B3: Organisation And The Digestive System🍔 Flashcards
What is a tissue?
A group of cells with similar structure and function that work together.
What is an organ?
Collections of tissues.
What is an organ system?
Groups of organs that work together to perform specific functions.
Name the parts of the digestive system. (IN ORDER)
Mouth, gullet, stomach, liver, bile duct, small intestine, large intestine, rectum, anus.
What do carbohydrates provide?
The fuel that makes all other reactions of life possible. (Hydrogen, carbon, oxygen)
What are lipids for?
They are the most efficient energy source in our diet.
What are proteins for?
They are for building up cells and tissues of your body.
What are lipids made up of?
Fatty acids joined to a molecule of glycerol.
What are proteins made of?
Amino acids.
How do you test for starch?
Iodine turns from yellow to blue-black if starch is present.
How do you test for sugars?
Benedict’s solution goes from blue to brick red on heating if sugar is present.
How do you test for protein?
Biuret goes from blue to purple if protein is present.
How do you test for lipids?
Ethanol has a cloudy white layer is lipids are present.
What is a catalyst?
They speed up chemical reactions without being used up themselves.
What are enzymes?
Biological catalysts.
How do enzymes work?
The substrate fits perfectly into the enzyme active site. The substrate splits into products which leave the active site.
What happens to enzymes if temperature is increased?
The reaction speeds up until a certain point. After that the amino acid chains making up the active site, begin to unravel. This is called DENATURING.
What happens to enzymes if the pH is changed?
Different enzymes work best at different pH levels. A change in pH can stop them working completely because it affects the forces holding together the different parts of protein molecules.
What does digestion involve?
The breaking down of large molecules into smaller ones.
Carbohydrases break down?
Carbohydrates to simple sugars.
Proteases break down?
Proteins to amino acids.
Lipases break down?
Lipids to fatty acids and glycerol.
What is the enzyme that is secreted from the stomach?
Pepsin.
In what pH does pepsin work best in?
An acidic pH.
In which pH do the enzymes that come from your pancreas work best in?
Alkaline pH
What does bile do? (pH levels)
Bile neutralises the acid that was added to the food in the stomach. It provides alkaline conditions for the enzymes in the small intestine so that the work best.
What does bile do?(emulsification)
It emulsifies the fats in your food. It breaks up large droplets of fat into smaller ones. It provides a bigger surface area for lipase to act upon.
