Download Cellular_Respiration2011

The Wonderful World of
Biology presents:
Cellular Respiration
What is Cellular Respiration?
The process of converting food
(chemical) energy into ATP energy
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + 36 ATP
Why are both Photosynthesis and Cell
Respiration important to Ecosystems?
Light is the ultimate
source of energy for
all ecosystems
Chemicals cycle and
Energy flows
Photosynthesis and
cellular respiration
are complementary
reactions
Why do plants need both
chloroplasts and mitochondria?
Chloroplasts use
energy from the
sun to make
glucose
Mitochondria
convert glucose
to ATP—the
energy currency
of the cell
What is ATP?
Adenosine triphosphate
– 5-Carbon sugar (Ribose)
– Nitrogenous base
(Adenine)
– 3 Phosphate groups
Energy currency of the
cell
The chemical bonds that
link the phosphate groups
together are high energy
bonds
When a phosphate group
is removed to form ADP
and P, small packets of
energy are released
How is ATP used?
As ATP is broken down, it
gives off usable energy to
power chemical work and
gives off some nonusable
energy as heat.
Synthesizing molecules for
growth and reproduction
Transport work – active
transport, endocytosis, and
exocytosis
Mechanical work – muscle
contraction, cilia and flagella
movement, organelle
movement
Why use ATP energy and not
energy from glucose?
Breaking down glucose yields too much energy
for cellular reactions and most of the energy
would be wasted as heat.
1 Glucose = 686 kcal
1 ATP = 7.3 kcal
1 Glucose → 36 ATP
How efficient are cells at converting glucose into
ATP?
– 38% of the energy from glucose yields ATP,
therefore 62% wasted as heat.
Cellular Respiration is a Redox Reaction
(Oxidation)
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O
(Reduction)
Oxidation is the loss of electrons or H+
Reduction is the gain of electrons or H+
Glucose is oxidized when electrons and H+ are
passed to coenzymes NAD+ and FAD before reducing
or passing them to oxygen.
Glucose is oxidized by a series of smaller steps so
that smaller packets of energy are released to make
ATP, rather than one large explosion of energy.
Cell Respiration can be divided into 4 Parts:
1)
2)
3)
4)
Glycolysis
Oxidation of Pyruvate / Transition Reaction
The Krebs Cycle
The Electron Transport Chain and
Chemiosmotic Phosphorylation
Where do the 4 parts of Cellular
Respiration take place?
Glycolysis:
– Cytoplasm
Oxidation of
Pyruvate:
– Matrix (mitochondria)
The Krebs Cycled:
– Matrix (mitochondria)
Electron Transport
Chain and
Cheimiosmotic
Phosphorylation:
– Cristae (folds of
mitochondria)
Parts of the Mitochondria
2 “types” of respiration:
Anaerobic respiration=fermentation
– Simple & yields energy quickly
– No O2 required
– Occurs in cytoplasm
– Net production of 2 ATP/molecule glucose
Anaerobic fermentation
Alcoholic
fermentation
– Bacteria & yeast
– Produces ethanol
and carbon
dioxide
Lactic acid
fermentation
– In animals
– Produces lactic
acid
Aerobic Respiration
Begins the same as anaerobic
– Glycolysis in the cytoplasm
– O2 not required for this stage
Added steps—require Oxygen
– Moves to the mitochondria
Kreb’s Cycle
Electron Transport Chain
– Net production of 36 ATP
Anaerobic Respiration (no oxygen required, cytoplasm)
1. Glycolysis
(substrate level)
Glucose
2 ATP

4 ATP (Net 2 ATP)
2 NADH
2 Pyruvate
Aerobic Respiration (oxygen required, mitochondria)
2. Oxidation
of
Pyruvate
2 Pyruvate

2 CO2
2 NADH
2 Acetyl CoA
3. Krebs Cycle
(substrate level)
2 Acetyl CoA

4 CO2
2 ATP
6 NADH
2 FADH2
4. Electron
Transport
Chain
(chemiosmotic)
10 NADH
2 FADH2
6 O2

32 ATP
6 H 2O
Total: 36 ATP produced
All Types of Molecules can be used
to form ATP by Cell Respiration:
Proteins, Carbohydrates,
and Lipids must first be
broken down into their
monomers and absorbed
in the small intestine.
Monomers may be
further broken down into
intermediate molecules
before entering different
parts of Cell respiration
to ultimately form ATP.