Chapter 4: Organising Plants and Animals II

Question 1

define epidermal

Answer 1

the name given to cells that make up the epidermis or outer layer of the organism

Question 2

what do the epidermal tissues do?

Answer 2

• secrete a waxy substance that waterproofs the surface of the leaf
• protects the leaf

Question 3

define palisade mesophyll

Answer 3

the upper layer of the mesophyll tissue in plant leaves made up of closely packed cells that contain many chloroplasts for photosynthesis

Question 4

define spongy mesophyll

Answer 4

the lower layer of mesophyll tissue in plant leaves that contains some chloroplasts and many large air spaces to give a big surface area for the exchange of gases

Question 5

what does xylem transport?

Answer 5

• water

- dissolved mineral ions from the roots up to the leaves

Question 6

what does the phloem transport?

Answer 6

-dissolved food from the leaves around the plant

Question 7

what is meristem tissue made up of?

Answer 7

rapidly dividing plant cells that grow and differentiate into all cell types needed

Question 8

what do the roots, stem and leaves form in the plant?

Answer 8

an organ system

Question 9

define translocation

Answer 9

the movement of sugars from the leaves to the rest of the plant through the phloem

Question 10

are mature xylem cells dead or alive?

Answer 10

dead

Question 11

what is the main difference between the xylem and the phloem?

Answer 11

phloem transports food (sugar) and xylem transport water

Question 12

why is transport so important? (food)

Answer 12

• cells need sugar for respiration and providing materials for growth
• mineral ions are needed for the production of proteins and other molecules

Question 13

why is transport so important? (water)

Answer 13

• plants need water for photosynthesis

- water is the main method of support, to make plants turgor

Question 14

what is stomata?

Answer 14

small openings all over the leaf surface

Question 15

define guard cells

Answer 15

surround the stomata in the leaves of plants and control their opening and closing

Question 16

Describe the role of stomata in a plant

Answer 16

• carbon dioxide from the atmosphere diffuses into the air spaces and then into the cells down a concentration gradient
• oxygen produced by photosynthesis is removed form the leaf by diffusion into the surrounding air

Question 17

define transpiration

Answer 17

the loss of water vapour from the leaves of plants through the stomata when they are opened to allow gas exchange for photosynthesis

Question 18

what is the transpiration stream?

Answer 18

As water is evaporated through the surface of the leaves, more water is pulled from the xylem to take its place.

Question 19

what factors increase the rate of photosynthesis or stomatal opening?

Answer 19

• temperature
• humidity
• air flow
• light intensity

Question 20

in what conditions are transpiration more rapid?

Answer 20

• hot
• dry
• windy
• bright

Question 21

what happens to a plant that loses water faster than it is replaced?

Answer 21

• plant may wilt to reduce the surface area available for water loss by evaporation
• stomata close