How Big is It? 1

The Plasma Membrane The Plasma Membrane - 2 Gateway to the Cell Allows molecules to move in and out of the cell

What needs to get into and out of the cell? 3

CO 2 and Oxygen 4 Blood cells take Oxygen and nutrients to every cell in the body and CO 2 is removed

Wastes, Carbon dioxide and Urea pass out of cells through membrane 5

Cells are limited to size due to its Volume to Surface area Ratio 6

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Photograph of a Cell Membrane 8

Cell Membrane flexible The cell membrane is flexible and allows a unicellular organism to move 9

Homeostasis Balanced internal condition of cells Also called equilibrium Maintained by plasma membrane controlling what enters & leaves the cell 10

Functions of Plasma Membrane 11 Protective barrier Regulate transport in & out of cell (selectively permeable) Allow cell recognition Provide anchoring sites for filaments of cytoskeleton

Structure of the Cell Membrane copyright cmassengale12

13 Structure of the membrane is Made up of phospholipids, Proteins and cholesterol

A mosaic A picture made of little tiles and pieces of glass gathered and stuck together

FLUID- because individual phospholipids and proteins can move side-to-side within the layer, like it’s a liquid. MOSAIC- because of the pattern produced by the scattered protein molecules when the membrane is viewed from above 15 FLUID MOSAIC MODEL

16 Semipermeable or selectively permeable Membrane Small molecules and larger hydrophobic molecules move through easily. e.g. O 2, CO 2, H 2 O

17 Cell Membrane hydrophilic Polar heads are hydrophilic “water loving ” hydrophobic Nonpolar tails are hydrophobic “water fearing” Makes membrane “Selective” in what crosses

Types of Transport Across Cell Membranes 18

Good Morning 19

20 Passive Transport Simple Diffusion  Doesn’t require energy  Moves high to low concentration Example: Oxygen or water diffusing into a cell and carbon dioxide diffusing out  Example: Oxygen or water diffusing into a cell and carbon dioxide diffusing out.

Passive Transport Simple Diffusion tion__how_diffusion_works.html

(a) Simple diffusion © Pearson Education Ltd 2008 This document may have been altered from the original

DIFFUSION PASSIVE Diffusion is a PASSIVE process which means no energy is used to make the molecules move, they have a natural KINETIC ENERGY 23

Diffusion through a Membrane Cell membrane Solute moves DOWN concentration gradient (HIGH to LOW) Solute= anything that is dissolved (in water)

Diffusion of Liquids 25

w0/chapter2/animation__how_facilitated_diffusion_works.html Facilitated diffusion  Doesn’t require energy  Uses transport proteins to move high to low concentration Examples: Glucose or amino acids moving from blood into a cell.

Osmosis Diffusion of water across a membraneDiffusion of water across a membrane Moves from HIGH to LowMoves from HIGH to Low Is a type of passive transportIs a type of passive transport smosis_works.html Diffusion across a membrane Semipermeable membrane

Diffusion of H 2 O Across A Membrane 28 High H 2 O potential Low solute concentration Low H 2 O potential High solute concentration

Aquaporins Water Channels Protein pores used during OSMOSIS copyright cmassengale29 WATER MOLECULES

Good Morning 11/19 Take out HW Do Now Review passive and active transport Finishing Part 2 of Lab from Monday Quiz tomorrow 30

Factors affecting the rate of diffusion The higher the surface area to volume ratio, the faster diffusion occurs. Vs a steep concentratio n gradient, diffusion rate increases Vs Temperature - molecules move faster in higher temperatures So diffusion will happen faster. Colder = slower

In a nutshell.. The larger the area and difference in concentration and the thinner the surface, the quicker the rate of diffusion In a nutshell.. The larger the area and difference in concentration and the thinner the surface, the quicker the rate of diffusion For example.. in the lung the surface area is made very large by the presence of many alveoli.

in-cells-definition-examples.html Active Transport  Requires energy or ATP  Moves materials from LOW to HIGH concentration  AGAINST concentration gradient

Carrier Proteins Other carrier proteins change shape to move materials across the cell membraneOther carrier proteins change shape to move materials across the cell membrane 34

Examples of Active transport Animal cells 35

Place these features in the correct part of the Venn Diagram Involves water only Requires energy Is passive Movement of particles Needs a semi-permeable membrane High to low concentration Against a concentration gradient Occurs in nature How minerals get into root hair cells How oxygen leaves a leaf How water keeps plant cells turgid Involves transport of solutes DIFFUSION OSMOSIS ACTIVE TRANSPORT

37 Endocytosis – Phagocytosis Used to engulf large particles such as food, bacteria, etc. into vesicles Called “Cell Eating”

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copyright cmassengale39 Phagocytosis Phagocytosis - Capture of a Yeast Cell (yellow) by Membrane Extensions of an Immune System Cell (blue)

40 Moving the “Big Stuff” Molecules are moved out of the cell by vesicles that fuse with the plasma membrane. Exocytosis Exocytosis - moving things out. This is how many hormones are secreted

41 Exocytosis The opposite of endocytosis is exocytosis. Large molecules that are manufactured in the cell are released through the cell membrane. Inside Cell Cell environment

42 Three Forms of Transport Across the Membrane

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44 Good Morning 11/30/15 Do Now : compare passive and active transport (you can use notes) Review what you need to know for transport of molecules (notes) - take out notebook Test on Plasma Membrane – 12/2 Review sheet is due tomorrow Ticket out- Osmosis problems Use tutorials on HW page

45 Things you must know about the plasma membrane It is the barrier between the inside and outside of the cell All cells have a membrane. Plant, animal, fungi, protists, and bacteria. VIRUSES ARE NOT CELLS! (they only have a protein coat and DNA)

46 The Job, the function, of the cell membrane is : it is a protective barrier. IT ALLOWS THINGS TO MOVE IN AND OUT OF THE CELL.

47 IT IS CALLED SELECTIVELY PERMEABLE BECAUSE IT ALLOWS SOME THINGS TO MOVE IN AND OUT DIFFUSION – MOVEMENT OF ANY MOLECULE (O 2, CO 2) EXCEPT WATER. MOVES WITHOUT ENERGY FROM HIGH TO LOW CONCENTRATION FACILITATED DIFFUSION - USES THE PROTEINS TO MOVE MOLECULES ACROSS FROM H  LOW, NO ENERGY OSMOSIS - MOVEMENT OF WATER WITHOUT ENERGY FROM HIGH TO LOW CONCENTRATION WITHOUT ENERGY IS – PASSIVE TRANSPORT

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50 IF MOLECULES NEED TO MOVE FROM AN AREA OF LOW CONCENTRATION TO AN AREA OF HIGHER CONCENTRATION, IT NEEDS ENERGY

Cell in Isotonic Solution 51 CELL 10% NaCL 90% H 2 O 10% NaCL 90% H 2 O What is the direction of water movement? The cell is at _______________. equilibrium ENVIRONMENT NO NET MOVEMENT

Cell in Hypotonic Solution 52 CELL 10% NaCL 90% H 2 O 20% NaCL 80% H 2 O What is the direction of water movement?

Cell in Hypertonic Solution 53 CELL 15% NaCL 85% H 2 O 5% NaCL 95% H 2 O What is the direction of water movement? ENVIRONMENT

Isotonic Solution NO NET MOVEMENT OF H 2 O (equal amounts entering & leaving) Hypotonic Solution CYTOLYSIS- cell busts Hypertonic Solution PLASMOLYSIS - shriveling of cell

Cytolysis & Plasmolysis 55 Cytolysis Plasmolysis

Osmosis in Red Blood Cells 56 Isotonic Hypotonic Hypertonic

57 hypotonichypertonic isotonic hypertonicisotonic hypotonic