1 minute read
Thermal physics ............................530
Getting the best from the book
Welcome to Collins Cambridge IGCSETM Combined Science.
This textbook has been designed to help you progress in your learning.
The textbook sections follow the same structure as the syllabus. Each section in the textbook covers the essential knowledge and skills you need.
SAFETY IN THE SCIENCE LESSON This book is a textbook, not a laboratory or practical manual. As such, you should not interpret any information in this book that relates to practical work as including comprehensive safety instructions. Your teachers will provide full guidance for practical work and cover rules that are speci c to your school.
A brief introduction gives context to the science covered in the section.
Starting points will help you to revise previous learning and see what you already know about the ideas in the section.
Section contents shows the syllabus topics covered in the section.
Multicellular organisms are made up of different cell types that each have a speci c job to do. The human body is made up of about 200 different cell types, ranging from muscle and fat cells, to blood, skin, and nerve cells. All ‘complex’ cells (those that contain a nucleus) in all animals, plants and protoctists on Earth have the same basic structure. Scientists say that this is because we have all evolved from a single complex cell. This rst complex cell evolved from a simple bacterialike cell (without a nucleus) more than 1600 million years ago. This is the origin of all the millions of different species of plants, animals, fungi and other living things that live on Earth today.
STARTING POINTS 1. What are cells made up of? 2. How are different types of cells specialised for their functions? 3. How can we calculate the magni cation and actual size of biological specimens viewed through a microscope?
SYLLABUS SECTIONS COVERED B2.1 Cell structure B2.2 Size of specimens
Δ A microscopic view of the leaf surface of the Tradescantia plant showing stomata.
