1.5 Blood

Exercise 1 Writing sentences about an analogy We use analogies to help us to understand a structure or a process. An analogy compares the structure or process to something familiar. In this exercise, you practise writing complete sentences. The way that water flows through a pipe can be used as an analogy to help us to think about how blood flows through blood vessels. a Describe how blood vessels are similar to a plastic water pipe. ………………………………………………………………………………………. ………………………………………………………………………………………. b Describe how blood vessels are different from a plastic pipe. ………………………………………………………………………………………. ………………………………………………………………………………………. c Describe how blood is similar to water. ………………………………………………………………………………………. ………………………………………………………………………………………. d Describe how blood is different from water. ………………………………………………………………………………………. ………………………………………………………………………………………. SAMPLE

Exercise 2 Vocabulary

There are many new words in this topic. This exercise helps you to check that you remember what each of them means. Draw a line from each word to its meaning. Words Meanings blood plasma a red substance inside red blood cells red blood cells microorganisms that cause disease white blood cells the liquid part of blood haemoglobin cells that help to destroy pathogens oxyhaemoglobin a bright red compound formed when oxygen combines with haemoglobin pathogens chemicals, produced by white blood cells, that kill pathogens phagocytosis taking something into a cell and digesting it antibodies cells whose function is to transport oxygen SAMPLE