quiz 5.1

what does 1 molecule of water contain?

-1 oxygen atom -2 hydrogen atoms -covalently bonded -bent shape

endocytosis

-Big things enter -Membrane folds in and forms a vesicle

exocytosis

-Big things exit -The vesicle becomes part of the P.M.

other parts of the fluid mosaic are

-Cholesterol acts as a stabilizer so phospholipids can move but not too far. -Proteins...many functions! We'll concentrate on one...

why does during osmosis the water molecules diffuse toward areas of more solute (less water)

-More solute, means more water bound to the solute -Less free water, so it's like a lower concentration of water

nonpolar substances

-Nonpolar substances are NOT attracted to water thus they DO NOT dissolve in water. -Charged water molecules are more attracted to each other than to substances without charges.

what type of molecules are are able to pass through the PM by diffusing ?

-Small, nonpolar molecules -Water even though it's polar, it can still diffuse because it's very small & it's everywhere

what is polarity caused by?

-This polarity is caused by oxygen -high electronegativity -more strongly attracts shared e- making O end slightly negative & H end slightly positive

Property 3: Water is a great solvent

-Water dissolves more substances than any other liquid! -Due to its polarity it can dissolve most polar/ionic compounds! (Think about the charges.)

Polarity/H Bonds Explain Water's Cool Properties- Property #1: Attraction

-Water molecules are attracted to each other other due to polarity -Water molecules are also attracted to any other charged or polar molecules!

Osmosis: the diffusion of water

-Water molecules move from high to low concentration. -This means that water molecules diffuse toward areas of more solute (less water). -Diffuses in opposite direction that solute would diffuse.

Since the environment both outside & inside our cells is watery...

-phosphate "heads" are attracted to the water (both in/out of cells). -the fatty acids turns inward This forms a double layer

what are characteristics of polar molecules?

-slightly positive H atoms -slightly negative O atom (A polar molecule is a molecule with a partial + charge in one location & partial - charge at another)

membrane transport protein

Allow for molecules to move in or out of the cell that can't normally cross the membrane

hydrophobic

Anything that does NOT dissolve in water is called HYDROPHOBIC (phobia = fear)

hydrophilic

Anything that does dissolve in water is called HYDROPHILIC (philic = love)

are lipids polar or nonpolar?

Because ALL lipids are non-polar they are not SOLUBLE (do not dissolve) in water.

are all water molecules polar or nonpolar?

Because all water molecules are polar, they are attracted to each other! The (-) end of one is attracted to the (+) end of another. We call this attraction a hydrogen bond

facilitated diffusion

Diffusion through a protein channel in the membrane

for example solute/solvent

Eg: Kool-aid...water is the solvent; sweet, sweet powder/sugar are the solute

If something is too big to enter/exit through a protein channel...

Endo/Exocytosis

function of the plasma membrane

Isolates the cell from external world Regulates entry and exit to the cell

phospholipids

PHOSPHOLIPIDS are a very important lipid in living organisms They are the main molecule of the plasma membrane

property #2: Water has a high surface tension

Penny = surface tension. why a belly flop hurts bc you're breaking the surface tension of the water.

review

Small, non-charged molecules can simply diffuse Small, polar or charged molecules can pass through a protein

cell size

Smaller cells have higher SA:V ratios than do larger cells. - This is good! Allows for the movement of necessary materials (O2, food molecules, H2O) & wastes (CO2, etc.) to occur quickly & efficiently. - So, diffusion explains why cells are small! smaller cells= disffuse faster!

solution

Solution = solute + solvent

what does specific heat capacity mean?

Specific heat capacity = amount of energy needed to raise 1 gram of a substance by 1 degree Celsius.

the plasma membrane is ?

THUS Membrane is selectively permeable - only lets certain molecules in/out.

Property 5: Water has a high specific heat capacity

Takes a good amount of heat energy to raise water's temperature Why? Gotta add enough energy to move molecules & for water this means that H bonds have to be disrupted.

what is the double layer called?

The 2 layers of phospholipid molecules = PHOSPHOLIPID BILAYER

what will nonpolar molecules do instead?

The nonpolar molecules, like oil, will group together... Oil is in a group of BIG (macro) molecules called LIPIDS

what does water with solute do?

WATER w/ solutes surrounds every cell in body (interstitial fluid) AND fills the inside of the cell (cytoplasm).This WATER has different combinations of solutes depending on the location (inside/outside of cell):

why do we not dissolve?

We do not dissolve in water because our cells' plasma membranes are made of phospholipids! The Phosphate head is hydrophilic. (water loving) The Fatty Acid tails are hydrophobic (water hating)

Property 4: Solid Water is Less Dense than Liquid Water = Ice Floats!

When water is frozen, the hydrogen bonds line up in a way that makes each molecule further apart than when liquid. when liquid the bonds are closer. solid water less dense than liquid water=ice floats.

solvent

component of solution that does the dissolving

solute

component of solution that is dissolved

the molecules will continue to move along this

concentration gradient until they reach eqauilibrium.

So...the water molecules AND all the dissolved solute molecules are constantly moving & passing in/out cell membranes... How do they do this?

diffusion and osmosis

low concentration solution

dilute. weak solution. the ratio of solute to solvent is low.

hypotonic

extracellular solution where the solute concentration is lower outside instead of the inside.

Lipids

fat, oil, wax, cholesterol & steroid hormones. Lipids are composed of Carbon, Hydrogen and Oxygen. Ex: Fat consists of long chains of H and C atoms joined to one smaller molecule. We use fats as an energy source, for energy storage & to build our cell membranes!

diffusion

is the net movement of molecules from an area of high concentration to an area of low concentration along the concentration gradient.

which two types of molecules appear to makeup the majority of the cell membrane?

lipids and protein

concentration

measure of the amount of solute in a solvent

what does active protein require?

membrane protein, AND energy! bc everything moves aganist the gradient.

dynamic equalirium-once equlibrium is reached, molecules will continue to

move acorss a membrane randomly.

does facilitated diffusion use energy?

no

does simple diffusion use energy?

no energy

what type of molecules are involved in simple diffusion?

non polar, small, and hydrophobic

is a membrane protein used in simple diffusion?

nope

plasma membrane aka Fluid Mosaic

phospholipids have ability to move (fluid) different parts embedded in the bilayer (mosaic).

what type of molecules are involved in facilitated diffusion?

polar, large &/or hydrophilic, ions

high concentrated solution

ratio of solute is higher than the solvent.

what types of molecules are moving across the membrane?

small and nonpolar molecules bc if they are nonpolar they wont be be able to se thru.

which type of molecules are moving by diffusion across the membrane?

small molecules that are nonpolar

osmosis

the diffusion of water molecules through the membrane.

active transport

the movement of molecules from LOW to HIGH concentration. UP/AGANIST THE GRADIENT

simple diffusion

the movement of molecules from high to low concentration. (moving DOWN a gradient)

molecules are usually moving in constant random motion however depending on the concentration of molecules there can be an overall direction of movement called

the net direction.

what exactly in the membrane do these molecules pass through?

the phospholipids

hypertonic

there is higher concentration of solute outside the cell and not the inside.

isotonic

when the solute concetration is the same on each side of the membrane it is cosidered isotonic.

concentration gradient

when there is a difference in concentration of particular particles aorss any space and concentration gradient exist.

example of P#1: attraction

why your pant legs get wet in the rain, How plants pull water up against gravity. when you put a tube in water, the water climbs up bc the water molecule is attracted to any other charged or polar molecules.

does faciliated go with or aganist concentration gradient?

with

does simple diffusion go with or against concetration gradient?

with

is a membrane protein used in facilitated diffusion?

yes