Enzymes Flashcards Preview

RUSVM Vet Prep Cell Bio Exam 2 > Enzymes > Flashcards

Flashcards in Enzymes Deck (46):
1

What is the definition of applications of biocatalysis?

Central role of enzymes in interdisciplinary sciences

2

What is fermentation?
A. synthesis and modification of antibiotics
B. Transformation of defined precursors to a desired target product
C. transformation of raw materials in industrial mixtures

C. Transformation of raw materials (sugar, starch, etc) in industrial mixtures (liquors)

3

What is biotransformation?
A. synthesis and modification of antibiotics
B. Transformation of defined precursors to a desired target product
C. When life depends on a complex network of chemical reactions

B. Transformation of defined precursors to a desired target product
(environmental friendly processes to treat waste)

4

What does the pharmaceutical industry do for enzymes?

synthesis and modification of antibiotics

5

*finish the sentence*
Enzymes have sites that...

...not only bind another molecules but then catalyze a chemical reaction involving that molecule

6

Is the binding from binding sites reversible or irreversible?

They are reversible, that means there is an equilibrium between the free and bound ligand

7

True or False:
Binding sites are not specific for particular ligands

False:
Binding sites are usually very specific for a particular ligand

8

True or False:
Enzymes are protein catalysts that decrease the rate of reactions with being changed in the process.

FALSE:
Enzymes are protein catalyst that INCREASE the rate of reactions WITHOUT being changed in the process.

9

Do enzymes reduce or increase the activation energy barriers that block chemical reactions?

They greatly REDUCE

10

What is the use of activation energy?
A. it is required to catalyze a chemical reaction
B. they help with the binding of ligands
C. it is needed to start chemical reactions
D. it is apart of the energy metabolism

C.
Because chemical reactions are normally blocked, so energy is needed to get them started (Activation energy)

11

What is a substrate?
A. enzyme reactants
B. catalyst
C. a class of enzymes
D. an active site

A. enzyme reactants

12

What are oxidoreductases?
A. Hydrolyze ATP (Na,K ATPase)
B. catalyze reactions in which one molecule is oxidized while the other is reduced
C. transfer carbon, nitrogen or phosphate containing groups
D. break down proteins by hydrolyzing bonds between amino acids

B. catalyze reactions in which one molecule is oxidized while the other is reduced
(oxidases, reductases, dehydrogenases)

13

What is the transfer of carbon, nitrogen or phosphate containing groups?

Transferases

14

What is the name when two molecules ligate in an energy-dependent process?

Ligases

15

What is the active site considered?
A. holoenzymes
B. high specificity
C. high affinity
D. apoenzyme

B. high specificity

16

What is ATPases?

hydrolyze ATP (NA,K ATPase)

17

What is the name when catalyze polymerization reactions occur?
A. Polymerases
B. Proteases
C. Lyases
D. Kinases

A. polymerases

(ex synthesis of DNA and RNA)

18

What is the break down proteins by hydrolyzing bonds between amino acids?

Proteases

19

What is lyase?
A. Catalyze the cleave of C-K and C-O bonds
B. Catalyze the cleavage of H20 bonds
C. Catalyze the binding of C- and P- groups
D. Catalyze the cleave of C-C, C-S, and C-N bonds

D. Catalyze the cleave of C-C, C-S, and C-N bonds

20

What are isomerases?

They catalyze the rearrangement of bonds within a single molecule

21

What is the name that catalyzes the addition of phosphate groups to molecules?

Kinases
(protein kinases are very common in physiology)

22

What is synthase?

Synthesize molecules in anabolic reactions by condensing two smaller molecules together (ATP synthase)

23

What happens when the substrate binds to the enzyme?

An enzyme-substrate complex (ES) is formed

24

How is EP formed?
Enzyme-Product

ES (enzyme-substrate) causes a conformational change in the enzyme that allows catalysis

25

What are the properties of enzymes?
A. Specificity
B. Efficiency
C. Presence of cofactors
D. Regulation
E. Location in the cell
F. All of the above
G. A, B, D, OR E

F - ALL OF THE ABOVE are properties of enzymes

26

Is this considered active or inactive?

E + CF
(enzyme + cofactor)

ACTIVE (holoenzyme)

27

What does the suffix -ase attach to?

Attaches to the substrate of the reaction -- to a ore complete description of the chemical reaction catalyzed

28

What is the complex molecular machine that facilitates the conversion of S --> P ?
A. Binding Protein
B. Active Site
C. Enzyme catalyze
D. The uncatalyzed reaction

B. Active Site

29

How will changes in substrate and/or enzyme properties be measured in?

In an enzyme assay
(absorption of light, viscosity, etc.)

30

What does the Michaelis-Menten equation describe?

How reaction velocity varies with substrate concentration

31

What are "K1, K-1, K2" considered?

Rate constants

32

An enzyme combines with its substrate to form what?

ES complex

33

What does the ES complex yield?

ES complex that yields a product releasing the enzyme

34

Is the concentration of substrate greater or lower than the concentration of enzyme?

GREATER

35

What is the initial velocity of the reaction used for?

Used to analyze enzymatic reactions

36

What is the characteristic of an enzyme and its particular substrate that reflects the affinity of the enzyme for that substrate?
A. Specificity
B. Viscosity
C. Velocity
D. Km

D. Km

37

What is equal to the substrate concentration at which the reaction velocity is 1/2 Vmax?

Km

38

True or False:
Km does not vary with enzyme concentration.

True!

39

What is the rate of the reaction that is directly proportional to the enzyme concentration?
A. Enzyme concentration
B. Reaction catalyze
C. Km
D. All of the above

A. Enzyme concentration

40

In the Michaelis-Menten curve,
At high concentrations of substrate, what is the velocity of the reaction?
A. Vmax
B. Zero Order
C. First Order
D. None

B. Zero Order

41

What is the plot of initial reaction velocity against concentration?
A. hypobolic curve
B. sigmoidal curve
C. hyperbolic curve

C. Hyperbolic curve

42

What curve does allosteric enzymes show?

A sigmoidal curve

43

What are the factors that affect the reaction velocity?

Substrate concentration, temperature, pH, inhibitor (competitive and noncompetitive)

44

What does the Lineweaver-Burk plot calculate?

Km and Vmax

45

What will a larger Km reflect in the Michaelis-Menten curve?

reflects a low affinity of enzyme for substrate

46

A low Km will reflect...

a high affinity of enzyme for substrate