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Thursday 11/21/13 AIM: Why do we eat proteins
DO NOW: What are biomolecules? Why are biomolecules organic compounds? HW:Read page 62. reading check on page 62 and question 4 on page 63
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Review What are the 4 categories of biomolecules?
Why are biomolecules called polymers? How do you build polymers? How do you break down polymers?
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(a) Dehydration reaction in the synthesis of a polymer
Synthesis of polymers Monomers form larger molecules by condensation reactions called dehydration reactions (a) Dehydration reaction in the synthesis of a polymer HO H 1 2 3 4 H2O Short polymer Unlinked monomer Longer polymer Dehydration removes a water molecule, forming a new bond Figure 5.2A
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The Breakdown of Polymers
Hydrolysis (b) Hydrolysis of a polymer HO 1 2 3 H 4 H2O Hydrolysis adds a water molecule, breaking a bond Figure 5.2B
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Which biomolecules can be found in the food sources below?
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Protein Carbon, Hydrogen, oxygen, nitrogen, sulfur
Structure for tissues and organs Hormones Metabolism Transport Receptors Catalysts
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Structural Support Collagen and elastin
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Hormones: chemical messengers
Human Growth Hormone, Insulin, Glucagon
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Transport across the cell membrane
In and out of cell
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Transport through the body
Hemoglobin
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Receptors
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Enzymes are protein catalysts
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How do we build large proteins?
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How are amino acids related to proteins?
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Friday 11/22/13 DO NOW: Motivation: draw an amino acid using the following colors
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Amino Acid All amino acids have the same fundamental structure
The R group gives the amino acid it’s unique properties Size, water solubility, electrical charge
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There are only 20 amino acids which account for all of the proteins in all organisms
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Proteins Polymers made of subunits called amino acids
Amino acids: form 1 or more chains which fold extensively to form a functional protein
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Dehydration synthesis of amino acids forms peptide bonds
Protein or polypeptide: 50 or more amino acids bonded together Peptide: shorter chains
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Shape of protein correlates to it’s function
Shape of protein is determined by exact type, position and number of it’s amino acids In many cases 2 or more amino acid chains join Amino acid chain undergoes a series of folds If the shape of protein is denatured, the protein may no longer be able to function properly
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Proteins ProteinsProtein structure
ProteinsProtein structure Primary structure Primary structure: Polypeptide chain
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ProteinsProtein structure Secondary structure
folding of polypeptide chain
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Tertiary structure ProteinsProtein structure Tertiary structure
Disulfide bridges
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Quaternary structure ProteinsProtein structure Quaternary structure
Functional protein
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Hemoglobin protein
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Protein Structure
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Assessment Create a table listing and describing each step in the development of a functional protein
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Monday AIM: How do enzymes catalyze metabolic reactions?
DO NOW: Use your notes to draw and label the structure of an amino acid
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Enzymes are proteins Built from amino acids
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Enzymes are catalysts
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Enzymes are organic catalysts
Speed up chemical reactions without being consumed by the reaction Proteins Built from amino acids Lower activation energy: the amount of energy needed for a chemical reaction to occur
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Naming enzymes Enzyme names end with the -ase suffix,
the -ase suffix is added to the substrate name. For example, sucrase is the enzyme that breaks down the substrate sucrose, a disaccharide, into the monosaccharides glucose and fructose. Protease: the enzyme that catalyzes the break down of proteins into amino acids
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AIM: why are enzymes protein catalysts?
DO NOW: What type of molecule are enzymes?
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How Do Enzymes Work?
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How do enzymes work? Enzymes are substrate specific
Substrate is the reactant Active site: part of the enzyme capable of recognizing and binding to substrate
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2 methods in which enzymes work
Induced Fit Model Lock and key model
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Induced fit model Actually the "fit" of the substrate and the active site is not a "perfect fit” enzyme slightly changes shape to fit the substrate
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Lock and key model Active site of the enzyme fits perfectly to only one type of substrate
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Enzyme-substrate complex
Lowers the activation energy causing the chemical reaction to happen
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Assessment In one complete sentence,explain why the shape of enzyme is important to its function.
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AIM: What factors effect the rate of enzyme activity?
DO NOW: What is activation energy? Enzyme Quiz Monday
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DO NOW Answer Activation energy: The amount of energy it takes for a chemical reaction to occur How do enzymes catalyze chemical reactions? By lowering the activation energy When do enzymes lower activation energy? Enzyme substrate complex
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At the enzyme substrate complex
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Factors that affect enzyme activity
1. Amount of enzyme 2. Amount of substrate 3. pH 4. Temperature
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Concentration of Enzyme
If the amount of substrate remains the same: As increase amount of enzyme, the rate of an enzyme action also increase UNTIL… All enzymes become saturated At this point all enzymes are working at maximum capacity
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Concentration of substrate
If the amount of enzyme remains the same: at low concentrations, of substrate, Enzyme activity is low Because all enzymes are NOT working As you increase the amount of substrate, you increase enzyme activity until all substrates are bound to enzymes At this point, enzyme activity is steady
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pH Each enzyme works best at a certain pH 2. At optimal (best) pH:
enzyme has the right shape to fit substrate 3. Changes in pH change the shape of enzymes and their ability to fit with substrates 4. Most enzymes work best at pH’s near 7 (neutral)
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Temperature Enzymes work best at a certain temperature
2. Optimum (best) temp. for human enzymes is near normal body temp. (37C) 3. Changes in temp. alter shape of enzyme 4. At extreme temp’s enzyme can ‘t fit with substrate 5. high temperatures denature the enzyme
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Which substrate would work with this enzyme?
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If I changed the shape of the active site, how would the enzyme activity change?
In this picture, name the products. When is the activation energy lowered?
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The most likely result of mixing both enzymes with their substrates in a single test tube is that:
A- only gastric protease would be active if the pH of the mixture was basic B- gastric protease would be more active than intestinal protease at pH 6 C-both enzymes would exhibit some activity at pH 5
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Which enzyme shows the greatest change in its rate of action with the least change in pH?
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Practice questions The picture below represents which type of organic compound?
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Practice question What type of chemical reaction is this and how do you know?
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What builds nucleic acids?
nucleotides
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Nucleic Acids Hereditary Information DNA and RNA
Passed down from parent to offspring DNA and RNA Deoxyribose Nucleic Acid Ribose Nucleic acid
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Nucleic acids are built from nucleotides
Phosphate group 5 carbon sugar Nitrogen base
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Friday 12/19/08
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DNA: deoxyribose nucleic acid
James Watson and Francis Crick DNA is a double helix Sugar-phosphate backbone 2 strands of nucleotides connected at nitrogen bases Weak Hydrogen Bonds hold Nitrogen bases together A-T G-C
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Nitrogen Base Pair Rules
Hydrogen bonds hold nitrogen bases together A-T C-G
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RNA Ribonucleic acid Single strand Ribose- 5 Carbon sugar AUCG
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How do Nitrogen bases specify protein production?
The sequence of Nitrogen bases A,T,C,G are what build a gene.
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How are genes related to DNA?
Genes: sequences of nitrogen bases that hold the code to build a protein DNA carries genes Chromosomes are condensed forms of DNA Many genes are found on 1 chromosome
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Chromosomes are made up of DNA
Specific sequences of nuleotides form genes Genes code for proteins EVERY SINGLE chromosome is copied before the cell divides ALL cells contain the same genes So how then are cells different Cells are different because they express different genes Therefore different cells build different proteins
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Assessment In your own words explain the difference between a DNA and RNA nucleotide
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