1.2 Cell membrane

what is cell theory

all living cells are composed of cells, the cell is the basic structural and functional unit of life, all cells come from division of pre-existing cells

what is the fluid mosaic model

it describes cell membrane as a dynamic and flexible double layer of phospholipids

what is the function of the plasma membrane

acts as a selective barrier that separates and protects cell contents from the outer environment

what is the plasma membrane composed of?

phospholipid bilayer (outer and inner)

the fatty acids tails in the plasma membrane is __?

hydrophobic

the phosphate polar head in the plasma membrane is __?

hydrophilic

properties of the peripheral membrane protein

attached to membrane surface (entirely outside or inside) by H-bonds, non-covalent, hydrophilic

function of the peripheral membrane protein

Form fibrillar network and acts as skeleton to function as anchor and mechanical support

properties of the integral membrane protein

they penetrate bilayer with hydrophilic and hydrophobic regions

what is the transmembrane membrane protein?

they are integral proteins that pass through membrane to connect interior and exterior of cell

what is Rhodopsin

a  light-sensitive, seven-transmembrane membrane found in rod photoreceptor cells of retina

what is transport membrane protein

proteins that transport materials across membranes

what is channel membrane protein

proteins that allow substances to move through. Voltage/mechanically/ligand-gated

what is carrier membrane protein

proteins that pass molecules across the membrane by changing shape

what is glycoprotein?

protein with carbs attached

passive transport goes from WHAT concentration to WHAT concentration

high concentration to low concentration

does passive transport go up or down the concentration gradient?

down the concentration gradient

is energy required for passive transport?

no

what are two types of passive transport?

simple and facilitated diffusion

is simple diffusion carrier-independent or dependent?

carrier-independent

what molecules go through via simple diffusion

lipid-soluble (non-polar) substances and water

is facilitated diffusion carrier-independent or dependent?

carrier dependent

is simple or facilitated diffusion faster?

facilitated diffusion

active transport goes from WHAT concentration to WHAT concentration

low concentration to high concentration

what type of transport system required energy?

active transport

what is primary active transport?

process where ATP is directly used to move substances against the concentration gradient

what is secondary active transport?

process where energy from a different electrochemical gradient used to move substances against their concentration gradient

What is the Na/K ATPase pump?

a primary active transport process where ATP is used to push 3 Na+ out of cell and bring 2 K+ into cell

what is antiporters?

membrane protein that move molecules in opposite directions

what is symporters?

membrane protein that move molecules in the same directions

what is osmosis

process where water molecules move from high to low concentration

is omosis passive or active transport?

passive transport

what is isotonic solution?

no net movement of water with equal concentration inside cell

what is hypotonic solution?

solution has low solute conc. compared to inside of cell and water enters cell

what is hypertonic solution?

solution has higher solute conc. compared to inside of cell and water exits cell.

in hypotonic solution, does cell burst or shrink?

cell burst

in hyeprtonic solution, does cell burst or shrink?

cell shrinks

what is osmolarity

measure of solute concentration in a solution

what is osmotic fragility

the measure of how easily red blood cells break open when placed in a salt solution that has a lower concentration than normal body fluids

what is aquaporins

integral proteins that allow passive movement of water

what is filtration

type of passive transport where water and small solutes are pushed through a selectively permeable membrane by hydrostatic pressure rather than a concentration gradient.

where does filtration happen in our body

kidney or renal system

what is endocytosis

process to bring extracellular substance in by membrane folding around, forming vesicle

what is phagocytosis

process where substances outside the cell are engulfed and form endosome vacuole

what is pinocytosis?

process where membrane pinches inwards to non-selectively uptake extracellular fluid and substances dissolved in the liquid

what is Receptor-Mediated Endocytosis

it is an endocytosis triggered by extracellular molecules binding to receptors on the cell membrane

what are the main steps of Receptor-Mediated Endocytosis

Cytoplasmic tail of receptor bound to clathrin forming “clathrin-coated vesicles”, then the internalization of vesicles cause clathrin to lose the coat. receptors are then recycled

what is exocytosis?

a process where substances exit the cell via the membrane pinching outward via vesicle

Why is it crucial for the Na+/K+ pump to utilize ATP for transporting sodium and potassium ions?

Because forcing sodium and potassium ions against their concentration gradients through active transport require energy

diffusion of oxygen through the plasma membrane is called what

simple diffusion