MCAT Biology 1: Molecules

Question 1

Major function of phospholipids:

Answer 1

Structural component of membranes

Question 2

Major function of triacylglycerols [2]:

Answer 2

1. Store metabolic energy

2. Thermal insulation and padding

Question 3

Major function of steroids:

Answer 3

Metabolic activities

Question 4

Major function of some fatty acids (eicosanoids):

Answer 4

Local hormones

Question 5

These organs can absorb glucose in absence of insulin [2]:

Answer 5

1. Brain (neural cells)

2. Liver (hepatic cells)

Question 6

Parts/components of DNA [3]:

Answer 6

1. Phosphate group
2. 5-carbon sugar
3. Nitrogenous base

Question 7

Name the purines in DNA [2]:

Answer 7

1. Adenine

2. Guanine

Question 8

Name the pyrimidines in DNA [2]:

Answer 8

1. Cytosine

2. Thymine

Question 9

Number of H-bonds between GC [2]:

Answer 9

3

Question 10

Number of H-bonds between AT [2]:

Answer 10

2

Question 11

Number of rings in purines:

Answer 11

2

Question 12

Number of rings in pyrimidines:

Answer 12

1

Question 13

Protein 2° structure (alpha-helix/beta-sheet) reinforced by type of bond:

Answer 13

Hydrogen bond

Question 14

Protein 2° structure (alpha-helix/beta-sheet) hydrogen bonds occur between:

Answer 14

Carbonyl oxygen – Hydrogen

Question 15

Forces/bonds that contribute to 3° and 4° structure [5]:

Answer 15

1. Covalent disulfide bonds
2. Electrostatic (ionic) interactions
3. Hydrogen bonds
4. van der Waals forces
5. Hydrophobic bonding

Question 16

Amino acid causes kink in alpha-helix and beta-sheet and contributes to 3° structure:

Answer 16

Proline

Question 17

Proline causes a kink by preventing type of bond:

Answer 17

Hydrogen bond

Question 18

Factors that cause protein to lose higher-level conformation [3]:

Answer 18

1. Heat
2. Salt
3. ∆pH

Question 19

Enzymes need these to function:

Answer 19

Cofactors

Question 20

Subcategories of cofactors [2]:

Answer 20

1. Minerals

2. Coenzymes

Question 21

Many coenzymes come from:

Answer 21

Vitamins (or their derivatives)

Question 22

Competitive inhibitor binding site:

Answer 22

Enzyme active site

Question 23

Competitive inhibitor effect on Km:

Answer 23

Increase

Question 24

Competitive inhibitor effect of Vmax:

Answer 24

No change

Question 25

Uncompetitive inhibitor binding site:

Answer 25

E-S complex

Question 26

Uncompetitive inhibitor effect on Km:

Answer 26

Decrease

Question 27

Uncompetitive inhibitor effect on Vmax:

Answer 27

Decrease

Question 28

Mixed inhibitor binding site:

Answer 28

E-S complex or Enzyme

Question 29

Mixed inhibitor effect on Km:

Answer 29

Increase or Decrease

Question 30

Mixed inhibitor effect on Vmax:

Answer 30

Decrease

Question 31

Noncompetitive inhibitor binding site:

Answer 31

E-S complex or Enzyme

Question 32

Noncompetitive inhibitor effect on Km:

Answer 32

No change

Question 33

Noncompetitive inhibitor effect on Vmax:

Answer 33

Decrease

Question 34

Enzyme class catalyze transfer of electrons or hydrogen ions:

Answer 34

Oxidoreductases

Question 35

Enzyme class catalyze transfer of groups b/w locations:

Answer 35

Transferases

Question 36

Enzyme class regulate hydrolysis reactions:

Answer 36

Hydrolases

Question 37

Enzyme class catalyze reactions where functional groups added to double bond or vise versa:

Answer 37

Lyases

Question 38

Enzyme class catalyze transfer of groups within molecule:

Answer 38

Isomerases

Question 39

Enzyme class catalyze condensation reactions coupled to hydrolysis of high energy molecules:

Answer 39

Ligases

Question 40

Type of lyase that catalyzes addition of substrate to double bond of another:

Answer 40

Synthase

Question 41

Type of ligase that requires energy input from ATP or some other nucleotide:

Answer 41

Synthetase

Question 42

Enzyme type that phosphorylates:

Answer 42

Kinase

Question 43

Enzyme type that dephosphorylates:

Answer 43

Phosphatase