Blood Cambridge IGCSE Co-ordinated Sciences (9–1) revision
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In plain words
Blood looks like a red liquid, but most of it is a pale yellow fluid with things floating in it: red cells carrying oxygen, white cells fighting infection, and tiny fragments that plug cuts.
Three things to know
- Red blood cells contain haemoglobin, which carries oxygen. White blood cells defend against disease: phagocytes engulf pathogens, and lymphocytes make antibodies.
- Platelets make blood clot at a cut, which stops bleeding and keeps microbes out. Clotting turns the soluble protein fibrinogen into a mesh of insoluble fibrin.
- Plasma is the liquid part. It carries blood cells, dissolved food, carbon dioxide, urea, hormones and heat.
Tips and tricks
- Four parts, four jobs: red cells (oxygen), white cells (defence), platelets (clotting), plasma (carrying everything else).
- Oxygen travels in red cells. Carbon dioxide mostly travels dissolved in the plasma.
It lands in your notebook with its questions as flashcards.
Blood: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
Which part of the blood carries oxygen?
They contain haemoglobin.
What do platelets do?
They gather at a wound and start the clot.
What is the liquid part of blood called?
Plasma is mostly water with substances dissolved in it.
What do lymphocytes produce?
Antibodies attach to pathogens and help destroy them.
What is phagocytosis?
The phagocyte surrounds the pathogen and digests it.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
3 questions, 8 marks. Write your answers on paper, then check them.
Blood
Cambridge IGCSE Co-ordinated Sciences (9–1) 0973 · 8 marks · papermunch.org
Name ______________________________ Date ______________
State the function of each of the four main components of blood.[4]
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Red blood cells carry oxygen. White blood cells defend against disease (phagocytosis and antibody production). Platelets cause clotting. Plasma transports cells, nutrients, carbon dioxide, urea and hormones.
Describe two ways in which white blood cells defend the body.[2]
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Phagocytes engulf and digest pathogens (phagocytosis). Lymphocytes produce antibodies.
Explain why blood clotting is important.[2]
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It stops blood being lost from a wound, and it stops pathogens getting in.
Answers: Blood
- 1. Red blood cells carry oxygen. White blood cells defend against disease (phagocytosis and antibody production). Platelets cause clotting. Plasma transports cells, nutrients, carbon dioxide, urea and hormones.
- 2. Phagocytes engulf and digest pathogens (phagocytosis). Lymphocytes produce antibodies.
- 3. It stops blood being lost from a wound, and it stops pathogens getting in.