GCSE Science₈₄₆₅

Larger organisms need systems to transport solids, liquids and gases over larger distances. These systems and processes are monitored and controlled by the human body, but this delicate balance can be disrupted. The topic moves from simple to complex, and outlines the challenges that this presents for any transport system in plants and animals.

4.2.1 Systems in the human body

Systems in the human body can be studied at macroscopic, microscopic and molecular scales. The study of respiration helps to account for the need for exchange surfaces in multicellular organisms, illustrated by the human circulatory system. The study of the digestive system focuses on the chemical changes to the main nutrients in the diet. Finally, examples of the way that body systems are controlled is illustrated with reference to the nervous system and the endocrine system. In Lifestyle and health the importance of the endocrine system is further illustrated in the context of lifestyle and health.

There are two required practicals: one is using reagents to test for a range of carbohydrates, lipids and proteins, the other is an investigation into the effect of a factor on human reaction times, which can be related to road safety in Stopping distances .

4.2.1.1 Respiration

4.2.1.2 Exchange surfaces

4.2.1.3 The human circulatory system

4.2.1.4 Blood cells

4.2.1.5 The human digestive system

Required practical activity 7: use qualitative reagents to test for a range of carbohydrates, lipids and proteins. To include: Benedict's test for sugars, iodine test for starch and Biuret reagent for protein.

AT skills covered by this practical activity: biology AT 2.

This practical activity also provides opportunities to develop WS and MS. Details of all skills are given in Key opportunities for skills development .

4.2.1.6 The human nervous system

Required practical activity 8: plan and carry out an investigation into the effect of a factor on human reaction time.

AT skills covered by this practical activity: biology AT 1, 3 and 4.

This practical activity also provides opportunities to develop WS and MS. Details of all skills are given in Key opportunities for skills development .

4.2.1.7 The human endocrine system

4.2.2 Plants and photosynthesis

The study of cells and transport into and out of cells in Cells in animals and plants is developed and exemplified here in the context of plant science. A key part is the study of photosynthesis because this underpins work on the carbon cycle and climate change in The Earth's atmosphere and the study of ecosystems in Ecosystems and biodiversity .

Plants can be attacked by bacteria and viruses so the successful growth of crops depends on methods to prevent or control infection.

There are two required practicals: one to investigate plant pigments by paper chromatography, another to investigate the effect of light intensity on the rate of photosynthesis.

4.2.2.1 Meristem tissue

4.2.2.2 Plant structures

4.2.2.3 Transpiration

4.2.2.4 Chlorophyll and other plant pigments

Required practical activity 9: investigate how paper chromatography can be used to separate and tell the difference between coloured substances. Students should calculate R_f values.

AT skills covered by this practical activity: chemistry AT 1 and 4.

This practical activity also provides opportunities to develop WS and MS. Details of all skills are given in Key opportunities for skills development .

4.2.2.5 Photosynthesis

4.2.2.6 Factors affecting the rate of photosynthesis

Required practical activity 10: investigate the effect of light intensity on the rate of photosynthesis using an aquatic organism such as pondweed.

AT skills covered by this practical activity: biology AT 1, 2, 3, 4 and 5.

This practical activity also provides opportunities to develop WS and MS. Details of all skills are given in Key opportunities for skills development .

4.2.2.7 Translocation

4.2.2.8 Plant diseases