2.5 organic molecules

• proteins: provide structual support and act as catalysts that facilitate chemical reactions
• nucleic acids: encode and genetic information
• carbohydrates: provide a source of energy and make up the cell wall in bacteria, plants and algae
• lipids: make up membranes, store energy and act as signaling molecules
• polymers: complex molecules made of repeated units of monomers joined together by covalent bonds
• proteins are polymers of
• nucleic acids are polymers of nucleotides, which are made up of a phosphate group, a pentose sugar and a nitrogenous base
• carbohydrates are polymers of simple sugars
• amino acids: an organic molecule containing a central carboxyl group and an amino group
• nucleotides: consisting of a 5-sugar carbonyl group, a phosphate group, and a nitrogenous base
• sugar (saccharide): the simplest carbohydrate molecule
• lipids are not defined by a chemical structure because they are hydrophobic
• macromolecules: a large molecule important to biological processes, composed of thousands of covalent bonds
• amino groups (-NH2)

  • polar and positively charged
  • behaves as a base, hydrophilic
  • found in amino acids and proteins
• carboxyl (-COOH)

  • polar, negatively charged
  • behaves as an acid, hydrophilic
  • found in fatty acids, amino acids and proteins
• enzymes: speed up the rates of chemical reactions
• $a$(alpha carbon): the central carbon atom in a carboxylic acid.
• R group: attached to the central carbon atom, structure and composition determine the identity of the amino acid
• peptide bond: a covalent bond that links the carbon atom in the carboxylic acid to the amino acid
• formation of a peptide bond involes the removal of a water molecule from the carboxyl group of one amino acid and the removal of a hydrogen atom from the amino group of another amino acid
• dehydration reaction: carbon atom of carboxyl group releases a hydroxyl group (-OH) and the nitrogens of the amino group combine to form a peptide bond
• DNA: a polymer of nucleotides that carries genetic information in the form of genes
• RNA: Ribonucleic acid, a nucleic acid that is the primary messenger in the cell
• ribose: sugar in RNA
• deoxyribose: sugar in DNA
• pyrimidine: nitrogen containing ring only single-ring
• cytosine: a base found in DNA and RNA
• thymine: a base found in DNA
• uracil: a base found in RNA, replaces where the thymine would be
• purine: in nucleic acids, bases that are joined together by condensation reactions
• guanine: a base found in DNA and RNA
• adenine: a base found in DNA and RNA, pairs with thymine
• phosphodiester bond: a bond that forms when a phosphate group in one nucleotide is covalently joined to the sugar unit in another nucleotide
• double helix: structure formed by z strands of complementary nucleotides that coil around each other
• sugar phosphate backbone is a polymer of pentose sugar units and phosphate groups
• bases form specific purine-pyrimidine pairs, which are complementary to each other (A-T and C-G)
• cyclic molecules: a compound in which at least some atoms are connected to form a ring
• monosaccharide: a simple sugar
• polysaccharide: caused by the condensation of many monosaccharides
• glycosdic bond: formed when carbon, one of monosaccharide and a hydroxyl group carried by a carbon atom in a different monosaccharide molecule