Whats the plasma membrane composed mainly of?

Phospholipids

the principal components of the plasma membrane?

lipids(phospholipids, and cholesterol), proteins, carbohydrates

what is NOT a cell membrane component?

Nucleic acids

what region of the cell membrane are hydrophobic?

the tails facing the interior

What region of the cell membrane is hydrophilic?

the head group which interacts with water

Membrane has hydrophobic or hydrophilic core?

Has hydrophobic core

what is imbedded in the membrane?

proteins, throughout the membrane

what carbohydrates are attached to lipids?

glycolipids

what are carbohydrates that are attached to proteins?

glycoprotein

Cholesterol exists where in the membrane?

embedded in hydrophobic core of the membrane

Fluid mosaic model

model of the membrane.

membrane is considered mosaic of?

lipids, phospholipids in cholesterol, proteins and carbohydrates.

why is mosaic fluid

its a fluid because it is not rigid, it is between solid, and liquid.

lipids can move relative to eachother

what are proteins in the membrane?

integral proteins, lipid anchored proteins, peripheral proteins

integral proteins

referred to as transmembrane protein, they span the entire membrane

lipid anchored proteins

covalently bonded to the phospholipids, an amino acid side chain in the membrane

peripheral protein

non-covalently bound to integral proteins. weak bond, can pop on and off membrane easily

why is the membrane fluid?

molecules can move in the membrane. they can spin in their axis, they can go in circles where they are, moving laterally in their membrane leaflet

what is a Membrane leaflet?

one side of the membrane

what can molecules NOT do in their leaflet?

move from 1 leaflet to another leaflet because the tails are hydrophobic and the head is hydrophilic.

whats the ONLY exception to molecules moving from leaflet to leaflet?

if their is a special protein, an enzyme called flippace, and you'll need ATP

flippace

an enzyme(proteins) embedded in the phospholipids bilayer that requires ATP to transport lipids from leaflet to leaflet

fluidity means

individual molecules remain in
close association yet have the ability to readily move within the membrane

semifluid

most lipids can rotate freely
around their long axes and move laterally
within the membrane leaflet

what are 3 factors affecting fluidity?

Length of fatty acid tails, presence of double bonds in fatty acid tail(acyl acid), and presence of cholesterol

factor affecting fluidity,

length of fatty acid tails

shorter tails mean more fluidity, they,re less likely to interact than if they were long tails, which makes the membrane more fluid.

factor affecting fluidity?

presence of double bonds in fatty acid tails

double bonds kink in fatty acid tails. making in more difficult for neighboring tails to interact and make the bilayer more fluid

factors affecting fluidity?

presence of cholesterol

cholesterol decreases the fluidity of the membrane, and stabilizes the membrane

cholesterol

4 interconnected carbon rings

what it means when proteins are anchored to cytoskeloton?

that they can NOT move

can lipids move in the membrane in all cellular ways?

Yes! they just CAN NOT flip

Selectively permeable

prevents certain molecules from getting in and getting out of the cell

selectively permeable structure ensures..

essential molecules enter, metabolic intermediates remain, and waste products exit

Diffusion

net movement of a solute from a region of high [ ] to low [ ]. does NOT require energy, is Passive.

example of diffusion

perfume, people on a bus

is diffusion passive?

Yes. it does not require any additional energy input from the cell. Cell doesn't have to expend any energy for diffusion to happen.

passive diffusion

Diffusion of a solute
through a membrane without transport protein

does the cell have to expend any energy for diffusion to take place?

NO

movement by thermal energy

high concentrated molecules are bouncing off of each other eventually into the open space randomly

brownian motion

random bouncing

what type of environment promotes molecules to move around fast and bounce around? and what happens with diffusion?

on hot plates molecules move/bounce around fast, increasing the rate of diffusion

what type of environment do molecules move around slowly, and what happens with diffusion?

in a freezer molecules will move slower, decreasing the rate of diffusion

phospholipid bilayer barrier

A barrier to molecules/ions that is hydrophilic due to hydrophobic interior.

what is a cell membrane impermeable to?

any polar charged molecules. only maybe a few glasses and water can directly diffuse through the membrane

what are the small glasses that can easily diffuse through the membrane?

O2, CO2, N2, CO

A gradient

the DIFFERENCE in concentration from 1 side of the membrane to another

a cell maintains gradients.

is equilibrium the goal for cells?

No, maintaining equilibrium is not the goal for cells

which of the following can diffuse through the membrane?

O2, glucose K+, amino acids

O2. glucose, K+, and amino acids are too big, and too polar, they diffuse slowely

concentration in a membrane

if one side of the membrane is high concentration, the other side is low concentration

osmosis

diffusion of free water toward higher concentrations through a selectively permeable membrane

what happens if solute's cannot move?

the movement of water will cause cell to swell when the water moves in, or shrink when water moves out

Tonicity

isotonic, hypertonic, hypotonic solutions

isotonic

Equal water and solute concentrations on either side of the membrane

hypertonic

Solute concentration is higher outside the cell (and water concentration lower)

hypotonic

Solute concentration is lower outside the cell (and water concentration higher)

Crenation

when cell shrivels due to water leaving the cell

(hypertonic solutions)

plasmolysis

when the cell membrane pulls away from the cell wall due to lack of turgor pressure

turgor pressure

pressure exerted onto the plasma membrane by the vacuole

force within the cell pushing the plasma membrane against the cell wall

aquaporin

transmembrane proteins that allow the passage of water much faster and efficiently through the membrane. water will flow toward the higher solution no matter which side its on

osmosis and diffusion

are passive processes they DO NOT require additional energy from the cell. energy comes from thermal energy

osmotic pressure

the tendency for water
to move into any cell

which of the following requires energy from the cell?

osmosis, active transport, diffusion, facilitated diffusion

active transport

active transport

REQUIRES energy from the cell to move solutes from low concentration to high concentration (against concentration gradient) energy required is usually in form of ATP. Also require a protein.

what is falicitated diffusion

the diffusion of a solute from high to low [ ]. diffusion is passive. DOES require a membrane protein to transport the molecules. proteins are specific to molecules they transport

facilitated diffusion of glucose

large molecule, cant diffuse through membrane itself, trans-membrane facilitating proteins helps

the DIFFERENCE between simple diffusion, and facilitated diffusion?

facilitated diffusion required a membrane protein to transport the molecule

under what condition would facilitated diffusion move a solute from the cell?

in a hypotonic condition

transport proteins // channel proteins

they don't change shape as solutes pass.

ligated channel, gated channel

ligated channel

is closed until a molecule binds to it, causing channel to open

gated channel

is closed until polarity of membrane changes.

carrier proteins

change shape as the solute passes

Uni-porters, symporters, antiporters

uniporters

single molecule or ion.

moves 1 solute for example (glut 1)

symporter/cotransporter

2 or more ions or molecules transported in same direction

antiporter

move 2 or more solute in opposite directions for ex. The Na+/K+ pump.

major limitation of simple/facilitated diffusion

them Going down the concentration gradient the opposite of the definition

cotransport

active transport of substance indirectly drives transport of other substances

downhill(energy release)

cell does nothing. Diffusion is downhill because it doesn't need energy.

uphill(requires energy)

this is an Active transport bc it requires energy to happen

are Exo/Endocytosis nonspecific?

yes

exocytosis

is bulk transport of solutes out of the cell.

endocytosis

is the bulk transport of molecules or solutes into the cell. Pinocytosis- the bulk uptake of liquid material containing dissolved solutes

phagocytosis

the bulk uptake of solid material. The vesicle with engulfed solid

be it a yeast or bacteria fusses with a lysosome to be degraded

tight junctions

so tightly attached that nothing can get between the cells. Proteins are attaching cells together.

gap junction

Communication junctions, passageways between cells allowing material to pass between them. Like a tunnel from one cell to the other able to pass material between cells.

anchoring junctions

they hold cells together like a bolt or staple. Material can get in between cells but they're still attached.