Biology 110

Leaves: structure promotes function

Leaf function: Photosynthesis requires the absorption of light and carbon dioxide from the atmosphere and water from the soil. A fundamental problem of terrestrial plants is the capture of carbon dioxide without excessive loss of water.

Macroscopic leaf structure:

Leaves are broad, thin, and air-filled to enable light capture and facilitate gas exchange with the atmosphere.

Microscopic leaf structure: Identify the three tissues, the cells that compose the tissues and their functions.

Ground tissue: function = photosynthesis

Vascular tissue: function = support and transport

Dermal tissue separates the inside of the leaf from the air outside the plant.

Stomata provide openings in the epidermis that enable gas exchange between the air inside the leaf and the outside air.

Sample question from past exams:

Name and draw a line to locate the three tissues common to all plant organs on this diagram (of a microscopic cross section of a leaf). Describe the function of each tissue in this organ.

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