1.Plant Leaves

Question 1

2.51 State the primary function of leaves

Answer 1

The primary function of leaves are

• Act as a site for photosynthesis, converting energy from sunlight into chemical energy that can be used by the plant
• Transpiration
• Gas exchange
• Storage and pernnination - Water and nutrients
• Protection - spiky spines
• Attract pollinators - Bract (coloured leaves)

Question 2

2.52c Describe the structure and state the function of the veins

Answer 2

• Strands of vascular tissue in the lamina often visible on the surface of the leaf
• Transport network linking leaf to the rest of the plant
• Translocation of water, nutrients,sugars and plant hormones to the plant.

Question 3

2.52d Describe the structure and state the function of the midrib

Answer 3

• Main vein
• Main vascular supply and support structure of a simple leaf blade or leaflet, a continuation of the petiole, running the full length of the leaf
• Translocation of water, nutrients, sugars and plant hormones to the rest of the plant.

Question 4

2.52e Describe the two different types of leaves and how they differ

Answer 4

Simple

• Undivided
• One continuous leaf blade surrounding a central stem (Midrib)

Compound

• Made up of leaflets
• They have a number for leaves which branch off from the central stem (Midrib)

Question 5

2.52f Describe two different compound leaf shapes and how they differ

Answer 5

Palmate (compound)

• Leaflets all join the stem at the same point
• Often have 5 distinct lobes like the psalm of a hand

Pinnate (compound)

• In rows on either side of a central stem.
• Separate leaflets each with an individual base on one leaf stalk

Question 6

2.53e Describe the structure and state the function of leaf palisade

Answer 6

• Located directly below the cuticle and epidermis
• Vertically elongated cells containing many chloroplast organelles
• Primary location of photosynthesis in plants

Question 7

2.53f Describe the structure and state the function of leaf spongy mesophyll

Answer 7

• Cells here are not so tightly packed
• Allow carbon dioxide and oxygen to diffuse in and out during photosynthesis and respiration
• Enables gas exchange

Question 8

2.53g Describe the structure and state the function of leaf cuticle

Answer 8

• A waxy layer covering the epidermis cells
• Protective film reducing water loss

Question 9

2.53h Describe the structure and state the function of leaf guard cells

Answer 9

• Specalised cells in the epidermis of leaves
• Regulate gas exchange needed for photosynthesis and respiration

Question 10

12.53i Describe the structure and state the function of leaf stomata

Answer 10

• Pores in the leaf epidermis
• Used for transpiration
• Found in greatest number underneath the leaf to minimise evaporation
• Enable gas exchange allowing the intake of CO2 and the release of oxygen