Fundamentals of Biochemical Reactions Flashcards Preview

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Flashcards in Fundamentals of Biochemical Reactions Deck (33):
1

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

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

2

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

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

3

Acid-Base rxn

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

4

Redox rxn

Transfer of an electron from one molecule to another. OILRIG

5

pH of blood

7.37-7.43

6

Blood buffering System equation

H + HCO3- H2CO3 CO2 + H2O
Carbonic anhydrase is between Bicarbonate and CO2 and H2O

7

Acid-base balance and kidneys

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-.

8

Respiratory Acidosis

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.

9

Respiratory Alkalosis

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.

10

Enzymes lower...

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.

11

Oxidoreducatases and examples

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

12

Induced fit hypothesis

binding induces conformational changes in active site

13

Lock and key hypothesis

substrate is a perfect fit for active site

14

Cofactors

noncovalent interaction, stabilize active site, how they interact

15

coenzymes

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

16

Cu

Cytochrome oxidase

17

Fe

Heme proteins

18

Mg

ATPases

19

Zn

Superoxide dismutase

20

Se

Glutathione peroxidase

21

Lactate dehydrogenase active sites

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

22

Enzymes need optimal...

pH and temperature

23

Gastric Proton pump inhibitors

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.

24

Competitive inhibiton

Same Vmax and increased Km

25

noncompetitive inhibiton

Lower Vmax and same Km

26

Uncompetitive inhibition

Lower Vmax and Lower Km

27

Inhibition of Metalloenzymes

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

28

Chelating Agents of Lead poisoning

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.

29

Irreversible Enzyme activation

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

30

Allosteric Enzymes vs Enzyme kinematics

Sigmoidal curve vs hyperbolic

31

Isozymes

Same catalytic function but different primary sequence

32

Troponin in Myocardial infarction

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.

33

Proenzymes (Zymogen)

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