Carbohydrates can be un-naturally linked to proteins resulting in glycated proteins – this is where monosaccharides, in particular glucose, can react chemically with amino acids directly often under oxidizing conditions

Another example of a disaccharide is sucrose – a disaccharide formed in nature enzymatically from a unit of glucose (a hexose) joined via an α-anomeric bond from the glucose to the β-anomeric position on fructose (a pentose) via condensation.

Oligosaccharides are compounds in which monosaccharide units are joined by glycosidic linkages. According to the number of units, they are called disaccharides, trisaccharides, tetrasaccharides, pentasaccharides etc.

An example of a disaccharide is maltose – a disaccharide formed in nature enzymaticaly from two units of glucose joined with an α(1→4) bond via condensation but with variation in the terminal anomeric position.

The generic term ‘monosaccharide’ (as opposed to oligosaccharide or polysaccharide) denotes a single unit, without glycosidic connection to other such units.

A well known example of a monosaccharide is glucose – a white crystalline solid, soluble in water and some organic solvents, interacts with plane polarized light

Carbohydrates received their name, historically, from the fact that monosaccharides often have a general formula Cm(H2O)n

Lipids – phospholipids

• made up of glycerol, two fatty acyl units and a phosphate(alcohol) unit

Lipids – plasmalogens

• made up of glycerol, fatty alcohol unit linked by ether, fatty acyl unit and a phosphate(alcohol) unit

Platelet Activating Factor (PAF) - Inflammation and immune mediator – responsible for platelet aggregation, anaphylactic shock. This is just one example of a lipid acting as a signaling molecule, there are many more. When these compounds are membrane derived this indicates that membranes are ‘active’ entities not just physical barriers.

Lipids – sphingolipids

• made up of Sphingosine, hydroxyl, fatty acyl amido unit and a phosphate(alcohol or glycoside)

Lipids – cerebrosides

• made up of Sphingosine, hydroxyl, fatty acyl amido unit and a phosphate(alcohol or glycoside)

A loosely defined term for substances of biological origin that are soluble in nonpolar solvents. They consist of saponifiable lipids, such as glycerides (fats and oils) and phospholipids, as well as non-saponifiable lipids, principally steroids.

Steroid family including:

• Glucocorticoids; e.g. cortisol, the major representative in most mammals
• Mineralocorticoids; e.g.aldosterone being most prominent
• Androgens; e.g. testosterone
• Estrogens;
  e.g. estradiol and estrone
• Progestogens; (aka: progestins)
  e.g. progesterone
  

DNA melting

• For the same length (no. of base pairs) of DNA the “melting point” depends on the GC/AT ratio of the sequence of DNA. Other factors such as pH and presence of denaturants such as urea may have an effect on denaturation. Melting can be monitored using UV spectroscopy and the process can be reversible.
  

DNA super coiling:

• Histones are +ve charged proteins that aid the coiling process and ion pair with the polyanionic DNA
  

DNA vs RNA:

• The presence of a hydroxyl group at the 2' position of the ribonucleotide sugar in RNA distinguishes it from DNA. This functional group causes any double helical regions to prefer an A-form geometry rather than the B-form most commonly observed in DNA.

  
  

• This also results in a very deep and narrow major groove and a shallow and wide minor groove. An important secondary consequence is that it also introduces extremely conformationally flexible regions within RNA when these regions are often not paired in a stable double helix. This introduces hairpin loops bulges and internal loops. Very unlike DNA.

DNA structure:
-DNA (DeoxyriboNucleic Acid), a relatively water soluble polymeric polyanion

• Phosphate – sugar backbone
  negatively charged phosphates
• Sodium cations as positive counterions
• Specific DNA base pairs linked by strong hydrogen bonding
• double helical shape
  

Nucleic acids are biological molecules essential for known forms of terrestrial life, they include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Alongside proteins, nucleic acids are one of the most important class of biological macromolecules; each type is found in abundance in nearly all living things, where they function in encoding, transmitting and expressing genetic information.

RNA types:

• RNAs involved in protein synthesis
• mRNA – messenger RNA that carries genetic code from DNA to the ribosome
• tRNA – transfer RNA moves specific amino acids to the growing polypetide chain at the ribosome
• rRNA – ribosomal RNA is a structural element of the ribosome that facilitates the reading of the mRNA and catalyses peptide bond formation of the growing chain
• RNAs involved in post-transcriptional modification
• Signal recognition RNA – directs trafficking of protein and is involved in secretion
• Ribonuclease P – a complex RNA that acts as a ribonuclease (yes, an enzyme!!) that cleaves RNA