CELLULAR RESPIRATIONChapter 7

ORGANELLE OF FOCUS

OVERALL EQUATION

C6H12O6 + 6O2 6CO2 + 6H2O + energy(ATP)

Glucose + Oxygen Carbon Dioxide + Water + ATP

Adenosine triphosphate

VOCABULARY• Autotrophs • Organisms that are able to produce their own chemical

energy (food), ex. plants

• Heterotrophs– Organisms that obtain their chemical energy from other sources,

by eating ex. animals

• Cellular Respiration – Breaking down organic molecules to produce energy

• Aerobic Respiration – Oxygen present for pathway of breaking down food

• Anaerobic Respiration – No Oxygen present - causes an alternative pathway

Focus on Aerobic Pathway for Cellular Respiration

• STEPS– 1. Glycolysis – splits the glucose in half (6C to 3C),

occurs in cytoplasm of cell

– 2. Pyruvic acid conversion – loss of CO2 produces a product ready for the next step, occurs in mitochondria

– 3. Kreb Cycle – breaks down the remaining carbons from what’s left of the glucose molecule, produces high energy products NADH and FADH2, , occurs in matrix of mitochondria

Steps continued

-4. Electron Transport Chain – a series of proteins along the inner membrane of mitochondria that pass e-

* OXYGEN is the final acceptor of electrons

* H+ build up powers ATP synthase (sound familiar)

Glycolysishttp://instruct1.cit.cornell.edu/courses/biomi290/ASM/glycolysis.dcr

Pyruvic Acid Conversion

Why twice?

Kreb Cyclehttp://www2.nl.edu/jste/aerobic_respiration.htm

Where does CO2 go?

Where do NADH and FADH2 go?

Electron Transport Chain (ETC)http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter9/animations.html#

Summary Chart

Step Input Output ATPGlycolysis Glucose 2 pyruvic

acids2 ATP

Pyruvic acid conversion

2 Pyruvic acids

2 CO2

2 Acetyl CoA0 ATP

Kreb Cycle 2 Acetyl CoA (1 per cycle)

4 CO2 2 ATP (1 made per cycle)

ETC O2

FADH2NADH

H2O 34 ATP

WHAT HAPPENS IF NO OXYGEN IS PRESENT??

Can’t do Electron Transport Chain so…no use doing Kreb cycle. Why not?

- NADH and FADH2 have nowhere to go if ETC not running.

ANAEROBIC PATHWAYS

• Alcohol Fermentation – organism produce alcohol from pyruvic acid ex. Yeast cells

• Lactic Acid Fermentation – muscle cells not receiving enough oxygen so they produce lactic acid from pyruvic acid

Alcohol FermentationHow many ATP?

2

Lactic Acid FermentationHow many ATP?

2

Pros and Cons of Lactic Acid Fermentation

• Pros – your muscle will keep working even without sufficient oxygen

• Cons – you feel it, lactic acid causes sore muscles and cramping

• Your body will get rid of lactic acid – it diffuses into blood and goes to liver where it is converted back to pyruvic acid – ready for O2

LIVER

RECAPC6H12O6 + 6O2 6CO2 + 6H2O + energy (ATP)

• GLUCOSE becomes…• CO2

• Oxygen is needed…• to accept the electrons at the end of ETC

• CO2 goes…• into blood, lungs, exhaled

• Water is produced when…• O2 collects enough e- and H+ to become water

• ATP is produced…• in glycolysis, Kreb Cycle and mainly in ETC due to

chemiosmosis

• Pyruvic acid is made …• at the end of glycolysis (3C)

• NADH and FADH2 carry …• Electrons and H+ to the ETC

• Protons (H+) build up in the …due to…• Intermembrane space, ETC pushing them out

• ATP synthase allows H+ to … and …• Back into the matrix, produces ATPs

• If no oxygen, yeast produce…• ethanol

• If no oxygen, muscle cells produce…• Lactic acid

• The ETC produces...• 34 ATPs

• In aerobic respiration, Pyruvic acid is converted to…

• Acetyl CoA

• The molecule that must be recycled in the Kreb cycle is…

• Oxaloacetic acid

• The break down of one glucose gives…• 38 total ATP

• Autotrophs…• Make their own food/chemical energy

• Heterotrophs…• Must eat other things to obtain chemical energy

• Aerobic respiration requires…• Oxygen

EAT AND BREATHE: IT’ GOOD FOR YOU!

The other half of the story=PHOTOSYNTHESIS