B3 - Organisation and the Digestive System Flashcards
Definition of a tissue
A group of cells with similar structure and function that work together to perform a task
Definition of an organ
An organ is a collection of tissues that work together to perform a function
Definition of an organ system
An organ system is a group of organs that make up an organism
Different tissues in stomach
- Glandular - produces + secretes enzymes
- Muscular - churns food
- Epithelial - coats the stomach
Adaptations of small intestines (4)
- Villi create a large surface area for more absorption
- Constant blood supply to maintain concentration gradient
- Long so more time to absorb molecules
- Short diffusion distance
Function of large intestines
To absorb water from the food to form faeces
Function of liver
Produces bile which is then stored in the gall bladder
Different types of carbohydrates
Simple sugars and complex carbohydrates
What are carbohydrates broken down into
Simple sugars e.g. glucose and sucrose
What are lipids broken down into
- Fatty acids (lower the pH)
- Glycerol
What are proteins broken down into
Amino acids
Definition of an enzyme
An enzyme is a biological catalyst that speeds up the rate of reactions without being used up. They also control metabolism
What is metabolism
The sum of all the reactions in the body
Explain the lock and key theory
- Substrate attaches to active site of enzyme as the active site has a complementary shape to the substrate
- This forms an enzyme - substrate complex
- The enzyme splits the substrate into products yet is unchanged itself
How many reactions will an enzyme catalyse
Only one. This is due to its active site shape being specific to the reaction/ substrate