Transcript Proteins and Nucleic Acids

Proteins
Examples of Proteins
Horns
Hair
Egg
Whites
Spider
Webs
Hair
Nails
Muscles
Enzymes
Functions of Proteins
• What do proteins do?
•Make up Antibodies in your Immune System
• Provide Structural Support
Example: Collagen in Skin
•Transport
Example: Hemoglobin
carries Oxygen
Proteins: How They’re Made

Made up of C, H, O, N, and sometimes S
Proteins: How They’re Made
• What are the monomers of a protein?
Amino Acids
• How many amino acids are there?
20
• What are the parts of an amino acid?
Amino Acids
Polymers
• How are amino acids joined?
With Peptide Bonds (in dehydration synthesis)
• Two amino acids together are called a
Dipeptide
• Many amino acids are called a
Polypeptide
Polymers
Which two groups of the amino acid
form a peptide bond?
Polypeptide
Amino Acid
Peptide Bond
Proteins
• Does the order of the amino acids in a protein
matter? Why?
The order of the amino acids affects the SHAPE
• Why is the shape of the protein important?
The shape determines the FUNCTION!
Denaturing Proteins
Two changes cause a change in the shape of the
protein…this is known as DENATURATION.
So if the shape changes, what’s affected?
The Function of the Protein!
Other Causes of Protein Denaturation
salt concentration and environmental factors
What are some examples of
Denatured Proteins?
•Raw Egg vs. Cooked Egg
•Raw Meat Vs. Grilled Meat
How is the consistency of raw vs.
cooked different?
ENZYMES
What is an enzyme?
A type of protein that speeds up
metabolic (chemical) reactions.
aka:
Catalysts
What is needed to
start a reaction?
reactant
Products
Why is the activation energy lower?
A Catalyst
was added!
Enzymes lower the
activation energy
reactant
Products
Comparing Reactions
Which line would
represent a reaction
with an enzyme
present?
Without an enzyme
Reactant
Products
How Do Enzymes Work?
• Enzymes work like a lock and
key.
• Specific enzymes work with
specific substrates.
enzyme
substrate
What’s a Substrate?
a substance on which an enzyme acts during a chemical
reaction
*enzymes act only on specific substrates
What is a product?
The substance is formed in a chemical reaction
Enzymes and Active Sites
• What is an Active Site?
The site on an enzyme that attaches to the substrate
• Is the active site the same for all enzymes and substrates?
NO! Only a certain substrate fits into a particular active site
Enzymes Activity
•
•
Changes in pH and temperature can affect the shape of an enzyme.
What will happen if the shape changes?
The enzyme can be denatured
Why is this not good?
Any factor that changes the shape of an
enzyme can affect the enzyme’s activity
Amylase
• Enzyme found in our saliva
• Breaks down some
starches into glucose
molecules
• So digestion of food occurs
in the mouth before it
reaches the stomach
Pepsin
• First animal enzyme to be
discovered
• Digestive protease in
stomach that works with
HCl acid to degrade food
proteins into peptides