Page 133 - Biology Form Two

Biology for Secondary Schools

Chapter Six

Gas exchange and
FOR ONLINE READING ONLY

respiration

Introduction

Respiration is one of the characteristics of living things. It is important for the
survival of living things as it leads to the production of energy used for various
body activities. Respiration in aerobic organisms is accomplished by gas
exchange. Gas exchange involves the exchange of oxygen and carbon dioxide
gases across the respiratory surface. In this chapter, you will learn about the
mechanisms of gas exchange and respiration in mammals, including aerobic and
anaerobic respiration. The competences developed will enable you to maintain a
healthy life style that helps to prevent infections and diseases of the respiratory
system.

Think diffusion across a surface, such as the
The organism’s body without gas exchange of oxygen gas and carbon
exchange mechanisms dioxide gas across the respiratory
surface. This takes place in different

Concept of gas exchange ways in various organisms. For
example, unicellular organisms carry
Task 6.1 out gas exchange by diffusion across
Search the library and internet sources the cell membrane. Large organisms

for the meaning of gas exchange and cannot carry out diffusion efficiently;
features of respiratory surfaces. instead, they have well developed and
specialised organs for gas exchange,
called respiratory surfaces. Table 6.1
Gas exchange is a physical process shows examples of respiratory surfaces
by which gases move passively by in various organisms.

Student’s Book - Form Two
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BIOLOGY FORM 2 NEW.indd 127 05/10/2024 15:36:42