Water And Its Functions

Question 1

why does water have unusual properties?

Answer 1

-due to its bipolar nature and subsequent hydrogen bonding

Question 2

what is a dipolar water molecule?

Answer 2

-although the molecule has no overall charge its oxygen atom provides a positive charge and the hydrogen atoms has a negative charge so the water molecule has both charges

Question 3

how are hydrogen bonds created in water molecules?

Answer 3

-different poles attract so the positive pole of one water molecule will be attracted to the negative pole of another water molecule. the attractive forces create a weak hydrogen bonds that cause water molecules to stick together

Question 4

what is the specific heat capacity of water?

Answer 4

• since water molecules stick together it takes more energy to separate them meaning the boiling point of is higher than expected
• it takes more energy to heat a given mass of water since it’s a liquid so has a high specific heat capacity
• water acts as a buffer agains sudden temperature variations as an aquatic environment and in organisms

Question 5

what is the latent heat of vaporisation of water?

Answer 5

• hydrogen bonding between water molecules means that requires a lot of energy to evaporate 1gram of water
• evaporation do water such as sweat in mammals is a very effective means of cooling because body heat is used to evaporate water

Question 6

what is the cohesion and surface tension of water?

Answer 6

• with its hydrogen bonds water had large cohesive forces and these allow it to be pulled up through a tube such as a xylem vessel in plants
• where water molecules meet air they tend to be pulled back into the body of water that escaping from it which is called surface tension meaning the water surface acts like skin and is strong enough to support small organisms like pond skaters

Question 7

why is water important to living organisms?r

Answer 7

• water is the main constituent of all organisms 95% in jellyfish and 65% in mammals
• water is also where life on Earth arise and it is the environment in which many species like

Question 8

how is water used in the metabolism?

Answer 8

• water is used to break down many complex molecules by hydrolysis
• water is produced in condensation reactions
• chemical reactions take place in and aqueous medium
• water is a major raw material in photosynthesis

Question 9

which substances are readily dissolved by the solvent water?

Answer 9

-water dissolves gases like oxygen waste like urea, inorganic ions and hydrophilic molecules like amino acids and enzymes whose reactions take place in solution

Question 10

what are some important features of water?

Answer 10

• evaporation cools organisms and allows them to control their temperature
• it’s not easy to compress so provides support in earth worms
• it’s transparent so aquatic plant can photosynthesis and light rays can fill the eye to reach the retina

Question 11

what are the functions of inorganic ions?

Answer 11

• the specific function of a particular ion depends on its properties
• for example iron ions are found in haemoglobin and help transport oxygen
• hydrogen ions are important in determining the pH of solutions and the function of enzymes

Question 12

Why are the hydrogen bonds in water important?

Answer 12

-without the hydrogen bonds water would be a gas at the temperatures found on earth and life as we know it would not exist

Question 13

What is the latent heat of vaporisation?

Answer 13

-the amount of energy required to evaporate 1 gram

Question 14

What does cohesion mean?

Answer 14

-the tendency for molecules to stick together

Question 15

Where are inorganic ions found?

Answer 15

-in organisms here they occur in solution in the cytoplasm if cells and in body fluids as well as part of larger molecule in high or low concentrations