Mass transport in plants

Question 1

What are plant cell walls made of?

Answer 1

Plant cell walls are made of cellulose

Question 2

What is the definition of a tissue?

Answer 2

A tissue is a group of cells with similar structure and function.

Question 3

Give some examples of plant tissues?

Answer 3

In a plant, the Xylem and Phloem are examples of tissues which transport substances around the plant

Question 4

What does transpiration mean?

Answer 4

Transpiration is the evaporation of water vapour, mainly through the stomata in the surface of a leaf

Question 5

What do the stomata do and whats a disadvantage of it?

Answer 5

The stomata open to let in carbon dioxide for photosynthesis however an issue with this is it allows water to diffuse out.

Question 6

Once water is lost from the stomata what happens?

Answer 6

Once the water in the stomata diffuses out the from the mesophyll fills the stomata. This is then replaced by water from the xylem.

Question 7

The system of water transfer is not possible in taller trees how is this overcome?

Answer 7

In taller trees, the xylem vessels are thinner so water is closer together. Water cohesion (attraction to itself) then pulls up other water particles.

Question 8

What is a polar molecule?

Answer 8

A molecule with a slight positive charge in one part of the molecule and a slight negative charge in another part

Question 9

By what process does water enter roots

Answer 9

Osmosis

Question 10

Fact

Answer 10

Very little of the water taken up by plants is used for photosynthesis or to make glucose but is just evaporated back out the plant. The excess water is needed so the little bit will always be there.

Question 11

What is the latent heat of vaporisation?

Answer 11

The heat required to turn liquid at its boiling temperature into a gas at the same temperature

Question 12

What is specific heat capacity (SHC)

Answer 12

The heat required to raise the temperature of a volume of liquid by 1 degree Celcius

Question 13

Why is waters high heat capacity important?

Answer 13

The high heat capacity of water stops bodies of water rapidly changing temperature as that would damage organisms such as fish and plants living in the water.

Question 14

Water in plants keeps them cool in direct sunlight explain what characteristic allows this?

Answer 14

Waters high specif c heat capacity means it can be used in plants to maintain temperature even in direct sunlight.

Question 15

What is a solvent?

Answer 15

A solvent is a liquid able to dissolve other substances

Question 16

What is sap?

Answer 16

Sap is the fluid that is transported in the phloem.

Question 17

What is translocation?

Answer 17

Translocation is the process of moving organic substances around plants.

Question 18

What is the purpose of the xylem?

Answer 18

The xylem carries water and minerals

Question 19

What is the purpose of the phloem?

Answer 19

The phloem carries food

Question 20

Name some features of the xylem?

Answer 20

The Xylem:

• Water
• Thick
• Impermeable

Question 21

Name some features of the phloem?

Answer 21

The Phloem:

• Food
• Thin
• Permeable

Question 22

How is transpiration affected by light?

Answer 22

The stomata opens for light and allows carbon dioxide and water to to diffuse out. In this process photosynthesis takes place water is lost through transpiration.

Question 23

How is transpiration affected by temperature?

Answer 23

Increased temperature means less water can be stored and water molecules will move faster.

Question 24

What is the definition of cohesion?

Answer 24

Cohesion is attraction between two water molecules due to their charge

Question 25

What is the definition of adhesion?

Answer 25

Adhesion is the attraction between water and an object

Question 26

How is transpiration affected by humidity?

Answer 26

Humidity is the measure of number of water molecules in the air and it effects the potential humidity and ability of water to move out. High humidity = low transpiration