Atp Water And Inorganic Ions

Question 1

State 4 biologically important properties of water.

Answer 1

due to polarity & intermolecular H-bonds:
• Metabolite / solvent for chemical reactions in the body.
• high specific heat capacity.
• high latent heat of vapourisation.
• cohesion between molecules.

Question 2

Explain why water is significant to living organisms.

Answer 2

• Solvent for polar molecules during metabolic reactions.
• Enables organisms to avoid fluctuations in core temperature.
• Cohesion-tension of water molecules in transpiration stream.

Question 3

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

Answer 3

lons that do not contain carbon atoms.
• Found in cytoplasm & extracellular fluid.
• May be in high or very low concentrations.

Question 4

Explain the role of hydrogen ions in the body.

Answer 4

High concentration of H+ = low (acidic)
pH.
• Ht ions interact with H-bonds & ionic bonds in tertiary structure of proteins, which can cause them to denature.

Question 5

Explain the role of iron ions in the body.

Answer 5

Fe?* bonds to porphyrin ring to form haem group in haemoglobin.
Haem group has binding site to transport 1 molecule of O, around body in bloodstream.
4 haem groups per haemoglobin molecule.

Question 6

Explain the role of sodium ions in the body.

Answer 6

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

Question 7

Explain the role of phosphate ions in the body.

Answer 7

component of:
• DNA
• АТР
• NADP
• CAMP

Question 8

Describe the structure of adenosine triphosphate

Answer 8

nucleotide derivative of adenine with 3 phosphate groups

Question 9

Explain the role of ATP in cells.

Answer 9

Energy released is coupled to metabolic reactions.
• Phosphate group phosphorylates compounds to make them more reactive.

Question 10

How is ATP resynthesised in cells?

Answer 10

ATP synthase catalyses condensation reaction between ADP & Pi
• during photosynthesis & respiration

Question 11

Explain why ATP is suitable as the
‘energy currency’ of cells.

Answer 11

High energy bonds between phosphate groups.
• Small amounts of energy released at a time = less energy wasted as heat.
• Single-step hydrolysis = energy available quickly.
• Readily resynthesised.