Biology - Enzymes

Question 1

List the enzymes involved in GLYCOLYSIS

Answer 1

Phosphofustokinase-1
Glyceraldehyde-3-phosphate dehydrogenase
Hexokinase
Glucokinase
Pyruvate kinase
Bisphosphoglycerate mutase
Pyruvate dehydrogenase (PDH)

Question 2

What is Glycolysis?

Answer 2

the enzymatic breakdown of a carbohydrate (such as glucose) by way of phosphate derivatives with the production of pyruvic or lactic acid and energy stored in high-energy phosphate bonds of ATP

Question 3

What is the function of phosphofructokinase-1 (PFK-1)?

Answer 3

Transforms fructose 6-phosphate into Fructose. 1,6-biphosphate. RATE LIMITING and irreversible step in glycolysis

Question 4

What promotes PFK-1 in glycolysis?

Answer 4

AMP, Fructose 2,6-biphosphate

Question 5

What inhibits PFK-1?

Answer 5

ATP and Citrate

Question 6

What is process is Lactate Dehydrogenase involved in?

Answer 6

Fermentation

Question 7

What function does Lactate dehydrogenase have?

Answer 7

Oxidizes NADH auto NAD+, replenishing NAD+ for glyceraldehyde 1,3-phosphate dehydrogenase function. Also reduces Pyruvate to lactate, RATE LIMITING step in fermentation

Question 8

What promotes lactate dehydrogenase?

Answer 8

Absence of oxygen

Question 9

What inhibits lactate dehydrogenase?

Answer 9

Oxygen

Question 10

What is process glyceraldehyde-3-phosphate dehydrogenase involved in?

Answer 10

glycolysis

Question 11

What is glyceraldehyde-3-phosphate dehydrogenase?

Answer 11

Phosphorylates glyceraldehyde 3-phosphate into glyceraldehyde 1,3-biphosphate by consuming phosphate while reducing NAD+ into NADH

Question 12

What are the properties of a biological calalegst?

Answer 12

Lowers activation energy
Affects the kinetics of the reaction, but not the thermodynamics or equilibrium constant (speeds up)
Regenerates itself

Question 13

What are the 2 models for describing the enzyme-substrate complex?

Answer 13

Lock and key model

Induced fit model

Question 14

What is the lock and key model?

Answer 14

Describes substrate as key, enzyme as lock, without changing any conformations they fit nicelytogether

Question 15

What is the induced fit model?

Answer 15

Upon substrate binding to on enzyme, both will undergo a slight conformational change to improve binding to one another

Question 16

What are the six well known types of enzymes?

Answer 16

Isomers
Ligase
Transferase
Lyase
Hydroplane
Oxioreductase

Question 17

What is the function of isomerase?

Answer 17

Catalyzes on isomerization reaction - intramolecular rearrangement of bonds in a molecule

Question 18

What is the function of ligase?

Answer 18

Catalyze the joining of two molecules

Question 19

What is the function of transferase?

Answer 19

Catalyze the transfer of a functional group from one molecule to another

Question 20

What is the function of lyase?

Answer 20

Catalyzes the breaking of a molecule without the use of water

Question 21

What is the function of hydrolase?

Answer 21

Catalyzes the breaking of a molecule by adding water

Question 22

What is the function of oxioreductase?

Answer 22

Catalyzes the transfer of electrons between molecules

Question 23

What is the function of cofactors/coenzymes?

Answer 23

Usually bind to the enzymes active site and assist in catalyzing the reaction

Question 24

What is the difference between coenzymes and cofactors?

Answer 24

Coenzymes = proteins
Cofactors = ions

Question 25

What is a prosthetic group?

Answer 25

If a cofactor or coenzyme is bound extremely tightly to the enzyme

Question 26

What is a holoenzyme vs apoenzyme?

Answer 26

``` Holoenzyme = enzyme with their coenzyme or cofactor Apoenzyme = enzyme without their coenzyme or cofactor ```

Question 27

What type of AAs are most likely to b catalytically important?

Answer 27

Charged, polar or nitrogen containing

Question 28

What specific conditions are needed to generate a Michaelis-Menten plot?

Answer 28

Enzyme concentration held constant | Substrate concentration increased

Question 29

What action does hexokinase perform in glycolysis?

Answer 29

Irreversibly phosphorylates glucose by using one ATP, facilitated by Mg2+ - this prevents glucose from exiting the cell

Question 30

What role does glucokinase have in glycolysis?

Answer 30

Functions like hexokinase but only found in liver cells and the pancreatic islet cells

Question 31

What role does pyruvate kinase have in glycolysis?

Answer 31

Irreversibly dephosphorylates phosphoenolpyruvate (PEP) into pyruvate while turning ADP into ATP

Question 32

What is the role of bisphosphoglycerate in glycolysis?

Answer 32

In RBCs, transformers 1-3-bisphosphoglycerate into 2-3-biophosphoglycerate which decreases hemoglobin’s affinity for oxygen. Shifts the oxygen dissociation curve right, does not bind well to fetal hemoglobin, which is why HbF has higher affinity for oxygen that HbA

Question 33

What is the role of pyruvate dehydrogenase in glycolysis?

Answer 33

Converts pyruvate irreversibly into Acetyl-CoA for krebbs or fatty acid cycle