Chapter 9

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. Note that you will lose points if you ask for hints or clues!



1. A seed contains an embryo and an shoot and their food store. These are surrounded by a protective seed .

2. Different types of food are found in the food store of seeds. The presence of starch can be demonstrated using solution. If positive, the result is a colour. The presence of glucose can be demonstrated using a strip. If positive, the result is a colour. The presence of protein can be demonstrated using an strip. If positive, the result is a colour.

3. During , an embryo plant uses the reserves of food in the seed to grow into a plant with green leaves.
4. Seeds need water, and a suitable (e.g. 200C) to germinate.
5. A plant’s life is the series of changes that it passes through from a certain stage in its development (e.g. germinating seed) until it reaches the same stage in the next .
6. Seeds which remain inactive even when given the conditions needed to germinate, are described as being . One type of dormancy can be broken by exposing the seeds to temperature (e.g. 40C) for a few months. Under natural conditions this form of dormancy is of to the plant because germination of the seeds is delayed until when the warmer soil temperature encourages growth.
7. During photosynthesis, green plants use energy to produce food needed for growth. Embryo plants inside germinating seeds cannot and need to use the seed’s food reserves for growth. Therefore germinating seeds show and overall in mass. Photosynthesising seedlings are able to produce the food they need for growth and therefore show an overall in mass.
8. To sow seeds means to put them in a place which provides the conditions needed for germination. Seeds need to be out during sowing to prevent overcrowding of seedlings following germination. Large seeds are sown individually by ; fine seeds are mixed with silver before sowing.
9. Seeds that have been enclosed in a ball of clay are said to have been . The pellets make the seeds smooth and easy to space out during planting. A pellet is made up of layers which may contain useful chemicals such as and/or nutrients. Pelleted seeds take to germinate than unpelleted seeds.
10. to pre-germinate (chit) a seed means to make it start to germinate before it has been planted. In some seed this can be done by them. Seeds with hard coats can be made to germinate more quickly by them open or ‘nicking‘ their seed coats with a knife before sowing.