1. Chapter 5 Photosynthesis and Cellular Respiration

2. Section 5-1
Directly/indirectly, almost all energy in LTs needed for metabolism comes from the sun.

3. Building Molecules that Store Energy:
Section 5-1
Building Molecules that Store Energy:
Photosynthesis: process by which light energy is converted to chemical energy.
Autotrophs:
Organisms that use energy from sunlight or from chemical bonds in inorganic substances to make organic compounds; plants, bacteria

4. Cellular respiration:
Section 5-1
Heterotrophs:
Organisms that must get energy from food instead of from sunlight/inorganic substances
Cellular respiration:
Metabolic process in which consumed food energy is converted to ATP energy
Most fungi
Most bacteria
Most protozoa
All animals

5. Transfer of Energy to ATP:
Section 5-1
Transfer of Energy to ATP:
When cells break down food molecules, some energy is released as heat. Most remaining energy is stored in ATP
Like money, ATP is a portable form of energy “currency” in cells and is delivered wherever it is needed in the cell
ATP
ATP

6. ATP (adenosine triphosphate):
Section 5-1
ATP (adenosine triphosphate):
nucleotide w/ 2 extra energy-storing phosphate groups
Energy is released when bonds holding phosphate groups together are broken
Removal of phosphate group from ATP produces adenosine diphosphate, ADP

7. Stages of Photosynthesis: Stage 1 Energy captured from sunlight
Section 5-2
Stages of Photosynthesis:
Stage 1 Energy captured from sunlight
Stage 2 Light energy converted to ATP and energy carrier NADPH
Stage 3 Using CO2 and energy stored in ATP and NADPH powers the formation of organic compounds
6CO2 +6H2O C6H12O6 +6O2

8. Stage 1: Capture Light Energy/O2 released Pigments:
Section 5-2
Stage 1: Capture Light Energy/O2 released
Pigments:
Contain light-absorbing substances
Chlorophyll:
Main pigment involved in photosynthesis, absorbs mostly blue/red light, reflects green/yellow light
Plants contain 2 types of chlorophyll, chlorophyll a and b
more…

9. Section 5-2
Carotenoids:
Pigments that produce yellow/orange fall leaf colors, fruits, vegetables, flowers
Carotenoids absorb different wavelengths from chlorophyll, so having both pigments enables plants to absorb more light energy during photosynthesis
more…

10. Stage 1: Capture Light Energy/O2 released Thylakoids:
Section 5-2
Stage 1: Capture Light Energy/O2 released
Thylakoids:
Clusters of pigments embedded in mem of disk-shaped structures
Light strikes thylakoid, energy is transferred to e- in chlorophyll
Causes e- to jump to higher energy level
e- are replaced by splitting water and O2 is released

11. Stage 2: Convert Light Energy to ATP/NADPH
Section 5-2
Stage 2: Convert Light Energy to ATP/NADPH
Excited e- leave chlorophyll to make ATP/NADPH that temporarily store energy
1st excited e- jumps to nearby molecule in thylakoid membrane; e- is passed through series of molecules along thylakoid membrane, electron transport chain (ETC) and ATP/NADPH are made

12. Stage 3: Store Energy in Organic Compounds Carbon dioxide fixation:
Section 5-2
Stage 3: Store Energy in Organic Compounds
Carbon dioxide fixation:
C atoms from atmospheric CO2 are used to store chemical energy in organic compounds
Calvin cycle:
series of enzyme-assisted rxn produces organic compounds

13. Factors that Affect Photosynthesis:
Section 5-2
Factors that Affect Photosynthesis:
Photosynthesis ↑ as light intensity ↑ until all pigments are being used
Photosynthesis is most efficient w/in certain temperature range

14. Metabolic processes that need O2 Anaerobic:
Section 5-3
O2 makes production of ATP more efficient, although some ATP is made w/o O2
Aerobic:
Metabolic processes that need O2
Anaerobic:
Metabolic processes that don’t need O2

15. 2 Stages of Cellular Respiration: Stage 1:
Section 5-3
2 Stages of Cellular Respiration:
Stage 1:
Glucose converted to pyruvate, makes small amt of ATP/NADH
Stage 2:
O2 present, pyruvate/NADH used to make large amt of ATP via ETC
O2 not present, pyruvate converted to either lactate or ethanol/CO2

16. Stage 1: Breakdown of Glucose/Glycolysis Glycolysis:
Section 5-3
Stage 1: Breakdown of Glucose/Glycolysis
Glycolysis:
1st stage of cellular respiration, glucose is broken down in cytoplasm
As glucose is broken down, some of its H atoms are transferred to an e- acceptor called NAD+ to form an e- carrier NADH
Some ATP, NADH, 2 pyruvates result

17. Stage 2: Production of ATP
Section 5-3
Stage 2: Production of ATP
O2 is present, pyruvate enters mitochondria and is converted to 2-C compd
This rxn produces 1 CO2 molecule, 1 NADH molecule, and 1, 2-C acetyl group
Acetyl group is attached to coenzyme A (CoA), forming acetyl-CoA that enters the Krebs Cycle
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18. Stage 2: Production of ATP via Krebs Cycle
Section 5-3
Stage 2: Production of ATP via Krebs Cycle
Krebs cycle: series of rxns in the mitochondria where 6 NADH, 2 FADH2, and 2 ATP are made
more…

19. Stage 2: Production of ATP via ETC
Section 5-3
Stage 2: Production of ATP via ETC
In aerobic respiration, e- donated by NADH and FADH2 pass through ETC
In eukaryotic cells, ETC is located in inner membranes of mitochondria
At end of ETC, H+ ions and e- combine w/ O molecules forming H2O
34 ATP made
via ETC

20. Respiration w/o Oxygen is Fermentation
Section 5-3
Respiration w/o Oxygen is Fermentation
When O2 is present, aerobic respiration occurs to produce ATP
When O2 isn’t present, fermentation occurs producing lactic acid in animals or in plants alcohol/CO2