Unit 4 1 Nutrients 4 1 Nutrients What

Unit 4. 1 Nutrients

4. 1 Nutrients What you need to be able to do: 1 List the chemical elements that make up: • carbohydrates, • fats, • proteins 2 Describe the structure of large molecules made from smaller basic units, i. e. • simple sugars to starch and glycogen, • amino acids to proteins, • fatty acids and glycerol to fats and oils.

Starter What is nutrition for? energy, growth, repair Definition: The taking in of nutrients which are organic substances and mineral ions, containing raw materials or energy for growth and tissue repair, absorbing and assimilating them What is an organic substance? Substances containing carbon

Starter Define these terms: Atom the basic unit of a chemical element the simplest chemical substances Element made of only one type of atom Molecules two or more atoms bonded together Watch Brainpop "Metabolism"

In the body there are many chemical reactions that together = metabolism Anabolic reactions - build up (body builders take anabolic steroids) + energy Catabolic reactions - break down + energy Can you think of examples?

Metabolism Anabolic Catabolic

Review Watch Brain. Pop "Metabolism"

Biological Molecules The main nutrients in foods are all polymers Look at the pictures on the following page Can you define the word polymer?

Biological Molecules Polymer = large molecule made up of smaller units ( called monomers) bonded together

Elements of Food Starch is a polymer made from glucose monomers Starch and glucose are carbohydrates "hydrated carbon" = carbon with water Formula for glucose? C 6 H 12 O 6 What elements does it contain? Carbon, hydrogen and oxygen

Elements of Food Proteins are polymers made of amino acid monomers My favourite amino acid, phenylalanine has this formula: C 9 H 11 NO 2 What elements do amino acids contain? Carbon, hydrogen, oxygen and nitrogen

Elements of Food What about fats? Polymers made from fatty acids and glycerol Carbon, hydrogen and oxygen

Tasks Watch Brain. Pop "Body Chemistry" Answer the questions on the video in your booklet

Review All foods are made out of chemicals. Would you eat these for breakfast? Try and identify the foods. There is a clue on the next slide if you need it!

Review Would you eat this for breakfast? Guess the food from the labels!

4. 1 Nutrients What you need to be able to do: 3 Describe tests for: • starch (iodine solution), • reducing sugars (Benedict’s solution), • protein (biuret test), • fats (ethanol).

Food Tests • Chemical tests for the main nutrients in foods • Starch, sugar, proteins and fats • • Carry out tests on standard solutions to identify positive results Use this knowledge to identify which biological molecules are found in different foods.

Starter Can you remember the tests for the four major food groups? Have a go at this key stage 3 review activity: http: //www. bbc. co. uk/bitesize/ks 3/science/orga nisms_behaviour_health/food_detective/activi ty/

Test for Starch Iodine in potassium iodide solution Iodine, Inky Colour change orange/brown to blue black

Test for reducing sugar (glucose) Blue, Benedict's, Boil Benedict's solution least most Colour change blue to green to orange to red

Test for Proteins Biuret reagent Protein, Purple Colour change blue to mauve

Test for Lipids (fats and oils) Ethanol emulsion (droplets of fat suspended in water) Fats dissolve in ethanol but are insoluble in water Colour change Colourless to white emulsion

4. 1 Nutrients What you need to know: 4 List the principal sources of, and describe the importance of: • carbohydrates, • fats, • proteins, • vitamins (C and D only), • mineral salts (calcium and iron only), • fibre (roughage), • water.

Starter Watch Brain. Pop "Nutrition"

Tasks Complete the table in your booklet

Component Carbohydrate s Protein Function in our body As a fuel for the process of respiration which releases energy For growth and to repair damaged tissues, helps build muscle, skin and hair Lipids For insulation, as a long term food store and to make cell membranes Fibre To help food pass through the digestive system Vitamins Needed in very small amounts to keep us healthy, e. g. for good eyesight and healthy gums Minerals Needed in very small amounts to keep us healthy, e. g. for strong bones and to make red blood cells Water As a solvent, to transport substances around the body and to maintain our body temperature Source

4. 1 Nutrients What you need to know: 6 Describe the deficiency symptoms for: • vitamins (C and D only), • mineral salts (calcium and iron only. 4. 3 Animal Nutrition 2 Describe the effects of malnutrition in relation to starvation, coronary heart disease, constipation and obesity.

Deficiency Diseases and Malnutrition Deficiency lack of something the insufficient, excessive or Malnutrition imbalanced consumption of nutrients Can be too little or too much of one or more of the components of a balanced diet

Starter Watch Brain. Pop "Obesity"

Obesity • • Too much fat/sugar Heart problems Atherosclerosis Diabetes

Kwashiorkor • • • Lack of protein in diet Wasted muscle, enlarged liver Flaky skin and thinning hair

Scurvy • • Lack of vitamin C (ascorbic acid) Citrus fruits Weakness Pale flaky skin Bleeding gums Tooth loss Poor healing

Anaemia • • • Lack of iron Tiredness Shortage of breath Pale skin Spoon shaped nails Fewer red blood cells

Rickets • • • Lack of vitamin D and calcium More common in cold countries (lack of sunlight) "bow" legs

Tasks Complete the table in your booklet Review Try past paper question 1.

4. 2 Animal Nutrition What you need to know: 1 State what is meant by the term balanced diet and describe a balanced diet related to age, sex and activity of an individual.

Starter What is a balanced diet? A balanced diet must contain the nutrients needed by the body in the correct proportions. List the 7 components of a healthy balanced diet: carbohydrates, proteins, lipids, vitamins, minerals, fibre and water

Watch this

Balanced Diet As a general rule, every day it’s considered a good idea to: • • drink 8 glasses of water eat 6 portions of cereal and starchy carbohydrates eat 3 -5 servings of vegetables eat 2 -4 portions of fruit have 2 servings of dairy products have 2 portions of meat, fish or vegetarian alternative limit the amount of fats, oils, sugar and salt eaten Different people may have different nutritional needs based on age and lifestyle.

What extra nutrients would these people need and why? 1. Bodybuilder? 2. Growing child? 3. Marathon runner? 4. Teenage girl? 5. Pregnant woman?

4. 3 Animal Nutrition What you need to be able to do: 3 Identify the main regions of the alimentary canal 4 Describe the functions of the regions of the alimentary canal. 5 Define digestion as the breakdown of large, insoluble food molecules into small, water soluble molecules using mechanical and chemical processes.

Starter Watch Brain. Pop "Digestive System"

Task Complete the echalk Digestive System Label the diagram in your booklet

Watch this

Review Complete the echalk Bounceword quiz

4. 3 Animal Nutrition What you need to be able to do: 6 Identify the types of human teeth and describe their structure and functions. 7 State the causes of dental decay and describe the proper care of teeth.

Starter Watch Brain. Pop "Teeth"

Review - Match them up! Incisors Found behind the canines and are used to grind soft food. Canines Sharp pointed teeth, which are used to bite and tear food. Premolars Found behind the premolars and are used to grind hard food. Molars Small rectangular shaped teeth, used for cutting food.

Tasks Complete the echalk teeth labelling activity Look at the internal structure of a tooth

Tooth Decay • • • Too much sugar Lack of dental hygiene Bacteria produce acid

Review and Homework Create a colourful leaflet for 11 year olds explaining the following: • • • Tooth Structure How bacteria cause tooth decay How you should look after your teeth In addition you could: Explain the action of fluoride in reducing tooth decay and present arguments for/against its addition to water supplies

4. 3 Animal Nutrition What you need to be able to do: 8 State the significance of chemical digestion in the alimentary canal in producing small, soluble molecules that can be absorbed. 9 Define absorption as movement of digested food molecules through the wall of the intestine into the blood. 10 Identify the small intestine as the region for the absorption of digested food.

Starter What can you remember about enzymes? I am going to read some text about enzymes. On your card you have a word or phrase. Shout your word when you think it fits!

Digestive Enzymes

Tasks Read the information in your booklet, complete the table and answer the questions. You might need to use your textbook for extra help.

Review Play the Enzymes loop game

Adaptations of the small intestine Food is absorbed in the small intestine. It is very long! Guess? 7 m Can you explain why? It also has villi

One cell thick - for rapid diffusion Rich blood supply - maintains concentration gradient Lacteals - for absorption of fats

Tasks Label the diagram Complete the table

Model Gut Experiment Review What is the purpose of digestion? List in order the organs of the digestive system What are the tests for a) Starch? b) Glucose?

Break down large insoluble molecules into small soluble molecules that can be absorbed and used by the body Mouth, oesophagus, stomach, small intestine (duodenum, ileum), large intestine, rectum, anus Starch – Iodine in potassium iodide solution Red brown – blue black Reducing Sugar – Benedict’s Solution Blue – green, yellow, orange, red

1. Draw a labelled diagram of the equipment 1. Explain what each part of the apparatus represents: a. Contents of visking tubing b. Solution around visking tubing c. Visking tubing itself 1. Predict what you expect to see when you test the water in the boiling tube for starch and sugar.

Results Write down the results What do they tell us about the need for digestion?

4. 1 Nutrients What you need to know: 5 Describe the use of microorganisms in the manufacture of yoghurt.

Microbes in yogurt production In the production of yoghurt, we use microorganisms to change one substance into another, which we use as food.

Yogurt making • • • Bacteria are used to ferment milk at 46 o. C. Lactic acid is produced. As fermentation progresses, the p. H drops. The lactic acid makes the milk coagulate. The temperature is then reduced to 5 o. C to prevent further bacterial action. • The whole process is carried out in sterile conditions.