s FactRecall - Chemistry Notes


Applicable for A-Level, IB, DSE, AP-Level Exams

Atomic Structure    Stoichiometry    Bonding    Energetics    Kinetics    Equilibria    Redox    Group 2    Group 7    Alkanes    Alkenes and Alcohols    Organic Analysis    Thermodynamics    Kinetics 2    Equilibrium Constant Kp    Electrode Potentials & Cells    Acids, Bases & Buffer    Periodicity    Transition Metals    Inorganic Compounds in Acqeous Solutions    Optical Isomerism    Aldehydes & Ketones    Carboxylic Acids & Derivatives    Aromatic Chemistry    Amines    Polymers    Amino Acids, Proteins & DNA    Organic Synthesis    NMR    Chromatography   

Amino Acids, Proteins & DNA

Amino Acids

Amino acids are monomers for protein and contain both an amino group and a carboxylic acid group. In addition, they form zwitterions which is a dipolar ion with both a positive charge on the amine group and a negative charge on the carboxylic acid group due to protonation and deprotonation. Except glycine, all amino acids are chiral due to 4 different functional groups bonded to the alpha carbon.

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Proteins are polymers of amino acids, also called polypeptides. Proteins contain a primary structure (sequence of amino acids), secondary structure (the formation of alpha helices or beta-pleated sheets due to hydrogen bonds), tertiary structure (overall 3D shape due to ionic interactions, hydrogen bonds and disulfide bridges).

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Enzymes are proteins that act as biological catalysts. Enzymes contain an active site in which a substrate bonds to. It is important to that that the active site is stereospecific meaning only one enantiomeric form of the substrate can bind to the enzyme.

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DNA contains the genetic material needed for organisms to grow and develop characteristics. Base codons on the DNA codes for an amino acid and ultimately all the proteins in your body. There are 4 bases within DNA: Adenine, Thymine, Cytosine and Guanine. Bases form hydrogen bonds to hold the double helix together. Individual nucleotides form phosphodiester bonds to form the sugar-phosphate backbone.

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Cisplatin is an Pt (II) complex anti-cancer drug that prevents DNA replication by binding to a nitrogen atom on of the DNA base guanine. The DNA canot unwind and be copied properly hence the cell replication is inhibited. However, there are adverse effects as cisplatin can also bind to normal cell DNA hence there are side effects such as hair loss and a weakened immune system by binding to white blood cells. The long term effect of treating cancer outweighs these short term adverse effects.

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