cellular respiration

2. Cellular Respiration

3. Respiration: An Overview
• The process by which cells
break down food sources such
as glucose, fats, and protein
and release their stored
energy.
• Two main types
– Anaerobic – no oxygen required
– Aerobic – requiring oxygen
• Both forms produce energy
storage molecules called ATP
– adenosine triphosphate.

4. Anaerobic Processes
• No oxygen is
required for these
processes.
• Includes glycolysis,
the breakdown of
glucose, and
fermentation.
• Some bacteria and
yeast are examples
of anaerobes.

5. Glycolysis
• Occurs in the cytoplasm.
• Breaks down glucose into 2
molecules of pyruvate (3-
carbon structures)
• 2 ATP molecules are
formed.
• 2NADH energy shuttles are
also formed.
• This pyruvate is further
metabolized during
fermentation

6. Fermentation
• Pyruvate can be metabolized by:
– Alcoholic fermentation
– Lactic acid fermentation
• AF produces ethyl alcohol and CO2 –
yeast can ferment apple juice to fill a
balloon.
• LAF produces lactic acid. It can build up
in muscles during strenuous exercise
and cause burning and soreness.

7. Aerobic Processes
• Requires oxygen.
• Most organisms are aerobes.
• Equation for Aerobic respiration:
C6H12O6 + 6O2  6CO2 + 6H2O + Energy
• Based on this equation – Why do we breathe?

8. The Mitochondria
• If O2 is present following
glycolysis, pyruvate is modified
and enters the mitochondria.
• Here food is broken down
completely into CO2.
• Energy storage molecules like
NADH and ATP are produced.
This is why the mitochondria is
called the power house of the
cell.

9. The Role of Oxygen
• Energy carriers like
NADH drop off
electrons and as they
“fall” to oxygen during
metabolism energy is
stored in a payload of
ATP.
• Oxygen picks up
electrons and
hydrogen ions to form
water.
ATP
ATP
ATP
Energy
from
electrons
O2
H2O

10. ATP: Adenosine Triphosphate
• ATP is the cells energy
currency.
• Cellular work such as
metabolism, transport,
and movement is
powered by the
breakdown of ATP.
ATP Structure
– Ribose – a 5-carbon sugar
– Adenine – a N-base
– 3 phosphate groups

11. ATP / ADP Cycle
• ATP is constantly being used and remade in the cell.
• Energy is released or stored by breaking or making a
phosphate bond.
http://www.columbia.edu/cu/biology/courses/c2005/purves6/figure06-09.jpg

12. Summary of Cellular Respiration
Respiration
Process
Where Process
Occurs
Net Gain of ATP
Per Glucose
Anaerobic
Glycolysis &
Fermentation
Cytoplasm 2 ATP
Aerobic Krebs
Cycle and
Electron
Transport
Mitochondrion 36 ATP

13. JAZAK ALLAH O
KHIRA