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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
Review
What are the 4 categories of biomolecules?
• Why are biomolecules called polymers?
• How do you build polymers?
• How do you break down polymers?
Synthesis of polymers• Monomers form larger molecules by
condensation reactions called dehydration reactions
(a) Dehydration reaction in the synthesis of a polymer
HO H1 2 3 HO
HO H1 2 3 4
H
H2O
Short polymer Unlinked monomer
Longer polymer
Dehydration removes a watermolecule, forming a new bond
Figure 5.2A
The Breakdown of Polymers
Hydrolysis
(b) Hydrolysis of a polymer
HO 1 2 3 H
HO H1 2 3 4
H2O
HHO
Hydrolysis adds a watermolecule, breaking a bond
Figure 5.2B
Which biomolecules can be found in the food sources below?
Protein• Carbon, Hydrogen,
oxygen, nitrogen, sulfur
• Structure for tissues and organs
• Hormones• Metabolism• Transport• Receptors• Catalysts
Structural Support
• Collagen and elastin
Hormones: chemical messengers
• Human Growth Hormone, Insulin, Glucagon
Transport across the cell membrane
• In and out of cell
Transport through the body
• Hemoglobin
Receptors
Enzymes are protein catalysts
How do we build large proteins?
How are amino acids related to proteins?
Friday 11/22/13
• DO NOW:
• Motivation: draw an amino acid using the following colors
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
• There are only 20 amino acids which account for all of the proteins in all organisms
Proteins• Polymers made of
subunits called amino acids
• Amino acids: form 1 or more chains which fold extensively to form a functional protein
Dehydration synthesis of amino acids forms peptide bonds
• Protein or polypeptide: 50 or more amino acids bonded togetherPeptide: shorter chains
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
• ProteinsProtein structure
• ProteinsProtein structure Primary structure
Proteins
• Primary structure: Polypeptide chain
• ProteinsProtein structure Secondary structure
Secondary structure:
folding of polypeptide chain
• ProteinsProtein structure Tertiary structure
Tertiary structure
• Disulfide bridges
• ProteinsProtein structure Quaternary structure
Quaternary structure
• Functional protein
Hemoglobin protein
Assessment
• Create a table listing and describing each step in the development of a functional protein
Monday
• AIM: How do enzymes catalyze metabolic reactions?
• DO NOW: Use your notes to draw and label the structure of an amino acid
Enzymes are proteins
• Built from amino acids
Enzymes are catalysts
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
QuickTime™ and a decompressor
are needed to see this picture.
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
• AIM: why are enzymes protein catalysts?
• DO NOW: What type of molecule are enzymes?
How Do Enzymes Work?
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
2 methods in which enzymes work
• Induced Fit Model
• Lock and key model
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
Lock and key model
• Active site of the enzyme fits perfectly to only one type of substrate
Enzyme-substrate complex
• Lowers the activation energy causing the chemical reaction to happen
Assessment
• In one complete sentence,explain why the shape of enzyme is important to its function.
• AIM: What factors effect the rate of enzyme activity?
• DO NOW: What is activation energy?
• Enzyme Quiz Monday
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
At the enzyme substrate complex
Factors that affect enzyme activity
1. Amount of enzyme
2. Amount of substrate
3. pH
4. Temperature
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
Concentration of substrate
If the amount of enzymeremains the same:
a) 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
pH
1. 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)
Temperature1. Enzymes work best at a certain temperature2. 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
Which substrate would work with this enzyme?
• 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?
• 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
• Which enzyme shows the greatest change in its rate of action with the least change in pH?
Practice questions
• The picture below represents which type of organic compound?
Practice question
• What type of chemical reaction is this and how do you know?
What builds nucleic acids?
nucleotides
Nucleic Acids• Hereditary
Information– Passed down from
parent to offspring
• DNA and RNA• Deoxyribose Nucleic
Acid• Ribose Nucleic acid
Nucleic acids are built from nucleotides
• Nucleotides• Phosphate group• 5 carbon sugar• Nitrogen base
Friday 12/19/08
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
Nitrogen Base Pair Rules• Hydrogen bonds hold
nitrogen bases together
• A-T• C-G
RNA• Ribonucleic acid• Single strand• Ribose- 5 Carbon
sugar• AUCG
How do Nitrogen bases specify protein production?
• The sequence of Nitrogen bases A,T,C,G are what build a gene.
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
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
Assessment
• In your own words explain the difference between a DNA and RNA nucleotide