Life Processes in Plants

Overview

Plants make their own food and move materials within themselves. This chapter explains photosynthesis, transport of water and food, and how plants breathe.

Key concepts

• Photosynthesis makes food using sunlight, water and carbon dioxide.
• Chlorophyll in leaves traps sunlight.
• Stomata allow gas exchange in leaves.
• Water and minerals rise through xylem; food moves through phloem.
• Plants release oxygen during photosynthesis.

Important terms / formulae

• Photosynthesis: carbon dioxide + water gives glucose + oxygen (in sunlight).
• Chlorophyll: green pigment that traps light.
• Xylem: tissue carrying water upward.
• Phloem: tissue carrying food.

Solved example or key process

In photosynthesis, a leaf absorbs sunlight through chlorophyll, takes in carbon dioxide through stomata and water through roots. Using light energy, it makes glucose and releases oxygen. The glucose gives the plant energy and is stored for later use.

Important questions

1. What is photosynthesis?
2. What is the role of chlorophyll?
3. How do xylem and phloem differ?
4. What gas do plants release during photosynthesis?

Quick revision

Plants make food by photosynthesis using sunlight, water and carbon dioxide, helped by chlorophyll. Xylem carries water up and phloem carries food. Oxygen is released as a by-product.