Download Photosynthesis and Respiration Notes

Photosynthesis
• Light energy is converted into chemical energy
– Make sugars
6 CO2 + 6 H2O
LIGHT
C6H1206 + 6 O2
Photosynthesis occurs in Chloroplast
Phase I: Light Dependent
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Light energy splits water
Electrons go through electron transport chain
Electrons used to make NADPH
Chemiosmosis gradient created
– H+ diffuses across ATP Synthase and creates ATP
Phase 2: Calvin Benson Cycle
• Light independent reactions
– Light is not necessary for reactions to occur
• Energy is converted and stored in organic
molecules
– Carbon dioxide and energy make Glucose
Uses of Sugars
What are the sugars created in photosynthesis
used for?
• Energy
– Stored energy and instant energy
• Building blocks for parts in the cell
– Glucose molecules are put together to form
polysaccharides
• Cellulose – structure for cell – structures for plants
Photosynthesis questions
1. Where does photosynthesis occur?
2. When is photosynthesis most likely to occur?
Why?
3. When is photosynthesis least likely to occur?
Why?
4. Where does the mass of a tree (or other plant)
come from?
Overview of Respiration
C6H1206 + 6O2
6CO2 + 6H2O + energy
• Organisms use stored energy in glucose
• 36 ATP per molecule of glucose is made
• 3 Parts: Glycolysis, Krebs Cycle, and Electron
transport
Mitochondria
Steps of Respiration
• Glycolysis - anaerobic
– Glucose is broken down into pyruvate
– 4 ATP produced, 2 used, Net 2 ATP
• Krebs Cycle - aerobic
– Pyruvate is broken down into citric acid
– Net Yield 6 CO2, 2 ATP, 8 NADH, 2 FADH2
• Electron Transport – aerobic
– NADH, FADH2, supply electrons/protons for chemiosmosis
– Net yield of electron transport: 32 ATP
Anaerobic Respiration
• No oxygen present:
• ATP can only be created through glycolysis
– Only 2 ATP produced
– Glycolysis stops when all NAD+ is used
• Fermentation – regenerates cell’s supply of
NAD+ and produces a small amount of ATP
2 Types of Fermentation
Lactic Acid fermentation
• Convert pyruvate to lactic acid
• Muscles produce lactic acid when not enough O2
• Produced by microorganisms
– Produce food such as yogurt, cheese, sour cream
Alcohol Fermentation
• Pyruvate is converted to ethyl alcohol and CO2
Photosynthesis
Phase 1: Light-Dependent Reactions
• Light energy breaks apart water
• Electron transport chain
– Produce ATP and NADPH
– Needed in light-independent reactions
Phase 2: Light-Independent Reactions
• Calvin Cycle
• Occur in light or dark conditions
• Change CO2 to glucose
*Alternative Cycles – environmental factors
Steps of Respirations
• Glycolysis
– Glucose is broken down into 2 pyruvate
– 4 ATP produced, 2 used, Net 2 ATP
• Krebs Cycle
– Pyruvate breaks down to release more energy
– Net Yield 6 CO2, *2 ATP*, 8 NADH, 2 FADH2
• Electron Transport
– NADH, FADH2, supply electrons/protons for chemiosmosis
– ATP Synthase creates ATP – 32 ATP created