8A Food and Digestion

Transcription

1 Food and Digestion

2 Year 8 Science Page 5 of 99 ZigZag Education, 2003

3 Food and Digestion Crossword ACROSS 4 Enzymes in our gut help us food (6) 8 This food group is our main source of energy (13) 10 Found particularly in fruit and vegetables, these nutrients are needed in small amounts (8) 11 The large ; where most of the water involved in digestion is reabsorbed (9) DOWN 1 This type of acid is found in the stomach (12) 2 This substance is an energy store in our bodies and keeps us warm (3) 3 Benedict's solution tests for this sugar (6) 5 Meat, eggs and fish are a good source of this (7) 6 Solution that tests for starch (6) 7 This mineral is needed for healthy teeth and bones (7) 9 Also known as roughage this is an important part of our diet and an aid to digestion (5) Year 8 Science Page 6 of 99 ZigZag Education, 2003

4 Food and Digestion Literacy Activities Task 1 Find the following in the word search below: protei carbohydrate vitamins minerals fibre digestive system stomach intestine digestion absorption enzyme faeces villus nutrition saliva Q A Z W S X E S D C E R F V T G B Y C D F A E C E S H T N U N J M I K O L A I P M N B V C X Z O L K Z J H G F V R G D S A P O I U Y T M R E Y W Q A I B E Q E R B I F W E R T A Y U M I V L O S O P A S D F G H J K L C Z X E I L H T C V B N M P R O T E I N H Q W L U Y I E R T Y U I O P A S D F G H J A S D O Z X C V E N I T S E T N I B S S N R N M A B S O R P T I O N M N B L V C A X Z L K J H G S F D S A P O I A U Y T T R E W Q Q N W E R T Y U I O R P A E S D F G H I J K L Z X C V B N E M N B V C X Z M L N U T R I T I O N N K J H G F D A S A P O I U Y T R E W I W Q Q W E T R T Y U I O P A S D F G M H J K L I Z X M E T S Y S E V I T S E G I D V M N V C X Z L K J H G F D S A Q W E Task 2 Fill in the gaps in the following sentences: is an important nutrient for growth and repair. The breaking down of food into smaller pieces is called. Pasta, potato and rice are all good sources of. Carbohydrates are digested by an called amylase. Calcium is a necessary for healthy teeth and bones. We need in our diet to keep our intestines healthy and to prevent constipation. Undigested food leaves the body as. Scurvy is cured by a found in citrus fruits. is a liquid in the mouth that moistens food and contains the enzyme amylase. Digested food is absorbed through the walls of the small. Task 3 In order to stay healthy we must have a balanced diet, which contains enough of the main food groups to keep our bodies functioning properly. Collect and read leaflets from supermarkets that give advice on eating a balanced diet. Keep a diary for one week of what you eat. Ask yourself, are you eating a balanced diet? You don t have to write this up in your exercise book. Year 8 Science Page 7 of 99 ZigZag Education, 2003

5 Task 4 Little words and phrases in sentences often let us communicate ideas subtly. Phrases such as resulting in, so that and in order to are useful. They let us link an idea with the consequence or purpose of that idea. Look at the following sentences to see what I mean: Melanie decided to eat less fat in her diet in order to lose weight. Melanie ate less fat resulting in her losing weight. Melanie should have eaten less fat so that she could lose weight. Doubts about an idea can be expressed using words like although, unless and if as in the following sentences: Although Melanie was eating less fat, she was still overweight. Melanie may lose weight if she eats fewer sweets. Melanie will not be healthy unless she eats a more balanced diet. Your task is to copy out and fill in the gaps in the following passage using those little words and phrases: 8A The importance of a balanced diet It is important to eat a balanced diet remain healthy. Our food should contain the right amounts of fat, protein, carbohydrates, vitamins, minerals, water and fibre. fibre cannot be digested, we need it to keep food moving along the gut. This prevents constipation. You also need to take in enough water everyday you do not become dehydrated. you don t have water, you will die after only a few days. Vitamins and minerals are needed we do not develop illnesses. We could suffer from the bone condition called rickets we get enough vitamin D and the mineral calcium. Some people do not eat enough foods containing the mineral iron problems with anaemia. Proteins are essential for the growth and repair of tissues. meat and fish are good sources of protein, we can get enough from a carefully balanced vegetarian diet. Carbohydrates and fats provide us with energy. people eat too much and exercise too little they can become obese health problems such as diabetes and heart disease. Extension activity - There are many more examples of little words and phrases such as even though that can be used to express reservations or doubts about an idea. Can you think of any more examples? If not, read some magazine or newspaper articles about diet. Highlight these words and phrases at the same time as looking out for some other examples. Year 8 Science Page 8 of 99 ZigZag Education, 2003

6 Task 5 The following article is about fat. Read it carefully and then answer the questions below: Fats Fats do not dissolve in water although some of them are liquid at room temperature and these are called oils. Fats are also known as lipids and the enzyme that digests them is called lipase. Even though too much fat in the diet is unhealthy, it is just as unhealthy to cut out fat altogether. We need some fat in our diet for making cell membranes, nerve cells and other substances. There are two groups of fats. Firstly, saturated fats, which usually come from meat and dairy products. These foods also contain a fat-like substance called cholesterol. People who eat too many saturated fats risk getting blocked blood vessels and heart disease. Secondly, there are unsaturated fats that usually come from plants e.g. sunflower oil, olive oil and much margarine. Most people think that this type of fat is better for their health. Obesity is being overweight and is caused by eating more carbohydrate and fat than the body needs. This excess is stored as fat by the body, under the skin and around organs. Obesity can put a strain on the heart and may lead to diabetes. (1) What are liquid fats called? (2) What is the scientific name for fats? (3) Which enzyme digests fat? (4) Why do we need some fat in the diet? (5) Where would you find saturated fats? (6) What health problems are associated with eating saturated fats? (7) Where would you find unsaturated fats? (8) What does obesity mean? (9) What health problems are associated with obesity? (10) Can you find a single word that means does not dissolve? Task 6 The statement we are what we eat is true. Our food makes an incredible journey from harvest, food preparation, ingestion, digestion, absorption and finally the egestion of undigested food. Some of the molecules that make up our food eventually become part of us. A carbon atom found in a loaf of bread may become part of one of our brain cells. (1) Look up the following words in a textbook glossary and write out their meaning: ingestion digestion absorption egestion (2) Chose a balanced meal that you would enjoy. Write an account of the incredible journey it takes after you have eaten it. The following prompts will help you: What food groups does it contain? How, where and why are the food groups digested? What happens to the digested food? Where are vitamins and minerals absorbed? What happens to the undigested food? Year 8 Science Page 9 of 99 ZigZag Education, 2003

7 Food and Digestion End of Topic Test Answer the following questions and then find the answers in the word search below. 1. There are six food groups that are needed to produce a balanced diet. One of these food groups is vitamins. What are the other five food groups called? 2. What other substance is very important to our survival, so we must drink it everyday? 3. A pupil tested three different foods with three different solutions (1, 2 and 3). Result Solution 1 changed from a blue colour to a brick red precipitate Solution 2 changed from a brown colour to a dark blue colour Solution 3 changed from a blue colour to a purple colour (a) Is solution 1 testing for a sugar, a starch or a protein? (b) From the solutions below, name solutions 2 and 3. Benedicts solution Biuret reagent Iodine solution Salt solution 4. Name the organ in our body: (a) that is very acidic; (b) that absorbs water into the blood; (c) that absorbs small food molecules into the blood. 5. Complete the following passage: Protein, fat and s are too large to be a into the b. Our body contains e that break these large molecules down into s molecules. The ph and the t need to be correct for the enzymes to work properly. The small molecules can then pass into the blood. The blood t the small molecules around the body. m r d s m a l l a s w e r u t a r e p m e t i w e n i t s e t n i e g r a l t f n b p h n z n t t e m p e r a f a s q u a t i n c e e e i x a s m a l l i n t e s t i n e r s j r r e q r w v t y e s d e b r o s b a u f r a b t l o u d e r p i s e v g i o t g d i d l i o d i n e s o l u t i o n x s a z a p o s f r q e r w r c a r b o h y d r a t e a o c a p r b s t o m a c h o e n z y m e s y l p o l i k s r e t t n e g a e r t e r u i b Year 8 Science Page 10 of 99 ZigZag Education, 2003

8 8A Solutions Food and Digestion Crossword Solution H F G Y A L D I G E S T U R C O P I C O C A R B O H Y D R A T E S H O D L E L T I C O E N I R I E F U 10 9 I N V I T A M I N S C B 11 R I N T E S T I N E Food and Digestion End of Topic Test Answers 1. protein, fat, carbohydrate, minerals, fibre 2. water 3. (a) sugar (b) iodine solution (c) biuret reagent 4. (a) stomach (b) large intestine (c) small intestine 5. starch, absorbed, blood, enzymes, small, temperature, transports m r s m a l l e r u t a r e p m e t i e n i t s e t n i e g r a l f h n n t a a c e e i a s m a l l i n t e s t i n e r s r r e w s d e b r o s b a u a b t p t g d l i o d i n e s o l u t i o n s a o s f r r c a r b o h y d r a t e o p s t o m a c h e n z y m e s l s t n e g a e r t e r u i b Year 8 Science Page 11 of 99 ZigZag Education, 2003