Explain why plasma is important for transporting substances around the body.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Blood is made up of several components, including a liquid called plasma. Plasma makes up approximately 55% of the total volume of blood and carries a variety of dissolved substances to and from the organs of the body.
Model answer (4 marks)
Plasma is a liquid, watery fluid that carries substances in solution or dissolved.
It transports digested food products – glucose, amino acids, fatty acids and glycerol – from the small intestine to body cells.
It also carries waste products such as carbon dioxide and urea, hormones, and heat around the body.
Because it circulates through all parts of the body, plasma allows these substances to be distributed to and collected from all organs via the circulatory system.
It transports digested food products – glucose, amino acids, fatty acids and glycerol – from the small intestine to body cells.
It also carries waste products such as carbon dioxide and urea, hormones, and heat around the body.
Because it circulates through all parts of the body, plasma allows these substances to be distributed to and collected from all organs via the circulatory system.
Examiner tips
- Use the word "plasma" first, then describe it as a liquid. Mention the main substances it carries. Show the link between plasma and the circulatory system. Keep each point brief and to the point.
Common mistakes
- Confusing plasma with blood cells. Omitting the role of plasma in carrying waste products or hormones. Using vague phrases like "fluid" without specifying it is plasma.
Mark scheme (4 marks)
- Plasma is a liquid / watery fluid that carries substances in solution / dissolved substances
- Plasma transports digested food products / glucose / amino acids / fatty acids and glycerol from the small intestine to body cells
- Plasma transports carbon dioxide / urea / hormones / heat around the body
- Plasma allows substances to be distributed to / collected from all parts / organs of the body via the circulatory system
Key terms in this question
Related
- All Pearson Edexcel International GCSE Biology (4BI1) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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