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Proteins

Learn about the structure, function, and importance of proteins in living organisms. Explore the different types of proteins and their roles in catalyzing reactions, transporting molecules, and maintaining cell structure. Understand the impact of environmental factors and inhibitors on protein function.

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Proteins

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  1. Proteins

  2. Objectives: Identify the structure and function of proteins. 2. Describe the action of enzymes.

  3. Organic compound • Made up of C, H, O, N and some with S • Proteins are polymers, made up of long chains of the repeating units called amino acids.

  4. There are 20 different types of amino acids that make up all proteins. 8 are essential to humans

  5. The 20 amino acids combine in different orders to make up 100’s of types of proteins found in all living organisms. • Similar to the letters of the alphabet • 26 different letters combine to make 500,000+ words

  6. Amino Acids

  7. Amino acids bond together into chains with peptide bonds • A type of covalent bond lysine Amino acid Dipeptide Tripeptide Polypetptide Peptide Bond

  8. Peptide Bonds • Two amino acids: • Dipeptide • Three amino acids: • Tripeptide • More amino acids: • Polypeptide

  9. S-T-E-A-K S E T K A S E T K A Blood Hair protein-keratin Muscle protein Skin protein-collagen

  10. Functions of Proteins: • Catalyze reactions • Transport molecules • Copy and synthesize DNA • Communicate between cells • Provide cell structure • Protect against pathogens

  11. Two types of proteins: 1. Structural Proteins: • They build and support our tissues • Examples: Collagen…………………skin Keratin……………………hair Myosin………….human muscles

  12. 2. Functional Proteins: They perform specific functions within our bodies. Examples: Enzymes…speed up chemical reactions like digestion Insulin….transports glucose into cells Antibodies….destroy bacteria and viruses Hemoglobin…transports oxygen to cells

  13. All proteins have a very unique 3-D shape • If 3-D shape is altered the protein will be damaged. • Extreme cold to collagen…………Frost bite • Extreme heat to collagen…………3rd degree burn

  14. Levels of organization of a protein: • 1st: Primary structure • Linear in shape • A specific chain of amino acids bonded in order according to the DNA code

  15. One single change… Amino Acid Sequence Normal Sickle -Threonine – Proline – Glucine– Glucine -Threonine– Proline – Valine - Glucine

  16. 2nd: Secondary Structure • Chain acquires of specific orientation • Coils • Pleated • Spiral • Shape held in place with Hydrogen bonds.

  17. 3rd: Tertiary Structure • 3-D globular shape • Each type of protein has its own 3-D shape • If shape is altered the protein can not function right.

  18. 4th: Quaternary Structure • This level is achieved when two protein chains bond together to create a new protein.

  19. Enzymes: -are complex proteins used as a catalyst for all chemical reactions with our bodies. -Catalysts are… -any substance that speeds up or slows down a chemical reaction Enzymes are responsible for: -cell respiration -photosynthesis -Protein synthesis -Digestion Enzymes control every reaction within our bodies.

  20. Take the example of digestion: Enzymes make the reaction of digestion occur 1 million times faster than it would without the enzymes. Digest candy bar with enzymes…. 20 min to 2 hours Digest same candy bar without enzymes…. 100 years

  21. Enzymes are substrate specific. Substrates are substances enzymes act upon like specific types of food. Enzymes are complex proteins. Therefore enzymes have specific 3-D shapes. For each substrate/substance there is only one enzyme that can act upon it.

  22. Enzymes in the human alimentary canal and what they digest: The name of enzymes end in the suffix “ASE”.

  23. Lock and Key hypothesis: For every substrate there is one and only one enzyme that causes that substrate to react just like there is only one specific key which fits into a specific type of lock.

  24. Let’s take a milk break….. Lactase Contains galactose and lactose sugars It’s a disaccharide

  25. -Enzymes are not altered or used up during a reaction. -Enzymes can be used over and over again.

  26. Enzyme Action • Substrate attaches to an enzyme’s active site • Enzyme decreases activation energy • Products are formed…Reaction completed…Enzyme NOT changed

  27. Frostbite How environmental factors affect enzymes: Denaturing of enzymes: -Agents such as extreme heat or coldness and strong acids and bases destroy the functional properties of an enzyme by slightly altering its shape. -this is called the denaturing of the enzyme

  28. Coenzymes: -Small organic molecules can bond to the enzyme and increase the rate of its function. Examples: vitamins and minerals

  29. Competitive Inhibitors: -Molecules that bond to the enzyme and block the active site rendering it useless for doing its real job. Example: The drug marijuana contains the chemical THC. THC temporarily bonds to enzymes in our brain cells causing them to not function correctly thus causing the temporary feeling of being “high”.

  30. Competitive Inhibitor- substance that is very similar in shape to the substrate.  Allosteric Inhibitor- substance that binds to the enzyme’s active site and changes the enzyme’s shape. (poisons like cyanide)  Coenzyme-small organic molecule such as a vitamin that binds to the enzyme and activates it or helps it function. 

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