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What are some sources of protein?. Proteins!. Organic Molecules - Proteins. Properties of Proteins: Proteins have a very specific SHAPE! Proteins are made of chains of amino acids The monomer is: __________________ The polymer is: ___________________
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What are some sources of protein? Proteins!
Organic Molecules - Proteins Properties of Proteins: • Proteins have a very specific SHAPE! • Proteins are made of chains of amino acids The monomer is: __________________ The polymer is: ___________________ • When two amino acids stick together – water is released (A condensation reaction!) • We use 20 amino acids that each have a different side group (R group). • The different R groups change the properties of the amino acid. Image: www.rothamsted.ac.uk/.../courses/guide/aa.htm
Organic Molecules - Proteins A dipeptide is two amino acids linked together. A polypeptide is more than two amino acids linked together. Image: homepages.ius.edu/GKIRCHNE/biomolec.htm
What happens when you cook an egg? Why can’t you turn it back into a raw egg?
Primary Structure • String of Amino Acids (Sequence of Amino Acids) The sequence is important! Amino acid substitution: hemoglobin; sickle-cell anemia
Secondary Structure • Coils & folds (held by hydrogen bonds) Two kinds: • Alpha Helix: • coiling • (Beta) Pleated Sheet: • Zig-zag
Tertiary Structure • Twisting from R group bonding Caused by: • Hydrophobic / Hydrophilic sections • Covalent bonds (usually bonds between sulfur atoms) • hydrogen bonds • ionic bonds • Acidic or Basic sections
Quaternary Structure • 2 or more amino acid chains stuck together Examples: • collagen (connective tissue) • hemoglobin
Levels of Protein Structure Every protein has at least three levels of structure, and some four. . Image: www.answers.com/topic/rosetta-home
Remember: A protein has a specific shape and needs to be that shape to function!
How to Destroy a Protein • Denaturation! • • Change a proteins shape by… • Adding heat • Adding acid or base • • A denatured protein can’t carry out its function. It needs to be the right shape to work!
Ways to “cook” (denature) proteins Add Acid Add Heat Add Base
Organic Molecules - Proteins Functions of Proteins: 1. ________________ • Structure in cell walls, membranes, and within cells. 2. ________________ • Chemicals that speed up, or increase the chance of a chemical reaction happening. 3. ________________ • Can start or stop other proteins or tell the DNA to make more proteins. 4. _________________ • Some act as channels and “pumps” that move things into or out of cells. 5. _________________ • Antibodies = proteins that defend your body against microorganisms • Some bacteria produce proteins that kill other bacteria.