For example NADPH participate in the final stage in one of the biosynthetic routes

1. For example NADPH participate in the final stage in one of the biosynthetic routes leading cholesterol. As in many other biosynthetic reactions, the reductions of the C=C bond is achieved by the transfer of a hydride ion from the carrier molecule NADPH, plus a proton (H+) from the solution.

2. There Are Many Other Activated Carrier Molecules in Cells There are other activated carries molecules present in cells e.g. Acetyl CoA, carboxylated biotin, S-adenosylmethionine, and uridine diphosphote glucose. Acetyl CoA is used to add two carbon units in the biosynthesis of larger molecules. Most of these carriers are small parts of the molecules that are transferable, the rest of bulk group facilitating the recognition of the carrier molecule by specific enzymes.

5. Condensation and hydrolysis are opposite reactions. Macromolecules are Formed by condensation, broken down by hydrolysis.

6. The synthesis of polysaccarides, proteins, and nucleic acids requires an input of energy

9. Synthesis of a polynucleotide, RNA or DNA, is a multistep process driven by ATP hydrolysis.

10. Protein Structure and Function Chapter 3 p119-167

11. Proteins are the building blocks from which cells are assemble, and they constitute most of the cell’s dry mass. But in addition to providing cell with shape and structure, proteins also execute nearly all its diverse functions. Some examples of protein functions: 1. Enzyme: Catalyze covalent bond breakage or formation 2. Structural protein: Provide mechanical support 3. Transport protein: Carries small molecules or ions 4. Motor protein: Generates movement in cells and tissues. 5. Storage protein: Stores small molecules or ions. 6. Signal Protein: Carriers signal from cell to cell 7. Receptor protein: Detects signal and transmits them cell to cell’s response machinery 8. Gene regulatory protein: Binds to DNA to switch gene on or off 9. Specialized proteins: act as antibodies, antifreeze

21. The Shape and Structure of Proteins Proteins are the most structurally sophisticated molecules known. Consistent with theirdiverse functions, they vary extensively in structure, each type of protein having a unique three dimensional shape. But as diverse as proteins are individually, they are the polymers constructed from the same set of amino acids, the universal monomers ofprotein.

22. The Shape of a Protein Is Specified by Its Amino Acid Sequence Proteins are assembled from a set of 20 different amino acids, each with different chemical properties. A protein molecule is made from a long chain of these amino acids, each linked to its neighbor through a covalent peptide bond. Proteins are, therefore, called polypeptide. Each polypeptide chain consists of a backbone that supports the different amino acids side chains. The polypeptide backbone is formed from the repeating sequences of atom along the polypeptide chain

25. The side chains give each amino acid its unique properties. Some are nonpolar or hydrophobic, some are negatively or positively charged, and some are chemically reactive, and so on.

29. Long polypeptide chains are very flexible: many of the covalent bonds that link carbon atoms in an extended chain of amino acids allow free rotation of the atoms they join. Thus protein can in principal fold in an enormous numbers of ways. Each of folded chain is constrained by many different sets of weak noncovalent bonds that formed within proteins.

31. A fourth weak force also plays a central role in determining the shape of a protein. Hydrophobic molecules, including the nonpolar side chains of particular amino acids, tend to be forced together in aqueous, watery environment to minimize their destructive effect on the hydrogen bonded network of surrounding water molecules. When polar amino acids are buried within the protein, they are usually hydrogen bounded to other polar amino acids or to the polypeptide backbone.

34. Proteins Fold into a Conformation of Lowest Energy Each Type of has a particular three-dimensional structure which is determined by the order of the amino acids in its side chain. The final folded structure, or conformation, adopted by any polypeptide chain is determined by energetic consideration: a protein in generally folds into the shape in which the free energy is minimized. Denatured proteins can recover their natural shapes. This type of experiment demonstrates that the conformation of a protein is determined by solely by its amino acids sequences.

36. If proteins fold improperly, they can form aggregates that can damage cells and even whole tissues. Aggregated proteins underlie a number of neurodegenerative disorder, including Alzheimer’s disease and Huntington’s disease. Alzheimer's disease is a progressive, degenerative disorder that attacks the brain and results in disorientation, with impaired memory, thinking, and judgment. People with Alzheimers also undergo changes in their behavior.

37. Huntington's Disease(HD) is a devastating, degenerative brain disorder for which there is, at present, no effective treatment or cure. HD slowly diminishes the affected individual's ability to walk, think, talk and reason. Eventually, the person with HD becomes totally dependent upon others for his or her care. Huntington's Disease profoundly affects the lives of entire families: emotionally, socially and economically

38. Prion diseases-such as scrapie in sheep, bovine spongiform encephalopathy (or mad cow disease) in cattle, and Creutzfeldt-Jacob disease (CJD) in humans- are also caused by protein aggregation.

39. Proteins come in a Wide variety of Complicated Shapes Proteins are the most structurally diverse macromolecules in the cell. They range in size from about 30 amino acids to more than 10,000 amino acids. Proteins can be globular or fibrous; they can form filaments, sheets, rings or spheres.

41. There are two ways to determine protein’s amino acid sequences. First, it is possible to purify proteins and then sequence the protein with different number of ways. The first protein was sequenced is insulin hormone. The second way also called indirect way is to deduce from its DNA sequence

44. Although all of the information required for a polypeptide chain to fold is contained in its amino acids sequence, we have not yet learned how to predict reliably a protein’s detailed three dimensional conformation-the spatial arrangement of its atoms. At the present, the only way to discover the precise folding pattern of any protein is by experiment, using either X-ray or nuclear magnetic resonance methods.

46. The α Helix and the β Sheet Are Common Folding Patterns Although the overall conformation each protein is unique, there are only two different folding patterns are present in all proteins, which are α helix and β sheet. α helix was first discovered in α-keratin, which is abundant in skin and its derivative. β sheet was found in protein fibroin, the major constituent of silk. These two folding pattern are particularly common because they result from hydrogen bonds forming between the N-H and C=O groups in the polypeptide backbone. Because amino acids side chains are not involve in forming these hydrogen bonds, α helices and β sheets can be generated by many different amino acids sequences.