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

Protein Structure

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