Intervention session 3

1. Intervention session 3 1.Infectious Diseases 2.Adaptation for survival 3.Variation Keywords: Suggest, Use information, Explain, Conclude, Calculate, Describe, Evaluate

2. Learning Objectives: • Understand what different questions are asking. • Know what answers are expected by AQA. I will be successful in this lesson if I can: • State what information is required to answer AQA set questions (Grade C) • Explain what ‘understanding’ questions are asking for (Grade C). • Identify the language sought for when answering examination questions (Grade B). • Structure long answers appropriately (Lvl B). • Identify strengths and weaknesses in example answers and explain why and where marks would be appropriate (Grade A).

3. 5 mins: On your own write down as many bits of information that you think belongs in that question. 10 mins: Swap your paper with your partner and add to their paper. starter

4. Speak to others in the room to find the answers to the questions that you have no bits of information on. Please no more than 5mins

5. Let’s review the key points for Infectious Diseases 1 Task 2 • Pathogens are micro-organisms that cause infectious diseases. Bacteria reproduce inside the body producing toxins that get to such a level that they make us feel ill. Viruses live inside the body cell. • Semmelweiss discovered that infection could be transferred between patients, but that washi9ng hands between treating patients helped to stop infection transfer. It was many years before his views were accepted • Its best to stop pathogens getting into your body, if they do then the white blood cells either 1) ingest them (digest & destroy), 2) produce antibodies to help destroy them or 3) produce antitoxins to counteract the toxins the pathogens produce. • Antibiotics kill bacteria eg penicillin. Viruses are more difficult to kill because they live inside cells and killing them means you also kill the healthy cells. Painkillers make you feel better but do not kill the pathogen • If a pathogen changes by mutation or natural selection, then it is more difficult to control as the drugs that were used to destroy it may no longer work now that it has changed. Very few people are immune to these new pathogens & so disease spreads quickly within a country (epidemic) or across countries (pandemic).

6. ASSESSOR TIPS • Pathogens need to reproduce before they make enough toxins to make you ill. • Semmelweiss had trouble persuading his peers to wash their hands as his peers did not want to be the reason why so many young mothers were dying. • Must remember all 3 things that the white blood cell does but never refer to ingestion as ‘EAT’ this is wrong. • Viruses are harder to get rid of because they reproduce inside the body cells so if you destroy the virus you also destroy the healthy body cell. • Bacteria do not have a brain so they don’t decide or want to mutate – they just do. • Make sure you know how bacteria become resistant to antibiotics by natural selection.

7. Let’s review the key points for Infectious Diseases 2 Task 2 • MRSA is a superbug that has evolved in hospitals through natural selection and is resistant to commonly used antibiotics. • It costs a lot of money & time to develop new medicines. They must be tested to see that they are not toxic, they are effective against the disease & that they can be stored for a long time. These tests are carried out in laboratories on animals and then on humans. • If these tests are not thorough then a new medicine may have a dangerous side effect eg thalidomide was use din 1950s as a sleeping pill & also helped to prevent morning sickness in pregnant women. It was not tested thoroughly enough and women started to give birth to babies with sever limb abnormalities. It is now used as an effective treatment for leprosy. • You can be immunised (a vaccine is made of dead or an inactive form of the disease) to stop you from getting a disease. • The white blood cells are stimulated to make antibodies (to destroy the pathogens antigens). Now your body can respond to this pathogen by rapidly to produce the correct antibody which would destroy the pathogen if infected.

8. ASSESSOR TIPS • Mutation takes place in an instant whereas natural selection is a gradual process over years & requires the genes to be passed onto the next generation. • It is important to test new medicines on animals first to see if they are toxic. Some people are against the use of animals for this. You must be able to argue both sides of this argument. • A vaccine is made of a dead or inactive form of the pathogen

9. Let’s review the key points for Adaptation for survival Task 3 • If animals were not adapted to survive in the areas they live, they would die. • The artic is cold & bleak but animals have a large volume to when compared to their surface area (small ears). They also have white fur (camouflaged), thick coat, thick fat layer under the skin (blubber) to conserve heat. • Bigger animals (eg elephants) have larger surface area compared to their volume which means they can conserve heat more easily but its also more difficult for them to lose heat. In the case of the elephant the wrinkly skin increases the surface area so the elephant can lose heat. • In dry conditions, animals are adapted to conserve water & stop getting too hot. So they may hunt or feed at night to remain cool during the day. • The white blood cells are stimulated to make antibodies (to destroy the pathogens antigens). Now your body can respond to this pathogen by rapidly to produce the correct antibody which would destroy the pathogen if infected.

10. Let’s review the key points for Adaptation for survival Task 3 • Plants compete for light, water & nutrients. In hot, dry areas they have long roots or widespread roots or thick stems or leaves or no leaves. Eg in woodlands, some plants will flower before the trees so they can get the sunlight first. • Some plants have developed thorns, poisonous chemicals & warning colours to put animals off. Some plants spread their seeds over a wide area so they do not compete with their offspring. • Animals compete for water, food, space, mates & breeding sites. An animals territory is large enough for it to find food, water & have enough space for breeding. • Predators compete with their prey because they want to eat them. Prey animals compete with each other as they want to escape predators & find food. Both predators & prey use camouflage. • Some animals use warning colours so that they are not eaten.

11. ASSESSOR TIPS • You must understand surface area:volume ration. The larger the animal, the smaller its surface area compared to its volume. • Adaptations are not just to do with what the animal looks like it also has to do with their behaviour. • A vaccine is made of a dead or inactive form of the pathogen. • There are many ways that plants conserve water in dry areas including waxy leaves, extensive roots, small leaves, water storage in stems. • There are many ways animals adapt including colour (for camouflage & to attract mates) speed to catch food & escape. • Plants compete by both their structures & flowering habits. Root systems can provide much water for the plant & early or late flowering can also allow the plant to compete for sunlight (because other plants are still dormant)

12. Let’s review the key points for Variation Task 4 • Animals are more difficult to clone. Embryo transplants are used to clone animals. In this process, embryos are split into smaller groups of cells and then each group is allowed to develop in a host animal. Each a clone of one another but not the original parent • Sexual reproduction involves the fusion of the sex cells (gametes) which causes the genetic information to mix forming a new individual that is similar but different to both parents. Some human characteristics are controlled by a single pair of genes eg attached/unattached ear lobes, dimples, straight/curved thumbs. • Asexual reproduction does not involve the fusion of the sex cells because all the genetic information comes from the one parent & so the offspring are identical to the parent. These are called clones. • Cloning can produce new individuals with the characteristics that you want. In plants this process is cheap and effective. They can be cloned by cuttings that you grow, or taking groups of cells & growing them under special conditions (tissue culture).

13. Let’s review the key points for Variation Task 4 • Genetic information from parents are past onto their offspring these are contained within the male & female sex cells (gametes). This occurs by DNA (a large molecules made up of smaller molecules). DNA makes genes, genes make chromosomes. These genes control the development of the characteristics in the offspring. • Fusion & adult cell cloning are also used to clone animals. In this process, the nucleus of the animal you want is placed into a empty egg cell which is then developed in a different animal. • Genetic engineering involves changing the genetic make-up of an organism. The genes are cut out of the chromosome of an organism using an enzyme, the genes are then placed in the chromosome of another organism (of the same species or an organism with desired characteristics or a different species) • The gene to produce insulin in humans can be placed in bacteria (actually the DNA ring called a plasmid) so that the bacteria produce the insulin which we can then collect for use. • Many people arguie whether or not genetic engineering is right.

14. ASSESSOR TIPS • It is the individual genes that control the characteristics of the offspring. Chromosomes are simply made up of genes. • Sexual reproduction leads to variation because the male & female gametes mix to produce a new individual. Asexual reproduction does not produce variation because the offspring are genetically identical to the parents. • Know why clones are identical to their parents & how the different types of cloning work. • You must be able to write a balanced argument for cloning. • It is the gene that controls how an organism develops. If you place a gene in a new organism it will develop that characteristic (the characteristic of the gene).

15. Learning Objectives: • Understand what different questions are asking. • Know what answers are expected by AQA. I will be successful in this lesson if I can: • State what information is required to answer AQA set questions (Grade C) • Explain what ‘understanding’ questions are asking for (Grade C). • Identify the language sought for when answering examination questions (Grade B). • Structure long answers appropriately (Lvl B). • Identify strengths and weaknesses in example answers and explain why and where marks would be appropriate (Grade A).