(Physiology)- Cell Membrane Structure and Composition(Lec.2)

Question 1

what makes up the cell membrane

Answer 1

LPC
lipids
proteins
carbohydrates

phospholipids

Question 2

glycocalyx

Answer 2

Glycoproteins and glycolipids on surface of
cell
Cell identity
Cell orientation

Question 3

Membrane proteins

Functions

Answer 3

Two types
Integral (transmembrane) proteins - transport proteins
Peripheral proteins- cell comm.

PAHECC
Be PUMPS for active transport.
Serve as ANCHORS for cell adhesion.
Act as HORMONE-BINDING sites.
Facilitate ENZYMATIC REACTIONS.
Act in cell to cell COMMUNICATION.
Be CHANNELS for passive transport.

Question 4

Selective Membrane permeability

Answer 4

Selective permeability of the cell membrane refers to its ability to differentiate between different types of molecules, only allowing some molecules through while blocking others.
-Diffusion
-Transport Proteins
-Endo, Exo

Question 5

Membrane gradients

Answer 5

Power movement without ATP
Concentration gradient
difference in substance concentration
across a membrane
Electrical gradient
difference in charge ( Conc. of ions)
Electrochemical gradient Combination of both

Question 6

Membrane transport

Simple diffusion

what does the rate of simple depend on

what does diffusion ACROSS the membrane depend on

Answer 6

SIMPLE DIFFUSION
Net diffusion from high to low concentration
Due to particle random collisions
Small molecules, Oxygen, carbon dioxide Steroids
they themselves are made of lipids

Simple diffusion is a two way movement

Rate of diffusion depends on :
Temperature
Concentration gradient
Diffusion distance
Mass of diffusion substance

Diffusion across a membrane
Depends on:
Permeability
Surface area
Gradient
Temp

Question 7

Diffusion vs osmosis

Answer 7

Diffusion is the movement of particles from a high to lower concentration. Osmosis is the diffusion of water across a membrane.

“Pulled” by non-
diffusible particles

make concentration the same on each side so water flows right to balance out the high number of sodium on the right

Question 8

In terms of solute concentration, what does hypertonicity mean? Hypotonicity?

when do cells shrink or grow

what is isotonicity

Answer 8

Hypertonicity: When there is an excess of solute(salt) outside of the cell. AKA less solvent
Hypotonicity: A Lack of solute outside the cell. AKA more solvent.

cells crenate in a HYPERTONIC SOLUTION

cells lysis in a HYPOTONIC SOLUTION

same concentration of solutes inside and outside of cell

Question 8

How does tonicity determine osmosis

Answer 8

Tonicity = # of non-diffusible particles
“Water magnets”

number or concentration of ions on the other side