BIOL 112 Lecture Notes - Nuclear Pore, Endocytosis, Symporter
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• requires energy (directly or indirectly)
• moving against the concentration gradient
Primary Active Transport
Sodium Potassium Pump
• in animals only
• pumps out 3 Na ions and 2 K ions
• uses energy from 1 ATP
used for osmolarity - net movement of one ion.
not needed for plants due to cell wall.
also used to generate membrane potential.
- creating concentration gradient to set up transport of other molecules
Secondary Active Transport
Use established gradients to move substances
Indirect use of ATP.
The Endomembrane System
Why are Cells so small ?
• reactions require diffusion in a cell
• diffusing molecules don't travel long distances due to their "random walk"
Cells are divided into two categories:
Prokaryotes (Bacteria & Archea)
No nucleus & hardly any membrane enclosed organelle
• inhabit environmental extremes
• largest metabolic diversity (digest pretty much anything)