Chapter 5: The Working Cell **This Power Point Presentation can be found on my eBoard**

Energy and the Cell Energy – The ability to do work Kinetic Energy – Energy of movement Potential Energy – Stored energy Heat – The energy associated with the movement of molecules in a body of matter. It is a type of kinetic energy Chemical Energy – Potential energy found in the bonds of molecules

What forms of energy are these?

Laws of Thermodynamics Thermodynamics – study of the energy transformations that occur in a collection of matter (“a system”) –Systems can be closed or open If the system exchanges energy with a surrounding environment, it is open If it does not, then it is closed

Laws of Thermodynamics Examples of Open Systems A human body Examples of Closed Systems Greenhouse

Laws of Thermodynamics First Law “Law of Conservation of Energy” -Energy cannot be created or destroyed; only transformed

Laws of Thermodynamics How is this picture showing the First Law?

Laws of Thermodynamics Second Law –Energy conversions increase entropy Entropy - The amount of disorder in a system

Laws of Thermodynamics This block shows Order.This block shows Entropy.

Laws of Thermodynamics What does this picture show in relation to thermodynamics and systems?

Laws of Thermodynamics

What does it all mean for Biology? –Cells cannot transfer or transform energy with 100% efficiency –Heat always escapes as leftover energy When light energy is converted to chemical energy When chemical energy is converted to kinetic energy

Two Types of Reactions Endergonic Reaction –Requires a net input of energy –Low-energy reactants make high-energy products

Two Types of Reactions Exergonic Reaction –Requires a net output of energy –High-energy reactants make low-energy products

Two Types of Reactions Cellular RespirationPhotosynthesis Know the products and reactants for Cellular Respration and for Photosynthesis.

Two Types of Reactions The products from one reactions become the reactants for the other..

Energy Coupling Using the energy released from an exergonic reaction to drive an endergonic reaction

Energy Coupling Hydrolysis of ATP allows a phosphate group to be available to drive many cell reactions.

Enzymes Proteins that speed up chemical reactions by lowering the activation energy

Enzymes Proteins that speed up chemical reactions by lowering the activation energy

Enzymes – Competitive Inhibition (a) Is the NORMAL Reaction; (b) is with a Competitive Inhibitor

Enzymes – Noncompetitive Inhibition (a) Is the NORMAL Reaction; (b) is with a Noncompetitive Inhibitor

Enzymes – Negative Feedback Control Making enough of the end product should stop Enzyme 1 from doing its job.

Membrane Structure and Function Cell Membrane –Selective Permeability It allows some substances to cross more easily than others It blocks passage of some substances altogether

Membrane Structure and Function Cell Membrane –Selective Permeability

Membrane Structure and Function Cell Membrane –Phospholipids

Membrane Structure and Function Cell Membrane –Fluid Mosaic “Fluid” because the proteins and phospholipids can drift laterally in the membrane. “Mosaic” because it has diverse proteins embedded in a framework or phospholipids

Membrane Structure and Function Cell Membrane –Fluid Mosaic

Membrane Structure and Function Cell Membrane –Fluid Mosaic – Bchttp:// Bc

Membrane Structure and Function Cell Membrane –Selective Permeability

Membrane Structure and Function Transporting Materials into the Cell –Diffusion Movement of substances into the cell or out of the cell without the use of energy The movement is always from high concentration to low concentration Concentration gradient – The spread of different concentrations of a substance across space. Equilibrium – The even distribution of substance across an area or space.

Membrane Structure and Function Transporting Materials into the Cell –Diffusion

Membrane Structure and Function Transporting Materials into the Cell –3 Types of Passive Transport Diffusion (already discussed this one) Facilitated Diffusion (diffusion with a “helper”) Osmosis

Membrane Structure and Function Transporting Materials into the Cell –Why can’t water gets past the phospholipids of the cell membrane? –Hint: Take a look at your notes about the structure of a phospholipid and hypothesize why.

Membrane Structure and Function Transporting Materials into the Cell –Osmosis: The movement of WATER from an area of [low solute] to [high solute]. –In other words: Water “stalks” Solute!

Membrane Structure and Function Transporting Materials into the Cell – Three Osmotic Situations

Membrane Structure and Function Transporting Materials into the Cell Questions 23 – 26 in the Notes will be answered in class on the Board. Please see me if you miss these questions and are unsure of how they should be answered.

Membrane Structure and Function Transporting Materials into the Cell –Facilitated Diffusion (PASSIVE) The movement of particles from [high] to [low] using a membrane protein. Otherwise the particle would not get in or out of the cell.

Membrane Structure and Function Transporting Materials into the Cell –Active Transport Requires Energy Spends ATP Works AGAINST the concentration gradient –Goes from [low] to [high] Classic Example: The Sodium-Potassium (Na + K + ) Pump in a cell –Works to send 3 Na + OUT and 2 K + IN the cell

Membrane Structure and Function Transporting Materials into the Cell –Active Transport

Membrane Structure and Function A Final Word on Energy Coupling… CO 2 & H 2 O O 2 & C 6 H 12 O 6