Download ppt - Cellular Respiration. I. What is Cellular Respiration? Cellular Respiration is the series of reactions by which organisms obtain energy by breaking

Cellular Respiration

I. What is Cellular Respiration?

Cellular Respiration is the series of reactions by which organisms obtain energy by breaking down organic molecules into ATP energy. Cellular Respiration occurs in three main phases: Glycolysis, which is an anaerobic process (meaning it does not require O2), Kreb’s Cycle, which is an aerobic process (meaning it does require O2), and Electron Transport, which is an aerobic process (meaning it does require O2).

I. What is Cellular Respiration?

C6H12O6 + 6O2 6CO2 + 6H2O + ATP

Glucose Oxygen Carbon Water Energy

Dioxide

II. Cellular Respiration Occurs in the Mitochondria

II. Cellular Respiration Occurs in the Mitochondria

A. Mitochondria are small compartments located inside plant and animal cells. 1) Outer Membrane – composed of a phospholipids

bilayer; protects the mitochondria and controls what comes in and out

2) Cristae – the inner membrane is composed of a series of folds to increase the surface area inside the mitochondria

3) Matrix – the fluid component of the organelle; contains enzymes responsible for the citric acid cycles as well as other recyclable molecules that will be used in the process of Cellular Respiration

III. Phase One: Glycolysis

III. Phase One: Glycolysis

A. Glycolysis is the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid, a 3-carbon compound. 1) 4 ATP Produced – 2 ATP Used = Net Gain

of 2 ATP 2) occurs in the cytoplasm of the cell 3) does NOT require O2 (anaerobic) 4) also produces two molecules of NADH

(energy)

IV. Phase Two: Kreb’s Cycle

IV. Phase Two: Kreb’s Cycle

A. During the Krebs cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions. 1) (1 ATP Produced per each turn of the cycle x 2

turns through the cycle) – 2 ATP used converting Pyruvic Acid to Acetyl-CoA = Net Gain of 0 ATP

2) occurs in the center cavity of the mitochondria 3) requires O2 (aerobic) 4) 2 ATP are used converting the Pyruvic Acid from

Glycolysis into a substance called Acetyl-CoA 5) enzymes break down the two smaller molecules

produced during Glycolysis in CO2

V. Phase Three: Electron Transport


A. The Electron Transport Chain uses the high-energy electrons from the Kreb’s Cycle to convert ADP to ATP. 1) Net Gain of 34 ATP 2) occurs in the cristae of the mitochondria 3) requires O2 (aerobic) 4) energy from hydrogen atoms produced

during the first two stages of Cellular Respiration is transferred to ATP


a) the hydrogen atoms carried by NADH are separated into their component parts electrons (e-) and protons (H+)


b) the electrons are passed to the chain of electron (e-) carrier molecules


c) as the electrons (e-) move from one carrier to the next, they release energy


d) some of this energy pumps the protons (H+) across the inner membrane of the mitochondria and they accumulate in the outer compartment


e) the concentration gradient produced results in diffusion of the protons (H+) back into the inner compartment


f) the protons pass through an enzyme complex located in the membrane which makes ATP from ADP and Phosphate


g) the transferred electrons combine with protons (H+) and molecular oxygen (O2) to form water (H2O)