Plant Biology & Environmental Science Study Guide

Posted on Nov 6, 2024 in Biology

Pre First Certificate: Water Loss, Transport, and Controlled Growth

Key Questions

  1. What are stomata and guard cells?
  2. How can we measure water loss in a plant?
  3. Describe the main principles of Osmosis, Diffusion, and Active Transport.
  4. How can the growth and shape of plants be affected?
  5. What is tropism?
  6. Why are stems ‘positively phototropic’? What does ‘negatively phototropic’ mean? What is auxin?
  7. What is the difference between hydrotropism and geotropism?
  8. How can artificial chemicals be used? Why are some of them banned?
  9. What does ethylene in bananas cause?
  10. What is rooting powder?
  11. What are weedkillers used for?
  12. What is the purpose of using artificial light?

Answers

  1. Stomata and Guard Cells: Leaves lose water through stomata. These open during the day to allow carbon dioxide to enter and oxygen to escape. Water vapor is also lost during this process. At night, stomata close to prevent water loss. Guard cells control the opening and closing of stomata. During the day, guard cells take in water, swell into a banana shape, and separate, creating a hole. At night, they lose water, shrink, and close the hole.
  2. Measuring Water Loss: A potometer measures water loss from a leafy stem. As water escapes from the leaves, more water moves up the stem to replace it.
  3. Osmosis, Diffusion, and Active Transport:
    • Osmosis: Water enters cells through osmosis, a slow, passive process requiring no energy. Plants develop extensive root systems and root hair cells to maximize surface area for water absorption.
    • Diffusion: The movement of particles from an area of high concentration to an area of low concentration.
    • Active Transport: Plant roots absorb minerals partly through active transport, a process requiring energy. This allows minerals to move against a concentration gradient, from low to high concentration.
  4. Factors Affecting Plant Growth and Shape: Light, water, and gravity are the three most important environmental factors.
  5. Tropism: A plant’s growth response to changes in light, water, or gravity.
  6. Phototropism and Auxin: Plants grow towards light (positive phototropism) for photosynthesis. Stems are positively phototropic, while roots are negatively phototropic (unaffected by light). The plant hormone auxin controls these responses.
  7. Hydrotropism and Geotropism: Roots grow towards water (positive hydrotropism) and downwards in response to gravity (positive geotropism).
  8. Artificial Chemicals: Humans use chemicals to control plant growth for various purposes, including stimulating root growth, controlling fruit development, and killing weeds. Some chemicals are banned due to health and environmental concerns.
  9. Ethylene in Bananas: Ethylene gas is used to ripen bananas, changing their color, flavor, and texture.
  10. Rooting Powder: Contains artificial auxin to stimulate root growth in cuttings.
  11. Weedkillers: Selective weedkillers target broad-leaved weeds without harming grass or crops.
  12. Artificial Light: Used to manipulate daylength and control plant growth and flowering.

It’s Our Environment

Habitats and Climate

Living things inhabit diverse habitats with specific characteristics. The presence of different species depends on their adaptation to climate and geological factors. Climate is crucial, with plants needing water, nutrients, air, and warmth. Plants and animals have adaptations to survive in various conditions, like desert plants storing water.

Plant Importance

Plants are essential for human and animal life, providing food and oxygen. They also remove carbon dioxide from the air. Within an ecosystem, plants and animals interact through food chains.

Human Influence

Humans significantly impact the environment, contributing to pollution and habitat destruction. Our actions can have negative consequences for other living things and our own future.

Unit 3.2: Places to Live

Habitats and Soil

Britain’s diverse habitats are influenced by its island geography and varied soil types. Natural habitats are shaped by natural forces and living things, while artificial habitats are human-made. Different habitats support different communities of plants and animals. Soil is crucial for plant growth, with different rock types producing different soil types. Some plants prefer alkaline soil from weathered limestone, while others thrive in acidic soil found on moors.

At Camp

Simple surveys can reveal the variety of plants and animals in any habitat.

Prehistoric World

Different Periods

  • Paleozoic Era: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian periods.
  • Mesozoic Era: Triassic, Jurassic, and Cretaceous periods.
  • Cenozoic Era: Tertiary and Quaternary periods.