metabolism: energy and enzymes chapter 6. lab tues 9/16 *next week! be there! lab 136 ...
TRANSCRIPT
Metabolism: Energy and Enzymes
Chapter 6
LAB
Tues 9/16*next week! Be there!
Lab 136 http://www.calstatela.edu/univ/ppa/campus_map.pdf
Biological Science buildingroom 136
-13 on mapextra 5 min to get there
Quiz Next Timemacromolecules
http://www.lachsa.net/apps/pages/index.jsp?uREC_ID=383647&type=u&pREC_ID=
507658
Energy = the ability to do workKinetic Energy (energy of motion)Potential Energy (stored energy)
First Law of Thermodynamics - the law of conservation of energy (not created or destroyed) Second Law of Thermodynamics - energy cannot be changed without a loss of usable energy (heat)
http://youtube.com/v/Jnj8mc04r9E
QODStaple/tape is the graphic organizer as last QODToday:• What are the 4 shapes of proteins?
Draw a small sketch to go with your explanation or each shape
MATCHINGa. carbohydrate b. lipidsc. protein d. nucleic acids
1. contains adenine and thymine2. lactose3. chains of amino acids4. long term energy storage5. cholesterol6. chains of fatty acids and glycerol7. plant cell walls
Reactants: starting substances, on the left side of the arrow.
Products: substances formed during the reaction, on the right side of the arrow.
Baking soda + vinegar
Reactants Products
water + CO2
Chemical Reaction
What are the reactants and products?
6CO2 + 6H2O C6H12O6
Reactants Products
H2O2 H2O + O2
Reactants Products
http://www.youtube.com/watch?v=Fz9eV-EWtpY
Metabolic ReactionsReactants --> Products
Exothermic - releases energy
Endothermic = absorbs energy
Chemistry in Biology
This reaction is exothermic and released heat energy.
The energy of the product is lower than the energy of the reactants.
Chapter 6
Chemistry in Biology
This reaction is endothermic and absorbed heat energy.
The energy of the products is higher than the energy of the reactants.
6.2 Chemical Reactions
Chapter 6
Metabolic Pathways & Enzymes (6-3)
Enzyme - protein molecule that functions as an organic catalyst to speed reactions
Substrate - reactants in the enzymatic reaction, this is what an enzyme attaches to
Activation Energy- the energy required to cause the reaction
Chemistry in Biology
activation energy: the minimum amount of energy needed for a reaction.
Enzymes lower the activation energy
Energy of Reactions
Properties of Enzymes:
•Enzymes are made of proteins.
•They speed up chemical reactions inside the cytoplasm.
•They are needed only in small amounts
•They remain unchanged after each reaction and can therefore be reused
•Each enzyme is specific for a substrate
Chemistry in Biology
Substrates: reactants that bind to the enzyme
active site: specific location where a substrate binds on an enzyme
Chapter 6
Lock and Key Model
Each enzyme acts on a specific substrate
Induced Fit Model - substrates and enzymes fit together like a lock and key.
Degradation vs Synthesis breaking down vs building
Factors Affecting Enzymatic Speed1. Substrate concentration2. Temperature & pH *3. Enzyme concentration
Enzymes can be denatured - they change shape so much that they are no longer effective. High temp or pH can cause denaturation.
Siamese cats have an enzyme that works at lower temperatures only, causing the nose and ears to become a darker color than the rest of the body.
Enzymatic Inhibition - when a substance binds to an enzyme and decreases its activity. (Usually reversible)
Competitive Inhibition vs.
Noncompetitive Inhibition (allosteric site)
**Both are forms of feedback inhibition
http://youtube.com/v/PILzvT3spCQ
Normal
competitive
Non-
competitive
Inhibited:
Some inhibitors are NOT reversible - poisons like cyanide, lead poisoning all affect enzymes
QUESTION: What type of inhibition is pictured below?
Enzyme Animation (Tutorial)
http://www.stolaf.edu/people/giannini/flashanimat/enzymes/prox-orien.swf
Enzyme Quiz
http://www.sciencegeek.net/Biology/review/U2Enzymes.htm
Enzyme Lab
2H2O2 ----> 2H2O + O2
Hydrogen Peroxide is broken down by the enzyme catalase within cells.
Potatoes hold the enzyme catalase, which will speed up the breakdown of hydrogen peroxide
Proteins have four shapes1. Primary Structure - sequence of amino acids that form the polypeptide chain2. Secondary Structure - Parts of the polypeptide fold into local patterns (alpha helix or pleated sheet)3. Tertiary Structure - the overall 3D shape (globular or fibrous)4. Quaternary Structure - consists of two or more polypeptide chains or subunits
Factors Affecting Enzymatic Speed1. Substrate concentration2. Temperature & pH *3. Enzyme concentration
Enzymes can be denatured - they change shape so much that they are no longer effective. High temp or pH can cause denaturation.
The activity of catalase can be seen by the bubbling of oxygen during the reaction
Generally speaking, catalase reactions occur faster at warmer temperatures.
If temperature is too hot (boiling) then the enzyme becomes denatured
Enzymatic Inhibition - when a substance binds to an enzyme and decreases its activity. (Usually reversible)
Competitive Inhibition Noncompetitive Inhibition (allosteric site)
**Both are forms of feedback inhibition
http://youtube.com/v/PILzvT3spCQ
Normal
competitive
Non-
competitive
Inhibited:
Both cofactors and coenzymes help to complete the structure of a conjugated enzyme
CO-ENZYME is a small organic non-protein MOLECULE that carries chemical groups between enzymes while a
ex: iron, magnesium or zinc.
CO-FACTOR is a non-protein CHEMICAL COMPOUND that is bound tightly to an enzyme and is required for catalysis.
ex: NAD+, NADP+ and FAD+
Virtual Labs with Enzymes
McGraw Hill LabBio 114 EnzymesLab Bench Enzyme Catalysis
ADP
ATP
Ribose (sugar)
rele
ase
ener
gy
Ad
d
ener
gy
Diphosphate
Energy stored in ATP is released by breaking the bond between the 2nd and 3rd phosphates.
Copyright Pearson Prentice Hall
ATP
Energy stored in ATP is released by breaking the bond between the 2nd and 3rd phosphates.
P
ADP
2 Phosphate groups
ATP - the energy currency of cells (adenosine triphosphate)
Functions:1. CHEMICAL WORK - Supplies energy needed to make macromolecules that make up the cell (and organism)2. TRANSPORT WORK - Supplies energy needed to pump substances across the cell membrane3. MECHANICAL WORK - supplies energy needed to make muscles contract and other cellular parts to move (flagella)
How do cells make ATP?
• Cellular respiration• Photosynthesis• Electron transport chain
Chemiosmosis= production of ATP due to hydrogen ion gradient across a membrane
ATP
Review videos
https://www.youtube.com/watch?v=ok9esggzN18 https://www.youtube.com/watch?v=5GMLIMIVUvo