Science at key stage 3    (Year 9)

• identify the sources of raw materials in photosynthesis
• explain the terms 'photosynthesis' and 'biomass'
• provide some evidence that plants do not obtain biomass from the soil
• construct the word equation for photosynthesis

• identify that the carbon dioxide level is lower in daylight
• explain this, eg the leaves are using carbon dioxide during the day
• conclude that photosynthesis takes place when there is daylight

• detect the presence of starch in a photosynthesising leaf and relate it to the presence of chlorophyll
• relate photosynthesis to exposure of the leaf to light, eg etiolation

• devise a way of measuring photosynthesis, eg by timing the collection of a fixed volume of oxygen; by using an oxygen probe
• describe how the rate of production of oxygen varies with light intensity
• produce appropriate graphs of their results and identify and explain any anomalous results
• explain that oxygen released from photosynthesis is used by animals in respiration

• describe differences between leaf cells, and explain that those close to the upper surface photosynthesise effectively, eg are long and thin, have many chloroplasts

• identify key ideas and summarise them correctly
• recognise that scientists draw conclusions from evidence in the light of what is currently known

• identify photosynthesis as the source of biomass in plants
• explain that glucose made in photosynthesis is used for respiration
• describe all parts of the plant as deriving from the products of photosynthesis
• select, compare and synthesise information from different texts

• explain the functions of water in plants, eg in photosynthesis, to transport minerals, to make the plant firm, for cell growth, to cool leaves, to form fruits
• describe how roots are adapted for taking in water, eg by being spread out, being branched, having a large surface area, having root hairs
• describe how the root-hair cell is adapted for its function
• explain that root cells need oxygen supplies in the soil for respiration
• suggest how substances from the soil enter and move through the plant
• recognise that plants need mineral salts for growth
• relate a plant's need for nitrates to making protein and hence healthy growth

• describe how carbon dioxide and oxygen concentrations in the air have varied over time
• explain how photosynthesis and respiration can help maintain the balance of gases in the air
• identify the main sources of oxygen from photosynthesis
• identify the advantages and disadvantages of forest conservation for a range of people and other living things

• summarise the key ideas encountered in the unit