CELLULAR RESPIRATION
Chapter 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)
Glycolysis
http://instruct1.cit.cornell.edu/courses/biomi290/ASM/glycolysis.dcr
Pyruvic Acid Conversion
Why twice?
Kreb Cycle
http://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
ATP
Glycolysis
Glucose
2 pyruvic
acids
2 ATP
2 CO2
2 Acetyl CoA
0 ATP
4 CO2
2 ATP
Pyruvic acid
conversion
2 Pyruvic
acids
Kreb Cycle 2 Acetyl
CoA (1 per
cycle)
ETC
O2
FADH2
NADH
(1 made per
cycle)
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 Fermentation
How many
ATP?
2
Lactic Acid Fermentation
How 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
RECAP
C6H12O6 + 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