CELLULAR RESPIRATIO

N OVERVIEW

CELLULAR RESPIRATION FORMULAS

Word Equation:

Glucose + Oxygen → Energy + Carbon Dioxide + Water

Symbol Equation:

C6H12O6 + 6O2 → Energy (ATP) + 6CO2 + 6H2O

CELLULAR RESPIRATION Step-wise release of energy from food

Allows for efficient energy use Removal and transfer of electrons from

simple food molecules to carriers to release energy for ATP synthesis

REDOX REACTIONS Involve the transfer of electrons from

one reactant to anotherOxidation = loss of electrons from a

substanceReduction = addition of electrons to a

substance (reducing the positive charge)Electron donor = reducing agentElectron accepter = oxidizing agent

A QUICK OVERVIEW OF THE MAIN STAGES

1. Glycolysis In cytosol Glucose is split into pyruvate Creates ATP and NADH

2. Krebs Cycle / Citric Acid cycleIn mitochondrial matrixPyruvate is broken downCreates ATP, NADH, and FADH2

Releases CO2

3. Oxidative Phosphorylation (Electron Transport Chain)In inner mitochondrial membrane NADH and FADH2 release hydrogen

(results: NAD+ and FAD)Creates lots of ATPReleases H₂O

SUMMARY

PHOSPHORYLATION OF ATP Substrate level- when an enzyme transfers a

phosphate from a substrate (organic molecule) to ADP

Oxidative phosphorylation – powered by electron transport chain and results in an inorganic phosphate is added to ADP to make ATP

GLYCOLYSIS

THE SPLITTING OF GLUCOSE Energy is harvested by oxidizing glucose to

pyruvate

Requires an initial input of energy to get energy out

GLYCOLYSIS I (ENERGY IN)

Glucose enters the cell and gains a phosphate from ATP

Glucose is rearranged by enzymes and gains another phosphate from ATP molecule (6 carbon sugar biphosphate)

Enzymes split 6 carbon sugar biphosphate into two 3-carbon sugar phosphates

GLYCOLYSIS II (ENERGY OUT) 3-carbon sugar phosphates gain 2 phosphates and

during the reaction energy is give off to cause 2 NAD+ 2NADH

One phosphate from each 3 carbon sugar biphosphate is given to 2 ADP 2 ATP

Phosphate groups get re-arranged release 2 H2O Phosphate from 3 carbon sugars given to 2ADP 2ATP Results in 2 molecules of pyruvate Net release of 2NADH and 2ATP

AEROBIC RESPIRATIONAerobic = O₂ present

If O₂ present pyruvate goes to mitochondria for Krebs cycle

Net ATP production = 36

ANAEROBIC RESPIRATIONAnaerobic = no O₂ present

Prokaryotes that live in oxygen free environmentsElectron transport chain present- oxygen is not

final electron acceptor

FERMENTATIONNo Oxygen or electron transport chain present

(can be used by prokaryotes and eukaryotes)Glycolysis products are fermented for energyLactic Acid Fermentation

Pyruvate takes energy from NADH (goes back to NAD+) and is converted to lactate (a 3 carbon acid)

Net ATP production = 2