Test I

• The sun supports almost all life-forms on Earth.
• Plants convert light energy into chemical energy, the by-product of which is oxygen, which all life-form directly or indirectly rely on to live.
• Plants are called producers because they can produce their own food.
• Leaves, stem, and roots are the main vegetative organ of the plant.
• Leaves are among the most variable parts of the plants, varying in size, shape, color, texture, and arrangement along the stem.
• Leaves are also classified as monocotyledonous or dicotyledonous based on whether they have one or two cotyledons or seed leaves.
• Blade is the flat, widest part of the leaf.
• Apex is the tip of the blade.
• Base is the lowermost part of the blade.
• Midrib is a slender structure that extended from the base to the apex.
• Vein are slender structure that branch off from the midrib.
• Veinlet are tiny structure that branch off from the veins.
• Margin is the surrounding edge of the blade.
• Petiole or leafstalk is a slender structure that attaches the leaf to the stem.
• The midrib, veins, and veinlets serve as the framework of the blade.
• The leaf is bifacial or has two surfaces: upper or ventral surface and lower or dorsal surface.
• Ventral surface is more exposed to sunlight than the dorsal surface.
• Epidermis is the outermost layer of the leaf, consisting of upper and lower epidermis.
• Cuticle is a waxy, thin film that covered the epidermis.
• Stomata are pores that contain the epidermis, which facilitate gas exchange between the plant and the atmosphere.
• Singular of stomata is stoma.
• Mesophyll is the middle layer of the leaf, consisting of palisade and spongy layers.
• Palisade Layer is composed of elongated, tightly-packed cells.
• Spongy Layer consists of irregular shaped cells, with prominent air spaces in between.
• Both layers of the mesophyll contain chlorophyll, the pigment that gives the plant its green color.