B2: Organisation Paper1 Flashcards
(43 cards)
What is a cell
The basic building block of a living organism
What is a tissue
A group of cells with similar structure and function working together. Eg muscular tissue contracts to bring about movement
What is an organ
A collection of tissues working together to perform a specific function eg the stomach contains glandular, muscular and epithelial tissues
What is an organ system
A group of organs working together to perform specific functions eg the digestive system contains organs such as the stomach the small and large intestine
What is the main function of the digestive system
To digest food and absorb nutrients obtained from digestion
What is the role of the pancreas and the salivary gland in the digestive system
The pancreas and the salivary gland 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 protease enzyme 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 (stored in the gallbladder) 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 rate of biological reactions (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 eg glucose to starch
Changing one molecule to another eg glucose to fructose
Breaking down larger molecules into smaller molecules eg carbohydrates to glucose
What is the lock and key hypothesis of enzyme function
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 temp increases enzyme action, as molecules have higher kinetic energy. Above certain temp, the shape of the active site is altered and the enzyme becomes denatured, so it can no longer catalyse the reaction, the optimum temp is around 37 degrees
How does pH affect enzyme function
The optimum pH for most enzymes is 7 (apart from proteases in stomach) if pH is too extreme the shape of active site may be altered and enzyme may no longer work
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
What is the role of carbohydrases in the digestive system
Carbohydrases break down carbohydrates into monosaccharides and disaccharides. Amylase breaks down starch into maltose, and maltase breaks down maltose into glucose
What is the role of proteases in the digestive system
Proteases break down proteins into amino acids
What is the role of lipases in the digestive system
Lipases break 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
Where is bile made and stored in the body
Bile is made by 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.
