Cell membranes Links to GCSE  Structure of animals & plant cells  Diffusion  Sensitivity  Hormones

State that plasma (cell surface) membranes are partially permeable barriers. State that plasma (cell surface) membranes are partially permeable barriers. Outline the roles of membranes within cells and at the surface of cells. Outline the roles of membranes within cells and at the surface of cells. © Pearson Education Ltd 2008 This document may have been altered from the original Week 3

Membranes play a role in:  Separating cell contents from the external environment  Separating cell components from cytoplasm  Cell recognition & signalling  Holding the components of some metabolic pathways in place  Regulating the transport of materials into & out of cells

Phospholipids A)Phospholipid molecule enlarged B)Layer of phospholipids at the surface of water

A phospholipid bilayer © Pearson Education Ltd 2008 This document may have been altered from the original Week 3

Through an electron microscope 7-10nm

Describe the fluid mosaic model of membrane structure. Describe the fluid mosaic model of membrane structure. Describe the roles of the components of the cell membrane, including phospholipids, cholesterol, glycolipids, proteins and glycoproteins. Describe the roles of the components of the cell membrane, including phospholipids, cholesterol, glycolipids, proteins and glycoproteins. © Pearson Education Ltd 2008 This document may have been altered from the original Week 3

The ‘Fluid Mosaic Model’ of cell membranes, Singer & Nicholson

Making a model of the ‘Fluid Mosaic Model’!  You will be provided with a range of materials to help you construct a large physical model of ‘The Fluid Mosaic Model of Membranes’  Your model should contain the key structures present in a cell membrane  You will be expected to present your model and explain the functions of ALL of the key structures  You have the remainder of this lesson and only one more for preparation, so will have to work on this outside of lessons (i.e. HOMEWORK!!)

Outline the effects of changing temperature on membrane structure and permeability. Outline the effects of changing temperature on membrane structure and permeability. © Pearson Education Ltd 2008 This document may have been altered from the original Week 3

Explain the term ‘cell signalling’. Explain the term ‘cell signalling’. Explain the role of membrane-bound receptors as sites where hormones and drugs can bind. Explain the role of membrane-bound receptors as sites where hormones and drugs can bind. © Pearson Education Ltd 2008 This document may have been altered from the original Week 3

Key definitions  Cell signalling: cells communicate with one another by signals. Many molecules act as signals –some signal during processes taking place inside cells; others signal from one cell to others. Cytokines are an example of cell signals.

Chemicals & receptor effects  Insulin  Medical drugs such as anti histamines/ beta blockers (high blood pressure), L dopa (schizophrenia) etc  Botox (botulism toxin!)  HIV entry into cells

Membrane transport  Links to GCSE  Diffusion  Osmosis

Describe and explain what is meant by passive transport (diffusion and facilitated diffusion). Describe and explain what is meant by passive transport (diffusion and facilitated diffusion). Describe the role of membrane proteins in passive transport. Describe the role of membrane proteins in passive transport. © Pearson Education Ltd 2008 This document may have been altered from the original Week 4

(a) Simple diffusion © Pearson Education Ltd 2008 This document may have been altered from the original Week 4 (b) Facilitated diffusion using a channel protein channel protein ( c) Facilitated diffusion using a carrier protein carrier protein

Key terms  DIFFUSION: the movement of molecules from a region of high concentration to a region of lower concentration (of that molecule) down a concentration gradient.  KINETIC ENERGY: movement energy possessed by molecules.  EQUILIBRIUM: no OVERALL movement of molecules

Describe and explain what is meant by active transport. Describe and explain what is meant by active transport. © Pearson Education Ltd 2008 This document may have been altered from the original Week 4

Describe and explain what is meant by endocytosis and exocytosis. Describe and explain what is meant by endocytosis and exocytosis. © Pearson Education Ltd 2008 This document may have been altered from the original Week 4

Explain what is meant by osmosis, in terms of water potential. Explain what is meant by osmosis, in terms of water potential. Recognise and explain the effects of solutions of different water potentials on plant and animal cells. Recognise and explain the effects of solutions of different water potentials on plant and animal cells. © Pearson Education Ltd 2008 This document may have been altered from the original Week 4

Osmosis and membrane © Pearson Education Ltd 2008 This document may have been altered from the original Week 4

Plant and animal cells in solutions of high water potential - before and after © Pearson Education Ltd 2008 This document may have been altered from the original Week 4

Plant and animal cells in solutions of low water potential - before and after © Pearson Education Ltd 2008 This document may have been altered from the original Week 4

State that plasma (cell surface) membranes are partially permeable barriers. State that plasma (cell surface) membranes are partially permeable barriers. Outline the roles of membranes within cells and at the surface of cells. Outline the roles of membranes within cells and at the surface of cells. Describe the fluid mosaic model of membrane structure. Describe the fluid mosaic model of membrane structure. Describe the roles of the components of the cell membrane, including phospholipids, cholesterol, glycolipids, proteins and glycoproteins. Describe the roles of the components of the cell membrane, including phospholipids, cholesterol, glycolipids, proteins and glycoproteins. Outline the effects of changing temperature on membrane structure and permeability. Outline the effects of changing temperature on membrane structure and permeability. Explain the term ‘cell signalling’. Explain the term ‘cell signalling’. Explain the role of membrane-bound receptors as sites where hormones and drugs can bind. Explain the role of membrane-bound receptors as sites where hormones and drugs can bind. Describe and explain what is meant by passive transport (diffusion and facilitated diffusion). Describe and explain what is meant by passive transport (diffusion and facilitated diffusion). Describe the role of membrane proteins in passive transport. Describe the role of membrane proteins in passive transport. Explain what is meant by osmosis, in terms of water potential. Explain what is meant by osmosis, in terms of water potential. Recognise and explain the effects of solutions of different water potentials on plant and animal cells. Recognise and explain the effects of solutions of different water potentials on plant and animal cells.