da Graciela Aguilar mancano 7 anni
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Basal level
Increased RNA transcription
CAM plants
open their stomata at night
C4 plants
then exported to bundle-sheath cells
Incorporate CO2 in mesophyll cells
C3 plants
Close stomata conserving water
Photorespiration
O2 subs for CO2 in rubisco sites
One molecule of G3P exits per three CO2
Uses ATP and NADPH to reduce CO2 and sugar
Electron flow
Cyclic
only one PS is used, produces only ATP
Linear
Uses both PS's and produces, NADPH, ATP, AND O2
Photosytems
Both contain a reaction-center complex and a light harvesting complex
PS II
P680 molecules
PS I
P700 molecules
Photon
Pigment absorbs
Wavelengths
Visible light wavelengths drive photosynthesis
Photosynthesis is a redox
CO2 is reduced
H2O is oxidized
6CO2 + 12H2O + Light Energy --> C6H12O6 + 6O2 + 6H2O
Choloroplasts
Stroma
Uses NADPH for reducing power
Uses ATP for energy
CO2--> sugar
Calvin cycle
grana
Thylakoid
Produce ATP and form NADHP
release O2
split water
Where light reactions occur
autotrophic
Makes its own food
Fermentation
Lactic acid fermentation
pyruvate is reduced by NADH to form lactate
Alcohol fermentation
Pyruvate is converted to ethanol
Chemiosmosis
26 or 28 ATP produced
H+ concentration gradient on the outside of the inner membrane couples the redox reactions of the ETC
makes ATP from ADP and inorganic phosphate
ATP Synthase
Electron carriers
Cytochromes
FADH2
NAD+
Electron Transport Chain
Occurs in the inner mitochondrial membrane
Total: 2 e-, 2H+, 1/2 O2
The electrons travel from complex I and II to complex Q, then to Complex 3 followed by complex 4.
When a complex receives en electron, it is reduced, then oxidized when it is passed onto the next complex
Total yield
One glucose--> 6 NADH, 2FADH2, 2 ATP
Step 4
Another CO2 is lost, NAD+ becomes NADH. a-ketoglutrate becomes Succinyl CoA
Isocitrate is oxidized, reducing NAD+ to NADH and losing a CO2 molecule. Isocitrate becomes a-ketoglutarate
Acetyl CoA becomes citrate
Two reduced carbons enter the cycle with Acetyl CoA, and two oxidized carbons leave in the form of CO2
Acetyl CoA is formed via coenzyme A
Step 2
Remaining fragment is oxidized forming acetate and releasing electrons forming NADH.
Methionine first amino acid placed in protein
Pyruvate dehydrogenase complex removes the CO2 from the pyruvate.
Occurs in the mitochondrial matrix
Occurs in the cytosol
Net
Glucose --> 2 Pyruvate + 2 H2O 2 ATP, 2 NADH, + 2 H+
Energy Payoff Phase
4 ATP formed, 2 NADH, 2 H+, 2 pyruvate, 2 H2O
Energy Investment Phase
Step 5
Two three carbon sugars are left (Glyceraldehyde 3-phosphate and Dihydroxyacetone Phosphate)
G3P and DHAP which convert between each other
Step 3
Phosphofructokinase transfers a phosphate from ATP to opposite end of the sugar (this is the second ATP)
Step 1
Hexokinase transfers phosphate from ATP to Glucose
Glycolysis occurs whether or not O2 is present
Powered by redox reactions
Substrate-level phosphorylation
Phosphate for ADP comes from substrate rather that an inorganic phosphate
NADH reduced state
NAD+ oxidized state
RIG (oxidizing agent)
OIL (Reducing agent)
affects other binding sites
amplifies enzyme response
substrate binds to active sites
allosteric activation
Enzymes and substrates are compartmentalized within the cell
Allosteric Regulation
Inhibitors
Activators
stabilize subunits
Oscillating subunits
Not bound on active site
How they work
Non competitive inhibitors
Bind somewhere other than active site
Competitive inhibitors
Bind to active site
Cofactors
Non protein helpers
Optimal conditions
Temperature
pH
Induced fit via malleable equilibrium
Enzyme -substrate complex
Converts substrate to products
They lower Ea
Catalyst
Activation Energy
Transition state
Has enough energy to break bonds
Energy required to get to the "top of the hill"
Phosphorylation
Coupling occurs by endergonic and exergonic reactions fueling each other.
Phosphorylated intermediate: key to coupling
Work
Mechanical Work
Transport Work
Chemical Work
Thermodynamics
Large amount of energy transferred is lost as heat
Entropy and Enthalpy
2nd Law: Energy transfer increases entropy of Universe
1st Law: Principle of Conservation of Energy
Surrounding vs. system
Chemical Energy
Heat: transfer of thermal energy
Thermal Energy
Kinetic Energy
Metabolic Pathways
Anabolic Pathway
Catabolic Pathway
Images
Subtopic
ΔG
ΔG = ΔG final - ΔG initial
ΔG< 0 , spontaneous, exergonic
ΔG> 0, non-spontaneous, endergonic
ΔG = ΔH -TΔS
When temp. and pressure are uniform
Universe = System + Surroundings
Equilibrium
Equilibrium= Dead System
System never moves away from Equilibrium Spontaneously
Free energy decreases closer to equilibrium & Vice Versa.
Max stability = Equilibrium
ΔG = 0 , Equilibrium
Structural
Cellulose
Storage
Glycogen
Starch
Sucrose
Lactose
Glucose
Fructose
Testosterone (hormones)
Cholesterol
Unsaturated fats
Important Energy source (oils)
Saturated fats
Energy source (butter)
Phospholipid bilayer
