Mass flow transport

Question 1

what is mass flow ?

Answer 1

-mass flow is brought upon by pressure differences existing within the organism
-materials are moved by the pressure difference between the area where the pressure is generated and the area where the pressure is much less

Question 2

what is meant by a source and a sink and what is an example of this?

Answer 2

-source is an area where pressure is generated
-sink is where the pressure is much less
-e.g. lungs= source and muscles/skin etc.= sink

Question 3

why is there a difference in pressure in the xylem?

Answer 3

-water evaporating from the leaf creates tension that pulls water up through the xylem as part of the transpiration stream

Question 4

why is there a difference in pressure in the phloem?

Answer 4

-energy expenditure is needed to transport sucrose into the phloem. ATP energy is used to move sucrose to the sieve tube

Question 5

what is the function of the phloem?

Answer 5

• transport sucrose (translocation) to roots for storage of carbohydrates and to growing regions to provide energy.

Question 6

why is there a difference in pressure in circulation in mammals?

Answer 6

-high pressure generated by the pumping of the heart

Question 7

what is the function of circulation in mammals ?

Answer 7

-transport of substances e.g. O2, CO2 and glucose

Question 8

why is there a pressure difference in ventilation in mammals ?

Answer 8

-reduction of pressure in the thorax causes air to enter the lungs and increased pressure in the thorax causes air to expel from the lungs
- inhalation and exhalation