Proteins

• Proteins are large, complex molecules that play many critical roles in the body. They do most of the work in cells and are required for the structure, function, and regulation of the body’s tissues and organs
• Amino acids are the monomers of proteins.
• R-groups determine the properties of individual amino acids.
• Peptide bonds are formed as two amino acids are joined together to form a protein.
• Actin and myosin fibers in muscle cells, spider webs, and silk are also structural proteins.
• Some proteins, such as insulin, are hormones.
• Some proteins are enzymes that build or break down other molecules in living cells.
• Some proteins are structured to carry or move substances, such as hemoglobin that carries oxygen, or cell membrane proteins that move substances across the membrane.
• Heat, acidity, or both can denature proteins. Denaturing changes the shape of a protein, which changes its appearance and functionality.
• use acids to turn milk into cheese (milk solids contain casein proteins)
• Denaturing is what happens when we fry an egg (egg whites contain albumin protein)
• The shape of an individual protein is determined by the order of amino acids in the primary chain, which affects how the amino acid chain twists and folds into the final shape of the protein.
• DNA contains the code that instructs the cell machinery to put amino acids together in a particular order to make a particular protein. As long as the DNA contains the correct code, the protein will function. Mistakes in the code (mutations) change the order of amino acids, which changes the structure of the protein, which prevents the protein from carrying out its function.
• Biuret Test- a chemical test to determine the presence of a peptide bond in a substance. The test yields a negative result if the Biuret reagent remains blue, and yields a positive result if the reagent changes from blue to purple.
• Peptide bonds are responsible for primary structure of proteins, while hydrogen bonds contribute to the secondary structure
• Nucleotides link together to form nucleic acids. The sugars bind to the phosphate groups to form the backbone of the chain.
• DNA is two strands of nucleotides side-by-side.
• Adenosine triphosphate, the universal energy carrier, is a single nucleotide (adenine) with two extra phosphate groups attached.