1. B1 Core revision Session 2 We are going to concentrate on the key knowledge needed for the exam

2. Drugs What is a drug? What is a stimulant? What is a depressant? How do stimulants affect reaction times? How do depressants affect reaction times?

3. Stimulants These increase your heart rate! Speed up the firing at synapses – increase neurotransmission. Some stimulants are legal. Often they will talk about caffeine

4. Depressants Slow your heart rate Slow down the firing at synapses – decrease neurotransmission. Usually they talk about alcohol They don’t make You sad!!!!!

5. How do stimulants affect reaction times? People get confused between reaction time and the speed of reactions Shorter reaction time = quick reactions Coffee reduces reaction time. (React in a shorter amount of time!).

6. Exam Question decreased reaction time / reaction time became quicker / increased speed of reaction (1) caffeine (is a drug that) is a stimulant (1) speeds up (nerve) impulses (1)

7. How do depressants affect reaction times? Long reaction time = slow reaction. If you increase the reaction time it takes LONGER. Alcohol increases reaction times. (It takes longer/more time to react to a stimulus).

8. Exam Question – 2 marks alcohol slows speed of reaction / increases reaction times (1) Because it reduces the speed at which impulses / messages can be sent (1) acts as a depressant (1)

9. Cigarettes Which chemical makes you addicted to cigarettes? Nicotine Which chemical in cigarettes causes cancer? Tar What is the name for all chemicals that cause cancer? Carcinogens Which chemical in cigarettes causes breathing difficulties? Carbon monoxide

10. Why will people who smoke have issues exercising? Carbon monoxide attaches to their red blood cells instead of oxygen. This means they can’t get enough oxygen to their muscles and become short of breath.

11. Alcohol What are three short term effects of alcohol? eyes/brain affected by blurred vision, dizziness, memory loss lowering of inhibitions (can lead to accidents), act differently, mood change slower reaction times (can lead to accidents) What are the long term effects of alcohol? Brain damage Liver Cirrhosis Which organs does alcohol damage? Brain and Liver

12. Pollution What is deforestation? Cutting down trees What human activities put more carbon dioxide into the atmosphere? Driving cars, cutting down trees, respiration, burning fossil fuels

13. Which are the indicator species for clean air? Clean Air indicators Blackspot fungus on roses. This only grows in clean air. Sulphur dioxide kills it. Some Lichen – different kinds of lichen grow depending on the levels of pollution.

14. Which are the indicator species for polluted air? Some species of Lichen like polluted air

15. Which are the indicator species for clean water? If it sounds nice, it likes it CLEAN Mayfly nymph. Stonefly larvae. Freshwater shrimps – could they be more obvious?

16. Which are the indicator species for polluted water? If it sounds nasty they like DIRTY water. Bloodworm Sludge worm

17. What is the name of the two chemical in fertilisers? NITRATES PHOSPHATES If they say anything about these and water THINK EUTROPHICATION

18. Stages of Eutrophication The nitrates cause water plants and algae to grow. They cover the surface and block light. The deeper plants don’t get any light and die. So cannot photosynthesise/do photosynthesis. Bacteria decompose the dead plants using oxygen. There is not enough oxygen for the fish. The FISH die. https://www.youtube.com/watch?v=6LAT1gLMPu4

19. Command Words Explain why… Say why something happens, what are the reasons for it to happen or for it to be that way. Explain… Say what happens AND why it happens. Say what something is AND why it is like that. Explain how… Say how something happens in detail. These questions are testing your knowledge of biological processes (eg. explain how a plant grows towards light).