proteins have many different functions in the body structure – proteins help provide structure...
TRANSCRIPT
Proteins have many different functions in the body
Structure – proteins help provide structure and support, make up muscles and bones
Protein Function
Transport – some proteins help to carry things around the body or into and out of cells
Protein Function
Hormones – messenger proteins that carry signals throughout your body
Enzymes – proteins that help with chemical reactions
Antibodies – proteins that help protect the body from infection
Protein Function
Primary protein organization = the initial chain of amino acids
Peptide bond – the bond between amino acids to form the long chain we call a protein
Primary Level
Secondary structure consists of two shapes◦Alpha helix◦Beta sheets
Caused by hydrogen bonding
Secondary Level
Three dimensional structure of a single protein molecule
Caused by hydrophobic interactions
Tertiary Level
Some proteins help to control reactions and cell processes
Enzyme – Specific proteins that can speed up reactions
Enzymes
Energy can be either released or absorbed whenever chemical bonds form or are broken
Living things carry out chemical reactions that require energy
Organisms need a source of energy◦ Plants have the sun◦ Animals eat food
Energy in Reactions
Chemical reactions that release energy often occur spontaneously
Chemical reactions that absorb energy won’t happen without an input of energy
Spontaneous Reactions
Catalyst –a substance that speeds up the rate of a reaction
Catalysts lower activation energy
Enzymes are biological catalysts! They help speed up chemical reactions in your body!
Catalyst
Enzymes are very specific!
A single enzyme usually only works with one type of reaction
HINT: The name of an enzyme usually has something to do with reaction it works with
Enzymes almost always end with –ase!!!
Enzymes Action
Each enzyme will combine with only a specific molecule
Substrate – the molecule an enzyme binds to in a reaction
We call this the “lock and key model”
Why are enzymes so specific?
Enzymes are picky…they only like to work under certain conditions
Each enzyme is designed to work in a certain temperature range
Enzymes in your body work best at 37 ºC
Temperature and pH
pH also plays a role on enzyme activity
Enzymes in your stomach work best at a pH of around 2
Each enzyme works best at a specific pH level◦ Most around 7.4 …Why?
Temperature and pH
What type of molecule are enzymes?
Proteins
Proteins are made up of what type of molecules?
Amino acids
Quick Review
The amino acids that make up proteins and enzymes are held together by which type of bond?
Peptide bond
Quick Review
How do enzymes help speed up a chemical reaction?
Lower the reactions activation energy
What are two things that can change how well an enzyme works?
Temperature and pH
Quick Review
Enzymes aren’t used up!
Once the reaction is done, the enzyme is left unchanged and can continue its job
So enzymes are reusable!
A few more things about enzymes…
pH and Temperature have an effect on enzyme activity
Denature – when a protein loses its shape and can no longer work
http://www.sumanasinc.com/webcontent/animations/content/proteinstructure.html
Stopping an Enzyme