year 7 REVISION Spring Assessment - Biology

Transcription

1 year 7 REVISION Spring Assessment - Biology

2 year 7 REVISION Microscope and Cells

3 THE MICROSCOPE Used to view things too small for the naked eye. Consists of lenses of different magnification to make things appear bigger in the viewfinder. Eye Piece x10 magnification Objective Lenses x10, x20 and x40.

4 MAGNIFICATION AND ESTIMATION It is often necessary to estimate the size of an organism from an image produced by a microscope. You need to know the magnification of the image and use a ruler to measure the image carefully. Magnification x 500

5 MAKING A TEMPORARY SLIDE Specimens viewed down a microscope are usually placed and possibly stained (to enable parts of the cell to be seen) on a glass slide to help isolate the specimen. Revise the process of producing the slide.

6 CELLS The building blocks of all living organisms. They combine to form tissues which combines to form organs.

7 ORGANELLES AND THEIR FUNCTIONS Found in both Animal and Plant Cells Cell Membrane: Cytoplasm: Nucleus: Controls what enters and exits the cell Where chemical reactions take place within the cell Contains DNA which controls the functions taking place in the cell

8 ORGANELLES AND THEIR FUNCTIONS Found only in Plant Cells Cell Wall: Chloroplast: Vacuole: Provides structure and support to the cell. Rigidity. Made of Cellulose. Contains chlorophyll which helps photosynthesis take place. Contains cell sap which helps maintain the shape of the cell.

9 SPECIALISED CELLS Please note that these are not the only specialised cells you need to know. Please utilise your class notes.

10 POSSIBLE REVISION METHOD - MIND MAP Mind maps can be used to represent key information. When designing a mind map you should look to connect ideas, using keywords and including diagrams to help you visualise a concept.

11 QUESTIONS If you have revised the previous sheets effectively you should be able to answer the following questions without difficulty. 1. What do microscopes enable scientists to do? 2. Which part of the microscope is responsible for magnifying the image? 3. Estimate the length of the head of the creature in the picture on the third page. 4. Why do you need to stain specimens occasionally? 5. Why do you think a cover slip is placed over the specimen? 6. What is a cell? 7. What do cells combine to form? 8. Name three organelles not present in an animal cell?

12 QUESTIONS If you have revised the previous sheets effectively you should be able to answer the following questions without difficulty. 9. What does the chloroplast do? 10. What is the nucleus for? 11. What is the job of the cell membrane? 12. What is the cell wall made from? 13. What is the main specialised feature of a sperm cell? 14. Why do root hair cells have small projections coming out of them? 15. Why does a red blood cell have a dimple?

13 For extra information or help with revision use the following pages in the KS3 CGP Study Guide, pages 1-3.

14 year 7 REVISION Health, Nutrition and Digestion

15 HEALTH Good for Health: Regular exercise Balanced diet Vitamins Hydration Bad for Health: Excessive eating Poor diet Lack of exercise Drug abuse Excessive alcohol intake

16 MICROBES AND DISEASE Microorganisms come in different varieties and sizes. From largest to smallest: protozoan bacteria virus They can use disease in living organisms e.g. smallpox or influenza. Pathogen - disease causing microorganisms Host - organism affected pathogen

17 PROTECTION FROM DISEASE Good levels of hygiene. Washing hands Prevention of entry of microorganisms into body - forming of scabs, wearing plasters White blood cells kill bacteria and viruses if unwanted in body Vaccination - prevention of infection BrainPOP video on { The Immune System

18 NUTRITION

19 FOOD TESTS Starch: Adding iodine solution to food. If starch is present the colour change is from BROWN to BLUE BLACK Sugar: Add Benedicts Reagent. If sugar is present a BRICK RED precipitate is formed in the reagent. Fats: Add one or two droplets of ethanol. Shake. If a WHITE suspension forms fats are present.

20 DIGESTION

21 ENZYMES Produced in the various glands including the pancreas. They are mostly secreted into the duodenum to be mixed with the food and to chemically breakdown the food. Different enzymes are produced for different substances (lock and key model) e.g. Amylase in saliva is used to breakdown starches. Can be denatured (stopped from working) if the ph or temperature is too high.

22 ADAPTATION OF VILLI - Increase surface area - Thin walls - Moist walls - Rich supply of blood

23 POSSIBLE REVISION METHOD - MIND MAP Mind maps can be used to represent key information. When designing a mind map you should look to connect ideas, using keywords and including diagrams to help you visualise a concept. Create a mind map on the different type of nutrients include food tests use a blank piece of paper POSSIBLE REVISION METHOD - FLOW CHARTS Write down the steps of a process (procedure) as keywords or short phrases that show the connections by using arrows. Create a flow chart on the digestive process use a blank piece of paper

24 QUESTIONS If you have revised the previous sheets effectively you should be able to answer the following questions without difficulty. 1. When does alcohol consumption become dangerous? 2. Name one factor that aids a healthy lifestyle. 3. Name three types of microorganism. 4. Which microorganism is the smallest in size? 5. Name two forms of defence against infection? 6. What is the difference between pathogen and host? 7. What is the role of Fat in our diet? 8. What food stuff contains high levels of complex carbohydrates?

25 QUESTIONS If you have revised the previous sheets effectively you should be able to answer the following questions without difficulty. 9. What is the difference between complex and simple carbohydrates? 10. What are proteins used for in our diet? 11. What is the test for starch in foods? Describe colour change. 12. What is the test for sugars in our diet? Describe colour change. 13. What is digestion? 14. Where is the first site of mechanical breakdown of food in the digestion process? 15. What is mixed with food in the duodenum? 16. Name one source of enzymes in the human body. 17. What can denature enzymes and stop them from working effectively?

26 For extra information or help with revision use the following pages in the KS3 CGP Study Guide, pages 6-9, and page 17.