Anatomy 1 Lecture 2

water-based chemical enviorment inside of a cell is the

intracellular fluid (ICF)

water-based chemical enviornment outside of a cell is

extracellular fluid (ECF)

the 2 places ECF is found

1. interstital fluid- the fluid that directly surrounds the cell in the tissue where it lives

2. blood plasma- remainder of the ECF that is the liquid part of the blood

all membranes (plasma and organelle) are

phospholipid bilayers

the hydrophobic core of the phospholipid bilayer forms the

boundary between the ICF and the ECF

both the ICF and ECF are

water-based environments filled with hydrophilic molecules

permability

molecule’s ability to pass through a membrane

a phospholipid bilayer is not permeable to

polar molecule and electrolytes

only ___ can freely enter and leave a cell

non-polar molecules

non-polar elements that can freely move through the membrane

oxygen and carbon dioxide

2 polar molecules that can also move through the membrane

ammonia and water

ammonia and water are so small that they can

slip between phospholipid molecules without interacting with them

even though these are permeable they move

very slowly and inefficietnly

the plasma membrane is also the structure that a cell uses to

interact with other cells and its environment

the plasma membrane is not just a phospholipid bilayer and not just a

boundary between the ICF and ECF

the plasma membrane contains ____ that allow the cell to ___

thousands of proteins, interact with other cells and its environment

the plasma membrane also contains many different kinds of ___ that act like ___ and some are___

polysaccharides, molecular glue, tags that identify the cell to other cells

a receptor is a protein that

binds to a signal in the ECF and then transmits a message to the ICF

receptors bind the signal in the ECF and then create a message inside of the cell that allows the cell to

adapt or change its function in response to the signal

responsiveness

function a receptor protein performs or cell

enzyme

a protein that speeds up one or more chemical reactions

some molecules must be

chemically modified or broken down before they enter or leave the cell

cells sometimes interact with other cells by

chemically modifying the molecules on their cell membranes

cells sometimes interact with their environment by

building or breaking down structures in the interstitial fluid

metabolism

function an enzyme performs for a cell

cell identity marker

protein that identifies a cell to other cells nearby

cell identity marker are usually modifies to have

polysaccharides attached to them

some cells change their structure and function based on

what kind of cells they are surrounded by

immune cells use cell identity makers to identify which cells

are part of the body and which are not

cell adhesion molecules are proteins that

attach to each other in order to stick cells together

cells that live at surfaces of the body that interact with the environment outside of the body must stick together very tightly to form a

closed boundary between the body and environment

a transporter is a protein that

moves hydrophilic molecules into and out of the cell

2 kinds of transporters

1. channel proteins

2. carrier proteins

channel proteins

open a water-filed hole in the membrane that molecules can move through by diffusion

carrier proteins

must bind to molecules and physically move them through the membrane

the transporters are needed because

the hydrophobic core of the membrane prevents the movement of hydrophilic molecules and electrolytes through the cell membrane

membrane transport

the process of moving molecules into and out of cells

because only certain molecules can move through a phospholipid bilayer the plasma membrane is considered

selectively permeable

diffusion

atoms and molecules will always move from the place with the highest concentration to the place with the lowest concentration

diffusion stops when

the concentration of the molecule is the same on both sides of the membrane

simple diffusion

movement through the membrane without a transport protein (only some kinds of molecules can do this)

facilitated diffusion

movement through the membrane with a transport protein

any polar molecule or electrolyte can use facilitated diffusion if

there is a transport protein for it in the plasma membrane

passive transport

simple diffusion and facilitated diffusion

passive transport does not spend energy but the process will

release energy that the cell can use to do work

in the air we breathe the oxygen concentration is ___ and the carbon dioxide concentration is ___ and in the blood the oxygen concentration is ___ and the carbon dioxide concentration is __

so oxygen will diffuse into ___ and carbon dioxide will diffuse into ___

high, low, low, high

the blood, the lungs

movement into/through a cell by diffusion is limited by the

amount of surface area for those molecules to move through

diffusion depends on

surface area to volume ration

to increase the ability of a molecule to diffuse across the body the structures must

maximize the amount of surface area and minimize the total volume of a cell

the body increases surface area to volume ration by

folding or extending the cell membrane or building branched structures

folding or extending the cell membrane is done by

microvilli that increases membrane surface area by a large amount while only increasing cell volume by a tiny amount

branched structures

increase surface area by a large amount and only increase volume by a small amount

in emphysema the branching structure of the lungs is damaged which casues

a loss of surface area in the lungs