water and inorganic ions

Question 1

Explain why water is a polar molecule

Answer 1

• O is more electronegative than H so attracts the electron density in the covalent bond more strongly, creating a partial charge

Question 2

State 4 biologically important properties of water

Answer 2

1. Metabolite/solvent for chemical reactions in the body
2. High specific heat capacity
3. High latent heat of vapourisation
4. Cohesion between molecules

Question 3

Explain why water is significant to live organisms

Answer 3

1. Solvent for polar molecules during metabolic reactions
2. High specific heat capacity enables organisms to avoid fluctuations in core temperature
3. Cohesion-tension of water molecules in the transpiration stream

Question 4

What are inorganic ions and where are they found in the human body?

Answer 4

• Inorganic ions are ions that don’t contain carbon atoms

- Found in the cytoplasm and extracellular fluid

Question 5

Explain the role of hydrogen ions in the body

Answer 5

• Maintains pH levels in the body

- It affects the rate of enzyme-controlled reactions and can cause enzymes to denature

Question 6

Explain the role of iron ions in the body

Answer 6

• Component of haemoglobin which is contained in red blood cells
• Transports oxygen around the body

Question 7

Explain the role of sodium ions in the body

Answer 7

• Involved in co-transport for absorption of glucose and amino acids in the lumen of the gut
• Involved in the propagation of action potentials in neurons

Question 8

Explain the role of phosphate ions in the body

Answer 8

• Attached to other molecules as a phosphate group
• In DNA nucleotides it enables nucleotides to join together to form phosphodiester bonds