B5- Animal tissues, organs and systems Flashcards
What is the main function of the digestive system?
To digest food and absorb the nutrients obtained from digestion.
What is the role of the pancreas and the salivary glands in the digestive system?
The pancreas and salivary glands are glands which produce digestive juices containing enzymes.
What is the role of the stomach in the digestive system?
Produces HCL- which kills bacteria present and provides optimum pH for the enzyme protease to function.
What is the role of the small intestine in the digestive system?
The small intestine is the site where soluble food molecules are absorbed into the bloodstream.
What is the role of the liver in the digestive system?
Produces bile (which is stored in the gallbladder) which emulsifies lipids and allows the lipase enzyme to work efficiently.
What is the role of the large intestine in the digestive system?
Absorbs water from undigested food, producing faeces.
What is the role of enzymes in the digestive system?
Enzymes act as a biological catalyst which speeds up the rate of biological reactions (the breakdown of food) without being used up.
How does the shape of an enzyme affect its function?
Enzymes have a specific active site which is complementary to the substrate.
Definition- Metabolism
The sum of all the reactions in a cell or organism.
What types of metabolic reactions do enzymes catalyse? (3)
- Building large molecules from smaller ones (e.g. glucose into starch)
- Changing one molecule to another (e.g. glucose into fructose)
- Breaking down large molecules into smaller ones.(e.g. carbohydrates into glucose)
Explain the lock and key analogy for enzymes
The shape of the enzyme active site is complementary to the substrate, so can bind together to form an enzyme-substrate complex.
How does temperature affect enzyme action?
Increasing temp. increases enzyme action as molecules collide more producing more energy.
What happens if you go above a certain temperature ?
Shape of the active site is altered and enzyme denatures and is no longer complementary to the substrate (no reaction)
How does pH effect enzyme action?
For most optimum is 7 (except for protease in the stomach). If pH varies too much active site denatures.
Where are lipases produced? (2)
-Small intestine
-Pancreas
