Transport Changes in Organisms

Introduction

Animal and plant transport systems are fundamental in maintaining physiological functions. They transport nutrients, gases, and waste products, ensuring life processes are sustained.

• Blood and Phloem Sap: Serve as the primary transport mediums in animals and plants.
• Functions: Involved in transporting nutrients, oxygen, and waste materials.

Changes in Transport Medium

Oxygen and Carbon Dioxide Variations in Blood

• Oxygenated vs. Deoxygenated Blood:
  • Oxygen Levels: High in lungs, lower in body tissues.
  • Haemoglobin: Acts as the essential oxygen carrier, binding oxygen in the lungs.
• Carbon Dioxide Transport:
  • Converted to bicarbonate ions for efficient transport to the lungs.

• Exercise Impact:
  • Necessitates increased oxygen levels (e.g., during running).
• Altitude Influence:
  • Low oxygen at high altitudes requires physiological adaptations.

Nutrient and Waste Product Fluxes

• Nutrient Uptake:
  • Nutrients are absorbed through the digestive tract, entering the bloodstream to nourish organs.
• Waste Transport:
  • The Kidneys play a crucial role in waste removal and maintaining chemical balance.

Phloem Sap Composition

• Main Components: Includes sucrose, amino acids, and nutrients.
• Companion Cells: Facilitate the flow of nutrients in the phloem.
• Environmental Impact:
  • Light and Temperature: Affect sap composition.

Gas Exchange in Organisms

Animal Respiratory Systems

Lungs in Mammals:

• Structure: Alveoli are the sites for gas exchange.
• Mechanisms: Inhalation increases blood oxygen levels; exhalation removes carbon dioxide.
• Adaptations: Species like whales have adaptations for deep-sea diving.

Gills in Fish:

• Structure: Lamellae maximise surface area for optimal oxygen absorption.
• Adaptations: Features such as the flow of water over gills enhance oxygen extraction efficiency.

Plant Gas Exchange Structures

• Stomata:

  • Function: Regulate gas exchange and water control.

  

Investigation Models and Techniques

Introduction

Investigation models and techniques are integral to biology as they bridge theory with practice.

Types of Models

• Micro Models: Focus on cellular and tissue-level processes.

  • Example: Examination of blood or plant tissues under a microscope.

  

• Macro Models: Apply to entire organisms.

  • Example: Studies examining systemic blood circulation.

  

Techniques

• Microscopy: Essential for the examination of cellular detail.

• Flow Rate Measurements: Important for understanding the speeds of transport systems.

• Digital Simulations: Offer interactive exploration of biological processes.

  

Addressing Misconceptions

Transport mediums such as sap and blood carry nutrients, gases, and waste products effectively.

Worked Example: Oxygen Transport in Blood

Problem: Calculate the amount of oxygen transported by haemoglobin in blood when 85% saturated.

Solution:

1. Remember that 1g of fully saturated haemoglobin can carry 1.34ml of oxygen
2. If blood contains 150g/L of haemoglobin and is 85% saturated:
   • Amount of oxygen = 150 × 1.34 × 0.85 = 170.85ml/L of blood

This shows how haemoglobin concentration and saturation directly affect oxygen transport capacity in the bloodstream.

Question: Gas Exchange Efficiency

Question: A student measured oxygen levels in blood before and after exercise. The concentration fell from 19.8ml/100ml to 12.3ml/100ml. Calculate the percentage decrease in oxygen concentration.

Solution:

1. Calculate the difference: 19.8 - 12.3 = 7.5ml/100ml
2. Calculate percentage decrease: (7.5 ÷ 19.8) × 100 = 37.9%
3. Therefore, exercise caused a 37.9% decrease in blood oxygen concentration.