Ions,water and ATP

• An ionis an atom or group of atoms with an electric charge
• A cation is an ion with a positive charge
• An anion is an ion with a negative charge
• An inorganic ion is a charged molecule that does not contain carbon
• A phosphlipid layer contains of a phosphate which is an inorganic ion
• Phosphate heads are polar so they are attracted to water as they are then hydrophilic so they are positioned towards the water
• Iron ions are found in each polypeptide chain of haemoglobin where it binds to oxygen
• Sodium ions are involved in the co-transport of glucose and amino acids into ileum cells of the small intestine
• Phosphate ions are found in ATP and are found in DNA and RNA
• Water consists of 2 hydrogen atoms covalently bonded to an oxygen atom
• Water makes up to 60%-90% of all living things
• Water is a solvent, involved in metabolic reactions which gives support and is involved in temperature regulation
• ATP stands for Adenosine Triphosphate
• ATP is madeup of a sugar called ribose, a base called adenine and 3 phosphate groups
• ATP is an energy store molecule
• Energy in ATP is stored in high energy bonds between the phosphate groups
• ATP is made in respiration
• Hydrolysis of ATP to ADP and an

  inorganic phosphate group (Pi) is catalysed by the enzyme ATP

  hydrolase
• ATP is resynthesised by the condensation of ADP and Pi. This

  reaction is catalysed by the enzyme ATP synthase during

  photosynthesis, or during respiration.
• Water is a metabolite in many metabolic reactions, including

  condensation and hydrolysis reactions
• Water is an important solvent in which metabolic reactions occur
• Water has a relatively high heat capacity, buffering changes in

  temperature
• Water has a relatively large latent heat of vaporisation, providing a

  cooling effect with little loss of water through evaporation
• Water has strong cohesion between water molecules; this supports

  columns of water in the tube-like transport cells of plants and

  produces surface tension where water meets air.
• Inorganic ions occur in solution in the cytoplasm and body fluids of

  organisms, some in high concentrations and others in very low

  concentrations
• The pH of hydrogen ions is a measure of the hydrogen concentration