© OUP: To be used solely in purchaser’s school or college 8A Food and digestion Food Balancing your diet Digestion 8A Food and digestion

© OUP: To be used solely in purchaser’s school or college Food 8A Food and digestion

© OUP: To be used solely in purchaser’s school or college What do we need food for? Energy to do things 8A Food – who needs it? Raw materials to grow larger Raw materials to repair damaged body parts

© OUP: To be used solely in purchaser’s school or college Proteins 8A So what’s in food? Food is a complicated mixture of different chemicals. We can sort these chemicals into different types. What are the main types? Fats Carbohydrates (starch and sugars) Vitamins Minerals Water Can you make up a sentence with words starting with the same letters – a mnemonic? Roughage

© OUP: To be used solely in purchaser’s school or college 8A Which food contains which chemical? Which foods belong to which food groups? ProteinsFatsCarbohydratesWater Proteins WaterCarbohydrates Fats

© OUP: To be used solely in purchaser’s school or college 8A What’s in food? We can test foods to find out what chemicals they contain. Orangey-brown iodine turns blue-black when it reacts with starch. drop iodine solution onto the food black = starch

© OUP: To be used solely in purchaser’s school or college 8A What’s in food? Blue Benedict’s solution turns orangey-red when it is boiled with glucose. blue turns orange/red = glucose heat chopped up food hot water

© OUP: To be used solely in purchaser’s school or college 8A What’s in food? In the Biuret test the solution turns purple. chopped up food potassium hydroxide shake copper sulphate purple = protein

© OUP: To be used solely in purchaser’s school or college 8A What’s in food? Fats go cloudy white when they are mixed with ethanol and water. Now see if you can use these tests to identify the food chemicals on the next slides. grind food with ethanol add water filter cloudy = fat

© OUP: To be used solely in purchaser’s school or college 8A What’s in food? For each food, decide on the chemicals found in them. FatsProteinStarchGlucose Food sampleTestResult Iodine solutionorangey-brown Benedict’s testblue Biuret testpurple Ethanol testcloudy white

© OUP: To be used solely in purchaser’s school or college 8A What’s in food? For each food, decide on the chemicals found in them. FatsProteinStarchGlucose Food sampleTestResult Iodine solutionblue-black Benedict’s testblue Biuret testblue Ethanol testclear

© OUP: To be used solely in purchaser’s school or college 8A What’s in food? For each food, decide on the chemicals found in them. FatsProteinStarchGlucose Food sampleTestResult Iodine solutionorangey-brown Benedict’s testorangey-red Biuret testblue Ethanol testclear

© OUP: To be used solely in purchaser’s school or college 8A What’s in food? For each food, decide on the chemicals found in them. FatsProteinStarchGlucose Food sampleTestResult Iodine solutionorangey-brown Benedict’s testorangey-red Biuret testblue Ethanol testclear

© OUP: To be used solely in purchaser’s school or college 8A Vitamins VitaminFound inGives you A B2B2 C D Liver, butter, green vegetables Cheese, milk, liver, eggs, green vegetables Citrus fruits, green vegetables, potatoes Fish liver oil, eggs, sunlight on the skin Healthy skin and teeth Healthy skin Healthy teeth and gums, without it you get scurvy Healthy bones – without it you get rickets (soft bones)

© OUP: To be used solely in purchaser’s school or college Balancing your diet 8A Food and digestion

© OUP: To be used solely in purchaser’s school or college 1. A balanced diet… a) contains the same amounts of the main food groups b) contains healthy amounts of the main food groups c) doesn’t fall off the table. 2. A balanced diet for most people has more… a) fat than water b) carbohydrate than protein c) crisps than fruit. 8A A food test for YOU!

© OUP: To be used solely in purchaser’s school or college 3. To test for protein in food you… a) add iodine solution b) do the Biuret test c) poke it with a big stick. 4. Sugar and starch are both… a) proteins b) fats c) carbohydrates. 8A A food test for YOU!

© OUP: To be used solely in purchaser’s school or college 5. Iodine solutions turns blue-black with… a) starch b) protein c) age. 6. A food went orangey-red when it was boiled with Benedicts solution. It could be… a) a carrot b) a boiled sweet c) a sausage. 8A A food test for YOU!

© OUP: To be used solely in purchaser’s school or college 7. Not enough vitamin C gives you… a) headaches b) scurvy c) weak bones. 8. Riboflavin is… a) a B vitamin b) a fruit drink c) an elf from The Lord of the Rings. 8A A food test for YOU!

© OUP: To be used solely in purchaser’s school or college Digestion 8A Food and digestion

© OUP: To be used solely in purchaser’s school or college 8A Why digestion? Food is a mixture of molecules. Some of these molecules are too large to pass into the body. Digestion breaks down food in the gut into smaller molecules. The body uses these smaller molecules for energy or to build body parts.

© OUP: To be used solely in purchaser’s school or college 8A Where it all happens What happens where? Follow the food down through the body. Mouth breaks large lumps of food into smaller lumps. Stomach produces enzymes to break down proteins. Intestines produce enzymes to break down proteins, carbohydrates and fats. Start to absorb food into body. Colon absorbs water and stores waste until time to pass out of the body.

© OUP: To be used solely in purchaser’s school or college 8A Watching the digestives

© OUP: To be used solely in purchaser’s school or college 8A Absorbing stuff

© OUP: To be used solely in purchaser’s school or college 1. Enzymes are made of protein. 2. Enzymes only work in acid solutions. 3. Enzymes can only break down molecules. 4. A protease is an enzyme that breaks down protein into smaller molecules. 8A Digestion - True or False? True or False? TRUE FALSE TRUE

© OUP: To be used solely in purchaser’s school or college 1. An enzyme works best at a particular temperature. 2. Most enzymes in the human body work best at about 57°C. 3. Enzymes work best in boiling water. 4. Snakes produce one enzyme that can digest everything in its victim from the skin to the bones. 5. Amylase is an enzyme that breaks down starch. 8A Digestion - True or False? True or False? TRUE FALSE TRUE