Download Chemistry Review

Cell Processes – Day 1
Homeostasis
= ability or tendency to maintain internal balance
AKA balance = equilibrium
Why important?
- Without this balance cells will die
Cell Membrane
- AKA
1) Fluid Mosaic Model
2) Plasma Membrane
3) Phospholipid Bilayer
- Composed of a lipid bi-layer w/ embedded proteins
- Functions:
1) Regulates what enters & exits cells
2) Provides protection & support
- Cell Membrane is selectively permeable
Types of Membranes
1)
2)
3)
Permeable = anything can cross
Impermeable = nothing can cross
Selectively Permeable = some things can cross but not
others
Definitions
Solution = mixture of 2 or more substances
Concentration = amount of substance you are dissolving in a
solution
Equilibrium = concentration on both sides of a membrane is equal
Diffusion
= movement of particles form area of higher concentration to area
of lower concentration
- Does NOT require energy
Facilitated Diffusion = moving larger particles with help from
proteins in membrane
Cell Processes – Day 2
Osmosis
= diffusion of water
3 Types Osmosis
1) Hypertonic = greater solution outside cell than inside
2)
Hypotonic = lower concentration inside cell than inside
3)
Isotonic = concentration outside cell equals inside cell
Osmotic Pressure
= pressure exerted on a cell membrane due to different
concentrations on the inside and outside of cell
Cell Processes – Day 3
Active Transport
= movement of molecules from low concentration to high
concentration (against concentration gradient)
- REQUIRES energy
Endocytosis
= cells take in materials they need
2 Types of Endosytosis:
1)
Phagocytosis = cells eat materials they need
2)
Pinocytosis = cells drink fluids they need
Exocytosis
= cells get rid of materials by passing them through the cell
membrane
Feedback Mechanism
= system responds positively in the same direction or negatively
in the opposite direction
Positive Feedback
= feedback results in growth of signal
- Example: If you eat a McDouble at McDonalds, a hormone is
released to your brain to signal satiation. You will feel the same
“happiness” each time you eat the hamburger.
Negative Feedback
= feedback in which system responds in opposite direction
- Example: If your blood sugar levels at continuously high it may
result in diabetes.