In this IBDP Biology blog post, we will be looking at how chemicals are associated with water, and what organisms are composed of.
Chemical elements and water
The most frequently chemical elements that are occuring in living organisms are:
- Carbon – 19%
- Hydrogen – 10%
- Oxygen – 65%
- Nitrogen – 3%
They are used in the molecular structures of all carbohydrates, proteins, lipids and nucleic acids.
Living organisms contain more than 20 other element which are also present, but far less common
Sulphur – 0.25%
- Found in certain amino acids (cysteine and methionine), needed for the synthesis of two amino acids, allows proteins to form disulphide bonds
Calcium – 1.5%
- Co-factor in some enzymes, can be found in bones and teeth, involved in neurotransmitter release in synapses
Phosphorus – 1%
- Phosphate groups in ATP, part of DNA molecules, component of nucleic acids and cell membranes
Iron - 0.7%
- Found in cytochromes and haemoglobin (animals), allowing oxygen transport (aerobic cell respiration)
Sodium - 0.15%
- Involved in the generation of nerve impulses in neurons, raises the solute concentration which causes water to enter by osmosis, in membrane function
That is all!
References:
https://www.google.com/url?sa=i&url=https%3A%2F%2Fslideplayer.com%2Fslide%2F9057778%2F&psig=AOvVaw22h12eGzY1sjSUOjhuDES9&ust=1627580161131000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCOiJo96mhvICFQAAAAAdAAAAABAI
Drafted by Venetia (Biology)