Exam 2 Study Guide -- Full Guide

Question 1

What chemical do yeast fermentations produce in high concentrations?

Answer 1

Ethyl alcohol (Ethanol) and CO_2

Question 2

In what types of cells do enzymes operate?

Answer 2

All cell types (Bacteria, animal, plant, and fungi).

Question 3

What is the general enzymatic equation?

Answer 3

E + S –> [E-S-C] –> E + P (Enzyme + Substrate –> Complex –> Enzyme + Product).

Question 4

Where do exoenzymes carry out their reactions?

Answer 4

Outside the cell.

Question 5

The Embden-Meyerhof pathway converts one glucose into what?

Answer 5

Two pyruvic acid molecules (this is the standard Glycolysis pathway).

Question 6

Which metabolic aspect involves synthesis of compounds and use of energy?

Answer 6

Anabolism (“Building up”).

Question 7

What are inorganic ions that serve as “enzyme helpers” called?

Answer 7

Cofactors.

Question 8

Most vitamins are converted into ______ in cells.

Answer 8

Coenzymes (organic helpers).

Question 9

What is the molecule upon which an enzyme exerts its effect?

Answer 9

The Substrate.

Question 10

The temperature at which an enzyme operates best is the ______.

Answer 10

Optimum temperature.

Question 11

T/F: Bonds between an enzyme and substrate are strong and irreversible.

Answer 11

False. They are typically weak, temporary bonds (hydrogen/ionic).

Question 12

Which of these is NOT an enzyme: lactose, dehydrogenase, lipase, peptidase?

Answer 12

Lactose (it’s a sugar; enzymes usually end in “-ase”).

Question 13

An enzyme produced only when its substrate is present is called ______.

Answer 13

An induced enzyme (or inducible enzyme).

Question 14

T/F: Metabolic reactions are multi-step series or pathways.

Answer 14

True. Each step is catalyzed by a different enzyme.

Question 15

Which media type allows the growth of only one type from a mixture?

Answer 15

Selective medium.

Question 16

Halophiles (osmophiles) live in solutions that are ______.

Answer 16

Hypertonic (High salt/solute concentration).

Question 17

Which amino acid contains sulfur?

Answer 17

Cysteine (and Methionine).

Question 18

Most enzyme cofactors are actually ______.

Answer 18

Ions

Question 19

A Staphylococcus aureus virulence factor that dissolves fat is ______.

Answer 19

lipase

Question 20

Lactose causing E. coli to produce lactase is an example of ______.

Answer 20

Enzyme induction.

Question 21

Amylase is an enzyme that decomposes ______.

Answer 21

Starch

Question 22

What ultimately determines the presence/absence of enzymes in a microbe?

Answer 22

Heredity (their DNA/Genetics).

Question 23

How is gas production indicated in fermentation tubes?

Answer 23

An air pocket in an inverted vial (Durham tube).

Question 24

Which substrate is used for the production of hydrogen sulfide (H_2S)

Answer 24

Cysteine (because it contains sulfur).

Question 25

Reactions observed in carbohydrate fermentation tests include ______.

Answer 25

Gas production AND Acid production.

Question 26

What is evidence for the production of H_2S in a medium

Answer 26

Formation of a black color

Question 27

Why do taxonomists study carbohydrate fermentation?

Answer 27

For the differentiation of species.

Question 28

How is the breakdown of gelatin detected?

Answer 28

Liquefaction of medium even at low temperatures (refrigerator).

Question 29

What is a Durham tube used for?

Answer 29

Collecting gas.

Question 30

What is used to test for the presence of coagulase?

Answer 30

Citrated human plasma.

Question 31

If gelatin medium turns liquid at cool temps after growth, you assume ______.

Answer 31

The gelatin was used as a nutrient (hydrolyzed) by the organisms.

Question 32

What chemical reagent detects the presence of indole?

Answer 32

Kovac’s reagent.

Question 33

Indole is formed by the action of bacteria on ______.

Answer 33

Tryptophan (an amino acid).

Question 34

The blackening of TSI agar is due to the interaction of H_2S and _____.

Answer 34

FESO4 (Ferrous sulfate/Iron)

Question 35

Which of these is a good example of a crystalloid: glucose, gelatin, starch, RBCs?

Answer 35

Glucose (small enough to pass through membranes).

Question 36

What does fermentation mean in the broadest sense?

Answer 36

The anaerobic degradation of carbohydrates and other compounds.

Question 37

Number of different carbohydrates in a fermentation broth test is usually ______.

Answer 37

1 (to ensure the result is specific to that sugar)

Question 38

No change, no gas, and no turbidity in a fermentation tube means ______.

Answer 38

The organisms did not grow in this medium.

Question 39

What does Phenol red do in acid vs. basic solutions?

Answer 39

Yellow in acid; Deeper red/magenta in base.

Question 40

Substances that bring about chemical changes without being changed themselves are ______.

Answer 40

Enzymes (Biological Catalysts).

Question 41

T/F: Plasma is serum less fibrinogen.

Answer 41

False. (Serum is plasma less fibrinogen).

Question 42

T/F: Anabolic enzyme reactions result in biosynthesis.

Answer 42

True. (Anabolism = building).

Question 43

T/F: Catabolic reactions result in cleavage of the substrate into smaller molecules.

Answer 43

True. (Catabolism = breaking down).

Question 44

T/F: Catabolic enzyme reactions are energy producing.

Answer 44

True. (They release energy stored in bonds).

Question 45

T/F: Amino acids are end products of protein hydrolysis.

Answer 45

True. (Proteins are broken down into their monomers).

Question 46

T/F: Gelatinase activity results in the disappearance of the protein substrate.

Answer 46

True. (The solid gel is "eaten" and becomes liquid).

Question 47

T/F: Catabolic reactions usually result in an increase in molecular size.

Answer 47

False. (They decrease size).

Question 48

T/F: A red color indicates a positive test for nitrate reduction (with correct reagents).

Answer 48

True.

Question 49

T/F: When litmus is not reduced (alkaline), it is a blue color.

Answer 49

True. (Litmus is red in acid, blue in base).

Question 50

T/F: A stab inoculation is executed by streaking the slanted area.

Answer 50

False. (Stab is into the "butt"; streaking is for the slant).