Mass Transport

Question 1

give features of a mass transport system

Answer 1

vessels
transport medium
maintains speed

Question 2

Why do some organisms require a mass transport system?

Answer 2

larger animals have a smaller surface area to volume ratio and a higher metabolic rate. diffusion alone is insufficient to supply all cells with the substances they need due to a larger diffusion distance so it is too slow.

Question 3

What makes water a dipolar molecule?

Answer 3

Oxygen is more electronegative (partially negative charge) than Hydrogen (partially positive charge) so attracts the electron density in the covalent bond more strongly. Forms O- and H+

Question 4

How is water used in transport?

Answer 4

Due to its polar nature it acts as a solvent, allowing transport of biological molecules. Acts as a median for chemical revaluing to occur. Hydrogen bonding between water molecules creates cohesion and adhesion which enables the effective transport of water and dissolved substances through xylem vessels.

Question 5

Give the properties of water

Answer 5

Cohesion, adhesion, high specific heat capacity, polar solvent, polar molecule

Question 6

Why does water have a high specific heat?

Answer 6

A lot of the energy is required to break hydrogen bonds so it can absorb a lot of heat energy before the bonds break. This minimises temperature fluctuations in living things which is an important part of homeostasis.

Question 7

What bonds join atoms within a water molecule?

Answer 7

Covalent bonds

Question 8

What bonds link water molecules together?

Answer 8

Hydrogen bonds

Question 9

Water is a metabolite. What does this mean?

Answer 9

It is necessary for metabolism
Condensation and hydrolysis used in forming/breaking chemical bonds

Question 10

Give examples of reactions where water is a metabolite

Answer 10

Photosynthesis, digestion, aerobic respiration. Because water reacts with a chemical to break it into smaller molecules (hydrolysis reaction)

Question 11

Why is water a good solvent?

Answer 11

because of its polarity and ability to form hydrogen bonds

Question 12

What property allows water to buffer changes in temperature?

Answer 12

High specific heat capacity

Question 13

What does large latent heat of vaporisation mean?

Answer 13

the thermal energy required for a liquid to vaporize to a gas

Question 14

What is the difference between cohesion and adhesion?

Answer 14

adhesion refers to the clinging of unlike molecules and cohesion refers to the clinging of like molecules

Question 15

When do plants use cohesion?

Answer 15

When transporting water molecules up the xylem vessel.

Question 16

What are pond skaters and how does cohesion help them?

Answer 16

Pond skaters are small bug creatures that live around ponds and cohesion helps them as cohesion creates surface tension on the surface of the pond which forms a thin skin like layer on top of the water which allows the pond skaters

Question 17

What are special properties of water?

Answer 17

• Metabolic importance.
• High heat capacity.
• High latent heat of vaporization.
• Cohesive properties.
• Useful as a solvent.