Biology Topic 1 - Biological molecules

• The three types of biological macromolecules are carbohydrates, lipids, and proteins.
• Monomers are smaller/repeating molecules from which larger molecules/polymers are made.
• Polymers are molecules made up of many identical/similar molecules/monomers.
• In a condensation reaction, two molecules join together, forming a chemical bond and releasing a water molecule.
• In a hydrolysis reaction, two molecules are separated, breaking a chemical bond and using a water molecule.
• Lipids are not made from repeating monomers and are not considered polymers.
• A polymer is made of two or more monomers, and 'poly' means many.
• Two monomers joined together is a dimer.
• The properties of ATP make it a suitable immediate source of energy for cells as it releases energy in small amounts, cannot pass out of the cell, and is used in single reactions.
• Inorganic phosphate released can be used to phosphorylate (add phosphate to) other compounds, making them more reactive.
• Water is a major component of cells and has five properties important in biology: it is used in condensation/hydrolysis/photosynthesis/respiration, it acts as a solvent (can dissolve solutes), it allows metabolic reactions to occur faster in solution, it allows transport of substances such as nitrates in xylem and urea in blood, it has a high specific heat capacity which buffers changes in temperature, it has a high latent heat of vaporisation which allows effective cooling via evaporation of a small volume, it has strong cohesion between water molecules which supports columns of water and pr
• ATP is resynthesised in cells as ADP + Pi → ATP (+ water) through a condensation reaction, removing a water molecule, catalysed by ATP synthase (enzyme), during respiration and photosynthesis.
• Phosphate ions (PO43-) are a component of nucleotides, allowing phosphodiester bonds to form in DNA or RNA.
• Phosphate ions phosphorylate other compounds, making them more reactive.
• Phosphate ions are a component of ATP, allowing energy release.
• Sodium ions (Na+) are involved in co-transport of glucose or amino acids into cells.
• ATP hydrolysis creates energy, which cannot be created but only transferred or released.
• Sodium ions affect water potential of cells or osmosis.
• It is a common mistake to name an ion as an element, for example, 'iron ions' and not just 'iron'.
• Hydrogen ions affect enzyme rate of reaction, causing them to denature.
• Hydrogen ions (H+) maintain pH levels in the body, which is high in acidity or low in pH.
• Iron ions (Fe2+) are a component of the haem group of haemoglobin, allowing oxygen to bind or associate for transport as oxyhaemoglobin.
• Phosphate ions are the hydrophilic part of phospholipids, allowing a bilayer to form.
• Sodium ions are involved in action potentials in neurons.
• DNA is a polymer of nucleotides (polynucleotide) formed from deoxyribose, a phosphate group and a nitrogen-containing organic base.
• Between specific complementary base pairs in DNA are adenine/thymine and cytosine/guanine.
• DNA is long and stores lots of genetic information that codes for polypeptides.
• DNA has many hydrogen bonds between bases, making it stable and strong.
• DNA is long, stores lots of genetic information that codes for polypeptides, and is coiled, making it compact.
• Two polynucleotide chains are held together by hydrogen bonds in DNA.
• DNA is coiled and compact.
• Each nucleotide in DNA is formed from deoxyribose, a phosphate group and a nitrogen-containing organic base.
• DNA is a double helix with a sugar phosphate backbone.
• Phosphodiester bonds join adjacent nucleotides in DNA.
• DNA has a double helix with a sugar phosphate backbone, which protects bases and hydrogen bonds.
• DNA has a double helix with a sugar phosphate backbone, which protects bases and hydrogen bonds, and is long, storing lots of genetic information that codes for polypeptides, making it compact.
• Bonds break when an enzyme denatures.
• Non-competitive inhibitors reduce the effect of inhibitors by binding to a site other than the active site, changing the enzyme tertiary structure, and altering the shape of the active site so that it is no longer complementary to the substrate.
• pH can be controlled by using a buffer solution and monitoring using a pH meter at regular intervals.
• The substrate changes shape in the induced fit model of enzyme action.