Cells and Their Housekeeping Functions Cell Membrane & Membrane Potential

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Cells and Their Housekeeping Functions Cell Membrane & Membrane Potential"

Transcription

1 Cells and Their Housekeeping Functions Cell Membrane & Membrane Potential Shu-Ping Lin, Ph.D. Institute of Biomedical Engineering Website:

2 * Cell membrane, also called plasma membrane, separates cell interior from surroundings Thin barrier = 7~10 nm thick Controls traffic in & out of the cell Selectively permeable * Made of phospholipids, proteins, carbohydrates & other macromolecules *Phospholipids arrange as a bilayer: Hydrophobic fatty acid tails Hydrophilic phosphate group head

3 Several important functions: polar hydrophilic heads Phospholipid Bilayer *A. Allow nutrients to enter cell, *B. Keep out unwanted molecules and particles, *C. Transport waste out into extracellular fluid, *D. Prevent needed metabolites and ions from leaving cell Inherently amphipathic nature: possess both hydrophilic & hydrophobic structures nonpolar hydrophobic tails polar hydrophilic heads TW&gl=tw&pid=bl&srcid=ADGEEShywZ9NflQ-GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY- X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp-LymP07E_VLiGzjkC-wqjHTg

4 More Than Lipids In 1972, S.J. Singer & G. Nicolson proposed that membrane proteins are inserted into the phospholipid bilayer It s like a fluid It s like a mosaic It s the Fluid Mosaic Model! GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T- ukl7xuvpyttyho3ib1sqth0eo8bd2zhkgculbozbeefafy- X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp-LymP07E_VLiGzjkC-wqjHTg

5 Cell membrane is composed of a double layer of phospholipid molecules (called phospholipid or lipid bilayer), protein molecules associated with lipid bilayer, and carbohydratecontaining cell coat called glycocalyx. Glycoprotein Extracellular fluid Glycolipid Phospholipids Peripheral protein Cholesterol Cytoplasm Transmembrane proteins Filaments of cytoskeleton TW&gl=tw&pid=bl&srcid=ADGEEShywZ9NflQ-GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY- X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp-LymP07E_VLiGzjkC-wqjHTg

6 Membrane Fat Composition Varies Fat composition affects flexibility membrane must be fluid & flexible about as fluid as thick salad oil % unsaturated fatty acids in phospholipids keep membrane less viscous cold-adapted organisms, like winter wheat increase % in autumn cholesterol in membrane ech/ch06cellmembranediffusion.ppt+cell+membrane+ ppt&hl=zh- TW&gl=tw&pid=bl&srcid=ADGEEShywZ9NflQ- GCRtlnAD5GIlGBWSBEKRBkJwIU3sr9wakHHx6SCbBg9TuKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFaf Y- X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp -LymP07E_VLiGzjkC-wqjHTg

7 Membrane Proteins Proteins determine membrane s specific functions Cell membrane & organelle membranes each have unique collections of proteins Membrane proteins: Peripheral proteins Loosely bound to surface of membrane Cell surface identity marker (antigens) Integral proteins Penetrate lipid bilayer, usually across whole membrane Transmembrane protein Transport proteins channels, pumps TW&gl=tw&pid=bl&srcid=ADGEEShywZ9NflQ-GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY- X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp-LymP07E_VLiGzjkC-wqjHTg

8 Why are proteins the perfect molecule to build structures in the cell membrane? TW&gl=tw&pid=bl&srcid=ADGEEShywZ9NflQ-GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY- X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp-LymP07E_VLiGzjkC-wqjHTg

9 Classes of Amino Acids What do these amino acids have in common? nonpolar & hydrophobic TW&gl=tw&pid=bl&srcid=ADGEEShywZ9NflQ-GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY- X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp-LymP07E_VLiGzjkC-wqjHTg

10 Classes of Amino Acids What do these amino acids have in common? I like the polar ones the best! polar & hydrophilic TW&gl=tw&pid=bl&srcid=ADGEEShywZ9NflQ-GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9TuKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY-X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp-LymP07E_VLiGzjkC-wqjHTg

11 Proteins Domains Anchor Molecule Within membrane Nonpolar amino acids Hydrophobic Anchors protein into membrane On outer surfaces of membrane Polar amino acids Hydrophilic Extend into extracellular fluid & into cytosol Polar areas of protein Nonpolar areas of protein GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY- X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp-LymP07E_VLiGzjkC-wqjHTg

12 Many Functions of Membrane Proteins Outside Plasma membrane Inside Transporter Enzyme activity Cell surface receptor Cell surface identity marker Cell adhesion Attachment to the cytoskeleton GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY- X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp-LymP07E_VLiGzjkC-wqjHTg

13 Membrane Carbohydrates The carbohydrates are not inserted into the membrane -- they are too hydrophilic for that. They are attached to embedded proteins -- glycoproteins. Play a key role in cell-cell recognition Ability of a cell to distinguish one cell from another Antigens Important in organ & tissue development Basis for rejection of foreign cells by immune system pt&hl=zh-tw&gl=tw&pid=bl&srcid=adgeeshywz9nflq-gcrtlnad5gilgbwsbekrbkjwiu3s- r9wakhhx6scbbg9t-ukl7xuvpyttyho3ib1sqth0eo8bd2zhkgculbozbeefafy- X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp-LymP07E_VLiGzjkC-wqjHTg

14 Movement Across the Cell Membrane GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY- X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp-LymP07E_VLiGzjkC-wqjHTg

15 Selectively Permeable What molecules can get through directly? Small nonpolar molecules such as carbon dioxide, nitrogen, and oxygen diffuse freely across the bilayer. Lipid bilayer is also permeable to small and uncharged polar molecules such as urea and ethanol. Other small hydrophobic molecules: fats and other lipids NOT get through directly? Ions: salts, ammonia (NH 3 ) Large uncharged or charged polar molecules: starches, proteins H 2 O molecule has 2 pathways: Lipid pathway Water channel-protein pathway (polar molecules)

16 Diffusion Across Cell Membrane Cell membrane is the boundary between inside & outside Separates cell from its environment Can it be an impenetrable boundary? NO! IN food carbohydrates sugars, proteins amino acids lipids salts, O 2, H 2 O IN OUT OUT waste ammonia salts CO 2 H 2 O products cell needs materials in & products or waste out GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY-X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp- LymP07E_VLiGzjkC-wqjHTg

17 Diffusion 2nd Law of Thermodynamics governs biological systems universe tends towards disorder (entropy) Diffusion movement from high low concentration GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY-X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp- LymP07E_VLiGzjkC-wqjHTg

18 Diffusion Move from HIGH to LOW concentration passive transport no energy needed Osmotic pressure: the pressure is required to stop the net flow of water across a membrane separating solutions of different particulate concentration diffusion movement of water osmosis /htm/asprague/biotech/ch06cell MembraneDiffusion.ppt+cell+mem brane+ppt&hl=zh- TW&gl=tw&pid=bl&srcid=ADGEES hywz9nflq- GCRtlnAD5GIlGBWSBEKRBkJwIU3 s-r9wakhhx6scbbg9tukl7xuvpyttyho3ib1sqth0eo8bd 2ZhKGcUlBOZBeeFafY- X0MbAXuEr5KIF3tINko9uVQlhxFR csi&sig=ahietbtyrp- LymP07E_VLiGzjkC-wqjHTg Zero flux

19 The Special Case of Water: Movement of water across the cell membrane GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY-X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp- LymP07E_VLiGzjkC-wqjHTg

20 Osmosis Osmosis is diffusion of water Diffusion of water from high concentration of water to low concentration of water across a semi-permeable membrane +cell+membrane+ppt&hl=zh-tw&gl=tw&pid=bl&srcid=adgeeshywz9nflq- GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T- ukl7xuvpyttyho3ib1sqth0eo8bd2zhkgculbozbeefafy- X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp-LymP07E_VLiGzjkC-wqjHTg

21 Concentration of Water Direction of osmosis is determined by comparing total solute concentrations Hypertonic - more solute, less water Hypotonic - less solute, more water Isotonic - equal solute, equal water water hypotonic hypertonic net movement of water GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY-X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp- LymP07E_VLiGzjkC-wqjHTg

22 Effect of Osmotic Pressure Suppose an animal or a plant cell is placed in a solution of sugar or salt in water. If the medium is hypotonic a dilute solution, with a higher water concentration than the cell The cell will gain water and wilt through osmosis. If the medium is isotonic a solution with exactly the same water concentration as the cell There will be no net movement of water across the cell membrane. If the medium is hypertonic a concentrated solution, with a lower water concentration than the cell The cell will lose water and shrink by osmosis.

23 Managing Water Balance Cell survival depends on balancing water uptake & loss freshwater balanced saltwater Animal cells culture: must maintain in isotonic cell culture medium (concentration of solutes is close to cell cytoplasm) GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY-X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp- LymP07E_VLiGzjkC-wqjHTg

24 Aquaporins Cores of these channel proteins are hydrophilic Water moves rapidly into & out of cells Multiple water molecules pass through membrane at a rate of 10 8 molecules/sec Evidence that there were water channels Peter Agre John Hopkins Roderick MacKinnon Rockefeller GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY-X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp- LymP07E_VLiGzjkC-wqjHTg

25 Channels Through Cell Membrane Membrane becomes semi-permeable with protein channels specific channels allow specific material across cell membrane inside cell H 2 O aa sugar NH 3 salt outside cell GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY-X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp- LymP07E_VLiGzjkC-wqjHTg

26 Facilitated Diffusion Diffusion through protein channels Channels move specific molecules across cell membrane No energy needed facilitated = with help open channel = fast transport high low The Bouncer GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY-X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp- LymP07E_VLiGzjkC-wqjHTg

27 Active Transport Cells may need to move molecules against concentration gradient Shape change transports solute from one side of membrane to other Protein pump Costs energy = ATP high conformational change ATP low The Doorman GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY-X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp- LymP07E_VLiGzjkC-wqjHTg

28 Many Models & Mechanisms of Active Transport Ions and polar molecules across cell membranes include: ATP-powered pumps Transporter proteins Ion channels The arrows indicate the direction from high to low concentration of the ion or polar molecule across membrane high low low low high high

29 Getting through cell membrane Passive Transport Simple diffusion diffusion of nonpolar, hydrophobic molecules lipids high low concentration gradient Facilitated transport diffusion of polar, hydrophilic molecules through a protein channel high low concentration gradient Active transport diffusion against concentration gradient low high uses a protein pump requires ATP ATP

30 Transport Summary simple diffusion facilitated diffusion active transport ATP GCRtlnAD5GIlGBWSBEKRBkJwIU3s-r9wakHHx6SCbBg9T-uKL7xUvpYTtYHO3iB1SQtH0eo8bD2ZhKGcUlBOZBeeFafY-X0MbAXuEr5KIF3tINko9uVQlhxFRcsI&sig=AHIEtbTYRp- LymP07E_VLiGzjkC-wqjHTg

31 Active Transport- Na + -K + Pump Sodium ion binds to transport protein in configuration 1 ATP molecule associates with transport protein After ATP hydrolysis, phosphate group is transferred to transport protein Causing to switch of configuration 2 Sodium ion is released to the outside of cell Potassium ion is bound to attachment site of transport protein Binding of potassium ion Result in the release of phosphate group Protein goes back to configuration 1 Potassium ion is released into cell Cycle is completed with the attachment of sodium ion into cavity of transport protein

32 Active Transport- Proton Pump Proton pumps, in a lysosomal membrane, are used by plants, bacteria, and fungi to create electrochemical gradients (sodium-potassium pumps are employed by animals for the same purpose)

33 Examples Retinal chromophore H + NH 2 Water channel in bacteria Porin monomer b-pleated sheets Bacterial outer membrane Nonpolar (hydrophobic) COOH a-helices in the cell membrane H + Cytoplasm proton pump channel in photosynthetic bacteria function through conformational change = shape change

34 Membrane Electrical Potential Membrane potential: The electrical charge across a cell membrane; the difference in electrical potential inside and outside the cell. Axons have two basic electrical potentials: 1. Resting membrane potential: The membrane potential of a neuron when it is not being altered by excitatory or inhibitory postsynaptic potentials. 2. Action potential: The brief electrical impulse that provides the basis for conduction of information along an axon.

35 Electrochemical Gradient An Electrochemical Gradient is a Concentration Gradient with Ions: - These ions want to move down their concentration gradient - These ions (particularly) also want to move towards the opposite charge found on the other side of the membrane - This attraction for the other side of membranes (membrane potential) can be harnessed to do work - Electrochemical gradients essentially are batteries, i.e., means of physically storing electrical energy

AP Biology. The Cell Membrane

AP Biology. The Cell Membrane The Cell Membrane Phospholipids Phosphate head hydrophilic Fatty acid tails hydrophobic Arranged as a bilayer Phosphate attracted to water Fatty acid repelled by water Aaaah, one of those structure function

More information

Ch. 8 - The Cell Membrane

Ch. 8 - The Cell Membrane Ch. 8 - The Cell Membrane 2007-2008 Phospholipids Phosphate head hydrophilic Fatty acid tails hydrophobic Arranged as a bilayer Phosphate attracted to water Fatty acid repelled by water Aaaah, one of those

More information

Division Ave High School AP Biology

Division Ave High School AP Biology The Cell Membrane https://youtu.be/y31dlj6ugge Journal Diagrams Shark book pg. 82 Wolves book pg. 88-89 Membrane Proteins Copy table Cell Membrane Proteins Fluid Mosaic Model Cell Membrane Phospholipids

More information

Chapter 8. Movement across the Cell Membrane. AP Biology

Chapter 8. Movement across the Cell Membrane. AP Biology Chapter 8. Movement across the Cell Membrane More than just a barrier Expanding our view of cell membrane beyond just a phospholipid bilayer barrier phospholipids plus Fluid Mosaic Model In 1972, S.J.

More information

The Cell Membrane: Structure and Func4on

The Cell Membrane: Structure and Func4on The Cell Membrane: Structure and Func4on Overview of the Cell Membrane All cells have a cell membrane Separates living cell from nonliving surroundings Mainly made of phospholipids proteins & other macromolecules

More information

Allows certain materials and of the cell. The cell membrane is selectively permeable

Allows certain materials and of the cell. The cell membrane is selectively permeable Overview The cell membrane forms a barrier around the cell and separates it from the outside environment What is the main function of the cell membrane? Allows certain materials and of the cell The cell

More information

1. The lipid layer that forms the foundation of cell membranes is primarily composed of molecules called.

1. The lipid layer that forms the foundation of cell membranes is primarily composed of molecules called. Cell Membranes 1. The lipid layer that forms the foundation of cell membranes is primarily composed of molecules called. 2. Due to the repellent nature of the polar water molecules, the tails of the phospholipids

More information

Cell Membrane Structure and Function. Prof. Dr. Turgut Ulutin

Cell Membrane Structure and Function. Prof. Dr. Turgut Ulutin Cell Membrane Structure and Function Prof. Dr. Turgut Ulutin Why do we need the plasma membrane? Keeping the goods concentrated Keeping harmful materials out Transports substances in and out of the cell

More information

A membrane s structure and functions are determined by its constituents: lipids, proteins, and carbohydrates.

A membrane s structure and functions are determined by its constituents: lipids, proteins, and carbohydrates. A membrane s structure and functions are determined by its constituents: lipids, proteins, and carbohydrates. The general design of membranes is known as the fluid mosaic model. Phospholipids form a continuous

More information

The Cell Membrane MEMBRANE STRUCTURE AND FUNCTION. Mader: Chapter Membranes are a fluid mosaic of phospholipids and proteins

The Cell Membrane MEMBRANE STRUCTURE AND FUNCTION. Mader: Chapter Membranes are a fluid mosaic of phospholipids and proteins The Cell Membrane Mader: Chapter 4 MEMBRANE STRUCTURE AND FUNCTION 5.1 Membranes are a fluid mosaic of! Membranes are composed of phospholipids and proteins Membranes are commonly described as a fluid

More information

Six major functions of membrane proteins: Transport Enzymatic activity

Six major functions of membrane proteins: Transport Enzymatic activity CH 7 Membranes Cellular Membranes Phospholipids are the most abundant lipid in the plasma membrane. Phospholipids are amphipathic molecules, containing hydrophobic and hydrophilic regions. The fluid mosaic

More information

Membrane Structure and Function

Membrane Structure and Function Membrane Structure and Function -plasma membrane acts as a barrier between cells and the surrounding. -plasma membrane is selective permeable -consist of lipids, proteins and carbohydrates -major lipids

More information

Cell Membrane & Tonicity Worksheet

Cell Membrane & Tonicity Worksheet NAME ANSWER KEY DATE PERIOD Cell Membrane & Tonicity Worksheet Composition of the Cell Membrane & Functions The cell membrane is also called the PLASMA membrane and is made of a phospholipid BI-LAYER.

More information

7-3 Cell Boundaries. Diffusion Through Cell Boundaries

7-3 Cell Boundaries. Diffusion Through Cell Boundaries Diffusion Through Cell Boundaries Every living cell exists in a liquid environment. The cell membrane regulates movement of dissolved molecules from the liquid on one side of the membrane to the liquid

More information

Chapter 5 The Plasma Membrane and Transport

Chapter 5 The Plasma Membrane and Transport Chapter 5 The Plasma Membrane and Transport State Standard Standard 1.a. Membrane Function 1, Forms a boundary between living cells and their surroundings. 2. Controls the movement of molecules into and

More information

Cell Membrane Coloring Worksheet

Cell Membrane Coloring Worksheet Cell Membrane Coloring Worksheet Composition of the Cell Membrane & Functions The cell membrane is also called the plasma membrane and is made of a phospholipid bilayer. The phospholipids have a hydrophilic

More information

BSC 2010 - Exam I Lectures and Text Pages. The Plasma Membrane Structure and Function. Phospholipids. I. Intro to Biology (2-29) II.

BSC 2010 - Exam I Lectures and Text Pages. The Plasma Membrane Structure and Function. Phospholipids. I. Intro to Biology (2-29) II. BSC 2010 - Exam I Lectures and Text Pages I. Intro to Biology (2-29) II. Chemistry of Life Chemistry review (30-46) Water (47-57) Carbon (58-67) Macromolecules (68-91) III. Cells and Membranes Cell structure

More information

The Lipid Bilayer Is a Two-Dimensional Fluid

The Lipid Bilayer Is a Two-Dimensional Fluid The Lipid Bilayer Is a Two-Dimensional Fluid The aqueous environment inside and outside a cell prevents membrane lipids from escaping from bilayer, but nothing stops these molecules from moving about and

More information

The structure and function of the plasma membrane

The structure and function of the plasma membrane The structure and function of the plasma membrane Our current view of membrane structure is based on the fluid mosaic model. This model proposes that membranes are not rigid, with molecules locked into

More information

BIOLOGICAL MEMBRANES: FUNCTIONS, STRUCTURES & TRANSPORT

BIOLOGICAL MEMBRANES: FUNCTIONS, STRUCTURES & TRANSPORT BIOLOGICAL MEMBRANES: FUNCTIONS, STRUCTURES & TRANSPORT UNIVERSITY OF PNG SCHOOL OF MEDICINE AND HEALTH SCIENCES DISCIPLINE OF BIOCHEMISTRY AND MOLECULAR BIOLOGY BMLS II / B Pharm II / BDS II VJ Temple

More information

4. Biology of the Cell

4. Biology of the Cell 4. Biology of the Cell Our primary focus in this chapter will be the plasma membrane and movement of materials across the plasma membrane. You should already be familiar with the basic structures and roles

More information

Transport Across Cell Membranes

Transport Across Cell Membranes Transport Across Cell Membranes CELL MEMBRANE STRUCTURE A phospholipid bilayer makes up the main part of the cell membrane Each phospholipid molecule contains a charged polar head (H 2 O-loving) and non-polar,

More information

CELL MEMBRANES, TRANSPORT, and COMMUNICATION. Teacher Packet

CELL MEMBRANES, TRANSPORT, and COMMUNICATION. Teacher Packet AP * BIOLOGY CELL MEMBRANES, TRANSPORT, and COMMUNICATION Teacher Packet AP* is a trademark of the College Entrance Examination Board. The College Entrance Examination Board was not involved in the production

More information

CHAPTER 5.1 5.2: Plasma Membrane Structure

CHAPTER 5.1 5.2: Plasma Membrane Structure CHAPTER 5.1 5.2: Plasma Membrane Structure 1. Describe the structure of a phospholipid molecule. Be sure to describe their behavior in relationship to water. 2. What happens when a collection of phospholipids

More information

1.1.2. thebiotutor. AS Biology OCR. Unit F211: Cells, Exchange & Transport. Module 1.2 Cell Membranes. Notes & Questions.

1.1.2. thebiotutor. AS Biology OCR. Unit F211: Cells, Exchange & Transport. Module 1.2 Cell Membranes. Notes & Questions. thebiotutor AS Biology OCR Unit F211: Cells, Exchange & Transport Module 1.2 Cell Membranes Notes & Questions Andy Todd 1 Outline the roles of membranes within cells and at the surface of cells. The main

More information

Unit 2: Cells, Membranes and Signaling CELL MEMBRANE. Chapter 5 Hillis Textbook

Unit 2: Cells, Membranes and Signaling CELL MEMBRANE. Chapter 5 Hillis Textbook Unit 2: Cells, Membranes and Signaling CELL MEMBRANE Chapter 5 Hillis Textbook HOW DOES THE LAB RELATE TO THE NEXT CHAPTER? SURFACE AREA: the entire outer covering of a cell that enables materials pass.

More information

The Cell Membrane and Transport

The Cell Membrane and Transport The Cell Membrane and Transport Membrane Structure Fluid Mosaic Structure: The Fluid Part Phospholipids: main lipid in the cell membrane; in a bilayer Polar head = attracted to water - hydrophilic Non-polar

More information

8.2 Cell Transport. **The cell must move different substances into and out of the cell. **8.2 discusses the different methods of cell transport

8.2 Cell Transport. **The cell must move different substances into and out of the cell. **8.2 discusses the different methods of cell transport 8.2 Bellringer.. (1)In your own words, define passive, active, and transport Now, imagine sitting in a boat that is moving downstream with the current. Then, imagine a small motor to move the same boat

More information

What will you learn?

What will you learn? What will you learn? Cell Membrane and Transport PLO B9 B10 It is expected that students will analyse the structure and function of the cell membrane explain why cells divide when they reach a particular

More information

FIGURE 2.18. A. The phosphate end of the molecule is polar (charged) and hydrophilic (attracted to water).

FIGURE 2.18. A. The phosphate end of the molecule is polar (charged) and hydrophilic (attracted to water). PLASMA MEMBRANE 1. The plasma membrane is the outermost part of a cell. 2. The main component of the plasma membrane is phospholipids. FIGURE 2.18 A. The phosphate end of the molecule is polar (charged)

More information

Homeostasis & Cell Transport

Homeostasis & Cell Transport In order to maintain life, organisms must regulate the balance of materials inside and outside of the cell. This is accomplished by the transport of materials through the plasma membrane. Homeostasis &

More information

Chapter 7: Membrane Structure and Function

Chapter 7: Membrane Structure and Function Name Period Concept 7.1 Cellular membranes are fluid mosaics of lipids and proteins 1. The large molecules of all living things fall into just four main classes. Name them. 2. Explain what is meant when

More information

CELL MEMBRANES and TRANSPORT. Regular Biology Mr. Wilbrandt

CELL MEMBRANES and TRANSPORT. Regular Biology Mr. Wilbrandt CELL MEMBRANES and TRANSPORT Regular Biology Mr. Wilbrandt 1 Targets I will be able to.. Identify the parts of the cell or plasma membrane Compare and contrast how the different parts of the membrane work.

More information

BIOLOGY 12 - Cell Membrane and Cell Wall Function: Chapter Notes

BIOLOGY 12 - Cell Membrane and Cell Wall Function: Chapter Notes BIOLOGY 12 - Cell Membrane and Cell Wall Function: Chapter Notes The cell membrane is the gateway into the cell, and must allow needed things such as nutrients into the cell without letting them escape.

More information

Biological cell membranes

Biological cell membranes Unit 14: Cell biology. 14 2 Biological cell membranes The cell surface membrane surrounds the cell and acts as a barrier between the cell s contents and the environment. The cell membrane has multiple

More information

" separate cell from its environment. " cell membrane is the boundary. Regents Biology. " phospholipids

 separate cell from its environment.  cell membrane is the boundary. Regents Biology.  phospholipids Cell (plasma) membrane! Cells need an inside & an outside " separate cell from its environment " cell membrane is the boundary Cell Membranes & Movement Across Them IN food - s - proteins - s salts O 2

More information

Membrane Structure and Function

Membrane Structure and Function Membrane Structure and Function Part A Multiple Choice 1. The fluid mosaic model describes membranes as having A. a set of protein channels separated by phospholipids. B. a bilayer of phospholipids in

More information

Membrane Structure and Function - 1

Membrane Structure and Function - 1 Membrane Structure and Function - 1 The Cell Membrane and Interactions with the Environment As mentioned earlier, the boundary between any cell and its environment is the plasma membrane. Each cell must

More information

Section 7-3 Cell Boundaries

Section 7-3 Cell Boundaries Note: For the past several years, I ve been puzzling how to integrate new discoveries on the nature of water movement through cell membranes into Chapter 7. The Section below is a draft of my first efforts

More information

The cell. Lecture 5. The Cell membrane and Membrane Proteins. Cellular membranes A cell is the simplest collection of matter that can live

The cell. Lecture 5. The Cell membrane and Membrane Proteins. Cellular membranes A cell is the simplest collection of matter that can live Lecture 5 The cell The Cell membrane and Membrane Proteins Ameoba- single celled organism A single human cell The Cell is the simplest collec4on of ma9er that can live Cells 4ssue organ Cellular membranes

More information

Cell membrane. Multiple Choice Identify the choice that best completes the statement or answers the question.

Cell membrane. Multiple Choice Identify the choice that best completes the statement or answers the question. Cell membrane Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Which of the following types of molecules are the major structural components of the cell

More information

Cell Biology - Part 2 Membranes

Cell Biology - Part 2 Membranes Cell Biology - Part 2 Membranes The organization of cells is made possible by membranes. Membranes isolate, partition, and compartmentalize cells. 1 Membranes isolate the inside of the cell from the outside

More information

Cell Transport and Plasma Membrane Structure

Cell Transport and Plasma Membrane Structure Cell Transport and Plasma Membrane Structure POGIL Guided Inquiry Learning Targets Explain the importance of the plasma membrane. Compare and contrast different types of passive transport. Explain how

More information

Chapter Plasma Membrane Structure and Function 1. The plasma membrane is a phospholipid bilayer with embedded proteins. 2. Phospholipids have

Chapter Plasma Membrane Structure and Function 1. The plasma membrane is a phospholipid bilayer with embedded proteins. 2. Phospholipids have Chapter 5 5.1 Plasma Membrane Structure and Function 1. The plasma membrane is a phospholipid bilayer with embedded proteins. 2. Phospholipids have both hydrophilic and hydrophobic regions; nonpolar tails

More information

IB104 - Lecture 9 - Membranes

IB104 - Lecture 9 - Membranes There have been many magnificent boats built to try to reach 50 knots. This was the creation of an Australian team that held the record for more than a decade, from 1993 till 2005, at 46.5 knots with their

More information

Modes of Membrane Transport

Modes of Membrane Transport Modes of Membrane Transport Transmembrane Transport movement of small substances through a cellular membrane (plasma, ER, mitochondrial..) ions, fatty acids, H 2 O, monosaccharides, steroids, amino acids

More information

Cell Membrane Properties

Cell Membrane Properties Cell Membrane Properties Purpose of the lab: review the structure and function of the cell membrane understand the three types of transport across a membrane, and the special case of osmosis using Elodea

More information

Osmosis, Diffusion and Cell Transport

Osmosis, Diffusion and Cell Transport Osmosis, Diffusion and Cell Transport Types of Transport There are 3 types of transport in cells: 1. Passive Transport: does not use the cell s energy in bringing materials in & out of the cell 2. Active

More information

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

Cell Membrane. The cell membrane is flexible and allows a unicellular organism to move Cell Membrane Outer membrane of the cell to protect its contents Regulates the molecules that pass in and out of the cell (selectively permeable) Give the cell its shape Cell Membrane Outer membrane of

More information

PASSIVE TRANSPORT PROCESSES

PASSIVE TRANSPORT PROCESSES BIOZONE Assignment #2 Cell Membrane Transport PASSIVE TRANSPORT PROCESSES 1. Describe two properties of an exchange surface that would facilitate rapid diffusion rates*: (a) thin membrane (b) porous membrane

More information

7. A selectively permeable membrane only allows certain molecules to pass through.

7. A selectively permeable membrane only allows certain molecules to pass through. CHAPTER 2 GETTING IN & OUT OF CELLS PASSIVE TRANSPORT Cell membranes help organisms maintain homeostasis by controlling what substances may enter or leave cells. Some substances can cross the cell membrane

More information

Keystone Study Guide Module A: Cells and Cell Processes

Keystone Study Guide Module A: Cells and Cell Processes Keystone Study Guide Module A: Cells and Cell Processes Topic 1: Biological Principles Cells and the Organization of Life Characteristics of Life all living things share the following characteristics:

More information

Homeostasis and Transport Module A Anchor 4

Homeostasis and Transport Module A Anchor 4 Homeostasis and Transport Module A Anchor 4 Key Concepts: - Buffers play an important role in maintaining homeostasis in organisms. - To maintain homeostasis, unicellular organisms grow, respond to the

More information

PSI Biology Membranes & Enzymes

PSI Biology Membranes & Enzymes Membranes Membranes, Diffusion Classwork 1. How does a phospholipid membrane create an isolated internal environment? 2. Draw and label a phospholipid. 3. In what way do the screen on a window and a cell

More information

Membrane Structure and Function

Membrane Structure and Function Chapter 7 Membrane Structure and Function Lecture Outline Overview: Life at the Edge The plasma membrane separates the living cell from its surroundings. This thin barrier, 8 nm thick, controls traffic

More information

Membranes very thin films of molecules that enclose cells, organelles, compartments

Membranes very thin films of molecules that enclose cells, organelles, compartments Membranes Overview Membranes very thin films of molecules that enclose cells, organelles, compartments Membrane composition Very different composition in prokaryotes and eukaryotes Typically composed of

More information

3.3 Cell Membrane (p. 81)

3.3 Cell Membrane (p. 81) Name Bio PreAP/GT 3.3 Cell Membrane (p. 81) Cell Membranes are composed of two phospholipid layers. The cell membrane, or the membrane, forms a boundary between a cell and the outside environment and controls

More information

CELL MEMBRANE & CELL TRANSPORT (PASSIVE and ACTIVE) Webquest

CELL MEMBRANE & CELL TRANSPORT (PASSIVE and ACTIVE) Webquest Name: Period: CELL MEMBRANE & CELL TRANSPORT (PASSIVE and ACTIVE) Webquest PART I: CELL MEMBRANES WEBSITE #1: http://www.wisc-online.com/objects/index_tj.asp?objid=ap1101 1. What is the BASIC UNIT of LIFE?

More information

Cell Membranes. Cell Membranes. Passive and Active Transport. Homeostasis Requires Exchange of Materials. Water and Solute Transport

Cell Membranes. Cell Membranes. Passive and Active Transport. Homeostasis Requires Exchange of Materials. Water and Solute Transport Homeostasis Requires Exchange of Materials Water and Solute Transport Transportation of solutes in solution Movement between external and internal environments Movement between internal environment and

More information

PART I: Neurons and the Nerve Impulse

PART I: Neurons and the Nerve Impulse PART I: Neurons and the Nerve Impulse Identify each of the labeled structures of the neuron below. A. B. C. D. E. F. G. Identify each of the labeled structures of the neuron below. A. dendrites B. nucleus

More information

Big Idea: The plasma membrane allows the cell to separate the extracellular (outside cell) environment from the inside of the cell while still

Big Idea: The plasma membrane allows the cell to separate the extracellular (outside cell) environment from the inside of the cell while still Big Idea: The plasma membrane allows the cell to separate the extracellular (outside cell) environment from the inside of the cell while still allowing nutrients in the cell and wastes out of the cell.

More information

Chapter 3. Cellular Structure and Function Worksheets. 39 www.ck12.org

Chapter 3. Cellular Structure and Function Worksheets. 39 www.ck12.org Chapter 3 Cellular Structure and Function Worksheets (Opening image copyright by Sebastian Kaulitzki, 2010. Used under license from Shutterstock.com.) Lesson 3.1: Introduction to Cells Lesson 3.2: Cell

More information

I. What is the structure of the plasma membrane and what functions does it make possible?

I. What is the structure of the plasma membrane and what functions does it make possible? Subquestions: I. What is the structure of the plasma membrane and what functions does it make possible? A. What is the structure of the membrane? B. What are the following terms, how does the membrane

More information

The Cell Membrane The barrier to the cell. Mrs. Dignan s Science Class

The Cell Membrane The barrier to the cell. Mrs. Dignan s Science Class The Cell Membrane The barrier to the cell Mrs. Dignan s Science Class Cell Membrane Physical Description: thin, flexible barrier made of phospholipids around the cell (just inside the cell wall OR the

More information

Chapter 5: Homeostasis and Transport Lesson 2: Cell Transport-Passive and Active

Chapter 5: Homeostasis and Transport Lesson 2: Cell Transport-Passive and Active Chapter 5: Homeostasis and Transport Lesson 2: Cell Transport-Passive and Active Lesson One helped us to learn the different cell structures that are involved in cell transport. In this lesson you will

More information

Objectives. Key Terms

Objectives. Key Terms Objectives Relate diffusion and equilibrium. Describe how passive transport occurs. Relate osmosis to solute concentration. Explain how active transport differs from passive transport. Describe how large

More information

Keystone Review Practice Test Module A Cells and Cell Processes. 1. Which characteristic is shared by all prokaryotes and eukaryotes?

Keystone Review Practice Test Module A Cells and Cell Processes. 1. Which characteristic is shared by all prokaryotes and eukaryotes? Keystone Review Practice Test Module A Cells and Cell Processes 1. Which characteristic is shared by all prokaryotes and eukaryotes? a. Ability to store hereditary information b. Use of organelles to control

More information

Transmembrane proteins span the bilayer. α-helix transmembrane domain. Multiple transmembrane helices in one polypeptide

Transmembrane proteins span the bilayer. α-helix transmembrane domain. Multiple transmembrane helices in one polypeptide Transmembrane proteins span the bilayer α-helix transmembrane domain Hydrophobic R groups of a.a. interact with fatty acid chains Multiple transmembrane helices in one polypeptide Polar a.a. Hydrophilic

More information

Date: Student Name: Teacher Name: Jared George. Score: 1) A cell with 1% solute concentration is placed in a beaker with a 5% solute concentration.

Date: Student Name: Teacher Name: Jared George. Score: 1) A cell with 1% solute concentration is placed in a beaker with a 5% solute concentration. Biology Keystone (PA Core) Quiz Homeostasis and Transport - (BIO.A.4.1.1 ) Plasma Membrane, (BIO.A.4.1.2 ) Transport Mechanisms, (BIO.A.4.1.3 ) Transport Facilitation Student Name: Teacher Name: Jared

More information

Cellular Transport Notes. Biology 2201

Cellular Transport Notes. Biology 2201 Cellular Transport Notes Biology 2201 About Cell Membranes 1.All cells have a cell membrane 2.Functions: a.controls what enters and exits the cell to maintain an internal balance called homeostasis b.provides

More information

Test Booklet. Subject: SC, Grade: 9- Quiz: Cell Processes. Student name:

Test Booklet. Subject: SC, Grade: 9- Quiz: Cell Processes. Student name: Test Booklet Subject: SC, Grade: 9- Quiz: Cell Processes Student name: Author: Jennifer Holm School: Lincoln High School Printed: Tuesday February 09, 2016 1 Which describes the cell theory? A Cells are

More information

15.2. Objectives At the end of this lecture, you should be able to

15.2. Objectives At the end of this lecture, you should be able to Lecture 15: Molecular Structure of the Cell Membrane 15.1. Introduction Welcome to this lecture on molecular structure of the cell membrane. In this lecture, we are going to look at the molecules that

More information

Cells Need to Exchange Materials with the Extracellular Fluid. Membrane Transport. Plasma Membrane. Cells Must Control Movements of Materials

Cells Need to Exchange Materials with the Extracellular Fluid. Membrane Transport. Plasma Membrane. Cells Must Control Movements of Materials Membrane Transport Chapter 6 Cells Need to Exchange Materials with the Extracellular Fluid Take in nutrients O 2 energy substrates building materials cofactors Dispose of wastes CO 2 Urea Cells Must Control

More information

water Passive transport moves solute from high to low concentration b) In active transport how do solutes move along their concentration gradient?

water Passive transport moves solute from high to low concentration b) In active transport how do solutes move along their concentration gradient? Membrane Transport Model 1: Active versus Passive Transport Body fluids are solutions of water and dissolved solutes (ions, glucose, amino acids, etc.). The plasma membrane is a selectively permeable barrier

More information

Anatomy and Physiology Placement Exam 2 Practice with Answers at End!

Anatomy and Physiology Placement Exam 2 Practice with Answers at End! Anatomy and Physiology Placement Exam 2 Practice with Answers at End! General Chemical Principles 1. bonds are characterized by the sharing of electrons between the participating atoms. a. hydrogen b.

More information

MEMBRANE STRUCTURE AND FUNCTION

MEMBRANE STRUCTURE AND FUNCTION Chapter 5 The Working Cell: Membranes, Energy, and s Chapter 5: Big Ideas Cellular respiration Membrane Structure and Function Energy and the Cell How s Function MEMBRANE STRUCTURE AND FUNCTION Membranes

More information

Cells, Membranes, Tissues and Skin

Cells, Membranes, Tissues and Skin Session Objectives. What you will cover Basic cell organelles Plasma membrane structure Basic function of membrane proteins Tissues Skin Cells, Membranes, Tissues and Skin Your objectives are List the

More information

The light comes from a set of chemical reactions, the luciferin-luciferase system Fireflies make light energy from chemical energy

The light comes from a set of chemical reactions, the luciferin-luciferase system Fireflies make light energy from chemical energy Cool Fires Attract Mates and Meals Fireflies use light instead of chemical signals to send a message to potential mates Females can also use light to attract males of other firefly species, as meals not

More information

Chapter 7: CELL MEMBRANE STRUCTURE AND FUNCTION

Chapter 7: CELL MEMBRANE STRUCTURE AND FUNCTION BIOLOGY I Chapter 7: CELL MEMBRANE STRUCTURE AND FUNCTION Evelyn I. Milian Instructor 2012 PLASMA MEMBRANE (Cell Membrane or Cytoplasmic Membrane) The plasma membrane is the cell s flexible outer limiting

More information

Active Transport Moves solute Against Their Electrochemical Gradient

Active Transport Moves solute Against Their Electrochemical Gradient Active Transport Moves solute Against Their Electrochemical Gradient Active transport of solutes against their electrochemical gradient is essential to maintain the intracellular ionic composition of cells

More information

The human respiratory system includes the nose, the larynx, and the lungs. This body system helps maintain homeostasis by

The human respiratory system includes the nose, the larynx, and the lungs. This body system helps maintain homeostasis by Study Island 1. During heatstroke, the body can't dispose of excess heat. As a result, the homeostatic balance is disturbed, and internal body temperatures can reach as much as 110. Heatstroke is dangerous

More information

Total body water ~(60% of body mass): Intracellular fluid ~2/3 or ~65% Extracellular fluid ~1/3 or ~35% fluid. Interstitial.

Total body water ~(60% of body mass): Intracellular fluid ~2/3 or ~65% Extracellular fluid ~1/3 or ~35% fluid. Interstitial. http://www.bristol.ac.uk/phys-pharm/teaching/staffteaching/sergeykasparov.htmlpharm/teaching/staffteaching/sergeykasparov.html Physiology of the Cell Membrane Membrane proteins and their roles (channels,

More information

Basic Characteristics of Cells. Cell Structure and Function. Each Cell Has Three Primary Regions. Basic Characteristics of Cells. The Plasma Membrane

Basic Characteristics of Cells. Cell Structure and Function. Each Cell Has Three Primary Regions. Basic Characteristics of Cells. The Plasma Membrane Basic Characteristics of Cells Cell Structure and Function Chapter 3 Smallest living subdivision of the human body Diverse in structure and function Small Basic Characteristics of Cells Each Cell Has Three

More information

Cell membranes and transport. Learning Objective:

Cell membranes and transport. Learning Objective: Cell membranes and transport Content Fluid mosaic model of membrane structure Movement of substances into and out of cells Learning Objective: a. Describe and explain the fluid mosaic model of membrane

More information

Electron Transport Generates a Proton Gradient Across the Membrane

Electron Transport Generates a Proton Gradient Across the Membrane Electron Transport Generates a Proton Gradient Across the Membrane Each of respiratory enzyme complexes couples the energy released by electron transfer across it to an uptake of protons from water in

More information

Name Date Class. This section describes cell structure and function in plant cells, animal cells, and bacteria.

Name Date Class. This section describes cell structure and function in plant cells, animal cells, and bacteria. Looking Inside Cells This section describes cell structure and function in plant cells, animal cells, and bacteria. Use Target Reading Skills Before you read, preview Figure 12. Then write two questions

More information

Transporting molecules across cell membranes. Nutrients, wastes, hormones, ions

Transporting molecules across cell membranes. Nutrients, wastes, hormones, ions Transporting molecules across cell membranes Nutrients, wastes, hormones, ions Recall phospholipid bilayer It s a barrier! Only a small subset of molecules may pass through without help Cell membrane Sense

More information

Cell Membrane Structure (and How to Get Through One)

Cell Membrane Structure (and How to Get Through One) Cell Membrane Structure (and How to Get Through One) A cell s membrane is a wall of sorts that defines the boundaries of a cell. The membrane provides protection and structure for the cell and acts as

More information

Biol 101 Exam 2: Cells & Cell Membranes Fall 2008

Biol 101 Exam 2: Cells & Cell Membranes Fall 2008 MULTIPLE CHOICE. There are 60 questions on this exam. All answers go on the Scantron. Choose the one alternative that best completes the statement or answers the question. 1. The cell theory is one of

More information

8.1 The Cell Membrane

8.1 The Cell Membrane CHAPTER 8 CELL PROCESSES 8.1 The Cell Membrane The cell membrane is kind of like a soap bubble (Figure 8.1). A soap bubble consists of a thin, flexible membrane. The soapy membrane seals the inside air

More information

BIO.2 a) water chemistry and its impact on life processes; b) the structure and function of macromolecules BIO.3 d) the cell membrane model

BIO.2 a) water chemistry and its impact on life processes; b) the structure and function of macromolecules BIO.3 d) the cell membrane model Membrane Transport Lesson Plan Topic: Membrane Structure and Passive Transport NSES: Content Standard A: Students will learn the abilities necessary to do and understand scientific inquiry SOLs: Date:

More information

The Cell Membrane Lecture Outline Introduction The Fluid Mosaic Model of the Cell Membrane

The Cell Membrane Lecture Outline Introduction The Fluid Mosaic Model of the Cell Membrane The Cell Membrane Lecture Outline Introduction The Fluid Mosaic Model of the Cell Membrane Structure of Phospholipids - The Amphipathic Nature of Phospholipids Asymmetry of Lipid Bilayer Micelles: An Alternative

More information

Introduction to Body Fluids

Introduction to Body Fluids Introduction to Body Fluids Graphics are used with permission of: Pearson Education Inc., publishing as Benjamin Cummings (http://www.aw-bc.com) Page 1: Introduction to Body Fluids The fluids in your body

More information

Human Anatomy & Physiology I with Dr. Hubley. Practice Exam 1

Human Anatomy & Physiology I with Dr. Hubley. Practice Exam 1 Human Anatomy & Physiology I with Dr. Hubley Practice Exam 1 1. Which definition is the best definition of the term gross anatomy? a. The study of cells. b. The study of tissues. c. The study of structures

More information

Membrane Structure, Transport, and Cell Junctions

Membrane Structure, Transport, and Cell Junctions Membrane Structure, Transport, and Cell Junctions 5 A model for the structure of aquaporin. This protein, found in the plasma membrane of many cell types, such as red blood cells and plant cells, forms

More information

Lecture 4 Cell Membranes & Organelles

Lecture 4 Cell Membranes & Organelles Lecture 4 Cell Membranes & Organelles Structure of Animal Cells The Phospholipid Structure Phospholipid structure Encases all living cells Its basic structure is represented by the fluidmosaic model Phospholipid

More information

Ch 1 - The Cell & Cell Processes

Ch 1 - The Cell & Cell Processes Ch 1 - The Cell & Cell Processes P All cells have Cell membrane - phospholipid bilayer surrounding cell parts Cytoplasm - everything between cell membrane + nucleus P Most cells have Nucleus - brain of

More information

What is the function of the cell membrane?

What is the function of the cell membrane? What is the function of the cell membrane? 1. DIFFUSION: The movement of molecules from an area of high concentration to an area of lower concentration. Why do molecules move from high concentration to

More information

Membrane Transport. Extracellular Concentration of X

Membrane Transport. Extracellular Concentration of X Use the following graph to answer questions 1 and 2. Rate of diffusion of X into the cell 1. Which of the following processes is represented by the above graph? c. Active transport 2. Molecule X is most

More information

Ordered Structures of Lipids - Bilayers form spontaneously over large areas

Ordered Structures of Lipids - Bilayers form spontaneously over large areas Membranes What are the purposes of membranes? Physical barriers/compartmentalization Gatekeepers exclusion of toxic molecules Energy and signal transduction Aid in cell locomotion Cell-cell interactions

More information