6 2 plant structure

Root hair cells absorb water and minerals from the soil.

Root hair cells are adapted for absorption as follows:

False. Mineral ions move into root hair cells by active transport. Only water can move by osmosis.

Root hair cells need energy to fuel the active transport of mineral ions from the soil against a concentration gradient.

Water moves into root hair cells by osmosis. Minerals, and other dissolved substances, in the cytoplasm of root hair cells lower the water concentration, so water moves into the cells down a water concentration gradient.

Xylem are vessels that transport water and mineral ions from the roots to the upper parts of plants.

Xylem vessels are adapted for water transport as follows:

The phloem is a tissue that transports dissolved sucrose around the plant.

Phloem tissue is adapted as follows:

The spongy mesophyll is the region of the leaf where gas exchange takes place. Gases are exchanged between the cells of the spongy mesophyll layer and the surrounding air spaces. Some photosynthesis also occurs here.

True. The air spaces increase the surface area of the leaf that is in contact with the air. Gases can diffuse in and out of the spongy mesophyll cells from and into the air spaces.

Stomata are small pores present in the epidermis of leaves that allow the movement of gases into and out of leaves by diffusion.

False. Being thin decreases the diffusion distance for gas exchange in leaves.

Adaptations of leaves for gas exchange include:

True. The waxy cuticle is a waterproof layer that reduces water loss by evaporation from the surface of leaves.

The palisade mesophyll layer contains tall, thin cells that pack together closely. These cells contain many chloroplasts to maximise light absorption.

It is beneficial for leaves to be broad and thin because:

Adaptations for survival in extreme conditions found in leaves include:

Adaptations for living in dry conditions shown by the cactus include: