Enzymes
Biological catalysts, which speed up the reactions, without being used themselves
What are enzymes made out of?
Protein
Active site
Part of an enzyme. It is shaped to fit its substrate
Substrate
The molecule the enzyme acts on
How many different substrates can one type of enzyme have effect on?
Only one, the shape of the active site is shaped so only one type of substrate can be fitted in
What is the best conditions at which enzymes work called?
Optimum conditions
What factors affect the rate of work of enzymes (2)
1) pH
2) Temperature
How does temperature affect the rate of work of enzymes
It changes the amount of energy available, changes number of collisions, until the temperature is to big and the enzyme is denatured
At what temperature do enzymes work best?
At an optimum temperature, which is different to all enzymes
What happens when an enzyme becomes denatured?
Its active site is damaged therefore the substrate can’t fit into
What can denature enzymes?
pH and Temperature
How does concentration affect the rate of reaction between enzymes and substrates
As the concentration increases there are more particles to react with, therefore the rate increases
What is the function of protein?
Growth and repair
Where can protein be found
Meat, fish, eggs, legumes
What are legumes?
Peas and beans
What is the function of carbohydrates?
Needed to release energy in cells
Where can carbohydrates be found?
Rice, bread, pasta, potatoes
What is the function of fat?
Insulation, maintain body temperature, protect organs from damage
Where can fat be found?
Oil, milk (products), nuts, oily fish
What is the function of Vitamin A?
Helps cells to grow and help eyes to see in poor light conditions
Where can Vitamin A be found?
Liver, vegetables, butter, fish, oil, milk
What is the function of Vitamin B?
Keep the nervous system working
Where can Vitamin B be found?
Meat, eggs, vegetables, milk, fish
What disease can a person get without having enough Protein in his diet?
Kwashiorkor: weight loss, poor muscle growth, swollen stomach
What disease can a person get without having enough Carbohydrates in his diet?
Weight loss, lack of energy
What disease can a person get without having enough Fat in his diet?
Weight loss, failure to maintain body temperature
What disease can a person get without having enough Vitamin A in his diet?
Night blindness, damaged cornea of eye
What disease can a person get without having enough Vitamin B in his diet?
Beri Beri: leg muscle are unable to grow properly
What is the function of Vitamin C?
Health skin and gums
Where can Vitamin C be found?
Citrus fruit and green vegetables
What disease can a person get without having enough Vitamin C in his diet?
Scurvy: bleeding gums and wounds do not heal properly
What in the function of Calcium?
Strong teeth + bones, involbed in clotting of blood
Where can Calcium be found?
Milk, eggs
What disease can a person get without having enough Calcium in his diet?
Rickets: Osteoporosis
What is the function of Iron?
Making hemoglobin in RBC
Where can Iron be found?
Meat and Spinach
What disease can a person get without having enough Iron in his diet?
Anaemia
What is the function of fiber (cellulose)
Adds bulk to food so it can be easily moved
Where can cellulose be found?
Cell walls of plants
What disease can a person get without having enough fiber?
Constipation, colitis, bowel cancer
What are carbohydrates made out of?
Simple sugars
What atoms do carbohydrate molecules contain?
Oxygen, Hydrogen, Carbon
What are proteins made out of?
Amino acids
What atoms to proteins contain?
Carbon, Nitrogen, Hydrogen, Oxygen
What are lipids made out of?
Fatty acids, glycerol
What atoms do lipids made out of?
Carbon, Hydrogen, Oxygen
What is the name for test for glucose?
Benedict’s test
How to carry out the test for glucose?
Add Benedict’s solution + heat, make sure the solution doesn’t boil - a colored precipitate will be formeed
What is the color of Benedict’s solution?
Blue
What is the change in color of precipitate in the test for glucose?
Blue–>Green–>Yellow–>Orange–>Brick Red
What can the color change tell?
How much glucose (relative) there is
Why molecules like starch, proteins, fats have to be broken down? (2)
Too bog to pass through the walls of digestive system, insoluble
What enzyme is used for breaking down of Starch?
Amylase
What enzyme is used for breaking down of Maltose?
Maltase
What enzyme is used for breaking down of Proteins?
Amino Acids
What enzyme is used for breaking down of Lipids?
Lipase
What is the product of breaking down of Starch?
Maltose
What is the product of breaking down of Maltose?
Glucose
What is the product of breaking down of Protein?
Amino Acids
What is the product of breaking down of Lipids?
Glycerol, Fatty acids
Where is bile produced?
Liver
Where is bile stored?
Gall bladder
Where is bile released to?
Small intestine
Why is bile needed?(2)
1) To neutralize the hydrochloric acid, which enters the intestine in order to provide the optimum pH for the enzymes
2) Emulsify fat
Emulsification of fat. Why needed?
Breaking down fat into tiny droplets. To make a greater surface area for the enzymes to break down
What happens in Mouth?(2)
1) Salivary grands produce amylase enzyme in the saliva
2) Teeth break down food(mechanically)
What is Oesophagus?
Muscular tube, connects mouth and stomach
How is the food transported in Oesophagus?
By peristalsis
What is produced in the liver?
Bile
What is stored in the Gall bladder?
Bile
What happens in Stomach?(3)
1) Pummels the food with muscular walls 2) Produces protease enzyme (pepsin) 3) Produced HCl
What are the 2 reasons for the stomach producing HCl?
1) Kill bacteria 2) Give the right pH for protease enzyme
What is the pH for HCl?
2
What does Pancreas produce?
Protease, amylase and lipase enzymes
Where are the enzymes from Pancreas released?
Small intestine
What does Large intestine do?
Adsorbs the excess water from the food
What happens in small intestine?
Nutrients are absorbed
Peristalsis
The movement of an object along the muscular tube, when the muscles behind it contract and in front of it relax
Stages of Digestion(5)
1) Ingestion 2) Digestion 3) Absorption 4) Assimilation 5) Egestion
Ingestion
Putting food/drink into mouth
Two types of digestion
1) Mechanical 2) Chemical
Digestion
The break down of large insoluble molecules into small soluble molecules
What carries out mechanical digestion?
Teeth, stomach muscles
What carries out chemical digestion?
Enzymes
Absorption
Moving molecules through the walls of the intestines into blood
Assimilation
When digested molecule becomes part of the cell
Egestion
Removing the waste products from the body
Where is Villi located?
Small intestine
How is the small intestine adapted for adsorbing the food? (4)
1) Long 2) Big surface area because of villi 3) Villi have a singles permeable layer of surface cells 4) Blood supply
Advantages of good blood supply to villi?
Increases absorption speed