Biology I CellsBiology I Cells

Why is it good that your house is Why is it good that your house is made out of many smaller rooms made out of many smaller rooms

rather than one big space?rather than one big space?

What is a cell?What is a cell?

A cell is a small specialized A cell is a small specialized compartmentcompartment

It keeps what is inside separate from the rest of the organism

Why must living things Why must living things be made of cells?be made of cells?

To have enzyme/substrate To have enzyme/substrate concentrations high enough so that concentrations high enough so that rates of reactions are reasonable to rates of reactions are reasonable to support life (Rates of Reaction)support life (Rates of Reaction)

Rates of DiffusionRates of Diffusion Rates of TransportRates of Transport Reactions can occur without Reactions can occur without

interference (conflicting reactions can interference (conflicting reactions can happen simultaneously)happen simultaneously)

Local environments can allow different Local environments can allow different reactions to happenreactions to happen

Why must living things Why must living things be made of cells - be made of cells -

continuedcontinued Specialization (different cells can Specialization (different cells can

do different things)do different things)

Damage can be containedDamage can be contained

Cell TheoryCell Theory

Cell Theory ContinuedCell Theory Continued

All Living Things are

Made of Cells

All Cells Come From Other Cells

Prokaryotic vs. Prokaryotic vs. Eukaryotic CellsEukaryotic Cells

Cell Membrane Cell Membrane StructureStructure

Phospholipid BilayerPhospholipid Bilayer

Cell Membrane Cell Membrane StructureStructure

Membrane ProteinsMembrane Proteins Protein Channels – Control what Protein Channels – Control what

moves in and out of membranemoves in and out of membrane– Passive TransportPassive Transport– Active TransportActive Transport

Receptors – Receptors – Receives messages so the Receives messages so the cell knows what to docell knows what to do

Marker or Signal Proteins – Marker or Signal Proteins – Identifies Identifies the cell so your immune system knows the cell so your immune system knows what belongs to you vs. foreign cellswhat belongs to you vs. foreign cells

Attachment Proteins – Attachment Proteins – attach cells to attach cells to other cells and ECMother cells and ECM

Ways Things Move Through Ways Things Move Through the Cell Membranethe Cell Membrane

DiffusionDiffusion – movement of molecules – movement of molecules from a high to low concentration due from a high to low concentration due to random motion of moleculesto random motion of molecules

OsmosisOsmosis – diffusion of water – diffusion of water Simple diffusionSimple diffusion – thru phospholipid – thru phospholipid

bilayer – driven by kinetic energy of bilayer – driven by kinetic energy of the molecules or atoms themselvesthe molecules or atoms themselves

Ways Things Move Through Ways Things Move Through the Cell Membranethe Cell Membrane

Facilitated diffusionFacilitated diffusion – using the – using the help of protein channelshelp of protein channels– Cell uses no energy, substances move from Cell uses no energy, substances move from

high to low concentration (still diffusion)high to low concentration (still diffusion)– Used when molecules are polar, charged, or Used when molecules are polar, charged, or

too bigtoo big– Channels are still small – nothing bigger than a Channels are still small – nothing bigger than a

monomer goes through protein channelsmonomer goes through protein channels

Ways Things Move Through the Ways Things Move Through the Cell MembraneCell Membrane

Active TransportActive Transport– Movement through protein channels Movement through protein channels

from low to high concentrationfrom low to high concentration– Cell must use energy to pump things Cell must use energy to pump things

throughthrough

Ocean Fish pump salt out of their cells

Muscle cells pump Na+ out so they can reset to contract again

How can big things like cholesterol and fatty acids get into cells since protein

channels can’t be big?

You will figure it out using the You will figure it out using the following materials:following materials:

A grocery bag as the cellA grocery bag as the cell Candy as the large particles being taken inCandy as the large particles being taken in 2 pieces of string and scissors2 pieces of string and scissors

The RulesThe Rules The inside of the bag (cell) cannot be open to the external The inside of the bag (cell) cannot be open to the external

environment at any timeenvironment at any time You can put your hands inside the bag to manipulate the cell You can put your hands inside the bag to manipulate the cell

membranemembrane You cannot turn the bag inside outYou cannot turn the bag inside out You cannot put the particles through the holeYou cannot put the particles through the hole Food particles must remain together during the whole Food particles must remain together during the whole

process including after they enter the cellprocess including after they enter the cell You cannot tie the food particles together with the stringYou cannot tie the food particles together with the string

You must demonstrate the process to me and show me You must demonstrate the process to me and show me how you did it to win!how you did it to win!

Ways Things Move Through Ways Things Move Through the Cell Membranethe Cell Membrane

EndocytosisEndocytosis – engulfing large particles – engulfing large particles with part of the cell membrane and with part of the cell membrane and bringing them into the cell in a vesiclebringing them into the cell in a vesicle

ExocytosisExocytosis – (secretion) – wrapping – (secretion) – wrapping molecules in a membrane vesicle inside molecules in a membrane vesicle inside the cell – having it fuse with the cell the cell – having it fuse with the cell membrane and dump the contents membrane and dump the contents outside the cell (with or against conc. outside the cell (with or against conc. Gradient – big stuff like proteinsGradient – big stuff like proteins

Onion Cells with and Onion Cells with and without stainwithout stain

Elodea Cells and Salt Elodea Cells and Salt WaterWater

cytoplasmic streaming in elodea

adding salt to a red onion cell

Pond WaterPond Water

https://www.youtube.com/watch?feature=player_detailpage&v=cwgGJaNlGKM