Download Cellular Respiration

Cellular Respiration
• Cellular Respiration: Process by which
mitochondria break down food molecules to
produce ATP in plants and animals
Nutrients + oxygen  water + ATP + CO2
• Changes the chemical energy in glucose into
the chemical energy in ATP
Cellular Respiration
• There are three stages of Cellular
Respiration
– Glycolysis
• Anaerobic – does not require oxygen
– Citric Acid Cycle
• Aerobic – does require oxygen
– Electron Transport Chain
• Aerobic – does require oxygen
Glycolysis
• Glycolysis: Breaks down glucose into two
molecules of pyruvic acid
• This reaction uses enzymes and takes
place in the cytoplasm of the cell
ATP
ATP
ATP
Enzymes + 2 ATP
Glucose
Pyruvate
Pyruvate
ATP
Glucose breaks down into 2 pyruvate and 4 ATPs (Net gain of 2 ATP)
Glycolysis
Glycolysis Animation
• Produces
– 2 pyruvic acid molecules (used in the
next step of Cellular Respiration)
– 2 ATP molecules (energy the cell can
use)
ATP
ATP
ATP
Enzymes + 2 ATP
Glucose
Pyruvate
Pyruvate
ATP
Glucose breaks down into 2 pyruvate and 4 ATPs (Net gain of 2 ATP)
Into the Mitochondria…
• Before the next step of Cellular
Respiration can occur, the pyruvic acid
molecules must go into the
mitochondria.
• The two aerobic reactions are the Citric
Acid Cycle (or Krebs Cycle) and the
electron transport chain (or ETC).
Pyruvic acid  CO2 + water + ATP
THE KREB’S CYCLE
ATP
Pyruvate
Pyruvate
Citric Acid
Cycle
(Kreb Cycle)
e
e- e
- NADH
+
FADH
CO2
Electron Transport Chain
ETC Animation
• Electron Transport Chain uses the electron carriers
(NADH and FADH2) to pass electrons down the
protein chain and slowly release energy that is used
to form ATP and water molecules
Cellular Respiration
2 ATP
Glucose
Pyruvic
Acid
NADH
and FADH
Oxygen
Glycolysis
Citric Acid Cycle
Pyruvic
Acid
CO2
NADH
and FADH
Water
Electron Transport Chain
ATPs
ATPs
Cellular Respiration Equation
Cellular Respiration Video
C6H12O6 + 6O2
Glucose made in
photosynthesis
by plants or
consumed by
animals
Used in
Glycolysis
Oxygen from the
atmosphere
Used in Electron
Transport Chain
6CO2 + 6H2O + energy
Carbon
Dioxide –
waste
product of
the Citric
Acid Cycle
Water –
released
from
Electron
Transport
Chain
ATP released from
Glycolysis, Citric
Acid Cycle, and
Electron Transport
Chain
Between 34-36 ATP can be made with this process.
This ATP can be used by the cells for cellular metabolism.
Fermentation
• When oxygen is not available (anaerobic
respiration) fermentation can follow glycolysis
in order to continue to produce energy.
• This is not as efficient as aerobic respiration
and produces far fewer ATPs
Fermentation
• Two types of fermentation:
–Lactic acid Fermentation
–Alcoholic Fermentation
Lactic acid Fermentation
• Lactic acid fermentation occurs in muscle cells
during strenuous exercise when a lot of
energy is required and oxygen is scarce
(oxygen debt).
Glucose  pyruvic acid  lactic acid + ATP
Lactic acid Fermentation
• The lactic acid is transferred from the
muscle cells to the liver where it will be
converted back to pyruvic acid.
• The build up of lactic acid in the
muscles is what causes them to
be fatigued and sore.
Alcoholic Fermentation
• Yeast and some bacteria cells are capable of
alcoholic fermentation during which glucose is
broken down to release CO2 and ethyl alcohol
Glucose  pyruvic acid  alcohol + CO2 + ATP
Alcoholic Fermentation
• The bubbles formed by the CO2 make
bread rise
• The alcohol released
turns grape juice into wine
Photosynthesis vs. Cellular Respiration
Photosynthesis
Stores Energy as glucose
Cellular Respiration


Releases Energy in glucose
Occurs in Living Cells
Uses an Electron Transport
Chain
Occurs in Plant Cells






Occurs in Animal Cells
Releases Oxygen


Releases Carbon Dioxide
Creates Energy

Neither!