Proteins Organic compounds made of C, O, H, N and S Building blocks – 20 different amino acids Peptide and Polypeptides: Dehydration (Condensation)/ Hydrolysis Reactions

Functions of proteins (directly related to the shape of the protein) Contraction of muscles Hormones (signals our cells) Receptors (found on surface of cells) Carriers (oxygen to cells) Antibodies (fight off invaders) Enzymes

20 Amino Acids

Amino Acids *color sheet Which part of this structure gives an amino acid its uniqueness? a. amino group b. side chain c. carboxyl group d. central carbon Review https://www.wisc-online.com/learn/natural-science/chemistry/bic007/peptide-bond-formation

Protein Structure www.rand.org/.../Rosetta/images/Proteins.gif

4 Classes of Protein Structure 1.Primary Structure-chain sequence of amino acids Phenylalanine

b. Pleated Sheet a. alpha helix The Secondary Structure is a. hydrogen bonds making alpha helix and pleated sheets b. chain of amino acids c. chain of monosaccharides d. folded chains of many amino acids b. Pleated Sheet a. alpha helix

3. Tertiary Structure-Attractions between alpha helix and beta sheets folding onto each other Hydrophobic interactions Disulfide bridges (bonding of 2 cysteine molecules)

4. Quarternary Structure- more than one amino acid chain Ex: Hemoglobin (transport protein)

FUNCTIONS LET’S REVIEW ON THE BOARD The following is what gives a protein its particular function. a. polarity b. shape c. activation energy d. number of substrates

Enzymes Enzymes - catalytic organic molecules Lock & Key model Induced fit model Enzyme Reactions – temperature & pH dependant

Enzyme Specificity Enzymes are nature’s catalysts Proteins or RNA Are reuseable Generally catalyze only one reaction Enzyme-substrate complex Substrate – reactant(s) an enzyme acts on Active site – where substrate binds to the enzyme; has a specific shape created by folds

This enzyme model is an example of lock and key or induced fit. a. lock and key b. induced fit

Induced Fit Model What happens to the enzyme after the product leaves? a. retains the shape of the substrate b. does not change at all c. goes back to its original shape d. keeps the shape of the product

Factors that affect enzyme activity Temperature – optimal temperature at which rate of reaction in fastest 2. pH – optimal pH at which rate of reaction is fastest

Denaturation Protein loses structure due to some other outside compound or stress - adding acid or base - change in temperature - large amounts of certain chemicals Enzymes will not function May or may not be reversable Ex: eggs and meat

Denaturation

Closing 1. What is the building blocks of proteins? 2. What are 2 functions of proteins? 3. What controls the function of a protein? 4. Explain what an enzyme is? 5. Why is it important for your body to maintain its internal temperature? 6. What does it mean for an enzyme to be denatured?

Animated Denaturation http://highered.mcgraw-hill.com/sites/0072943696/student_view0/chapter2/animation__protein_denaturation.html

Nucleic Acids Very large & complex molecules Store hereditary information for cells DNA & RNA Building block: Nucleotide A nucleotide contains a Phosphate Group 5 – C sugar Nitrogen Base

Differences between DNA and RNA Double stranded Deoxyribose sugar (5C) Nitrogen bases Thymine Adenine Guanine Cytosine Single strand Ribose sugar (5C) Nitrogen bases Uracil Adenine Guanine Cytosine

Nucleic Acid www.steve.gb.com/.../nucleotides/ssRNA.png