Organisation

What is a cell?

• the basic building block of a living organism

What is a tissue?

• group of cells with similar structures and functions working together

• E.g Muscular tissue contracts cause movement

What is an organ?

• a group of tissues working together to perform a specific function.

• E.g the stomach contains glandular,muscular and epithelial tissues

What is an organ system?

• A group of organs working together to perform specific functions.

• E.g the digestive system contains organs such as the stomach, the small intestine and the large intestine

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?

• the pancreas and the salivary glands are glands that produce digestive juices containing enzymes

What is the role of the stomach in the digestive system?

• produces HCL, killing any bacteria present and providing the optimum acidic pH for the protease enzyme 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 gallbladder. Bile 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 a biological catalysts which speed 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 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 into smaller molecules. e.g carbs 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 temperature increases enzyme action to a certain point as the kinetic energy of the particles is higher. Above a certain temperature however, the shape of the active site is altered and the enzyme becomes denatured so it can lo longer catalyse the reaction. The optimum temperature is around 37 degrees celcius

How does pH affect enzyme function?

• for most enzymes the optimum ph is 7 (excluding protease in the stomach) the active site of an enzyme may be altered if the pH is too high, and the enzyme may no longer work