Leaf And Functions

Question 1

What is the upper epidermis

Answer 1

Upper epidermis.This is a single layer of cells containing few or no chloroplasts. The cells are quite transparent and permit most of the light that strikes them to pass through to the underlying cells. The upper surface is covered with a waxy, waterproof cuticle, which serves to reduce water loss from the leaf.

Question 2

What is the lower epidermis

Answer 2

The most important structure on a leaf’s lower epidermis is the mouth-shaped opening called the stoma. There are many stomata on each leaf - up to one million per square centimeter, and they have two main functions: to regulate gas exchange and to help prevent water loss.

Question 3

What is the leaf vein

Answer 3

Veins provide support for the leaf and transport both water and minerals (via xylem) and food energy (via phloem) through the leaf and on to the rest of the plant.

Question 4

What are the guard cells

Answer 4

Guard cells are cells surrounding each stoma. They help to regulate the rate of transpiration by opening and closing the stomata. To understand how they function, study the following figures.

Question 5

Spongy mesophyll layer

Answer 5

A layer of cells in the interior of leaves, consisting of loosely arranged, irregularly shaped cells that have chloroplasts. The spongy parenchyma has many spaces between cells to facilitate the circulation of air and the exchange of gases. It lies just below the palisade layer. Also called spongy mesophyll.

Question 6

Palisade mesophyll layer

Answer 6

Palisade cells are plant cells located in leaves, right below the epidermis and cuticle. They are vertically elongated, a different shape from the spongy mesophyll cells beneath them in the leaf. Their chloroplasts absorb a major portion of the light energy used by the leaf.