Lesson 7 - Cell Membrane Part 1 (1-23)

Question 1

What is the cell membrane and function

Answer 1

Protects, Physical Barrier - Phospholipid bilayer

Is a gateway for exchange, through protein channels

Communication

And cell structure

Question 2

Parts of a cell membrane

Answer 2

Carb trees which attach to different things

Gycloprotein connects to proteins (intergral or stem)

Glycoprotein connects to the phospholipid molecules

Cholesterol molecule, fats, yellow internal drops

Question 3

Phospholipids

Answer 3

Choline (polar) head and fatty acid tail (non polar)

Head is water soluble and tails are hydrophobic and creates barrier

Both want to be near its own kind

Question 4

Glycocalyx

Answer 4

Glycoproteins and glycolipids on surface of cell

cell identity- cell fingerprint for things entering/attacking. makes it reconizable

cell orientation- villi, organized based on other cells

Question 5

Membrane proteins

Answer 5

Integral proteins-important for cell transport with its own gate (open/closed). Helps things through water soluble channels

Peripheral proteins-important for communication

Question 6

Functions of membrane proteins

Answer 6

1. Ion channels-moves sodium/potassium in/out.
2. Carriers - move bigger molecules like amino acids and glucose
3. Receptor sites-places for binding
4. Enzymes- catalyst that helps with chemical reactions making them faster/possible
5. Pores-move water, like channels
6. Structural- strength
7. Cell adhesion- cell junctions, linkers that hold things together

Question 7

Membrane permeability

Answer 7

Selectively permeable

Permeable to small uncharged non polar molecules. these can move freely through

Transmembrane proteins move polar particles, these are channels/carries

Macromolecules use vesicles (proteins, big fats and carbs)

Question 8

Passive vs active diffusion

Answer 8

Passive - moves along gradient, no energy/ATP

Simple diffusion- high to low concentration

Facilitated diffusion -helped

Osmosis - movement of water

Question 9

Diffusion

Answer 9

Two-way movement

Considered net movement

Question 10

Simple diffusion

Answer 10

High to low concentration, due to random particle collisions, small molecules and steroids. spreads out until equilibrium

Rate of diffusion depends on

-temp
- concentration gradient
-diffusion distance
-mass of diffusion substance

Question 11

Membrane gradients

Answer 11

Gradient=different

Concentration gradient
-difference in substance across membrane

against concentration gradient= low to high concentration

Electrical gradient-charges of ions, wanting to be neutral, moving to opposite charge

Electrochemical gradient
-combination of both

Question 12

Diffusion across membrane

Answer 12

Permeability-more permeable the faster

Surface area-more gates the faster (stadium)

Gradient- more the faster

Temp- higher the faster

Question 13

Osmosis

Answer 13

Uses water to dilute when solute can’t move (diffusion vs osmosis)

Net diffusion of water against its own concentration gradient

Question 14

Toncity

Answer 14

Tonicity =#of the non diffusible particles

Hypertonic = too much solute
Iso=equilibruim
Hypotonic=too much water (too few particles)

Water move from HYPOTONIC TO HYPERTONIC

Hypertonic = cell shrink (crenate)
Hypotonic= swell/repture (hemolysis)