BCOR 103 1st Edition Lecture 3 Outline of Last Lecture I II III IV The Evolution of Cells Basic Physics and Energy Basic Chemistry Organic Bio molecules Outline of Current Lecture I II III IV Amino Acids The Peptide Bond Levels of Protein Structure Protein Alterations Current Lecture There are twenty amino acids commonly used in biological organisms All have the same basic structure an amino group a single hydrogen atom a carboxyl group and an R group The R group stands to mean any sort of substitution The acidic basic and polar amino acids are classified as hydrophilic lysine arginine histidine serine threonine aspartic acid glutamic acid asparagine and glutamine The Amino acids that contain a ring are considered to be hydrophobic alanine valine isoleucine leucine methionine phenylalanine tyrosine and tryptophan The remaining amino acids are classified as special amino acids and this is because they are particularly apt at creating specific bonds cysteine glycine and proline The peptide bond is the one that links amino acids together Amino acids are the basic structural unit of proteins when linked together they form a protein Amino acids are linked by a process called dehydration The oxygen atom of one carboxyl group of one amino acid links with the two hydrogens present in the amino group of a second amino acid When the oxygen and hydrogens join a water molecule is released and the two amino acids are linked Inversely peptide bonds can be broken by hydrolysis Hydrolysis is when water molecules are added to an amino acid chain breaking them back into individual amino acids There are four structures of proteins primary secondary tertiary and quaternary The primary structure of a protein is just a sequence of amino acids Primary structures are held together by peptide bonds Secondary structure proteins form beta pleated sheets and alpha helices Secondary structures are held together with hydrogen bonds Tertiary structures are mainly held together by hydrophobic interactions Some amino acids as previously mentioned are hydrophobic When hydrophobic amino acids are in a sequence together they can fold to form a hydrophilic surface outside the hydrophobic interior Not all proteins can form a These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute quaternary structure Quaternary structures are when two or more individual proteins condense together There are five ways that proteins can be altered after they are synthesized A protein can be linked to a cell membrane by adding a fatty acid tail this process is call fatty acid acylation Some proteins have specific modifications that only that protein does A protein can have a phosphate added to it called phosphorylation The N terminus of a protein can be acetylated to protect it from degrading over time acetylation And lastly a protein can have sugars added to protect the surface this process is called glycosylation
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