Download Cellular Respiration

Cellular Respiration
Honors Biology
2012
Comprehension Check
What types of organisms need energy?
What types of organisms can make
their own energy?
Cellular Respiration:
 DEFINITION: Complex process in which cells
break down organic compounds to make
ATP (ADP +  ATP)
 We feel hungry because food provides us
energy, the biochemical pathway that allows us
to get energy from our food is cellular
respiration.
Equation for Cellular Respiration:
602 + C6H1206  6CO2 +6H2O +Energy
 FACT: A working muscle cell converts ADP to
ATP at a rate of 10 million molecules per
second.
Main Reactions in Cellular Respiration
(depending on presence of O2)
Overview of Glycolysis
Glycolysis: Biochemical pathway which begins both types of cellular
respiration.
 Occurs in cytosol of cell
 Breaks down one glucose into two 3-carbon molecules of
pyruvic acid (pyruvate)
** Note: 2 ATP’s were used in step 1, but 4 ATP’s were made in
step 4. This is called a NET GAIN of 2 ATP
Glycolysis Animation
ANAEROBIC RESPIRATION
1.
2.
Glycolysis
Fermentation: absence of oxygen, some organisms can
convert pyruvic acid into another 3-carbon compound,
but NO ADDITIONAL ATP ARE FORMED
Energy released from anaerobic respiration:





2 ATP molecules released by glycolysis
0 ATP result because of fermentation
TOTAL ENERGY GAIN = 2 ATP
This is only 3.5% of all the energy stored in a single glucose
molecule
Much of energy originally contained in glucose is still held in
the bonds that make up pyruvic acid
Alcoholic Fermentation
 Process where yeast and bacteria convert
pyruvic acid into ethyl alcohol and CO2
 No ATP are gained (regenerates NAD+ for
glycolysis)
 Basis of the wine, beer, and baking industries
Lactic Acid Fermentation
Enzyme reactions convert pyruvic acid into
another 3-carbon compound, lactic acid
– No ATP are gained
– LAF occurs in your muscle cells
– Once oxygen is available, the body converts lactic
acid back to pyruvic acid in our liver
AEROBIC RESPIRATION
Stage 1: GLYCOLYSIS
Stage 2: KREBS CYCLE / CITRIC
ACID CYCLE
Stage 3: Electron Transport Chain
 Requires oxygen to be present
 Produces 20 times more ATP than
Glycolysis alone!
 Prokaryotes can do it, but it occurs
in the cytosol
 Eukaryotes have mitochondria
(matrix and cristae) for this specific
purpose
AEROBIC RESPIRATION
Krebs Cycle/Citric Acid Cycle
-Pyruvic acid produced by glycolysis enters
mitochondrion
-Krebs Cycle occurs in mitochondrial matrix
-2 pyruvic acid  2 acetyl CoA  Citric Acid
-The cycle begins and ends with citric acid
-Krebs Cycle produces NADH, FADH2, and
ATP
Steps to the Krebs Cycle
1. Acetyl CoA combines with Oxaloacetic
Acid to form 6-carbon Citric Acid
2. Citric Acid releases CO2 and H to form a
5-carbon compound
3. 5-carbon compound releases another CO2
and H to form a 4-carbon compound
4. 4-carbon compound releases H to
regenerate oxaloacetic Acid
5. Krebs Cycle runs 2x (1x for each acetyl
CoA)
6. There is a net gain of 2 ATP
http://people.unt.edu/~hds0006/tca/index.htm
Citric Acid
Oxaloacetic
Acid
Electron Transport Chain
 Electrons pass through molecules in cristae towards a
lower energy level to final electron acceptor, oxygen
 NADH and FADH2 supply protons (H+) which make ATP
through chemiosmosis
 In matrix, H+ combines with oxygen to form water and
use the extra H+ floating around
 34 ATP are gained
Aerobic Respiration Energy Yield
 38 ATP from a single glucose molecule
 2 ATP in glycolysis (made 4, but used 2)
 2 ATP in Krebs cycle
 34 ATP in ETC
 This total varies from cell to cell, and is usually
only 36 ATP per glucose molecule
 Plant and animal cells spend 2 ATP in moving
products though membranes and only net 36 ATP
per 1 molecule of glucose
 66% efficient at releasing the energy in the
molecule
 20X more efficient than anaerobic respiration
Energy and Exercise
ATP comes from:
Cellular Respiration
(long term)
Lactic Acid Fermentation
(short term)
Muscle storage
(short term)
Why are you “out of breath” after strenuous exercise?
Comprehension Check
Anaerobic Respiration
STAGES
1. ___________
2. ___________
Aerobic Respiration
STAGES
1. _____________
2. _____________
3. _____________
# of ATP Gained
_____
_____
TOTAL: _____
# of ATP Gained
_____
_____
_____
TOTAL: _____
SUMMARY
Anaerobic Respiration
STAGES
1. GLYCOLYSIS
2. FERMENTATION
# of ATP Gained
2
0
TOTAL: 2
Aerobic Respiration
STAGES
# of ATP Gained
1. GLYCOLYSIS
2
2. KREBS CYCLE
2
3. ELECTRON TRANSPORT CHAIN 34
TOTAL: 38
Review Animations
Overall Review:
http://www.qcc.cuny.edu/BiologicalScienc
es/Faculty/DMeyer/respiration.html
Glycolysis:
http://instruct1.cit.cornell.edu/Courses/bi
omi290/MOVIES/GLYCOLYSIS.HTML
Overview of Photosynthesis and Cellular
Respiration
http://highered.mcgrawhill.com/sites/dl/free/0078617022/164155
/00053412.html