Upload
stephanie-petrucci
View
58
Download
0
Tags:
Embed Size (px)
Citation preview
POP QUIZ
• 1. The process of cellular respiration begins with _______________.
• 2. ____________ and _____________ are the reactants for cellular Respiration.
• 3. Glycolysis breaks down ______________ molecules.
• 4. How many ATP molecules are needed to start Glycolysis
• 5. How many ATP molecules are made by the end of glycolysis?
• 6. T or F: Animals cannot photosynthesize.
• 7. T or F: Plants undergo Cellular Respiration.
• 8. What is the energy needed to raise 1 g of water by 1 degree Celsius?
• When no oxygen (anaerobic) is present, this pathway follows glycolysis.
Living things get the energy they need from food. Both plants and animal cells carry out the final stages of cellular respiration in the mitochondria
Chemical Energy and Food• How much energy is actually present in food?
• One gram of the sugar glucose (C6H12O6), when burned in the presence of oxygen, releases 3811 calories of heat energy.
Cellular Respiration Begins….
• There are three stages of cellular respiration
• Glycolysis
• The Krebs Cycle
• The Electron Transport Chain
Glycolysis
ATP Production Add 2 molecules of ATP to start process
Investment: 2 ATPsFinal balance: 4 ATPsNet gain: 2 ATPs
GYLCOLYSIS RECAP
glucose oxidized yields pyruvic acid
reactions take place in cytosol
NAD+ to NADH (electron acceptor)
Pyruvic acid yields 4 ATP but 2 used in process (so net yield is 2 ATP)
Fermentation• When oxygen is NOT present, glycolysis is followed by a different
pathway: Fermentation.
Fermentation•fermentation is the formation of alcohol from sugar.
•Occurs in cytosol when “NO Oxygen” is present (called anaerobic).
•Remember: glycolysis is part of fermentation.
•Two Types:
1. Lactic Acid (animal cells)
2. Alcohol (plant cells)
Lactic acid fermentation
•NADH oxidized to NAD+
e.g. Yogurt, cheese
•*in muscle – not enough oxygen so switch
to anaerobic respiration b/c oxygen is
depleted which makes cytosol acidic so
produces cramps
Lactic Acid Fermentation
Animals (pain in muscle after a workout).
2 Lacticacid
2NADH 2 NAD+
CCC
Glucose
GlycolysisCCC
2 Pyruvicacid
2ATP2ADP+ 2
2NADH
P
2 NAD+
CCCCCC
Lactic Acid Fermentation
End Products: Lactic acid fermentation
2 - ATP (phosphorylation)
2 - Lactic Acids
Alcoholic Fermentation
•convert pyruvic to ethyl alcohol by
removing CO2
e.g. bread, beer, wine - need enzymes in
yeast
Alcohol Fermentation
Plants and Fungi beer and wine
glucose
Glycolysis
CCCCCC
CCC
2 Pyruvicacid
2ATP2ADP+ 2
2NADH
P
2 NAD+
CC
2 Ethanol2CO2
released
2NADH 2 NAD+
•glycolysis is not efficient but unicellular
organisms don’t need much energy to function
•E.g. paramecium, ameoba
•probably evolved early in history of life