Biochemistry Notes pt. 4

Organic Molecules 4 Main Macromolecules Carbohydrates Proteins Lipids Nucleic Acids We are here!

Macromolecule 2: PROTEINS WHAT DO THEY DO? They are the major structural molecules in living things for growth and repair : muscles, ligaments, tendons, bones, hair, skin, nails…IN FACT ALL CELL MEMBRANES have protein in them They make up antibodies in the immune system They make up enzymes for helping chemical reactions They makeup non-steriod hormones which THINK: Proteins= Membranes, Enzymes, Antibodies, Non-steroid hormones, Structural molecules : “MEANS”

Proteins: antibodies Antibodies are part of the immune system. When something enters the body that isn’t supposed to be there, like certain bacteria, antibodies find the invader and stick themselves onto it. When a white blood cell finds the invader covered with antibodies, it knows it doesn’t belong there and kills it.

PROTEINS: Found Where? In plant foods- in the cell membranes In animal products- in the cell membranes- in the muscles of living things- cows, chicken, fish…

Proteins

Proteins Aside from the protein found in animal sources…protein can also be found in fruits, vegetables, grains, and nuts

THINK: “CHONS” Each protein is made up of… PROTEINS AT THE ATOM LEVEL Each protein is made up of… Carbon, Hydrogen, and Oxygen, Nitrogen and sometimes Sulfur THINK: “CHONS”

PROTEINS MADE UP OF... Proteins are made of long chains (polymers) made of monomers. All proteins are made of the monomer… AMINO ACID

Protein A protein is a polymer of just 20 kinds of monomers called amino acids. Proteins are responsible for almost all of the day-to-day functioning of organisms.

What is an Amino Acid? Each amino acid monomer consists of a central carbon atom bonded to four partners. Three of the central carbon's partners are the same in all amino acids.

Consists of… The three bonds that are the same are: Amino Group Carboxyl Group Carbon bonded to Hydrogen Every amino acid will have an ‘R’ side chain, but it will be different in each amino acid

Differences What is different about each type of amino acid is the "side group" that attaches to the fourth bond of the central carbon. The side group, sometimes called the "R-group," is responsible for the particular chemical properties of each amino acid.

Examples… Methionine Serine

Let’s Build a Protein Amino acids are connected by peptide bonds Each link is created by a dehydration reaction (LOSS OF WATER – WATER WILL BE A PRODUCT!!) between the amino group of one amino acid and the carboxyl group of the next amino acid in the chain. A long chain of amino acids is called a polypeptide (many peptides)

So…

Shape Determines… The shape of the polypeptide is determined by the sequence of amino acids, therefore determining the function

The sequence of letters in a word determines the word that is formed: RAT

The sequence of letters in a word determines the word that is formed: RAT TAR ART

Form Determines Function One change in the sequence #6 (glutamine to valine) changes the protein formed Sickle Cell: Most common in Black People Hemoglobin protein that carriers O2 is mishaped Can block blood vessels, prevent O2 from getting to cells No cure

4 Levels of Protein Structure 1. Primary Structure: The sequence of Amino Acids

4 Levels of Protein Structure 2. Secondary Structure: Twisting of the Polypeptide Helix Pleated Sheet

4 Levels of Protein Structure 3. Tertiary Structure: -The polypeptide folding back on itself -Globular, 3-D Shape -Determines the protein function 4. Quaternary Structure: -The combination of multiple polypeptide structures

Primary Secondary Tertiary Quaternary

Denaturation The change in form causes a change in function. Protein shape (conformation) can be denatured (changed) by changing temperature or pH. The change in form causes a change in function.

Warm Up Using your notes, make a Venn Diagram comparing and contrasting carbohydrates and proteins

Biochemistry Notes Pt. 4.2

Review Amino acid = Monomer Amino acids bond together through peptide bonds to form proteins (polypeptides) There are 20 Kinds of amino acids that differ by their R-group

Hydrophobic = Non Polar Some molecules do NOT want to hydrogen bond with water and therefore avoid it. Think oil & water Some amino acids act this way

Hydrophilic = Polar Some substances with partial or full charges like to interact with water (hydrogen bond) and tend to mix with it. Some amino acids behave this way.

Proteins form different levels of structure These determine the overall 3-D shape of the protein

Primary Structure Order of Amino Acids

Secondary Structure How the protein folds due to hydrogen bonding Usually a helix or pleats

Tertiary Structure How the protein folds due to disulfide bonds, charges (negative & positive)and hydrophobic/hydrophilic(nonpolar & polar) regions

Quaternary Structure More than one polypeptide coming together.

AMINO ACID SEQUENCE DETERMINES PROTEIN STRUCTURE AND FUNCTION Remember, Remember! AMINO ACID SEQUENCE DETERMINES PROTEIN STRUCTURE AND FUNCTION

Proteins Called Enzymes Enzymes are special proteins that speed up reactions (this is called a catalyst). Enzyme names end is “-ase” There are many enzymes in the body that do jobs like speed up digestion. Every process going on in your body = METABOLISM

How Enzymes Work In order for an enzyme to work, it needs to attach itself to a substrate like a puzzle piece (lock & key). A specific reactant acted upon by an enzyme is called the enzyme's substrate. The substrate fits into a particular region of the enzyme, called the active site.

Examples of Enzymes Salivary amylase Catalase Sucrase In spit, helps to break down food Catalase Breaks down peroxide in to H2O and O H2O2  H2O + O Sucrase Breaks down sucrose into simple sugars

Enzymes Continued Enzymes help to maintain homeostasis in the body They make sure that all the reactions happen AND that they happen at the right time If enzymes become heated too much or too little OR if they are put into and acidic/basic solution, they will denature Not work as well!