Cellular Respiration

The Equations… Photosynthesis: 6CO 2 + 6H 2 O + energy  C 6 H 12 O 6 + 6O 2 (sun) (sun) Cell Respiration: C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O + energy (ATP)

Cellular Respiration…What is it? -process by which cells produce ATP by breaking down organic compounds. Why is it important? -cells need “usable” forms of energy to function and maintain homeostasis. ATP is the usable form.

Overview of Cell Respiration…

Pathway 1: Glycolysis Function: anaerobic (no oxygen) process in which organic compounds (sugar) is converted to pyruvic acid, producing ATP and NADH. Location: cytosol Reactants:organic compounds (sugar) Products:pyruvic acid 2 ATP’s (energy) 2 NADH (energy)

Pathway 2 (if no oxygen is present): Fermentation Function: since no oxygen is present, fermentation allows cells to regenerate NAD + from the NADH produced in glycolysis. Many types of fermentation pathways, but two of the more common are: 1. Lactic Acid Fermentation 2. Alcoholic Fermentation Location: cytosol

Lactic Acid Fermentation Reactants:pyruvic acid NADH Product:lactic acid NAD + -Lactic Acid Fermentation is important in the manufacturing of various foods. (yogurt, cheese) -Athletes also experience Lactic Acid buildup…cramping and fatigue.

Alcoholic Fermentation Reactants:pyruvic acid NADH Product:alcohol NAD + -Process occurs in plants and yeast. -This process is important in making bread and alcohol products.

Pathway 2 (if oxygen is present): Aerobic Respiration Function: two major stages (Krebs cycle and the ETC) produce majority of the ATP for the cell from the pyruvic acid produced in glycolysis. Location: eukaryotes- mitochondrial matrix (Krebs) & the inner mitochondrial membrane (ETC) prokaryotes- cytoplasm & cell membrane prokaryotes- cytoplasm & cell membrane

Krebs Cycle (Citric Acid Cycle) Reactants:pyruvic acid converted to Acetyl CoA NADH Products:CO 2 ATP (2 molecules) NADH, FADH 2

Electron Transport Chain & Chemiosmosis (uses enzyme, ATP synthase) Reactants: NADH, FADH 2 Products:ATP water

Final Analysis: Net production of ATP through aerobic respiration…38 ATP (2 from glycolysis 2 from Kreb’s and 34 from ETC/Chemiosmosis) Aerobic Respiration is much more efficient in producing ATP! Why…oxygen is present.