Enzymes and Energy

Question 1

What is enthalpy?

Answer 1

heat content

Question 2

what is change in enthalpy? (delta H)

Answer 2

amount of heat absorbed/released during a reaction

Question 3

What is entropy?

Answer 3

the measure of chaos: how much thermal energy per unit of temperature is UNavaliable.

Question 4

What is the calculation for Gibbs Free Energy?

Answer 4

G= enthalpy - Temp x entropy

Question 5

What is Gibbs Free Energy?

Answer 5

Change in free energy

Question 6

Describe exergonic reactions.

Answer 6

The energy of the reactants is higher than the products: energy released

Question 7

Describe endogonic reactions.

Answer 7

The energy of the reactants is lower than the products: energy is added.

Question 8

How do cells attain energy?

Answer 8

from chemical bonds of organic molecules (oxidation)

Question 9

What is oxidation?

Answer 9

removal of electrons from an atom

Question 10

what is reduction?

Answer 10

addition of electrons to an atom

Question 11

What is a REDOX reaction?

Answer 11

The simultaneous occurrence of oxidisation and reduction

Question 12

What happens to C-H bonds in an oxidization reaction?

Answer 12

the number of them decrease

Question 13

what happens to a C-H bond in reduction?

Answer 13

the number of them increase

Question 14

What are the electron carriers?

Answer 14

NADH, NADPH and FADH

Question 15

What do the electron carriers do and become?

Answer 15

Carry hydride ions, pass them onto a donor atom and become oxidised (NAD+, NADH+ and FAD+)

Question 16

what is the reaction for ATP?

Answer 16

ATP + H2O –> ADP + P + free energy

Question 17

what does ATP do?

Answer 17

Captures and transfers free energy by phosphorylating other molecules

Question 18

is the conversion of ADP –> ATP exo or endergenic?

Answer 18

Endergonic

Question 19

what are the three basic steps of a basic enzyme catalysed reaction?

Answer 19

Binding of a substrate- E + S <–> ES

Conversion of bound substrate to bound product ES <–> EP

Release of product EP <–> E + P

Question 20

What do enzymes lower and what do they NOT change?

Answer 20

Lower energy barrier for reactions

final equilibrium and Gibs Free energy does not change

Question 21

What does Glucokianse catalyse?

Answer 21

the transfer of P from ATP to C6 of glucose

Question 22

What are two general ways that drugs can impact enzymatic activity?

Answer 22

Drugs can inhibit or activate it

Alter V or Km

Question 23

what is the Michaelis-Menten Equations

Answer 23

Describes rate of enzymatic reactions by relating reaction rate (V) to substrate concentration (S)

Question 24

What is Km?

Answer 24

Affinity constant

Question 25

What can sulfa drugs do that impact enzymatic activity?

Answer 25

inhibit folic acid synthesis is essential for the metabolism and growth of disease-causing bacteria

Question 26

What happens to Km and S when competitive inhibition occurs?

Answer 26

Increase S= decreased inhibitor action Km higher

Question 27

What do Non-competitive inhibitors do to enzymes?

Answer 27

react with enzymes and alter its structure and activity. less activity = slow reaction rate

Question 28

what happens when increase in entropy?

Answer 28

increased disorder

Question 29

Describe the nature of catabolic reactions.

Answer 29

bonds broken, disorder and negative Gibbs Free Eneregy

Question 30

Describe the nature of anabolic reactions.

Answer 30

bonds created, more order and positive Gibbs Free Energy

Question 31

What do you need for a negative Gibbs Free?

Answer 31

negative delta H (exergonic)

Question 32

what do you need for a positive Gibbs Free?

Answer 32

positive delta H (endergonic)

Question 33

What occurs in Cellular Respiration (reference glucose bonds)

Answer 33

Energy in glucose bonds is broken down and used to create other compounds. 6C6h12O6 + 6O2 --> 6CO2 + 6H20 + energy oxidization

Question 34

What is the difference between NADP+ and NADPH?

Answer 34

NADP+ = oxidised form NADPH = reduced as H added to the nicotinamide ring

Question 35

What is the structure of NADPH?

Answer 35

Two phosphates attached to ribose with added H on the nicotinamide ring

Question 36

What is the chemical reaction for Flavin Adenine Dinucleotide.

Answer 36

Succinate <-Succinate dehydrogenase-> Fumarate succinate dehydrogenease= FAD--> FADH2

Question 37

How much can enzymes speed reactions by?

Answer 37

10^6 - 10^17

Question 38

How do enzymes lower energy barriers for reactions?

Answer 38

bring substarte, coenzyme and metals to enzyme --> change shape

Question 39

Describe the graph that represents Michaelis-Menten Kinetics

Answer 39

Reaction rate (v) (vertical axis) vs Substrate concentration

Question 40

What does Km tell us?

Answer 40

Concentration of substrate = velocity that is 1/2 maximal velocity

Question 41

what does a low Km tell us?

Answer 41

high affinity

Question 42

Decribe the Km of isomers Hexokinase 1 vs Glucokinase (in liver)

Answer 42

Hexokinase: Km= 0.05 = high affinity for glucose = low glucose concentartion glucokinase =Km= 5-6 low affinity for glucose = needs a High glucose concentration

Question 43

what are the units for reaction velocity? (Vmax units)

Answer 43

Vmax units = umol/min/mg protein

Question 44

How can we analyse the impact of drugs on enzymes?

Answer 44

use lineweaver-burk plots

Question 45

What does the lineweaver-burk plot determine and what is the formula?

Answer 45

Determines Km and Vmax 1/v = km/Vmax (1/{s} + 1/Vmax

Question 46

What is the impact of increases [S] in Competitive inhibition?

Answer 46

decrease inhibitors actions

Question 47

In competetive inhibition, can the same Vmax be reached with more [S]?

Answer 47

Yes

Question 48

Describe what happens to V, Vmax and [S] in non-competitive inhibition.

Answer 48

V is lower (slower rate of reaction) = less product increasing [S] NOT stop inhibition Vmax desceases

Question 49

What is the impact on Vmax and Km with competitive inhibition?

Answer 49

Same Vmax will be met (despite inc [s]) Km will be higher

Question 50

What are allosteric enzymes?

Answer 50

enzymes that have an additional binding site for effector molecules. Not an active site.

Question 51

Why are allosteric enzymes important for regulating the entire metabolic pathway?

Answer 51

They provide inhibitory and stimulatory responses. So will inhibit to slow down process that are not needed and allow for extra binding sites if need to have an increased reaction.

Question 52

What is the function and common features of a activation-transfere coenzyme?

Answer 52

Functions -participate directly in catalysis by forming a covalent bond - features Two groups in the coenzyme: * Forms a covalent bond (functional group) * Binds tightly to the enzyme (binding group)

Question 53

what is an example of an activation-transfer coenzyme?

Answer 53

Thiamine pyrophosphate

Question 54

Where is the highest energy phosphate on ATP found?

Answer 54

The bonds between phosphate groups, especially the second and third.

Question 55

Why is there a higher level of glucose but not glycogen in the liver for a patient with a glucokinase mutation?

Answer 55

Glucokinase is not functioning correctly = glucose not broken into glycogen correctly = as glycogen is the store of glucose in the blood, the body does not recognise that it has glucose in it. Thus the BG levels will contain to rise rather than raise and plateau.

Question 56

What happens to the Km, Substrate concentration and V-Max in a patient with glucokinase mutation?

Answer 56

Km will increase as the body needs a higher substrate concentration to absorb the glucose, and V-max stays the same.

Question 57

What is the importance of Mg2+ in ATP hydrolysis?

Answer 57

Activator of hydrolysis and increases metabolic state

Question 58

26. How can Positive Delta G reactions go in the forward direction

Answer 58

high reactants and low product levels

Question 59

What is the name of the enzyme that breaks down alcohol?

Answer 59

aldehyde dehydrogenase.

Question 60

what are isozymes and an example?

Answer 60

enzymes that catalyze the same type of reaction but are created by different genes and have different molecular shapes. creatine kinase

Question 61

What is the difference between NADH and NADPH?

Answer 61

NADPH has a phosphate group which alters its shape. NADPH= anabolic (energy added) NADH= catabolic (energy released)

Question 62

what is the role of thiamine? What can be caused when

Answer 62

enzymatic cofactor in alcohol metabolism. heart and over issues

Question 63

What is the highest energy phosphate found in ATP?

Answer 63

Alpha and beta phosphate (2nd and 3rd)

Question 64

What promotes the forward direction of glycolysis? (Glucose-6-phosphate --> Glucose 1-phosphate)

Answer 64

Delta is positive = non-spontaneous = needs energy [subrate] high enough and products low enough

Question 65

If the Delta G is negative =

Answer 65

spontaneous

Question 66

f delta G is positive =

Answer 66

non-spontaneous

Question 67

Which parto of the enzyme catalyst has the product inhibition?

Answer 67

first