Organisation Flashcards
(105 cards)
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. For example, muscular tissue contracts to bring about movement.
What is an organ?
A collection of tissues working together to perform a specific function. For example, the stomach contains the glandular, muscular and epithelial tissues.
What is an organ system?
A group of organs working together to perform specific functions. For example, the digestive system consists of the stomach, large intestine and small intestine working together.
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 salivary gland in the digestive system?
They produce digestive juices containing enzymes.
What is the role of the stomach in the digestive system?
Produces hydrochloric acid which kills bacteria and provides the optimum acidic pH for protease enzymes to function.
What is the role of the small intestine in the digestive system?
It 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 gall bladder).
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?
They act as biological catalysts which speed up the rate of biological reactions (the breakdown of food) without being used up in the process.
How does the shape of an enzyme affect its function?
They have a specific active site which is complementary to their substrate.
What types of metabolic reactions do enzymes catalyse?
Changing one molecule to another - e.g glucose to fructose.
Breaking down larger molecules into smaller molecules - e.g carbohydrates to glucose.
Building larger molecules from smaller molecules - e.g. glucose to starch.
What is the lock and key hypothesis of enzyme function?
The shape of an enzyme’s active site and the substrate are complementary so can bind together to form an enzyme-substrate complex.
How does temperature affect enzyme action?
Up to a certain point, increasing temperature increases enzyme reaction as molecules have a higher kinetic energy. Above a certain temperature the active site is altered and the enzyme becomes denatured so it can no longer catalyse the reaction. The optimum temperature is 37 degrees celsius.
How does pH affect enzyme function?
The optimum pH for most enzymes is 7 (apart from protease in the stomach). If the pH is too extreme, the shape of the active site may be altered and the enzyme will no longer work.
Where are carbohydrases, lipases and proteases found in the body?
Carbohydrase: amylase - salivary gland and pancreas; maltase - small intestine.
Protease: pepsin - stomach; others - pancreas and small intestine.
Lipases: pancreas and small intestine.
What is the role of carbohydrases and amylase in the digestive system?
Amylase breaks down starch into maltose and maltase breaks maltose into glucose.
Carbohydrases break down carbohydrates into simple sugars.
What is the role of protease in the digestive system?
Breaks down proteins into amino acids.
What is the role of lipase in the digestive system?
Lipase breaks down lipids into fatty acids and glycerol.
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.
What is the function of bile?
Neutralises the hydrochloric acid.
Emulsifies fats to form small droplets which increase the surface area for the lipase enzyme to work on.
What is the heart?
An organ that pumps blood around the body.
What is the purpose of the circulatory system?
Carries oxygen and other useful substances to bodily tissues and removes waste substances.