Leaf as an example of a plant organ Flashcards Preview

Gd 10 - Life Sciences 2017 > Leaf as an example of a plant organ > Flashcards

Flashcards in Leaf as an example of a plant organ Deck (21):
1

Organs

  • groups of tissues 
  • perform specialised functions

2

Main angiosperm plant organs

  • roots
  • stems
  • leaves
  • flowers
  • fruit

3

Root - primary function

  • anchor plants
  • absorb water and minerals

4

Stem - primary function

Support leaves, flowers and fruit

5

Leaf - primary function

  • Photosynthesis
  • Transpiration
  • Gaseous exchange

6

Flower - primary function

Reproduction through pollination

7

Fruit - primary function

  • Protect seed
  • Help disperse seed

8

Leaves where both surfaces look the same

Isobilateral

9

Leaves where both surfaces different

Dorsiventral

10

Leaf cuticle

  • Waxy surface layer
  • Prevents unwanted water loss
  • Protects against infection

11

Leaf epidermis

  • Outer cell layer of leaf
  • Protects
  • Prevents unwanted water loss

12

Palisade parenchyma

  • Cells closely packed on dorsal side
  • Mainly for photosynthesis
  • Slightly elongated with lots of chloroplasts

13

Transport system in leaf

  • Vascular system
  • xylem for water and minerals
  • phloem for sugars

14

Ventral leaf surface consists of...

  • Epidemis - protect
  • Stoma - pores allowing gases in and out of leaf

15

Spongy mesophyl

  • Chlorenchyma loosely packed with lots of air spaces
  • Gas exchange and some photosynthesis

16

Guard cells

  • two per stoma
  • can open and close stoma
  • regulate and control water loss and gas exchange

17

Movement of carbon dioxide in the leaf

  • Made during cellular respiration
  • Excess exits the leaf into atmosphere esp. at night
  • Required for photosynthesis esp. in the day
  • Movement by diffusion through stoma (and some through epidermis)

18

Movement of water in the leaf

  • Comes from xylem in vascular bundles (diffusion)
  • Moves between cells (diffusion through intercellular spaces)
  • Moves into cells (osmosis across membrane)
  • Moves out stoma (diffusion into atmosphere)

19

Movement of sugars in the leaf

  • Glucose made by photosynthesis in the day
  • Dissolves in water
  • Moves in solution out of cell into phloem in vascular bundle
  • Transported to other parts of plant where needed
  • If excess sugar then starch stored in chloroplasts in day
  • Starch used up at night

20

Movement of oxygen in the leaf

  • Slowly through epidermis by diffusion
  • quickly through leaf in intercellular air spaces and stoma by diffusion
  • excess produced by photosynthesis
  • required for cellular respiration

21

When do a leafs stoma usually open up and close?

  • Open when light strikes leaf in morning
  • Close during night, too hot (midday)
  • Closed and when water uptake reduced (to reduce transpiration and water loss)