Tissues — Important Questions

Stomata

Step 1: Stomata are tiny pores present in the epidermis of leaves. Step 2: Each stoma (singular of stomata) is surrounded by two kidney-shaped cells. Step 3: These special cells are called guard cells because they guard or control the opening and closing of stomata. Step 4: This opening and closing controls gas exchange and water loss. Step 5: Hair, cuticle, and cork are other epidermal structures but are not surrounded by guard cells.

Xylem

Step 1: Plants need to transport water absorbed by roots to all parts. Step 2: Xylem is the complex tissue responsible for this upward transport. Step 3: It contains vessels and tracheids which are tubular structures perfect for water transport. Step 4: Water moves from roots through stem to leaves via xylem. Step 5: Phloem transports food (not water), cambium is for growth, and cork is for protection.

Epithelial tissue

Step 1: The mouth needs a protective lining that can handle food and saliva. Step 2: Epithelial tissue specializes in covering and protecting body surfaces. Step 3: The mouth lining is made of squamous epithelial tissue - flat cells arranged in layers. Step 4: This tissue protects the mouth from wear and tear during eating and speaking. Step 5: Connective tissue connects parts, muscular tissue causes movement, and nervous tissue carries signals - none of these form protective linings.

Plasma

Step 1: Blood is a connective tissue with a liquid matrix. Step 2: This liquid portion of blood is called plasma. Step 3: Plasma contains water, proteins, salts, hormones, and other dissolved substances. Step 4: Blood cells (RBCs, WBCs, platelets) float in this plasma matrix. Step 5: Serum is plasma without clotting factors, lymph is tissue fluid, and cytoplasm is cell contents - not blood matrix.