Food Test & Enzymes B1b(2)

OBJECTIVES Identify what carbohydrates, proteins and fats are made up of Explain what happens during chemical digestion Identify which enzymes break down which food types

I can carry out simple food tests Can-do task 2 points

Method

Results Food sample Test Chemicals used Treatment Result if present Our result potato starch (carbohydrate) iodine solution add blue/black sweet drink (glucose) simple sugar Benedict’s solution add then heat orange precipitate egg white protein few drops of 10% sodium hydroxide solution, then few drops of 1% copper(II) sulfate solution rose pink or purple cooking oil fats and oils paper translucent mark (lets light through when dry)

I can carry out an experiment on enzyme action and record the results and conclusion Can-do task 3 points

Method While you are waiting for the experiment to finish, complete Q13-17 on page 21 in the orange text book

Results and Conclusion To get the marks you must have written a conclusion based on your results. You need to: Describe what happened What this means (i.e. what does amylase do?) Amylase is found in the mouth so; What types of food will it work on as you are chewing? How will you know it is working (what would you taste?)

What are carbohydrates? Starchy foods contain carbohydrates which are made of long chains of identical small sugar molecules. carbohydratemolecule one sugar molecule The long chains of carbohydrates are broken down into the smaller sugar molecules by the body. The small molecules from carbohydrates are used by the body to release energy and make the body work.

What are proteins? Proteins, like carbohydrates, are made of long chains of small molecules. In proteins, these small molecules are not identical. protein molecule one amino acid Proteins are made up of chains of small molecules called amino acids. There are over 20 different kinds of amino acid. Proteins are used by the body for growth and repair.

What are fats? Fats are made up of fat molecules which contain fatty acids and glycerol. fat molecule fatty acids glycerol Fat molecules have to be broken down by the body so that they can be used for energy storage. Fats are also used by the body to keep heat in and to make cell membranes.

What happens to food so we can digest it? Chemicals called enzymes act to break down food into smaller pieces so we can absorb them – a process called CHEMICAL DIGESTION. There are specific enzymes for specific foods: Carbohydrates are broken down by carbohydrases Proteins are broken down by proteases Fats (also known as lipids) are broken down by lipases

long carbohydrate molecule Carbohydrates are chains of identical sugar molecules. The digestive enzymes called carbohydrases break the chemical bonds between the individual sugar molecules in each carbohydrate chain. carbohydrase long carbohydrate molecule sugar molecules

long protein molecule amino acid molecules Proteins are made up of amino acids. There are 20 different types of amino acids. Proteins are digested by digestive enzymes called proteases. These enzymes work in an acidic environment to break proteins into smaller amino acids. protease long protein molecule amino acid molecules

+ bile lipase fat molecule fatty acids glycerol Fats are digested in two stages: Firstly, bile (released by the gall bladder) allows the fat to “mix” with water by breaking the fat into smaller droplets. This is called emulsification. bile Secondly, the digestive enzyme lipase breaks each fat molecule into the smaller glycerol fatty acid molecules . + lipase fat molecule fatty acids glycerol

At what temperature does this enzyme work best?

OBJECTIVES What are carbohydrates, fats & proteins made up of? Carbohydrates - simple sugars such as glucose fats - fatty acids and glycerol proteins - amino acids What happens in chemical digestion? the digestive enzymes break down large food molecules into smaller ones for absorption into the blood plasma or lymph Which enzymes break down the different food groups? Carbohydrates - carbohydrases Fats - lipases Proteins - proteases