 Materials:  PICK UP A COPY OF THE LAB  Notes pages and pencil  The Plan:  Macromolecule review  Macromolecule Quiz  Begin Eggcellent Lab  Take Energy in a Cell notes  The Assessment:  Cell Organelle Quiz on Monday

Microtubules that allow these single-celled organisms (protists) to move.

 General Information:  Organic vs. inorganic molecules  Monomer vs. polymer  Dehydration synthesis vs. hydrolysis  Carbohydrate monomer, function, test  Lipid monomer, function, test  Protein monomer, bonds, function, test  Nucleic acid monomer, monomer parts, function

Energy of Chemical Reactions Basics of Energy Enzymes & Substrates Movement of Substances Passive Transport: Diffusion & Osmosis Active Transport: Proteins, Exocytosis, & Endocytosis Energy Organelles Chloroplasts Mitochondria

 Energy is defined as the capacity to do work  All organisms require energy to stay alive  Energy makes change possible, for example chemical changes  Two types of energy:  Kinetic Energy: energy that is actually doing work  Potential Energy: stored energy

 First law of thermodynamics  “Law of Conservation of Energy”  Energy can be changed from one form to another  Energy cannot be created or destroyed  Second law of thermodynamics  Energy changes are not 100% efficient

 Cells carry out thousands of chemical reactions  The sum of these reactions constitutes cellular metabolism

 There are two types of chemical reactions: 1. Endergonic reactions absorb energy and yield products rich in potential energy AKA: Endothermic reactions Reactants Potential energy of molecules Products Amount of energy INPUT

2. Exergonic reactions release energy and yield products that contain less potential energy than the reactants  AKA: Exothermic reactions Reactants Potential energy of molecules Products Amount of energy OUTPUT

Biological catalysts Lower activation energy needed for a chemical reaction in the cell

11 (  Most enzymes are proteins (tertiary and quaternary structures)  Act as catalyst to accelerate a reaction  Not permanently changed in the process

12  Are specific for what they will catalyze  Are reusable  End in –ase  Sucrase  Lactase  Maltase ENZYME

13  Enzymes work by weakening bonds which lowers activation energy

14 Free Energy Progress of the reaction Reactants Products Free energy of activation Without Enzyme With Enzyme

15 substance enzyme  The substance (reactant) an enzyme acts on is the substrate. Enzyme Substrate Joins

16  Active Site: A restricted region of an enzyme molecule which binds to the substrate. Enzyme Substrate Active Site

17  Enzymes are specific. The shape of the active site only fits a certain substrate.  An enzyme that hydrolyzes protein will not act on starch. Enzyme Substrate Active Site

18  Induced fit: A change in the shape of an enzyme’s active site  Induced by the substrate

19  Environmental Conditions  Extreme temperatures are most dangerous (high temp can denature (unfold) the enzyme)  pH (need to remain 6-8)  Tonic concentration (salt ions)  Enzyme Inhibitors  Competitive Inhibitors: chemicals that look like the normal substrate and compete for the active site  Noncompetitive Inhibitors: chemicals that do not enter the active site but bind to another part of the enzyme causing the enzyme to change shape.

20 Enzyme Substrate

21 Enzyme active site altered Noncompetitive Inhibitor Substrate

 Materials:  Notes pages and pencil  Eggcellent Lab  PICK UP 5 PIECES OF PAPER  The Plan:  Macromolecule Quiz – return papers  Day 1: Eggcellent Lab  Take Energy in a Cell notes  Start Cell Organelle flipbook  The Assessment:  Cell Organelle Quiz on Monday

Moving necessary molecules into and out of the cell through the cell membrane

24  Function: Cell membranes organize the chemical reactions making up metabolism by controlling the flow of substances into and out of the cell.  Membranes are selectively permeable.

 Phospholipids are the main structural components of membranes  Membrane phospholipids form a bilayer  They each have a hydrophilic (polar) head and two hydrophobic (nonpolar) tails Head Symbol Tails

 In water, phospholipids form a stable bilayer  The heads face outward and the tails face inward Hydrophilic heads Hydrophobic tails Water

 The membrane is a fluid mosaic of phospholipids and proteins  Phospholipid molecules form a flexible bilayer  Cholesterol and protein molecules are embedded in it  Carbohydrates act as cell identification tags

 The plasma membrane of an animal cell Fibers of the extracellular matrix Glycoprotein Carbohydrate (of glycoprotein) Microfilaments of the cytoskeleton Phospholipid Cholesterol Proteins CYTOPLASM Glycolipid

 Proteins make the membrane a mosaic of function  Some form cell junctions  Others transport substances across the membrane  Some are receptors for chemical messages TransportEnzyme activity Signal transduction Activated molecule Messenger molecule Receptor

 FOCUS: Transport  Passive transport  Active transport  In passive transport, substances diffuse through membranes without work by the cell  A type of diffusion  Substances spread from areas of high concentration to areas of lower concentration EQUILIBRIUM Molecule of dye Membrane EQUILIBRIUM

 Osmosis is the passive transport of water.  In osmosis, water travels from an area of lower solute concentration to an area of higher solute concentration Hypotonic solution Solute molecule HYPOTONIC SOLUTION Hypertonic solution Selectively permeable membrane HYPERTONIC SOLUTION Selectively permeable membrane NET FLOW OF WATER Solute molecule with cluster of water molecules Water molecule

 Achieving water balance between cells and their surroundings is crucial.  Osmosis causes cells to shrink in a hypertonic solution and swell in a hypotonic solution  The control of water balance (osmoregulation) is essential for organisms ISOTONIC SOLUTION HYPOTONIC SOLUTION HYPERTONIC SOLUTION (1) Normal (4) Flaccid (2) Lysing (5) Turgid (3) Shriveled (6) Shriveled ANIMAL CELL PLANT CELL Plasma membrane

 Transport proteins in the cell membrane facilitate diffusion across the membrane.  Small nonpolar molecules diffuse freely through the phospholipid bilayer  Many other kinds of molecules pass through selective protein pores by facilitated diffusion Solute molecule Transport protein

 In active transport, cells use energy.  Transport proteins can move solutes across a membrane against a concentration gradient, which means from low concentration to high concentration.  Active transport requires ATP

 Active transport in two solutes across a membrane Transport protein 1 FLUID OUTSIDE CELL First solute First solute, inside cell, binds to protein Phosphorylated transport protein 2 ATP transfers phosphate to protein 3 Protein releases solute outside cell 4 Second solute binds to protein Second solute 5 Phosphate detaches from protein 6 Protein releases second solute into cell

 Other active transport methods: Exocytosis and endocytosis transport large molecules.  Exocytosis: a vesicle from inside the cell may fuse with the membrane and expel its contents outside of the cell. FLUID OUTSIDE CELL CYTOPLASM VESICLE

 Endocytosis: the membrane may fold inward, trapping material from the outside. A vesicle forms and moves into the cell. AKA: phagocytosis

Organelles that make energy available for cellular work (like active transport)

 Chloroplasts carry out photosynthesis, using solar energy to produce glucose and oxygen from carbon dioxide and water  Mitochondria consume oxygen in cellular respiration, using the energy stored in glucose to make ATP

 Nearly all the chemical energy that organisms use comes ultimately from sunlight  Energy and chemicals are recycled. Sunlight energy Chloroplasts, site of photosynthesis CO 2 + H 2 O Glucose + O 2 Mitochondria sites of cellular respiration (for cellular work) Heat energy