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Biochemical Pathways
Photosynthesis and
Cellular Respiration
AUTOTROPHS
○make their own food.
○ Ex: Phototrophs….Use light energy○ Ex: Chemotrophs…Use inorganic compounds
HETEROTROPHS
○Must eat org. mol. for energy (carbon source).
LightLight Form ofForm of energy energy
Other forms: Other forms: ○ thermal, electrical, kinetic, sound, chemicalthermal, electrical, kinetic, sound, chemical
Travels in waves Travels in waves (diff. wavelengths) (diff. wavelengths)
Wavelength (λ)
FM
TheElectromagneticSpectrum
Photosynthesis (Psyn):
Process: Process:
Light energy Light energy converts to converts to chemical energy (sugars) chemical energy (sugars)
Pigments used to capture light energy
Pigments
Chlorophyll a
Chlorophyll aC55H72O5N4Mg
Molecular wt. 893.5
Blue-Green
(Not on test)
Chlorophyll b
Chlorophyll bC55H70O6N4Mg
Molecular wt. 907.5
Yellow-Green
(Not on test)
Anthocyanin C15H11O+
Blue, red, pppp fruit, flowers fruit, flowers
(Not on test)
ß Carotene
C40H56
Mol. wt. 536.9 OrangeOrange, RedRed
(Not on test)
Xanthophyll
C40H56O2
Mol. Wt. 568 Yellow
(Not on test)
Chromatography
Splitting pigmentsapart
Evergreen plantspsyn. year round.
Deciduous plants affected by temp. and light changes;
leaves change color - drop.
Factors affecting the rate of psyn.TemperatureWater availabilityIntensity of lightCO2 availability
Vocabulary ChloroplastChloroplast-- plant cell organelle ; uses light energy
to make chemical energy thru psyn., has chlorophyll ChlorophyllChlorophyll-- pigment: captures light energy Stoma- opening under leaves; allows CO2 and O2 to
diffuse in/out of leaf. (stomata, pl.) ThylakoidsThylakoids-- saclike body in chloroplast;
made of photosynthetic membranes GranumGranum-- stack of thylakoids (grana, pl.) StromaStroma- fluid region outside thylakoid membranes in
chloroplast. NADPNADP++- - molecule that carries energy and hydrogen -
becomes NADPH ATPATP- chemical compound used to store energy
A closer look at leaves:
See this web page
PHOTOSYNTHESISPHOTOSYNTHESIS
Let’s draw this process…
6 CO2 + 6 H2O → C6H12O6 + 6 O2
light energylight energy
Carbon dioxide and water are used to make sugar, with oxygen as a byproduct.
Balanced equation
ChloroplastChloroplast Psyn. occurs here Inside:
Thylakoids = flattened membrane-bound sacks; has chlorophyllschlorophylls.
Grana- stacks of thylakoids.
Stroma= fluid matrix surrounding stacks.
Photosynthesis: two Photosynthesis: two stagesstages
Light Dependent Reaction (LDR)
Light Independent Reaction (LIR) or Calvin Cycle(used to be “dark Rx”)
Both occur in chloroplast
Photosynthesis: Light Dependent Rx light energy captured by chlorophyll H2O split – photolysis
O2 released
only takes place in light occurs in thylakoids makes NADPH & some ATP
nicotinamide adenine dinucleotide phosphate-oxidase
(Not on test)
Light Rx Process (site) (Light
reaction animation)(Not on test)
ATP Production during Aerobic Respiration involving the ETC and Chemiosmosis (Not on test)
Chemiosmosis
Photosynthesis: Light Independent Rx (Calvin Cycle) No light needed occurs in stroma fluid outside thylakoids NADPH & ATP powers cycle. CO2 is carbon source to make glucose
RESPIRATION: all organisms Converts sugars to other power molecules Stages:
1. Glycolysis
THEN:
2a. Aerobic Resp. of Mitochondrion (in eukaryotes)
OR:
2b. Anaerobic Resp. (Fermentation) (in pro/eu)
How do cells get energy from glucose?
GLYCOLYSISGLYCOLYSIS Splits glucose into 2 Splits glucose into 2 pyruvic acidspyruvic acids Takes place in the cytosolcytosol Doesn’t need oxygen (anaerobic) Very fast process
GLYCOLYSISGLYCOLYSIS Splits glucose into 2 Splits glucose into 2 pyruvic acidspyruvic acids Takes place in the cytosolcytosol Doesn’t need oxygen (anaerobic) Very fast process
C6H12O6 2 Pyruvic acids (3C ea.)
C6H12O6 2 Pyruvic acids (3C ea.)
2ATP2ATP
4 ADP4 ADP
2NAD+2NAD+
4ATP4ATP
2NADH2NADH
2ADP2ADP
CCCCCC
CCCCCC
Cellular Respiration
Step 1
Glycolysis Glycolysis (in cytosol, anaerobic)(in cytosol, anaerobic) Requires 2 ATP to start the Requires 2 ATP to start the
process process Net gain of 2 ATP and 2 NADH 2 pyruvic acids made
Cellular RespirationCellular Respiration
Step 2, 3 (in mitochondrion of eukaryotes)Step 2, 3 (in mitochondrion of eukaryotes) Kreb’s Cycle-Kreb’s Cycle-
In matrix fluid- breaks pyruvic acids into acetyl CoA In matrix fluid- breaks pyruvic acids into acetyl CoA and COand CO22 ( (2 ATP 2 ATP formed)formed)
Electron Transport chain-Electron Transport chain- In cristae membrane: In cristae membrane:
ATP synthaseATP synthase converts ADP to ATP ( converts ADP to ATP (32 ATP 32 ATP formed)formed)
CO2
O2
H2O
Total ATP YieldsTotal ATP Yields
Glycolysis 2 ATPGlycolysis 2 ATP Krebs Cycle 2 ATPKrebs Cycle 2 ATP Electron Transport 32 ATPElectron Transport 32 ATP
Total ATP from one glucose = Total ATP from one glucose = 36 molecules36 molecules.. CC66HH1212OO66 + + 66OO22 66COCO22 + + 66HH22O + O + 36ATP36ATP
This is the balanced equation for resp.This is the balanced equation for resp.
Respiration
schematic
Photosynthesis and Cellular Respiration form a continuous cycle : the products of one process are the
reactants for the other.
Photosynthesis
6CO2 + 6H2O lightlight C6H12O6 + 6O2
Cellular Respiration
C6H12O6 + 602 6 CO2 + 6 H2O + energy (ATP)
What’s the actual difference between the two (besides the order in which things appear)?
How Energy Cycles
If NO Oxygen present… Fermentation occurs (in cytosol)
Sustains glycolysisKeeps 2 ATPs forming from each glucoseTwo types:
○ Alcoholic ferm. (in prokaryotes, some eukaryotes)Some bacteria, yeast.
Byproducts: Ethyl alcohol and CO2
○ Lactic Acid ferm. (in YOU, and other eukaryotes)Muscle tissue
Byproduct: Lactic acid
How fermentation sustains glycolysisKeeps NADH cycle going