Scientist and Cell Transport MNHS

Robert Hooke  Saw the first cells and named them after the cells of monasteries  Looked at cork (dead)  Contemporary of Isaac Newton (they didn’t like each other)  Contemporary of van L., who was Dutch, they wrote letters to each other and had interpreters, Hooke was English

Anton von Leeuwenhoek  Was the first to observe living single-cells & organelles under the microscope.  Pond water, sperm  Great lens grinder

Matthias Schleiden  German Botanist  1800s  Said all plants were made of cell

Theodor Schwann  German Physiologists  1800s  All animals are made of cells  “Schwann” cell of nervous system

Rudolph Virchow  German doctor  1800’s  Determined that cells come from other cells.

Diffusion Someone go to the back of the room and squirt some perfume….. Raise your hand when it hits you….. What is happening?

How would diffusion happen in a cell?

Diffusion  Movement of molecules from area of high concentration to low concentration  Not water  Passive! No Energy! No ATP!  Reaches dynamic equilibrium, balanced but still moving

Homeostasis Cells exist in an aqueous environment…. What part of the cell is responsible keeping the inside of the cell different from the outside?

Plasma membrane  is selectively permeable  hydrophilic heads and hydrophobic tails  forms a lipid bilayer to enclose the contents of a cell  Responsible for homeostasis by regulating the movement of materials in and out of the cell

Other names for the cell membrane Plasma membrane Lipid bilayer Fluid mosaic model Semi-permeable membrane

Transport in the cell

Passive Transport  No energy needed!  No ATP needed!  Particles move from area of high concentration to low concentration  Osmosis  Diffusion  Facilitated Diffusion

Move in and out by Diffusion or are “pumped” Osmosis- special diffusion of water across semi-permeable membrane What is it permeable to?

Solutes & Solvents Solute- substance that gets dissolved, like salt or sugar Solvent- does the dissolving, like water or alcohol

Osmosis Osmosis is diffusion of water toward a high concentration of solute. No energy needed! Passive! No ATP!  Which way will the water move in this picture?

Osmosis is a type of diffusion Cell Membrane

Osmosis is a type of diffusion Cell Membrane

Osmosis is a type of diffusion Cell Membrane

Osmosis is a type of diffusion Cell Membrane

Osmosis is a type of diffusion Cell Membrane

Osmosis is a type of diffusion Cell Membrane

Osmosis is a type of diffusion Cell Membrane

Osmosis is a type of diffusion Cell Membrane

Osmosis cells placed in solutions with solute concentrations higher than that of their cytoplasm, are in a…. Hypertonic solution Which way did the water move? Why? Watered with NaCl water

Osmosis Cells placed in solutions with lower concentrations of solutes than their cytoplasm are in Hypotonic solution What is happening to these cells? Why?

Osmosis Cells in solutions with concentrations of solutes equal to that of the cytoplasm are in Isotonic solution These cells are maintaining their normal shape. Why?

Which way did the water move? 75% H20 25% Solute 20% H 2 O 80% Solute Why did the cell get so big?

Which way did the water move? 80% Water 20% Dissolved Substances 80% H 2 O 20% Solute Why did the cell stay the same size?

Which way did the water move? 30% Water 70% Solute 60% H 2 O 40% solute Why did the cell get so small?

Dynamic Equilibrium Relative concentrations of solute/solvent become equal Still “dynamic” or moving No net change

Relate Osmosis to your egg…. Once shell is removed… In Kayro syrup? What kind of solution is it? What will happen? In distilled water? What kind of solution is it? What will happen?

Active Transport  Requires Energy  Requires ATP!  Going against concentration gradient  From Lo to Hi concentration  Protein pumps in cell membrane  Endocytosis  Exocytosis

Proteins are embedded/floating in the lipid bilayer.

Cell Membrane Structure-Proteins These proteins are needed for the membrane to function properly. 3 Types of Membrane Proteins 1. Transport—regulate what enters or leaves cell 2. Marker—identify the cell 3. Receptor—allow cells to communicate

Transport Proteins—Channel Proteins  Function as “ gates/passageways ”  Allow polar sugars, amino acids, and ions to cross the membrane.  Special channel proteins:  Gated ion channels—gates that open/close  Carrier proteins—change shape to allow specific molecule to pass  Aquaporins—allow water to diffuse through (called osmosis)

HELP WANTED! I’m a Channel, I can help!

HELP WANTED! I’m a Channel, I can help!

HELP WANTED! I’m a Channel, I can help!

HELP WANTED! I’m a Channel, I can help!

HELP WANTED! I’m a Channel, I can help!

HELP WANTED! I’m a Channel, I can help!

HELP WANTED! I’m a Channel, I can help!

HELP WANTED! I’m a Channel, I can help!

Marker Proteins  Cell ’ s “ Name Tag ”  Protein sticks out of phospholipid layer  Functions in cell identification to identify the cell to other cells and molecules  Important in  immunity—so various white blood cells in your body do not mistake your cells for foreign cells - blood typing – so you can ’ t receive just any ol ’ type of blood

Receptor Proteins  Function as “ messenger/receiver ”  Receive information from the environment (extracellular fluid, blood, interstitial fluid) and transmit that info to the inside of the cell  Protein has specific shape/charge to only allow certain molecules (like hormones) to bond  Triggers a response in cell  Ex) epinephrine can bind to a receptor protein and send a message inside that says “ break down glycogen ”

Active Transport Using Vesicles Endocytosis & Exocytosis

Exocytosis  Active Transport  Vesicles fuse with membranes to  Remove cell waste  Export cell products

Endocytosis  “Into cell”  Cell takes in materials by pinching cell membranes into vesicles Once ingested, how will the amoeba digest this protist?