B2 - Organisation Flashcards
- Principles of Organisation - Animal Tissues, Organs & Systems - Plant Tissues, Organs & Systems
What is a cell?
The basic building block of a living organism.
What is a tissue?
A group of cells with a similar structure and function working together.
What is an organ?
A collection of tissues working together to perform a specific function.
What is an organ system?
A group of organs working together to perform specific functions.
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 gland in the digestive system?
They are glands which produce digestive juices containing enzymes.
What is the role of the stomach in the digestive system?
Produces hydrochloric acid which kills any bacteria present and provides the optimum acidic pH for the enzyme to function.
What is the role of the small intestine in the digestive system?
The site where soluble food molecules are absorbed into the bloodstream.
What is the role of the liver in the digestive system?
Produces bile (stored in the gall bladder) which emulsifies lipids and allows the lipase enzyme to work more 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 biological catalysts which speed up 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 their substrate.
What is metabolism?
The sum of all the reactions in a cell or an organism.
What types of metabolic reactions do enzymes catalyse?
- Building larger molecules from smaller molecules e.g glucose to starch.
- Changing one molecule to another e.g glucose to fructose.
- Breaking down larger molecules e.g carbohydrates to glucose.
Explain the lock and key theory for how enzymes work?
The shape of the enzyme active site and the substrate are complementary, so can bind together to form an enzyme-substrate complex.
How does temperature affect enzyme action?
- Increasing temperature increases enzyme action, as molecules have a higher kinetic energy.
- Above a certain temperature, the shape of the active site is altered and the enzyme becomes denatured, so it can no longer catalyse the reaction. The ideal temperature is around 37°.
How does pH affect enzyme function?
- The ideal pH for most enzymes is 7 (apart from proteases in the stomach).
- If the pH is too extreme, the shape of the active site may be altered and the enzyme may no longer work.
What do carbohydrases, proteases and lipases do?
- Carbohydrases convert carbohydrates into simple sugars.
- Proteases convert proteins into amino acids
- Lipases convert lipids into fatty acids and glycerol
Where are carbohydrases, proteases and lipases produced in the body?
- Carbohydrases: - amylase - salivary gland and
pancreas.
- maltase - small intestine. - Proteases: - pepsin - stomach.
- others - pancreas and small intestine. - Lipases: pancreas and small intestine
How are the products of digestion used?
- They are used to build bigger molecules such as carbohydrates and proteins.
- Glucose is used as a substrate in respiration.
Where is bile made and stored in the body?
Bile is made in the liver and stored in the gallbladder.
What is the role of bile in the digestive system?
- Bile is an alkaline substance which neutralises the hydrochloric acid secreted by the stomach.
- Bile emulsifies lipids to form droplets - this increases the surface area for the lipase enzyme to work on.
What is the purpose of the circulatory system?
Carries oxygen and other useful substances to bodily tissues, and removes waste substances.
How does the double circulatory system work?
- One pathway carries blood from the heart to the lungs - where the gaseous exchange of oxygen and carbon dioxide takes place.
- One pathway carries blood from the heart to the rest of the organs.
