Cells And Cellular Transport. Where does the name “cell” come from? “Cells” were named by Englishman Robert Hooke in 1665. He observed that cork wood.

Cells

And

Cellular Transport

Where does the name “cell” come Where does the name “cell” come from?from?

““Cells” were named by Englishman Robert Cells” were named by Englishman Robert Hooke in 1665.Hooke in 1665.

He observed that cork wood looked like He observed that cork wood looked like monk’s cells in a monastery.monk’s cells in a monastery.

http://upload.wikimedia.org/wikipedia/commons/c/c2/Hooke-microscope.png

The Cell: Those Who Discovered ItTheodor Schwann: Stated that all animals were made of cells.

Matthias Schleiden: Stated the all plants were made of cells. What a stretch, eh?

Ruldolph Virchow: Stated that all cells come from pre-existing cells. Hmmm…isn’t that the chicken and the egg argument?

http://scienceworld.wolfram.com/biography/photo-credits.html#Schwann

http://scienceworld.wolfram.com/biography/photo-credits.html

The Cell Theory1. The cell is the basic unit of structure and

function.

2. All organisms are made of one or more cells.

3. All cells come from pre-existing cells.

Red blood cellsColonies of bacteria Plant cells showing chloroplasts

http://uk.encarta.msn.com/media_461521734/Members_of_the_Kingdom_Prokaryota.html

This is the human Herpes Virus!

Exceptions to the Cell Theory

1. Viruses!! They have DNA and/or RNA inside a protein shell. They are capable of reproduction inside another living cell, but not on their own.

2. Mitochondria and chloroplasts have their own DNA and can reproduce inside a cell.

3. Obviously….the first cell.

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Types of CellsTypes of CellsProkaryotic CellsProkaryotic Cells

The first and most primitive The first and most primitive cells cells

Lack a nucleus and other Lack a nucleus and other membrane bound membrane bound organelles (mitochondria, organelles (mitochondria, etc) = Smallest cells!etc) = Smallest cells!

ALL bacteria are ALL bacteria are prokaryotesprokaryotes..

Eukaryotic CellsEukaryotic Cells Most organisms have Most organisms have

eukaryotic cells (ex: all eukaryotic cells (ex: all plant and animal cells!)plant and animal cells!)

All genetic material is All genetic material is contained in a nucleuscontained in a nucleus

Have many membrane Have many membrane bound organelles = larger bound organelles = larger cells!cells!

Examples: ALL living Examples: ALL living things things exceptexcept bacteria! bacteria!

http://www.rkm.com.au/BACTERIA/bacterial-cell.html

The Cell Membrane

Also called:

The Phospholipid Bi-Layer

or

The Plasma Membrane

A barrier that separates a cell from its surroundings.

Cell membranes are “semi-permeable” because they allow some molecules to pass through, while others cannot.

Membrane Structure

MOVIE!

The lipid bilayer consists of two (bi) layers of phospholipids.

The ____________ heads point to the outside and the ____________ tails point to the inside of the membrane.

hydrophilic

hydrophobic

Various _________ molecules are embedded in the membrane as well.

protein

Membrane Proteins1. Marker Proteins: Like a “name tag” for the cell. Used in cell recognition together with carbohydrates.

2. Receptor Proteins: A messenger molecule binds to one side of the membrane protein and the message is sent to the other side (the messenger molecule is not.)

3. Enzymes: A protein catalyst can be embedded in the plasma membrane to facilitate chemical rxns of the cell.

Membrane ProteinsContinued…

4. Channel Proteins: Trans-membrane proteins which allows specific molecules to pass from one side of the membrane to the other. Often transport LARGE molecules.

YouTube - Cell membrane animation

Watch it!!!

Cellular TransportThe movement of molecules across the cellular membrane.

Cellular TransportCellular Transport

Passive Passive TransportTransport

does NOT require cellular does NOT require cellular energy (ATP)energy (ATP)

Moves molecules from Moves molecules from high to low concentrationhigh to low concentration

Active Active TransportTransport

DOES require ATPDOES require ATP

DiffusionThe movement molecules from an area of HIGH concentration to an area of LOW concentration.

•Molecules diffuse along, or down the concentration gradient until dynamic equilibrium is attained (equal conc. of molecules)

• oxygen, CO2, glucose, glycerol and other small molecules diffuse. This is a form of passive transport. (no ____ is needed)

_________ molecules CANNOT diffuse across membranes, regardless of concentration gradient!

LARGE

ATP





ExamplesExamples- diffusion- diffusion



OsmosisOsmosis is the diffusion of _______ across a semi-permeable membrane.water

This is passive transport, meaning _____ _______ is needed for it to occur.

Water always moves from low to high SOLUTE concentration until equilibrium is established. This is osmosis!

NO ATP

Definition: SOLUTE –A substance that is dissolved in another substance.

Examples: salt or sugar in water.

OSMOSISOSMOSIS…continued…continued•If a cell is placed in a solution with a LOWER concentration of solute, it will _________ (water will _________ the cell)

•If a cell is placed in a solution with a HIGHER concentration of solute, it will _________ (water will _________ the cell)

enterswell

shrivelleave





ExamplesExamples- diffusion- diffusion- osmosisosmosis



Moving Molecules Against the Concentration Gradient

•The sodium ions are more highly concentrated on the inside of the cell.

•With the help of ATP, the sodium ions are still pumped back into the cell (against the concentration gradient).







DOES require ATPDOES require ATP Moving molecules from Moving molecules from

low to high concentration low to high concentration

PhagocytosisThis is “cell eating”. A cell engulfs (or wraps itself around) a food particle thus creating a food vacuole.

This is a type of ACTIVE TRANSPORT!








low to high concentration low to high concentration PhagocytosisPhagocytosis

PinocytosisThis is “cell drinking”. The cell membrane pinches inward (like a pin poking a hole) and creates a vacuole of dissolved particles.

This is a type of ACTIVE TRANSPORT!








low to high concentration low to high concentration PhagocytosisPhagocytosis PinocytosisPinocytosis

Membrane Proteins Using Cellular Energy




Moves molecules from Moves molecules from high to low concentrationhigh to low concentrationExamplesExamples- diffusion- diffusion- osmosisosmosis



low to high concentration low to high concentration PhagocytosisPhagocytosis PinocytosisPinocytosis Use of membrane Use of membrane

proteins, carriers, proteins, carriers, receptorsreceptors

Levels of OrganizationAtoms

Molecules

**Cells**

Organelles

Tissue ?? Cells with a similar structure and function.

http://www.cellsalive.com/cover3.htm

http://www.kathleensworld.com/mitochondria.jpg

Levels of Organization…ContinuedOrgans

Organ Systems

Organism

Can we keep going???

http://images.google.com/imgres?imgurl=http://www.umm.edu/digest/images/digest.gif&imgrefurl=http://www.umm.edu/digest/howworks.htm&h=450&w=391&sz=35&tbnid=lLmWAg2j2jAJ:&tbnh=123&tbnw=107&prev=/images%3Fq%3Ddigestive%2Bsystem%26hl%3Den%26lr%3D&oi=imagesr&start=2

http://images.google.com/imgres?imgurl=http://www.thehumanbody.ecsd.net/the_hu10.gif&imgrefurl=http://www.thehumanbody.ecsd.net/the_human_body.htm&h=1780&w=1113&sz=77&tbnid=b8nHrzeYPmMJ:&tbnh=149&tbnw=93&prev=/images%3Fq%3Dhuman%2Bbody%26hl%3Den%26lr%3D&oi=imagesr&start=1

http://images.google.com/imgres?imgurl=http://www.cincinnatichildrens.org/NR/rdonlyres/32143992-B411-43F4-8B25-AB3A460A3478/0/LiverFINALweb.jpg&imgrefurl=http://www.cincinnatichildrens.org/health/info/liver/anatomy/liver-anatomy.htm&h=180&w=183&sz=10&tbnid=GyW5rcbCOjoJ:&tbnh=94&tbnw=96&prev=/images%3Fq%3Dliver%26hl%3Den%26lr%3D&oi=imagesr&start=3

Cells And Cellular Transport. Where does the name “cell” come from? “Cells” were named by Englishman Robert Hooke in 1665. He observed that cork wood.

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