Biology 1002B Lecture Notes - Lecture 1: Zoospore, Volvox, Cell Membrane
Document Summary
Bio 1002b - lecture 1 - first class. Course will examine evolution on molecular level. Model system: has fundamental eukaryotic structure, small, grows rapidly, simple. Also use light for information: have ability to sense external environment and respond. Have eyespot in chloroplast, on plasma membrane. Evolutionarily, on the branch that leads to plants, but diverged much earlier. When nutrients are limited, zoospores act like gametes: sexual reproduction only occurs under stressful conditions. Related to other green algae that are multicellular: ex. Volvox is type of green algae that is multicellular: clamydomonas and volvox have very similar genomes. Photo-transduction of light in eyespot leads to movement in flagella. Every cell is polarized, outside is more positively charged. Channel rhodopsin on plasma membrane acts like pore: when channel absorbs light, pore opens up and ions (calcium and protons) can move across, therefore, plasma membrane of cell is depolarized. Depolarization produces action potential: runs from channel rhodopsin to flagella, causes flagella to move.
