9.1 Plant Structure and Growth

Question 1

Define Vascular plant

Answer 1

Vascular Plants have conductive tissues (a vascular system) for transporting water, minerals and nutrients throughout the plant

Question 2

Describe the difference in number of cotyledons between monocotyledons and dicotyledons

Answer 2

Monocotyledons have one cotyledon; dicotyledons have two

Question 3

Describe the difference in leaf shape between monocotyledons and dicotyledons

Answer 3

Monocotyledons have oblong or linear shaped leaves; dicotyledons have broad leaves

Question 4

Describe the difference in leaf veins between monocotyledons and dicotyledons

Answer 4

Monocotyledons have parallel venation; dicotyledons have net-like venation

Question 5

Describe the difference in root structure between monocotyledons and dicotyledons

Answer 5

Monocotyledons have fibrous, adventitious roots; dicotyledons have tap roots with lateral branches

Question 6

Describe the difference in number of floral organs (petals) between monocotyledons and dicotyledons

Answer 6

Monocotyledons have them in multiples of 3; dicotyledons have them in multiples of 4 or 5

Question 7

State the location of the phloem, and the importance of this

Answer 7

Found in middle of leaf, allowing for optimal access for all cells

Question 8

State the function of the phloem

Answer 8

Transports the products of photosynthesis (sugars, amino acids) to the rest of the plant

Question 9

State the location of the xylem, and the importance of this

Answer 9

Found in middle of leaf, allowing for optimal access for all cells

Question 10

State the function of the xylem

Answer 10

Transports water and minerals into the leaf tissue from the stem and roots

Question 11

State the location of the upper epidermis, and the importance of this

Answer 11

On top of leaf, where light intensity and heat are greatest

Question 12

State the function of the upper epidermis

Answer 12

Secretes waxy cuticle which conserves water

Question 13

State the location of the lower upper epidermis

Answer 13

Bottom of leaf

Question 14

State the function of the lower epidermis

Answer 14

Contains stomata pores which allows for gas exchange, mainly CO2

Question 15

State the location of the palisade mesophyll and the importance of this

Answer 15

Upper half of leaf where light intensity is greatest (upper epidermal cells are transparent)

Question 16

State the function of the palisade mesophyll

Answer 16

Main region of photosynthesis; cells absorb light

Question 17

State the location of the spongy mesophyll and the importance of this

Answer 17

Lower half of leaf, near stomatal pores where gases and water are exchanged with the atmosphere

Question 18

State the function of the spongy mesophyll

Answer 18

Main site of gas exchange

Question 19

State the location of the vascular bundles, and the importance of this

Answer 19

Middle of leaf, allowing for optimal access for all cells

Question 20

State the function of the vascular bundles

Answer 20

Spread through the leaf like a network, providing support and transporting water and the products of photosynthesis

Question 21

State the location of the stomata

Answer 21

Bottom of leaf

Question 22

State the function of the stomata

Answer 22

Allows movement of gasses in and out of the leaf

Question 23

Define Storage organ

Answer 23

A storage organ is a part of a plant specifically modified to store energy. They are usually found underground (better protection from herbivores).

Question 24

State the function and give an example of storage roots

Answer 24

Modified roots which store water or food; carrots

Question 25

State the function of and give an example of stem tubers

Answer 25

Horizontal underground stems which store carbohydrates; potatoes

Question 26

State the function of and give an example of bulbs

Answer 26

Modified leaf bases which allow for food storage and contain layers called scales; onion

Question 27

State the function of and give an example of tentrils

Answer 27

Modification to leafs which allow for climbing support and attachment; cucumber

Question 28

Define meristems

Answer 28

Regions of plant tissue where undifferentiated cells undergo rapid cell division (mitosis), and therefore growth occurs.

Question 29

State the two kinds of meristems which are found in dicots

Answer 29

Apical meristems and lateral meristems

Question 30

State the location of apical meristems

Answer 30

Occur at the tips of the shoots and roots

Question 31

State the location of lateral meristems

Answer 31

Formed from the cambium cells

Question 32

Outline the function of apical meristems

Answer 32

Responsible for primary growth
Increases height/depth of plant
Produces new leaves and flowers

Question 33

Outline the function of lateral meristems

Answer 33

Responsible for secondary growth
Increases girth of stem for strength
Produces bark on trees

Question 34

Define tropism

Answer 34

Bending growth of a plant towards or away from a directional stimulus

Question 35

Define phototropism

Answer 35

Bending growth of a plant towards a source of light

Question 36

Define auxin

Answer 36

A group of substances that promote plant growth

Question 37

Explain the role of auxin in phototropism

Answer 37

• Auxin makes plant cells enlarge and grow
  
  • Auxin causes cell elongation by activating pumps that expel H+ ions from the cytoplasm into the cell wall
  • The resulting decrease in pH within the cell causes cellulose fibres to loosen, as the bonds which hold them together are broken
  • This makes the cell wall flexible and capable of stretching when water influx promotes cell turgor
    
    • In the shoot, auxin is eradicated by light
  • The greater presence of auxin on the shaded side of the plant causes this side to lengthen, making the shoot curve towards the light