cellular respiration. i. general info a. definition: cellular respiration is the break down of food...
TRANSCRIPT
I. General InfoA. Definition: Cellular respiration is
the break down of food to get energy (ATP)
B. Enzymes control every step of this process
C. All living things respireD. Overall chemical equation:C6H12O6 + 6O2 —> 6CO2 + 6H2O + 36 ATP
II. Functions of ATPA. Chemical work –supplies energy needed
to make macromoleculesB. Transport work –supplies energy to
transport substances across the cell membrane.
C. Mechanical work –supplies energy to allow muscle contraction, separation of chromosomes etc.
III. Respiration Pathways
A. Food is broken down and energy is released in a three stage process1. Glycolysis
2. Kreb’s Cycle
3.Electron Transport Draw Fig. 9-2, pg. 222
Glucose(C6H1206)
+Oxygen
(02)
GlycolysisKrebsCycle
ElectronTransport
Chain
Carbon Dioxide
(CO2)+
Water(H2O)
Cellular Respiration
IV. GlycolysisA. Takes place in the cytoplasm of a cell.B. Does not require oxygen.C. Two ATP molecules are formed.D. Summary: Glucose (has 6 carbons) is
broken down into 2 pyruvic acid molecules (each has 3 carbons)
E. Chemical overview
Glucose
To the electron transport chain
2 Pyruvic acid 2 Pyruvic acid
DRAW FIG 9-3, pg. 223
What does anaerobic mean?A. When oxygen is not present, glycolosis is
followed by fermentation (2 types)1. Alcohol Fermentation
a) In yeast
CH3—CH2OH +
Pyruvic AcidEthanol
O2
b) ATP is produced and NADH is converted to
NAD+ allowing glycolysis to continue
V. Anaerobic Pathways
CO2 + NAD++ NADHCH3—C—COO
O
2. Lactic Acid Fermentation (feel the burn!)
a) Lactic acid is produced in muscles of birds and mammals when the body can’t supply enough O2 to tissues
b) Regenerates NAD+ so glycolysis can continue
c) Oxygen debt: the amount of O2 required to convert lactic acid back to pyruvic acid.
Glucose Pyruvic acid Lactic
acid
O2
Glycolysis Lactic Acid Fermentation
DRAW FIG. 9-4,pg. 225
VI. MitochondriaA. Double membrane
organelleB. Central cavity known
as matrix C. Inner membrane folds
known as cristae Draw Fig. 9-1, pg
221
VII. Krebs Cycle (Citric Acid Cycle)
A. Requires oxygen.B. Takes place in the mitochondrial matrix.C. 2 ATP molecules are generated.D. Pyruvic acid (made during glycolysis) is
broken down into CO2 in a series of energy-extracting reactions.
E. High-energy electrons are generated and accepted by electron carriers (NAD+ and FAD)
F. Requires an intermediate step before the cycle can begin…
G. Intermediate Step
1. One C atom from a pyruvic acid molecule becomes part of CO2
2. The other two C atoms combine with CoEnzyme A to form Acetyl-CoEnzymeA
3. Then Acetyl-CoEnzyme A enters the Kreb cycle by combining with a 4-carbon compound to form a 6-carbon compound (citric acid)
Draw Kreb’s Cycle
Pg. 227
Why is it called a cycle?
What happens to the high energy electrons carried on FADH2 and NADH?
VIII. Electron Transport Chain
A. High energy electrons from the Kreb’s cycle are transported by NADH and FADH2 to the Electron Transport Chain.
B. On the cristae of the mitochondria, electrons are transferred from one carrier protein to another creating energy.
C. This process produces 32 ATP.D. At the end of the chain an enzyme
combines these “used up” electrons with H+ ions and oxygen to form water.
Electron Transport Chain (Fig 9-7, pg. 228)Electron Transport
Hydrogen Ion Movement
ATP Production
ATP synthase
Channel
Inner Membrane
Matrix
Intermembrane Space