Plant Organs (Leaf) - Cycle 2

Question 1

Leaves

Answer 1

• Main photosynthetic organ that exchange gases with the atmosphere, dissipate heat and defend themselves from herbivores and pathogens
• Main site of transpiration

Question 2

Characteristics of Leaves

Answer 2

• Leaf is a lateral appendage of the stem.
• It is borne at the node of the stem.
• It is exogenous in origin.
• It has limited growth.
• It does not posses apical bud
• It has three main parts namely, leaf base, petiole and lamina.
• Lamina of the leaf is traversed by vascular strands, called veins.

Question 3

Primary Functions of Leaves

Answer 3

• Manufacture food through photosynthesis
• Site for gas exchange —CO2, O2 out
• Evaporation of water through transpiration
• Protection of buds
• Conduction of water and dissolved solutes
• Prevent water loss through stomata

Question 4

Secondary Functions

Answer 4

• Storage
• Protection
• Support
• Reproduction

Question 5

Anatomy of a Leaf: Leaf Epidermis, Cuticle

Answer 5

helps keep it from dying out

Question 6

Anatomy of a Leaf: Leaf Epidermis, Stomata

Answer 6

opening where gas exchange occurs; to prevent water loss

Question 7

Anatomy of a Leaf: Leaf Epidermis, Guard Cell

Answer 7

regulate the opening and closing of the stomata

Question 8

Opening and Closing of Stomata

Answer 8

• When water enters the guard cells, turgor pressure increase, and the unique “banana” shape of the guard cells causes them to bow out and expose the pore (stoma); when water leaves and the guard cells, turgor pressure decreases, and the pore is once again covered
• Opening and closing of stomata is for gas exchange

Question 9

Anatomy of a Leaf: Leaf Ground Tissue, Palisade mesophyll

Answer 9

consists of one or more layers of elongated parenchyma cells on the upper part of the leaf.

Question 10

Anatomy of a Leaf: Leaf Ground Tissue, Spongy mesophyll

Answer 10

found below the palisade mesophyll with parenchyma cells that are more loosely arranged

Question 11

Anatomy of a Leaf: Leaf Vascular Tissue, Vein

Answer 11

vascular bundles that provide support for the leaf and transport substances

Question 12

Anatomy of a Leaf: Leaf Vascular Tissue, Xylem

Answer 12

transports water and minerals from roots to leaves

Question 13

Anatomy of a Leaf: Leaf Vascular Tissue, Phloem

Answer 13

transports sugar from one part of the plant to another

Question 14

Transpiration

Answer 14

• Transpiration is the loss of water to the environment, mainly through evaporation from leaf stomata.
• If temp is high, the rate of evaporation is also high, so transpiration is also high

Question 15

Transpiration: Cohesion

Answer 15

Water’s ability to stay linked in a chain

Question 16

Transpiration: Adhesion

Answer 16

its ability to stick to the inside of the xylem tube