Transcript Cellular Respiration Notes - Mrs. DeNicola's Science Corner

Cellular Respiration!
What do living things do with food?
• Produce materials that bodies need to grow
• Materials can be converted to energy
C6H12O6 + 6O2
Enzymes
6CO2 + 6H2O + energy
things
release
energy
from
Cellular respiration!
• Begins with
glycolysis
food??
• break down glucose  pyruvic acid
• small amount energy released (ATP)
Overview
No oxygen
Fermentation
Lactic Acid
Alcoholic
Glycolysis (in cytoplasm)
• Glucose (6C) split into:
– 2 pyruvic acid (3C)
– Result: 2 ATP & 2
NADH
• **4ATP formed, 2
used → net gain =
2ATP
Who uses
glycolysis?
• ALL organisms!!!
• Glycolysis does NOT require oxygen
→ small amts of energy formed
without O2
• As form ATP, available NAD+
decreases  decreases ATP synthesis
of glycolysis
Fermentation!
•
NADH converted to NAD+
•
Anaerobic respiration - does not require O2
Two Types
1. Lactic Acid
2. Alcoholic
What do these
items have to
do with
fermentation?
1. Lactic acid fermentation
• Pyruvic acid converted to lactic acid
• Lactic acid forming microorganisms used in
making foods (Ex: yogurt, cheese, sour cream)
• Lactic acid build up in muscles causes cramps
1. Alcoholic fermentation
• Pyruvic acid converted to CO2 and ethyl alcohol
• Basis for wine and beer industry; bread
Efficiency of anaerobic respiration
• Glycolysis produces how many ATP molecules?
TWO
• This is ~2% energy in glucose
Can any
organisms
Aerobic Respiration
No oxygen
Fermentation
Lactic Acid
Alcoholic
Aerobic respiration
•
Energy in pyruvic acid released using oxygen
•
Produces 20x more ATP than glycolysis!
2 major stages
1. Krebs cycle
2. Electron transport chain
Where does respiration occur?
Prokaryotes
• Respiration occurs in cytosol
Anaerobic or aerobic?
Eukaryotes
• Kreb cycle and ETC occur in
mitochondria
A little about the mitochondria…
1. Pyruvic acid diffuses
across membrane,
enters matrix
• Matrix – contains
enzymes used in Krebs
cycle
2. Pyruvic acid reacts
with Coenzyme A to
form acetyl CoA
(produces 2 NADH)
Pyruvic Acid (C-C-C)
Coenzyme A
Acetyl CoA (C-C)
Part I. The Krebs Cycle
Overview: energy molecules & waste products formed
as Acetyl CoA broken down
• Acetyl CoA forms citric acid
• CO2 molecules are released
• **NADH, FADH2, ATP formed
Energy Tally
• Glycolysis –
2 ATP
2 NADH
• Conversion to – 2 NADH
Acetyl CoA
• Krebs cycle –
2 ATP
6 NADH
2 FADH2
12 energy molecules to next stage
Part II. Electron Transport Chain
• Embedded in inner membrane of mitochondria
• Water released as waste byproduct
• High energy electrons converted to ATP
• Each NADH forms 3 ATP
FADH2 forms 2 ATP
Energy Conversion
**The Rules: NADH = 3 ATP
FADH2 = 2 ATP
 Glycolysis
–
2 NADH
_____ ATP
 Conversion
to – 2 NADH
_____ ATP
Acetyl CoA
 Krebs
 ETC
cycle - 6 NADH
2 FADH2
____ ATP?
____ ATP
____ ATP