Chapter 3- Cellular level of Organization pt.2 Flashcards
Plasma membrane is SELECTIVELY PERMEABLE meaning
it allows some materials to move freely, and restricts other materials
Active transport
requires energy & ATP
Passive transport
no energy required
Diffusion (Passive)
-can be simple/channel-mediated
Always follows concentration gradient, moves “down” concent. from high to low concentration gradient which allows movement
Carrier-mediated transport (passive/active)
-of ions and organic substances
movement of molecules across cell membrane via special transport proteins that are embedded
Vesicular transport (active)
movement within a vesicle
5 factors that influence rate of diffusion in cells
- Distance particle has to move
- effective across short distances - Molecule size
- smaller is faster - Temperature
- more heat, faster motion - Concentration Gradient
- larger gradient, faster diffusion - Electrical Forces
- opposites attract, likes forces repel
Intracellular
Potassium
Extracellular
Sodium & Calcium, Chloride
Why is there a bigger concentration of amino acids inside the cell than outside?
Because amino acids are the building blocks of all cells
Simple Diffusion
Materials diffuse directly through plasma membrane w/o use of protein channel.
EX: triglycerides, lipids, steroids, testosterone, estrogen, cholesterol
Lipid soluble molecules pass into a cell by what method?
Simple diffusion
Channel-mediated diffusion
A concentration gradient drives movement of solute through a transmembrane channel protein
EX: Leak channels for Na, K, or Cl
Channel-mediated diffusion (polar & ionic molecules)
A concentration gradient drives movement of solute through a transmembrane channel protein
EX: Leak channels for Na, K, or Cl
Osmolarity
measure of solute concentration