B3-Digestion Flashcards
(26 cards)
What is a balanced diet?
A diet containing all of the different essential nutrients in the right quantities, preventing malnutrition.
What do carbohydrates provide?
A source of chemical energy.
What is the difference between simple sugars and complex carbohydrates?
Simple- quick source of energy + rapid rise in blood sugar levels
Complex- slow release energy + gradual rise in blood sugar levels
What do proteins provide, and how are they formed?
Help growth and repair of new cells, replacement of damaged cells. Made of chains of amino acids.
What do lipids provide?
Protection of vital organs, insulation, concentrated energy store
What do vitamins and minerals do?
Help metabolism, prevent malnutrition, ensure that the body functions properly
What does fibre do?
Adds solidity to stool, helps digestion
What does water do?
Keeps cells hydrated, dissolves and transports chemicals.
Explain the food test for sugars.
Add blue Benedicts solution to food, mix
Heat to 70 degrees C
No sugar=blue
Small amount of sugar=green
Medium amount of sugar=orange/yellow
High amount of sugar=brick red
Explain the food test for starch.
Add iodine solution to food
Orange/red=no starch
Blue/black=starch
Explain the food test for proteins.
Add biurets solution to crushed food, mix
Protein=purple
No protein=blue
Explain the food test for lipids.
The emulsion test- Add ethanol to food and mix thoroughly, pour into test tube with distilled water.
Milky white emulsion=lipids
Clear=no lipids
Name the organs that food goes through during digestion.
Mouth–oesophagus–stomach–small intestine–large intestine–rectum–anus
Explain digestion in the mouth.
The food is mechanically and chemically digested-the teeth crush the food into small pieces for higher S.A. , then salivary amylase digests starch into sugars. The enzymes work optimally at pH 7
Explain digestion in the stomach.
The food is mechanically and chemically digested-the stomach muscles churn and mix the food with stomach acid while protease digests proteins into amino acids. The enzymes work best in pH 2/3. The mucus lining protects the stomach from the acid.
Explain the role of the liver in digestion.
The liver produces bile to neutralise the stomach acid and to create an alkaline environment for the lipase enzymes to work optimally. The bile emulsifies the lipids, giving them a larger S.A. for faster digestion.
Explain digestion in the small intestine.
The food is chemically digested-bile emulsifies the lipids for lipase to work, other undigested nutrients are fully digested and all nutrients are absorbed into the bloodstream.
Explain the role of the large intestine during digestion.
Absorbs water from waste to make it more solid.
What is the definition of an enzyme?
A biological catalyst that increases the rate of reactions, whilst not being used up
How do enzymes digest substrates?
The enzymes active site is complementary to the substrate, and it attaches. Then, many collisions occur to beak the bonds between the substrate
Explain how temperature effects enzyme activity.
Higher temperatures=more kinetic energy at active site=more collisions=faster rate of digestion, but too much heat causes the enzyme to be denatured, and too little heat causes the enzyme to become inhibited.
Explain what inhibited, optimum, and denatured mean in terms of enzymes.
Inhibited–Temperature/pH is too low, and the enzymes activity is slowed and digestion time is increased.
Optimum–Conditions are perfect, and enzyme activity is at its peak with the fastest rate of digestion.
Denatured–The enzyme no longer works as the shape of its active site has changed and it is no longer complementary to its substrate (caused by extreme temperatures and pH)
Where is protease produced?
Stomach
Small intestine
Pancreas
Where is lipase produced?
Pancreas
Small intestine
