B3 Life on Earth - revision

1. B3 Life on Earth - revision

2. What makes organisms members of the same species? • If they can mate and produce fertile young

3. What are the two different causes of variation in living things? • Genes and environment

4. What is the evidence for evolution? • Fossils and the similarities between living things

5. Describe selective breeding and give an example? • Selecting which pigs (for example) to breed because they produce the right meat

6. Briefly describe Natural selection • Survival of the fittest (and passing on your genes

7. Why is the idea of competition important • If animals compete with each other only the most successful will survive to pass on their genes

8. Why did Darwin’s ideas take time to be accepted • Because people believed that the Bible was factually true

9. What is a mutation? • A sudden random change in the genes

10. What were the first living things like? • Very simple – molecules that could copy themselves

11. What are the advantages and disadvantages of being multicellular? • Different cells do different jobs but they need to be able to communicate

12. What are the body’s two main communication systems? • Hormones and nervous system

13. What do we mean when we say humans and chimps have a common ancestor? • Humans have not evolved from chimps but we have both evolved from something else

14. How long ago were the first hominids and what made them different from other apes? • Between 1.5 and 4 million years ago – it walked upright

15. how do humans cause the extinction of other organisms? • By destroying or disrupting natural environments or food supplies

16. C3 Food Matters - revision

17. Why do plants need Nitrogen in the soil? • To make protein

18. Why do we need to keep adding fertilizer to our fields? • To replace nitrogen and other minerals needed for growth

19. What are the two different approaches to modern farming? • Intensive – lots of fertiliser and pesticides • Organic – none of the above

20. What are pesticides? • Chemicals used to kill animals and diseases that damage the crops

21. How can we control pests without using chemicals? • Natural predators like ladybirds

22. What is meant by sustainability? • A process is sustainable if it can continue without harming the earth.

23. What chemicals are added to foods and what do they do? • Preservatives – stop it going off • Colours – make it look nice • Flavourings – make it taste nice • Emulsifiers & stabilisers – stop it separating

24. What are the 5 main nutrients and what do they do? • Carbohydrates – for energy • Proteins – for growth and repair • Vitamins & minerals – to keep healthy • Fats – store energy

25. Why do large molecules like starch need to be digested? • So they can be dissolved and absorbed into the blood

26. What is a food allergy • When someone has a reaction to a particular food eg peanuts.

27. What happens to excess amino acids in our bodies? • Broken down into urea

28. What do the kidneys do? • Urea and excess water is removed and stored in the bladder

29. What is the difference between the two types of diabetes? • Type 1 In younger people – controlled by insulin • Type 2 In older people – controlled by diet, medicine and sometimes insulin

30. What is a risk factor for diabetes • Being overweight or obesity

31. What is the purpose of the FSA and what do they do? • Food standards agency – encourage people to eat healthily by promoting labelling and good practice

32. P3 Material choices - revision

33. What do radioactive materials produce and what does this mean? • Produce ionising radiation which can damage living tissues

34. what are the three types of ionising radiation? • Alpha beta gamma

35. what are the properties of the 3 types of ionising radiation? • Alpha – low penetration – high ionisation • Gamma – high penetration – low ionisation

36. what is the difference between irradiation and contamination? • Irradiation – radiation goes through it • Contamination – contains something that is making radiation

37. what affects the radiation dose that you could receive? • Time, how close you are (proximity) and type of radiation

38. how does ionising radiation affect living cells? • Breaks molecules like DNA and can lead to cancer

39. describe the structure of an atom • Small dense nucleus (protons & neutrons) surrounded by cloud of electrons

40. what are isotopes? • Atoms that have a different number of neutrons than normal – often radioactive

41. what is meant by half life? • The time taken for the radioactivity to drop to half its value

42. give some uses of ionising radiation. • Medical imaging, sterilising, treating cancer

43. what are the three categories of radioactive waste and how are they disposed of? • LLW/ILW/HLW – High/intermediate/low • It is sealed in glass or concrete and buried

44. what is nuclear fission and what is it used for? • Splitting heavy elements like uranium to release heat energy

45. what are the stages of electricity production in a power station? • Heat released 2. Water boiled 3. Steam turns turbines 4. Generator turned

46. What do we mean when a resource is sustainable? • It will never run out and the environment will not be ruined

47. What is the precautionary principle? • Better safe than sorry

48. why are nuclear power stations better than coal-fired power stations? • Don’t produce CO2

49. why are coal-fired power stations better than nuclear power stations? • Don’t produce radioactive waste

50. What is radon gas and how do we protect ourselves against it? • Produced by radioactive rocks – we should keep our houses well ventilated