Double Award - Science for GCSE

Summaries

The following summaries contain the key facts and ideas chapter-by-chapter in Science for GCSE and Foundation Science for GCSE. One summary covers the relevant chapter in both books with topics and sections for the higher tier
only written in italics.

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Chapter 1	Cells and life
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1.	There are thousands of different living things on the Earth. The different places where living things can be found are called habitats.
2.	Living things are often adapted to the habitat in which they live. For example, fish are adapted to life in water and polar bears are adapted to the Arctic. This is called adaptation.
3.	Living things are called organisms. All organisms carry out seven important life processes to stay alive:
	An easy way to remember these seven processes is MRS. NERG.
4.	All organisms are made up of cells which are the building blocks for living things. Cells can only be seen under a microscope.
5.	All cells have three important structures.
6.	Plant cells have three other structures.

7.	There are different kinds of cells for doing different jobs. We say that the different cells are ‘adapted’ to their different functions. For example, muscle cells can contract and relax causing movement.
8.	Water is constantly moving into and out of cells through the cell membranes. Some dissolved substances with small molecules, like oxygen and carbon dioxide, can also pass through cell membranes. However, other substances with large molecules, like starch, are blocked. Cell membranes are therefore described as being partially permeable.
9.	Particles pass into and out of cells by three processes: diffusion osmosis active transport
10.	Diffusion occurs due to the random movement of particles in a liquid or a gas. Diffusion is simply spreading out. When diffusion occurs, the particles spread from a region of higher concentration to a region of lower concentration.
11.	Osmosis is the special name for the diffusion of water through a partially permeable membrane.
12.	Active transport involves the selective movement of dissolved particles through a partially permeable membrane, from a region of lower concentration to one of higher concentration. For example, particles of salts pass through the cell membranes of root cells into plants where the concentration of salts is greater.
13.	The table below (HT) shows the important differences between diffusion and active transport.