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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?

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Thursday 11/21/13

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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


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








Unlinked monomer

Short polymer

Dehydration removes a watermolecule, forming a new bond








Longer polymer

(a) Dehydration reaction in the synthesis of a polymer

Figure 5.2A

The Breakdown of Polymers








Hydrolysis adds a watermolecule, breaking a bond









(b) Hydrolysis of a polymer

Figure 5.2B

Which biomolecules can be found in the food sources below?


Carbon, Hydrogen, oxygen, nitrogen, sulfur

Structure for tissues and organs






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


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


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


  • 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


  • Create a table listing and describing each step in the development of a functional protein


  • 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


Built from amino acids

Lower activation energy: the amount of energy needed for a chemical reaction to occur

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


  • 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


All enzymes become saturated

At this point all enzymes are working at maximum capacity

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, enzymeactivity is steady


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)


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

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?

What type of chemical reaction is this and how do you know?

Practice question

What builds nucleic acids?


Nucleic Acids

Hereditary Information

Passed down from parent to offspring


Deoxyribose Nucleic Acid

Ribose Nucleic acid

Nucleic acids are built from 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



Nitrogen Base Pair Rules

Hydrogen bonds hold nitrogen bases together




Ribonucleic acid

Single strand

Ribose- 5 Carbon sugar


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


  • In your own words explain the difference between a DNA and RNA nucleotide

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