.	3 prime end.
B.	N terminal.
C.	C terminal.
D.	5 prime end.

Answer 23

A. 3 prime end.

Question 24

The primary structure in a protein:

A.	refers to the initial folding of a protein.
B.	refers to the sequence of amino acids.
C.	refers to two or more polypeptides linked to one another.
D.	refers to the helical folding of a protein.

Answer 24

B. refers to the sequence of amino acids.

Question 25

The negatively charged component of the atom is the: A. electron. B. proton. C. nucleus. D. neutron.

Answer 25

A. electron.

Question 26

The carbohydrate(s) found in nucleic acids is/are : ``` A. deoxyribose. B. ribose. C. galactose. D. glucose. E. ribose AND deoxyribose. ```

Answer 26

E. ribose AND deoxyribose.

Question 27

Protein denaturation can: ``` A. occur due to certain chemicals. B. occur due to pH changes. C. occur due to high temperature. D. cause the protein to no longer function. E. All of the choices are correct. ```

Answer 27

E. All of the choices are correct.

Question 28

Acidic or basic amino acids are: ``` A. considered hydrophilic. B. able to form ions. C. readily soluble in lipids. D. readily soluble in water, able to form ions, AND considered hydrophilic. E. readily soluble in water. ```

Answer 28

D. readily soluble in water, able to form ions, AND considered hydrophilic.

Question 29

If electrons are shared unequally, this forms a(n): A. ionic bond. B. non-polar bond. C. polar bond. D. weak bond.

Answer 29

C. polar bond.

Question 30

The components of fats are fatty acids and: ``` A. amino acids. B. nucleotides. C. phosphate. D. glycerol. E. All of the choices are correct. ```

Answer 30

D. glycerol.