Biochemical Pathways Photosynthesis and Cellular Respiration
AUTOTROPHS • make their own food. • Ex: Phototrophs….Use light energy • Ex: Chemotrophs…Use inorganiccompounds • HETEROTROPHS • Must eat org. mol. for energy (carbon source).
Form of energy Other forms: thermal, electrical, kinetic, sound, chemical Travels in waves (diff. wavelengths) Light
FM The Electromagnetic Spectrum
Photosynthesis (Psyn): • Process: Light energy converts to chemical energy (sugars) • Pigments used to capture light energy
Chlorophyll a • Chlorophyll a • C55H72O5N4Mg • Molecular wt. 893.5 • Blue-Green (Not on test)
Chlorophyll b • Chlorophyll b • C55H70O6N4Mg • Molecular wt. 907.5 • Yellow-Green (Not on test)
Anthocyanin • C15H11O+ • Blue, red, pp • fruit, flowers (Not on test)
ß Carotene • C40H56 • Mol. wt. 536.9 • Orange,Red (Not on test)
Xanthophyll • C40H56O2 • Mol. Wt. 568 • Yellow (Not on test)
Chromatography • Splitting pigmentsapart
Evergreen plants • psyn. year round. • Deciduous plants • affected by temp. and lightchanges; leaves change color - drop. • Factors affecting the rate of psyn. • Temperature • Water availability • Intensity of light • CO2 availability
Vocabulary • Chloroplast- plant cell organelle ; uses light energy to make chemical energy thru psyn., has chlorophyll • Chlorophyll- pigment: captures light energy • Stoma- opening under leaves; allows CO2 and O2 to diffuse in/out of leaf. (stomata, pl.) • Thylakoids- saclike body in chloroplast; made of photosynthetic membranes • Granum- stack of thylakoids (grana, pl.) • Stroma- fluid region outside thylakoid membranes in chloroplast. • NADP+- molecule that carries energy and hydrogen - becomes NADPH • ATP- chemical compound used to store energy
PHOTOSYNTHESIS Carbon dioxide and water are used to make sugar, with oxygen as a byproduct. Let’s draw this process… 6 CO2 + 6 H2O → C6H12O6 + 6 O2 light energy Balanced equation
Chloroplast • Psyn. occurs here • Inside: • Thylakoids = flattened membrane-bound sacks; has chlorophylls. • Grana- stacks of thylakoids. • Stroma= fluid matrix surrounding stacks.
Photosynthesis: two stages 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
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 outsidethylakoids • 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? • GLYCOLYSIS • Splits glucose into 2 pyruvic acids • Takes place in the cytosol • Doesn’t need oxygen (anaerobic) • Very fast process
What does that look like? C6H12O6 2 Pyruvic acids (3C ea.) 2ATP 2ADP CCCCCC CCCCCC 4 ADP 4ATP 2NADH 2NAD+
Cellular Respiration Step 1 • Glycolysis(in cytosol, anaerobic) • Requires 2 ATP to start the process • Net gain of 2 ATP and 2 NADH • 2 pyruvic acids made
Cellular Respiration Step 2, 3 (in mitochondrion of eukaryotes) • Kreb’s Cycle- • In matrix fluid- breaks pyruvic acids into acetyl CoA and CO2 (2 ATP formed) • Electron Transport chain- • In cristae membrane: ATP synthase converts ADP to ATP (32 ATP formed)
O2 CO2 H2O
Total ATP Yields • Glycolysis 2 ATP • Krebs Cycle 2 ATP • Electron Transport 32 ATP • Total ATP from one glucose = 36 molecules. • C6H12O6 + 6O26CO2 + 6H2O + 36ATP This is the balanced equation for resp.
How Energy Cycles • Photosynthesis and Cellular Respiration • form a continuous cycle : the products of one process are the reactants for the other. • Photosynthesis • 6CO2 + 6H2O light 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)?
If NO Oxygen present… • Fermentation occurs (in cytosol) • Sustains glycolysis • Keeps 2 ATPs forming from each glucose • Two types: • Alcoholic ferm. (in prokaryotes, some eukaryotes) • Some bacteria, yeast. Byproducts: Ethyl alcohol and CO2 • Lactic Acid ferm. (in YOU, and other eukaryotes) • Muscle tissueByproduct: Lactic acid
How fermentation sustains glycolysis • Keeps NADH cycle going