Powerpoint 6A – Enzymes and energy

1. Enzymesa. Proteins that act as biological catalysts. They bind substrate and convert into product.b. Increase rate of reactionc. No changed itself at end of reactiond. Does not change reaction, just accelerates ite. Activation energy – amount of energy needed for reaction to occurf. Active site of enzyme is continually reshaped by interactions with the substrate as it interacts with

enzyme.g. Effect of temperature and pH on enzyme pH and temperature are important for enzymatic

reactioni. Increasing temperature increases rate of non-enzyme-catalyzed reactions, not enzyme

catalyzed reactions

2. Cofactors and Coenzymes both are helpful to enzymesa. Cofactors

i. Some enzymes cannot function without their cofactors. They also help accelerate enzymatic reaction.

ii. Can be inorganic metal ions1. Ex: Ca+, Mg+

b. Coenzymesi. Organic molecules derived from water soluble vitamins

1. Ex: niacin, riboflavin, folic acid3. Oxidation and reduction

a. Oxidation – loss of electrons (OIL)b. Reduction – gain of electrons (RIG)

Powerpoint 6b – Cell respiration and metabolism (part 1)

4. Metabolism – all the reactions in the body that involved energy transformation a. All chemical reactions that occur in living cells

5. Catabolism – reactions that release energy by breakdown of larger organic molecules into smaller ones. a. Examples of cells that undergo catabolism

i. Glucoseii. Fatty acids

iii. Amino acids

6. Anabolism – require input of energy and include synthesis (building up) of large energy-storage molecules.a. Examples of energy storing molecules

i. Glycogenii. Fat

iii. Protein

7. Aerobic cell respirationa. The last molecules used in production of ATP is oxygen. Requires oxygen in order to generate

energy (ATP). b. The last molecule the cell uses for production of ATP is oxygen molecule which is called cell

respiration.c. ATP production appears in mitochondria which consumes the product of glucose. Target cell uses

glucose and breaks it down to produce ATP. d. Process for aerobic cell respiration

i. Glucose (C6H12O6) travels from blood vessel to target cell. Glucose breaks down into two pyruvic acid molecules (C3H4O3). NAD is a coenzyme in cytoplasm gains 4 hydrogens. 2 hydrogens are lost to cytoplasm while the other 2 hydrogens reduce 2 NAD coenzymes forming 2 NADH+ coenzymes.

ii. If there is sufficient oxygen to cell, pyruvic acid is able to enter into mitochondria to participate in Krebs’s cycle in mitochondria. Krebs’s cycle in mitochondria produces ATP (don’t need to know Krebs’s cycle). NAD undergoes reduction to become NADH+ (gains electrons).

iii. Formula for Glycolysis1. Glucose + 2NAD + 2ADP + 2Pi 2 P.A. + 2 NADH+ + 2 ATP

e. Glycolysisi. Glucose is broken down into 2 pyruvic acid for production of ATP. ii. The reaction that converts 1 glucose (1 C6H12O6) to 2 molecules of pyruvic acid (2 C3H4O3).

iii. Glycolysis is exergonic, and a portion of the energy released is used to power the endergonic reaction ADP + Pi ATP

8. Anaerobic Cell respirationa. When there is not sufficient oxygen in target cell, pyruvic acid cannot enter into mitochondria for

production of ATP. Pyruvic acid stays in cytoplasm and is converted into lactic acid by getting reduced by NADH+. All this is called anaerobic cell respiration. Glucose (C6H12O6) conversion into pyruvic acid (C3H4O3) which is converted to lactic acid (C3H6O3).

1. Pyruvic acid gains hydrogens (and electrons) to form lactic acid. Pyruvic acid is reduced by NADH+.

b. Hypoxemia – deficiency of oxygen in cell. Use lactic acidi. Lactic acid level increases in…

1. Myocardial infarction2. When you go to gym. After working out, your muscle feels pain because in the short

time of exercising, your muscle cannot acquire the oxygen it needs and so it produces lactic acid due to deficiency of oxygen. This is aerobic cell respiration.

c. Ischemiai. Inadequate blood flow to an organ, resulting in insufficient oxygen delivery to maintain

aerobic respiration.

1. Ischemia can occur in heart if coronary blood flow is obstructed by atherosclerosis, a blood clot, or an artery spasm. Lactic acid builds up in chest and left arm area since not enough oxygen from blood and this causes severe pain in chest (angina) and left arm.

9. Glycogenesisa. Conversion of glucose into glycogen in liver. b. Process

i. Liver obtains glucose then converts it into glucose-6-phosphate. ii. Glucose-6-phosphate is converted to glucose-1-phosphate.

iii. The enzyme glycogen synthase converts glucose-1-phosphate into glycogen.c. Liver should control the glucose when high. Liver absorbs extra glucose for your body and converts

it into glycogen. Glucose is large molecules and liver stores glycogen in cells. This process is called glycogenesis which is formation of glycogen from glucose.

10. Glycogenolysisa. When your muscles require more glucose, liver breaks down glycogen and converts into glucose.

This is called glycogenolysis.b. Process

i. Conversion of glycogen into glucose-1-phosphate.ii. Glucose-1-phosphate is converted into glucose-6-phosphate.

iii. Glucose-6-phosphate is converted back into glucose. That glucose is released into blood and blood carries glucose to different cells such as…

1. CNS2. Muscle

c. This occurs in…i. Liver

1. Liver can make fresh glucose from different products gluconeogenesis

ii. Skeletal muscles

11. Gluconeogenesis a. Formation of glucose from different products by liver. b. Liver can produce new glucose from different products such as…

i. Glycerol ii. Fatty acids

iii. Lactic acid

iv. Amino acids

12. Fermentation – in these cells, they don’t need oxygen. Without oxygen, we have fermentation. Mechanism is anaerobic cell respiration.

13. We said that lactic acid level increases in ischemia – means lack of oxygen supply to tissue. This can happen in myocardium which leads to myocardial infarction. Check lactic acid levels as doctor.

14. Cori Cyclea. Process

i. Muscle releases lactic acid when you work out and that lactic acid gets into blood and then to liver.

ii. Liver uptakes it then converts it into pyruvic acid then pyruvic acid is converted into glucose.iii. Then glucose gets carried by bloodstream back to muscle. This is good source of energy for

muscle. b. This is a cycle because muscle produces lactic acid and liver uptakes and lactic acid, converts to

glucose and carries it back to muscle.

15. Krebs’s Cyclea. You don’t need to remember entire Krebs’s cycle. b. Exists in mitochondriac. Pyruvic acid participates in Krebs cycled. Goal (cell respiration)

i. Releasing of waterii. Consuming of oxygen

iii. Releasing of CO2. Bloodstream carries that CO2 to lung for gas exchangee. Has two important coenzymes

i. NAD

ii. FAD

Powerpoint 6C – Cell Respiration and Metabolism (Part 2)

16. Mitochondriaa. Structure

i. Has different parts1. Outer membrane2. Inner membrane

a. Cristaeii. Two compartments

1. The matrix inner2. Intermembrane space outer, between outer and inner membrane

b. Inner membrane of mitochondria has electron transport

17. Production of ATP by mitochondriai. 2 coenzymes, FAD and NAD are reduced by hydrogen ion and electron. They carry these to

matrix of mitochondria.ii. First, they release electrons and electrons pass through electron transport chain of

membrane. iii. Hydrogen loses its power as it passes through electron transport chain and then that

hydrogen moves from matrix to outer compartment of mitochondria through a proton pump. The outer membrane has high concentration of hydrogen ion. This leads to a really important process we call chemiosmosis which means concentration of hydrogen ion is high in outer compartment.

iv. Hydrogen ion diffuses (simple diffusion) from high to low concentration and moves from outer membrane through ATP synthase channel back into matrix. This gives us two important things…

1. Combination of ADP + Pi ATP2. It obtains oxygen molecules and releases water.

18. Lipolysis – breakdown of fata. When fat stored in adipose tissue is used as energy source, lipase enzymes hydrolyze triglycerides

into glycerol and free fatty acids.b. These molecules can be used as energy for liver, skeletal muscles, and other organs for aerobic

respiration.