Cellular Respiration
Unit
Overview of Respiration
aerobic = requires oxygen to occur
(ex: cellular respiration)
vs.
anaerobic = does not require oxygen
to occur
(ex: glycolysis and fermentation)
Overview of Respiration (cont)
Organic Compounds
Glycolysis
Oxygen Present
Cellular Respiration
(aerobic)
Oxygen Absent
Fermentation
(anaerobic)
Glycolysis
- takes place in the cytoplasm of
cells
- always occurring and does not
require oxygen
- occurs before cellular
respiration or fermentation
Glycolysis (cont)
- 2 ATP are used to start
process
- breaks down glucose into a
net of 2 ATP, 2 pyruvate, and 2
NADH
- Why is there a net of 2 ATP?
Glycolysis (cont)
- Why is there a net of 2 ATP?
Glycolysis (cont)
- products (pyruvate and NADH) enter either
cellular respiration or fermentation
- Efficiency = 3.5 % (only 2 ATP are made)
Overview of Cellular Respiration
= releases chemical energy
from sugars and other organic
compounds to make ATP when
oxygen is present
Overview of Cellular Respiration (cont)
- occurs in the mitochondria of
cells
Overview of Cellular Respiration
1) Mitochondria
2) Pyruvate (from
glycolysis)
3) Krebs Cycle
takes place in
matrix of mitochondria
4) ATP and CO2
5) Movement to Stage 2
6) Energy from Krebs
Cycle & O2
7) ATP and H20
Overview of Respiration
Organic Compounds
Glycolysis
Oxygen Present
Cellular Respiration
(aerobic)
Oxygen Absent
Fermentation
(anaerobic)
Cellular Respiration – 2 Stages
* occurs in the mitochondria
1) Krebs Cycle
= produces molecules that carry
energy to the second stage of
cellular respiration
Cellular Respiration – 2 Stages (cont)
- pyruvate from glycolysis is
broken down
- some ATP and other energy
forms are made
- carbon dioxide is given off as a
waste product
Krebs Cycle
Cellular Respiration – 2 Stages (cont)
2) Electron Transport Chain
- made of proteins
- uses energy from Krebs cycle
and oxygen to make ATP
- water and heat are given off as
waste products
Electron Transport Chain
Cellular Respiration – 2 Stages (cont)
Efficiency of Cellular Respiration
= 66% (38 ATP are made)
Equation for Cellular Respiration
Reactants
Products
C6H12O6 + 6O2  6 CO2 + 6 H2O
(sugar = (oxygen)
(carbon (water)
glucose)
dioxide)
Fermentation
- starts with glycolysis
- does not make ATP
(but allows glycolysis to continue)
Overview of Respiration
Organic Compounds
Glycolysis
Oxygen Present
Cellular Respiration
(aerobic)
Oxygen Absent
Fermentation
(anaerobic)
Fermentation (cont)
Types
1) Lactic Acid Fermentation
- occurs in your muscle cells
- produces lactic acid, results in
muscle fatigue and cramps
- produces NAD+ that goes back
to glycolysis
Lactic Acid Fermentation
Fermentation (cont)
2) Alcoholic Fermentation
- produces alcohol (ethyl) and
carbon dioxide
- produces NAD+ that goes back
to glycolysis
Alcoholic Fermentation
Importance of Fermentation
- produces food products we use
(bread, cheese, yogurt)
- allows glycolysis to continue
- microorganisms in digestive
tract break down food (allows
more nutrients to be absorbed)