BIOL 371 Lecture Notes - Lecture 6: Photosynthesis, Turgor Pressure, Vacuole
Biol 371 Notes
Lecture 6
Diversity of Opisthokonts and Archaeplastidae
• Groups of organisms that acquired features of eukaryotic cells
• Progenitor eukaryotes required mitochondria
o Multicellularity evolved independently in plants and animals
• Only plants were the ones who acquired plastids
o Another endosymbiotic event where they acquired chloroplasts
• Opisthokonts and Archaeplastida diverge
o Cell structures differ
o In plants we see
▪ Cell wall
• Important for water transport
• Especially bulk transport
• Prevents diseases
• Prevents plants from engulfing things
▪ Large vacuole
• Mostly filled with water
• Also contains salts, organic molecules etc
• Allows plats to pressurize vacuole
o Turgor pressure
▪ Contributes the structural rigidity by maintaining
turgor pressure against the cell walls
▪ Chloroplast
• Enable plant cells to photosynthesize
o Harness energy of sunlight to synthesize sugars
• Some have lost their chloroplasts over evolutionary time
o Use other mechanisms to harness energy
o Still considered as a typical feature of a plant cell
• Photoautotrophic vs chemoheterotrophic
o Photoautotrophic
▪ Use energy from the light to fix inorganic carbon in the atmosphere
which is carbon dioxide into carbohydrates (organic carbon)
▪ 130 terawatts across the earth being harnessed to fix carbon
▪ 120 billion metric tonnes of organic carbon every year are produced as a
result
▪ Chemoheterotrophic
• Use chemical energy of the bonds in food they eat
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