Biological molecules Flashcards
What chemical elements are present in carbohydrates?
Carbon, hydrogen and oxygen.
What chemical elements are present in proteins?
Carbon, hydrogen, oxygen and nitrogen
What chemical elements are present in lipids?
Carbon, hydrogen and oxygen
What is the structure of starch?
Starch and glycogen are large, complex carbohydrates, which are made up of many smaller units (eg: glucose or maltose) joined together in a long chain
What is the structure of proteins?
Proteins are made up of long chains of amino acids
What is the structure of lipids?
Lipids are built from fatty acids and glycerol
How do you test for glucose in food?
You add Benedict’s solution to the food sample and put it in a water bath so that it heats up.
If the sample contains glucose, it will turn from being blue to green or yellow in low concentrations and brick red in high concentrations.
How do you test for starch in food?
Make a 5 cm cubed food sample and put it in a test tube. then add a few drops of iodine solution to your sample and gently shake the tube. if the sample contains starch it will turn from a browny orange to a back or blue/black.
How do you test for proteins in food?
Prepare 2 cm cubed of food sample and put in test tube. Then add 2 cm cubed of biuret solution and gently shake the test tube. if the food sample contains protein it will turn from blue to pink/purple.
How do you test for lipids in food?
Prepare a 5 cm cubed sample of the food and transfer it into a test tube. Add 3 drops of Sudan III stain solution and gently shake. This solution will stain the lipid. If lipids are present, the mixture will separate into 2 layers. The top layer will be bright red. If not, it will not form a separate red layer on top.
What is the role of enzymes as a biological catalyst?
A catalyst is a substance which increases the speed of a reaction without being changed or used up. Enzymes reduce the need for high temperatures and speed up metabolic reactions.
How does temperature affect enzyme function?
Changing the temperature changes the rate of an enzyme-catalyzed reaction. A higher temp increases the rate at first. The enzymes and the substrates gain more kinetic energy and result in more successful collisions. However if the temp goes past the optimum level for that particular enzyme then the shape of the active shape will change and the substrate can no longer bind with the active site (it becomes denatured).
