1. Biological Molecules - Water And Inorganic Ions

Question 1

Give 5 properties of water:

Answer 1

-Is a metabolite in many metabolic reactions
-An important solvent
-Has a relatively high heat capacity
-Has a relatively large latent heat of vaporisation
-Has strong cohesion between water molecules

Question 2

Which reactions is water an important solvent for?

Answer 2

Metabolic reactions, including condensation and hydrolysis reactions.

Question 3

What is the purpose of water having a relatively high heat capacity?

Answer 3

It buffers changes in temperature.

Question 4

What is the purpose of water having a relatively large latent heat of vaporisation?

Answer 4

It provides a cooling effect with little loss of water through evaporation.

Question 5

What is the purpose of water having strong cohesion between water molecules?

Answer 5

This supports columns of water in the tube-like transport cells of plants and produces surface tension where water meets air.

Question 6

Where are inorganic ions found?

Answer 6

In organisms, specifically solutions such as cytoplasm or body fluids.

Question 7

Give 4 functions of sodium ions in organisms:

Answer 7

-Involved in regulation: osmotic pressure, control of water levels in body and ph maintenance
-Affects absorption: carbohydrates in the intestine, water in the kidneys
-Contributes to nervous transmission and muscle contraction
-Constituent of vacuole in plants which helps maintain turgidity

Question 8

Give 6 functions of potassium ions in organisms:

Answer 8

-Involved in: control of water levels in body fluid, maintenance of pH
-Assists active transport of materials across the cell membrane
-Involved in: synthesis of glycogen and protein, breakdown of glucose
-Generates healthy leaves and flowers in flowering plants
-Contributes to: nervous transmission, muscle contraction
-Component of vacuoles in plants, helping to maintain turgidity

Question 9

Give 4 functions of chloride ions in organisms:

Answer 9

-Helps production of urine in the kidney and maintaining water balance
-Involved in: transport of carbon dioxide into and out of the blood, regulation of pH
-Regulates affinity of haemoglobin to oxygen through allosteric effects on the haemoglobin molecule
-Used to produce hydrochloride acid in the stomach

Question 10

Give 4 functions of phosphate ions in organisms:

Answer 10

-Increases rigidity of bone, teeth, cartilage and is a component of the exoskeleton of crustaceans
-Component of: phospholipids, ATP, nucleic acids, several important enzymes
-Involved in refutation of blood pH
-Helps root growth in plants which