Photosynthesis

1
Photosynthesis

• light reactions (thylakoid)
• 6CO2 12 H2O C6H12O6 6O2 6H2O
• dark reactions (stroma)
• photoenergy is required (endergonic)

2
Leaf Disk Assay exerciseRole of light and CO2 in
photosynthesis

• place 10 leaf disks in syringe with 8cc H2O
• place 10 leaf disks in a second syringe with 8cc
  NaHCO3
• remove O2 from leaf disks, disks sink
• place disks in light for photosynthesis to occur
  (CO2 H2O C6H12O6 O2 H2O)
• if CO2 present, O2 will form
• record number of disks rising to top every 2
  minutes for 20 minutes, graph

3
Light Absorption exercise Spectroscope

• view white light w/ spectroscope
• record colors seen
• view red, blue, and green filters w/ spectroscope
• record colors seen
• view spinach extract w/ spectroscope
• record colors seen

4
Light Absorption exercise Spectrophotometry

• tube 1 extract
• tube 2 (blank) solvent
• record T from 400-700 nm
  in 25nm increments, graph
• 100 T must be reset whenever ? is changed

5
Chromatography

• solvent line
  carotenoids
• carotenes orange
• xanthophylls yellow
• chlorophylls
• chlorophyll a blue-green
• chlorophyll b yellow-green
• baseline

6
Chromatography, Rf values

• Rf pigment distance
• solvent distance
• affinity for the solvent high Rf value
• affinity for the paper low Rf value
• everyone must turn in a labeled chromatogram with
  Rf values next week

7
Products of Photosynthesiseffect of light on
photosynthesis

• Boiling the geranium leaf will removes the
  pigments, it will turn white
• flood leaf w/ iodine
• iodine starch blue-black
• before boiling after staining

8
Chloroplast Model

• outer membrane
• inner membrane (cristae)
• intermembrane space
• stroma (dark reactions)
• thylakoid (light reactions), granum, grana

9
Blackmans Experiment

• inc light intensity inc rate of photosyn
• inc temp (0-30) inc rate of photosyn
• above 40 C, no further increase
• count bubbles rising to the top of funnel
• record temp of solution
• record distance from light source
• (25cm, 50cm, 75cm)

10
CO2 Consumption in Plantsnot in lab manual

• plant twig phenol red water in test tube
• blow CO2 into test tube H2O H2CO3
• record color of solution, estimate pH of solution
  
• place under light, photosynthesis
• CO2 H2O C6H12O6 O2 H2O
• removes CO2 from H2CO3 H2O
• record color of solution,estimate pH of solution
• observe O2 formation on leaf surface