Metabolism and food requirements

Today we're going to start looking at what our bodies need to work efficiently and how they get these things from food.  To start with, have a read through the information on http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/human/dietandexerciserev1.shtml and try the test questions at the end.
Once you've finished those, either find your own information or use the sites at the bottom to answer the following questions:

1. Define the word metabolism.
2. Explain why pregnant women usually need to eat differently to women who aren't pregnant.  Explain what issues this helps address.
3. Find out what percentage of the energy in the food you eat each day is used for growth, and what process uses the most energy.
4. Why do we need to eat food?

http://www.fao.org/docrep/007/y5686e/y5686e04.htm - Go down the page to section 2.3
http://www.sport-edge.co.uk/gi2.htm
http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/pregnancy_and_diet?open

When you've finished, try this link - http://www.purposegames.com/game/microbial-metabolism-quiz