CELLULAR RESPIRATION
CELLULAR RESPIRATION
• The process that converts the energy from glucose
(food) into ATP
• Occurs in the mitochondria of eukaryotic cells
(animals AND plants)
• Happens in three stages
• Glycolysis
• Citric acid cycle
• Electron transport chain
NET EQUATION
C6H12O6 + 6O2  6 CO2 + 6 H2O + ATP
Glucose
oxygen
carbon
dioxide
water
energy
molecule
• This is the NET equation because it doesn’t happen all at once
• There are three stages of cellular respiration, with many “in between”
molecules at work
1ST STAGE: GLYCOLYSIS
•
•
•
•
Glucose is broken down into smaller molecules
2 ATP are produced in the process
Occurs in the cytoplasm of the cell
Anaerobic- does NOT require oxygen
ADP + P
ADP + P
1 Glucose
ATP
2ND STAGE: THE CITRIC ACID CYCLE
• Carbon compounds left after glycolysis go through a series of
reactions
• CO2 is produced as a byproduct
• FADH2 and NADH are produced to carry H+ to the next stage
• 2 ATP are produced
• Occurs in the mitochondria of cells
• Aerobic- requires oxygen
3RD STAGE: ELECTRON TRANSPORT CHAIN
• FADH2 and NADH produced in the citric acid cycle
provide hydrogen (H+) ions and electrons to power the
“chain” and pump H+ ions (AKA: protons) across the
membrane to build up a high concentration
• Ions (H+) that have been building up now flow across
the inner membrane
• This flow of H+ ions across the membrane powers an
enzyme called ATP synthase, which performs
dehydration synthesis reactions to make ATP from ADP
and phosphate
STAGES OF CELLULAR RESPIRATION
Stage
Description
Glycolysis
Glucose is broken
down
Citric Acid
Cycle
Carbon compounds
are converted to CO2
# of ATP per byproduct
Glucose
2
2
NADP and FADH are
made and carry H+
ions to the next stage
Electron
Transport
Chain
Flow of ions is used to
power the production
of ATP
location
cytoplasm
CO2
FADH2
NADH
mitochondria
(electron
carriers)
32-34
H2O
mitochondria
ANAEROBIC RESPIRATION
• Anaerobic= NO oxygen
• Glycolysis does not require oxygen
• If there is no oxygen available, cells can’t move to the next
two stages (citric acid cycle/electron transport chain)
• Instead, the next step is FERMENTATION:
• Glucose is converted into ethanol and CO2 (like in yeast)
or
• Glucose is converted into lactic acid (like in humans)
• Creates less ATP than aerobic cellular respiration
CRASH COURSE VIDEO:
ATP AND RESPIRATION
• https://www.youtube.com/watch?v=00jbG_cfGuQ