Enzymes, Mechanisms, Hemoglobin

Question 1

Tells us whether a reaction will occur spontaneously

System at equilibrium

Answer 1

Thermodynamics

Question 2

Tells us what the speed (rate) of a reaction will be

System not at equilibrium

Answer 2

Kinetics

Question 3

How does an enzyme increase the rate of a reaction?

Answer 3

They recognize a substrate S (the reactant) and speed up its conversion to product P

Question 4

The standard free energy change under standard conditions

Answer 4

ΔG°

Question 5

What is the equation for Keq?

Answer 5

A + B ↔ C + D.

K’eq = [C][D]

[A][B]

so ΔG°’ = -RT lnK’eq

Question 6

What is the equation for Ka?

Answer 6

Ka = H+ [A −]

[HA]

Question 7

What is the relationship between Ka and pKa?

Answer 7

pKa = -logKa

Question 8

What is the equation for pH?

Answer 8

pH = pKa + log ([A −] / [HA])

Question 9

What is the opposite of a log?

Answer 9

10^{log number}

Question 10

What additional equation is necessary for finding specific concentration of the acid?

Answer 10

[HA] = M – A

Question 11

What will a Ka equation look like given only M?

Answer 11

Ka = (x)(x)

(M − x)

Question 12

What two equations do you need when adding a strong base?

Answer 12

[A-] = M_{of given base}

[HA] = M_{of solution} − M_{of given base}

Question 13

In physical terms, how do enzymes lower the activation energy?

Answer 13

All enzymes will lower the activation energy by providing energy derived from weak interactions (H-bonds, hydrophobic interactions, ionic interactions, and Van der Waals forces). This occurs through formation of the ES complex and is called binding energy.

Question 14

An enzyme conforms to the shape of a substrate

Answer 14

Induced fit

Question 15

Pocket or cleft on the enzyme where the catalytic reaction occurs

Answer 15

Active Site

Question 16

Molecule that binds in the active site and is chemically transformed

Answer 16

Substrate

Question 17

Catalytically active version of an enzyme

Answer 17

Holoenzyme

Question 18

Catalytically inactive version of an enzyme

Answer 18

Apoenzyme

Question 19

Affinity for processing S to P

Answer 19

larger kcat/Km

Question 20

Affinity for binding

Answer 20

Small Km

Question 21

Affinity for processing the fastest

Answer 21

large kcat

Question 22

Best overall substrate

Answer 22

large kcat/Km

Question 23

Change the equilibrium between the T and R states

Answer 23

Effector molecules

Question 24

The enzyme-substrate transition-state complex

Enzymes (typically proteins) are biological catalysts

Answer 24

[E] + [S] → [ES] → [E] + [P]

ES

Question 25

What is the y-intercept when looking at a Km Vmax graph?

Answer 25

1/Vmax

Question 26

Nucleophile in the active site temporarily forms a covalent bond

Answer 26

Covalent Catalysis

Question 27

An amino acid sidechain acts as a proton donor/acceptor

Answer 27

Acid-Base Catalysis

Question 28

Can work in multiple ways, electrophile, nucleophile, acid/base etc.

Answer 28

Metal ion catalysis

Question 29

Act of bringing two substrates into close proximity at a reactive surface

Answer 29

Catalysis by approximation

Question 30

Inhibitor resembles the substrate and binds to the active site thereby preventing binding of the substrate

Answer 30

Competitive

Question 31

Inhibitor binds to the enzyme substrate complex created only when substrate binds to enzyme

Answer 31

Uncompetitive

Question 32

Inhibitor binds at different site on enzyme (like allosterism).

Answer 32

Noncompetitive

Question 33

What type of inhibition is this?

Answer 33

Competitive

Question 34

What type of inhibition is this?

Answer 34

Uncompetitive

Question 35

What type of inhibition is this?

Answer 35

Noncompetitive

Question 36

What type of inhibition is this?

Answer 36

Competitive

Question 37

What type of inhibition is this?

Answer 37

Uncompetetive

Question 38

What type of inhibition is this?

Answer 38

Non-competitive

Question 39

Carries O2 from lungs to tissue Hb-O2 and CO2 and H+ from tissues to lungs HB-CO2/H+.

Answer 39

Hemoglobin

Question 40

Where is myoglobin found?

Answer 40

Muscles, not RBCs

Question 41

The low oxygen affinity state of the oxygen carrier

Answer 41

T-state

Question 42

The oxygen-bound state of the oxygen carrier

Answer 42

R-State

Question 43

An increase in blood CO2 concentration leads to a decrease in blood pH and will result in hemoglobin proteins releasing their load of oxygen. Conversely, a decrease in carbon dioxide provokes an increase in pH, which results in hemoglobin picking up more oxygen

Answer 43

The Bohr Effect

Question 44

What makes hemoglobin allosteric?

Answer 44

multimeric state, sigmoidal V vs **S curve**, cooperativity

Question 45

Hb can bind __ O2 while Myoglobin can bind \_\_

Answer 45

4 1

Question 46

Found in RBCs Active form is a tetramer

Answer 46

Hemogloblin

Question 47

Found in muscle tissue Active form is a monomer

Answer 47

Myoglobin

Question 48

Would equilibrium would be shifted towards the T state or R state of hemoglobin with an increase in O2 concentration?

Answer 48

R-State

Question 49

Would equilibrium would be shifted towards the T state or R state of hemoglobin with an increase in CO2 concentration?

Answer 49

T-State

Question 50

Would equilibrium would be shifted towards the T state or R state of hemoglobin with a decrease in 2,3-DPG concentration?

Answer 50

R-State

Question 51

Would equilibrium would be shifted towards the T state or R state of hemoglobin with an increase in cellular pH (decrease in H+)?

Answer 51

R-State