Water And Inorganic Ions

Question 1

5 main properties of water + 3 extra

Answer 1

1. Metabolite in many reactions
2. Universal solvent
3. Cohesion
4. High latent heat of vaporisation
5. High specific heat capacity
6. Ice less dense than water
7. Water is viscous
8. Water is transparent

Question 2

describe the structure of a water molecule

Answer 2

1 delta -ve oxygen atom joined to 2 delta +ve hydrogen atoms by covalent bonds

Question 3

why is the O atom i water delta -ve

Answer 3

it has the greater share of electrons

Question 4

what gives water high cohesion?

Answer 4

H-bonds between delta -ve O of one molecule and delta +ve H of another molecule

Question 5

what makes water stable?

Answer 5

many weak hydrogen bonds between molecules of water

Question 6

what is the biological importance of water being cohesive? (2 things)

Answer 6

long columns of water don’t break so plants can pull water up from roots to leaves in one column through xylem
cohesion creates surface tension which allows some animals and plants to be supported on the surface of water

Question 7

surface tension

Answer 7

at air-water interface,water molecules at the top are held to each other and those below, creating an elastic film

Question 8

water as a universal solvent

Answer 8

water can dissolve more substrates than any other solvent as it is dipolar and can form H-bonds
this is vital to cells as most chemical reactions occur in cells in aqueous solutions

Question 9

explain the importance of water having a high latent heat of evaporation

Answer 9

water requires a large amount of heat energy to break H-bonds and turn water into water vapour
means that when water evaporates from the skin of mammals, it removes much body heat to break H-bonds. this loss of energy cools the animal

Question 10

explain the feature and importance of water having a high specific heat capacity

Answer 10

water requires much heat energy to increase 1kg of water by 1 degree C
ensures temperatures are stable for cellular reactions which are sensitive to temp change and prevents enzymes denaturing
allows organisms (especially aquatic) to experience extreme and fatal fluctuations in temperature

Question 11

water as a metabolite

Answer 11

required in PS
required in condensation reactions to synthesise biological polymers
required in hydrolysis reactions to digest biological polymers

Question 12

metabolite

Answer 12

any substance used or produced in a metabolic reaction

Question 13

2 functions of hydrogen ions

Answer 13

used in loading sucrose in phloem
controlling pH of body fluid

Question 14

2 functions of calcium ions

Answer 14

involved in muscle contractions
involved in synaptic transmission

Question 15

function of iron ions

Answer 15

in haem groups of Hb, help associate with and transport O2

Question 16

function of magnesium ions

Answer 16

component of chlorophyll

Question 17

function of sodium and potassium ions

Answer 17

involved in absorption in the ileum

Question 18

function of phosphate ions

Answer 18

involved in nucleotide synthesis

Question 19

inorganic ion

Answer 19

an ion without a carbon atom

Question 20

ion

Answer 20

an atom or group of atoms with an electrical charge

Question 21

cation

Answer 21

ion with a positive charge

Question 22

anion

Answer 22

ion with a negative charge