Question 1

Prions are pathogenic proteins that are linked to different neurodegenerative diseases. Investigations of some have indicated that normal cellular proteins and prions have the same amino acid sequence. How is this possible?

Accepted Answer

A)  Though the primary structure is the same between the prion and the normal cellular protein, differences at higher levels (secondary or tertiary) alter protein activity. 
B)  The amino acid sequence is not important to the function of the protein because protein function is completely determined by the pH of the environment. 
C)  The double helix structure of proteins is easily altered by separating the nitrogenous bases holding the strands together, allowing for a protein to act as a prion. 
D)  The amino acids of the prion must have more hydrophilic sections, causing it to interact with the lipids of the plasma membrane and disrupting cell activity.

Question 2

During the first step of gene expression, an RNA copy of a gene is made. Which of the following represents the correct sequence produced from a gene segment with the following sequence: GAACTAAGC?

Accepted Answer

A)  CUUGAUUCG 
B)  GAACUAAGC 
C)  CTTGATTCG 
D)  GUUCTUUGC

Question 3

Which of the following subatomic particles can be changed in number without affecting the element identity of the atom?

Accepted Answer

A)  Electrons 
B)  Protons 
C)  Neutrons 
D)  Both "electrons" and "neutrons" are correct.

Question 4

Normal blood pH is maintained within a range of

Accepted Answer

A)  7.35 - 8.5. 
B)  7.35 - 7.45. 
C)  4.5 - 5.5. 
D)  1.0 - 14.0. 
E)  6.5 - 9.5.

Question 5

Which of the following is not an organic compound?

Accepted Answer

A)  C16H18N3ClS 
B)  Na2HPO3(H2O)5 
C)  CH4 
D)  C3H7O2N

Question 6

A base is a proton ________.

Accepted Answer

A)  donor 
B)  converter 
C)  acceptor 
D)  creator 
E)  Both acceptor and creator are correct.

Question 7

An organic molecule such as a vitamin that makes an enzyme functional is called a/an ________.

Accepted Answer

A)  buffer 
B)  coactivator 
C)  catalyst 
D)  coenzyme

Question 8

The amount of matter in an object is its ________.

Accepted Answer

A)  mass 
B)  weight 
C)  density 
D)  volume 
E)  size

Question 9

When ionic compounds dissolve in water, their ions

Accepted Answer

A)  cling tightly together. 
B)  dissociate or separate from one another. 
C)  lose their charge. 
D)  get lost in the solvent. 
E)  settle to the bottom of the container.

Question 10

Henry's science fair project focused on variation in the very obvious reaction between vinegar and baking soda. He noted that as he ________ the volume of vinegar, he saw a/an ________ in bubbling in the beaker.

Accepted Answer

A)  increased; increase 
B)  decreased; decrease 
C)  increased; decrease 
D)  decreased; increase

Question 11

Hydrogen bonds form between molecules containing ________ bonds; the hydrogen bond is between a hydrogen atom of one molecule and a partially ________ charged atom of another.

Accepted Answer

A)  polar covalent; negatively 
B)  polar covalent; positively 
C)  nonpolar covalent; positively 
D)  nonpolar covalent; negatively 
E)  ionic; positively

Question 12

Fatty acid A has 10 double covalent bonds scattered throughout its carbon chain while fatty acid B has only single covalent bonds between the carbons in its chain.

Accepted Answer

A)  Fatty acid A is saturated. 
B)  Fatty acid B is unsaturated. 
C)  Both fatty acids are saturated. 
D)  Both fatty acids are unsaturated. 
E)  Fatty acid B is saturated.

Question 13

Which of the following is NOT a function of carbohydrates in the body?

Accepted Answer

A)  Structural component of DNA 
B)  Protection 
C)  Bulk in feces 
D)  Energy 
E)  Structural component of RNA

Question 14

ATP

Accepted Answer

A)  is a nucleotide found in DNA. 
B)  stores genetic information. 
C)  is a sugar found in transfer RNA. 
D)  serves as the energy currency of the cell. 
E)  can store, but cannot release energy in the cell.

Question 15

Chemical reactions with the property of being able to proceed from reactants to products and from products to reactants are called ________ reactions.

Accepted Answer

A)  exchange 
B)  synthesis 
C)  decomposition 
D)  reversible 
E)  mirrored

Question 16

Oxygen has an atomic number of 8 and an atomic mass of 16. How many valence electrons does it have?

Accepted Answer

A)  2 
B)  4 
C)  6 
D)  8 
E)  16

Question 17

The smallest particle of an element that still exhibits the chemical characteristics of that element is a/an ________.

Accepted Answer

A)  electron 
B)  atom 
C)  chemical bond 
D)  orbital 
E)  proton

Question 18

In ionic bonding,

Accepted Answer

A)  only non-polar molecules are involved. 
B)  a "sea of electrons" forms. 
C)  electrons are transferred from one atom to another. 
D)  two hydrogen atoms share one pair of electrons. 
E)  the charge of the ion does not play a role in the bond.

Question 19

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

Accepted Answer

A)  Adenine 
B)  Guanine 
C)  Thymine 
D)  Uracil 
E)  Cytosine

Question 20

-The sodium chloride molecule breaks apart in water. What does "E" represent (the process)?

Accepted Answer

A)  Chloride ion 
B)  Dissociation 
C)  Water molecule 
D)  Sodium ion 
E)  Salt crystal

Exam 2: The Chemical Basis of Life