define macro-elements

1

• define macro-elements
• 4 of the 13 essential elements that are required
  in larger quantities
• state the importance of the macro-elements
• nitrogen (N)
• component of amino acids, proteins and nucleic
  acids
• phosphorus (P)
• component of nucleic acids, ATP and cell
  membranes
• potassium (K)
• required for membrane transport
• magnesium (Mg)
• component of chlorophyll

2

• describe the deficiency symptoms for each
  macro-element
• nitrogen
• chlorotic (pale green or yellow) leaves
• long, thin roots
• red leaf bases
• stunted growth
• phosphorus
• poorly developed roots
• red leaf bases
• stunted growth

3

• potassium
• premature death of leaves
• stunted growth
• magnesium
• chlorotic leaves
• stunted growth
• comment on set-up of water culture experiments
• one macro-element absent from each beaker
• beaker wrapped in black plastic to exclude
  light and prevent algal growth
• air bubbled in to supply oxygen to roots
• beaker rinsed in nitric acid to remove any
  minerals

4

• discuss the importance of iron in animals
• RDA is 14mg meat, green veg, beans
• iron lost daily in urine, bile and dead skin
  cells
• women require more iron due to blood loss
  during menstruation / provide growing foetus with
  blood
• iron is a component of
• haemoglobin
• hydrogen carriers
• many enzymes
• deficiency symptoms include fatigue and anaemia

5

• discuss the importance of calcium in animals
• RDA of 800mg dairy products, green veg, nuts
• plays a key role in
• formation of bones, teeth and shells
• blood clotting
• muscle contraction
• deficiency symptoms include osteoporosis and
  rickets