water

Question 1

what is water ?

Answer 1

water is a dipolar molecule
- some parts are slightly negatively charges and some parts are slightly positively charged
- water has an unevenly distributed charge

Question 2

properties of water that make it important for living things :

Answer 2

• it is a metabolite
• it is a solvent
• has a high heat capacity
• has a large latent heat of vaporisation
• has strong cohesive bonds between water molecules
• it is adhesive

Question 3

metabolite

Answer 3

used in chemical reactions such as condensation , hydrolysis and photosynthesis reactions

Question 4

solvent

Answer 4

allows solutes to dissolve in it and to be transported in it
- so it allows transpiration o occur

Question 5

high heat capacity

Answer 5

thermoregulation
- temperature control so that a constant temperature is maintained as the temp of water remains relatively stable
- a lot of energy is required to raise the temperature of water as some of the energy is used to break the hydrogen bonds
- so enzymes do not denature

Question 6

large latent heat of vaporisation

Answer 6

enables sweat to evaporate off the surface of the skin as it provides a cooling effect
- it means that a lot of energy is required to convert water in its liquid state to a gaseous state as energy is needed to break the hydrogen bonds between water molecules

Question 7

strong cohesive bonds between water molecules

Answer 7

its sticky so it has large surface tension

Question 8

it is adhesive

Answer 8

sticks to many surfaces

Question 9

at temperatures of 0 degrees and below, what does water form ?

Answer 9

water forms a crystalline substance called ice

Question 10

what does the arrangement of water molecules in ice allow it to have the property of ?

Answer 10

it makes ice less dense than water so ice will form at the surface of a body of water such as a pond or lake

Question 11

because ice floats to the top of the body of water, what does this help with ?

Answer 11

this insulates the water beneath and thus prevents the whole of the body of water freezing solid so living organisms can survive beneath the ice providing there is sufficient food and oxygen available

Question 12

what kind of property makes water a useful lubricant ?

Answer 12

its viscosity

Question 13

what are examples of water being a lubricant ?

Answer 13

• mucus
• synovial fluid
• pleural fluid
• perricardial fluid
• perivisceral fluid

Question 14

what is the supporting role of water ?

Answer 14

mechanical support
with its large cohesive forces, water molecules lie close together
water is therefore not easily compressed , making it useful min supporting organisms

Question 15

state the examples of mechanical support of water ?

Answer 15

• hydrostatic skeleton
• turgar pressure
• humours of the eye

Question 16

hydrostatic skeleton

Answer 16

animals (earthworm) supported by pressure of aqueous medium

Question 17

turgar pressure

Answer 17

supported by osmotic influx of water

Question 18

humours of the eye

Answer 18

shape of the eye is maintained by aqueous and virreous humours

Question 19

what are the 3 miscellaneous functions of water ?

Answer 19

• temperature control
• a medium for dispersal
• hearing and balance

Question 20

what is meant by the fact that water can be used as a medium for dispersal ?

Answer 20

water can be used to release sex cells as pressure of the water can be used to disperse seeds

Question 21

how much percent of your body is mainly water ?

Answer 21

60 - 70%