Fundamentals of Biochemical Reactions

Question 1

Identify what free energy change indicates in terms of Gibbs free energy?

Answer 1

Delt G < 0 = spontaneous, Keq > 1, exergonic, rxn proceeds to right
Delt G > 0 = non spontaneous, Keq < 1, endergonic, rxn proceeds to left

Question 2

ATP -> ADP + Pi
ATP -> AMP + PPi
PPi -> Pi + Pi

Answer 2

Delt G = -7.3 kcal/mol
Delt G = -10.9 kcal/mol
Delt G = -4.0 kcal/mol

Question 3

Acid-Base rxn

Answer 3

Involves molecules that donate protons (acids) and accept protons (bases)

Question 4

Redox rxn

Answer 4

Transfer of an electron from one molecule to another. OILRIG

Question 5

pH of blood

Answer 5

7.37-7.43

Question 6

Blood buffering System equation

Answer 6

H + HCO3- H2CO3 CO2 + H2O

Carbonic anhydrase is between Bicarbonate and CO2 and H2O

Question 7

Acid-base balance and kidneys

Answer 7

Kidneys remove H+ from blood in the form of NH4+ and reabsorb HCO3-. Low blood pH (metabolic acidosis) increases removal of H+ and reabsorption of HCO3- -> results in equation shifting to right. High pH (metabolic alkalosis) results in fewer H+ removed and less reabsorption of HCO3-.

Question 8

Respiratory Acidosis

Answer 8

Hypoventilation leads to a high concentration of CO2 and shifts the equation to the left, which causes and increase in H+ and a decrease in pH.

Question 9

Respiratory Alkalosis

Answer 9

Hyperventilation leads to a low concentration of CO2 and shifts the equation to the right, which causes a decreases in the amount of H+ and an increase in pH.

Question 10

Enzymes lower…

Answer 10

Activation energy and speed the rate of the reaction. They do not increase or decrease the free energy, nor do theyt alter the conc of reactants and products.

Question 11

Oxidoreducatases and examples

Answer 11

enzymes that transfer electrons from a donor to an acceptor. Ex. lactate Dehyrdogenase, oxidases,

Question 12

Induced fit hypothesis

Answer 12

binding induces conformational changes in active site

Question 13

Lock and key hypothesis

Answer 13

substrate is a perfect fit for active site

Question 14

Cofactors

Answer 14

noncovalent interaction, stabilize active site, how they interact

Question 15

coenzymes

Answer 15

small organic molecules, derived from vitamins. Two classes-> co-substrate and prosthetic (Heme)

Question 16

Cu

Answer 16

Cytochrome oxidase

Question 17

Fe

Answer 17

Heme proteins

Question 18

Mg

Answer 18

ATPases

Question 19

Zn

Answer 19

Superoxide dismutase

Question 20

Se

Answer 20

Glutathione peroxidase

Question 21

Lactate dehydrogenase active sites

Answer 21

Essential AA: R, H, R
Substrate: Lactate
Coenzyme: NAD+

Question 22

Enzymes need optimal…

Answer 22

pH and temperature

Question 23

Gastric Proton pump inhibitors

Answer 23

AKA H+/K+ ATPase. Is found in the parietal cell lining gastric lumen, which pumps H+ into the lumen where it combines with Cl- to form HCl. Conditions such as heartburn and ulcers require decrease in gastric acid. Proton pump inhibitors are prescribed and reduce HCL production.

Question 24

Competitive inhibiton

Answer 24

Same Vmax and increased Km

Question 25

noncompetitive inhibiton

Answer 25

Lower Vmax and same Km

Question 26

Uncompetitive inhibition

Answer 26

Lower Vmax and Lower Km

Question 27

Inhibition of Metalloenzymes

Answer 27

These are enzymes that require metal ions as a cofactor such as Mg and Zn. Chelating of cofactors will inhibit enzyme activity.

Question 28

Chelating Agents of Lead poisoning

Answer 28

Pb inhibits 2 important enzymes for heme biosynthesis and since Heme is a coenzyme of hemoglobin, RBC are not able to bind oxygen and deliver oxygen to the body. Symptoms of lead poisoning include abdominal pain, sideroblastic anemia, irritability, and headaches. Neurological defects indicate impaired nervous system and encephalopathy. Treatment for lead poisoning involves administering Ca-EDTA with dimercoprol. Since lead has a higher affinity for EDTA, lead will displace Ca and form Pb-EDTA, which can then be excreted out.

Question 29

Irreversible Enzyme activation

Answer 29

Irreversible loss of function. Decrease Vmax and Km remains unchanged. This can only be overcome by synthesis of new enzyme.

Question 30

Allosteric Enzymes vs Enzyme kinematics

Answer 30

Sigmoidal curve vs hyperbolic

Question 31

Isozymes

Answer 31

Same catalytic function but different primary sequence

Question 32

Troponin in Myocardial infarction

Answer 32

Calcium binding causes conformational change, transmitted to tropomyosin, allowing myosin to bind to actin filaments. Troponin cTn-1 used as biomarker for detection of MI when found in serum.

Question 33

Proenzymes (Zymogen)

Answer 33

Inactive precursor of enzyme. Needs proteolytic breakdown to become active.