Topic 2 - Organisation

Question 1

What is a cell?

Answer 1

The basic building block of a living organism

Question 2

What is a tissue?

Answer 2

A group of cells with a similar structure and function working together. For example, muscular tissue contracts to bring about movement.

Question 3

What is an organ?

Answer 3

A collection of tissues working together to perform a specific function. For example, the stomach contains glandular, muscular and epithelial tissues.

Question 4

What is an organ system?

Answer 4

A group of organs working together to perform specific functions. For example, the digestive system contains organs such as the stomach, the small intestine and the large intestine.

Question 5

What s the main function of the digestive system?

Answer 5

To digest food and absorb the nutrients obtained from digestion

Question 6

What is the role of the pancreas and the salivary gland in the digestive system?

Answer 6

The pancreas and the salivary gland are gland are glands which produce digestive juices containing enzymes.

Question 7

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

Answer 7

Produces hydrochloric acid - kills any bacteria present and provides the optimum acidic pH for the protease enzyme to function.

Question 8

What is the role of the small intestine in the digestive system?

Answer 8

The small intestine is the site where soluble food molecules are absorbed into the bloodstream

Question 9

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

Answer 9

Produces bile (stored in the gallbladder) which emulsifies lipids and allows the lipase enzyme to work more efficiently.

Question 10

What is the role of the large intestine in the digestive system?

Answer 10

Absorbs water from undigested food, produces faeces.

Question 11

What is the role of enzymes in the digestive system?

Answer 11

Enzymes act as biological catalysts which speed up the rate of biological reactions (the breakdown of food) without being used up.

Question 12

How does the shape of an enzyme affect its function?

Answer 12

Enzymes have a specific active site which is complementary to their substrate

Question 13

What is metabolism?

Answer 13

The sum of all the reactions in an organism.

Question 14

What types of metabolic reactions do enzymes catalyse?

Answer 14

• 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

Question 15

What is the lock and key hypothesis of enzyme function?

Answer 15

The shape of the enzyme active site and the substrate are complementary, so can bind together to form an enzyme-substrate complex.

Question 16

How does temperature affect enzyme action?

Answer 16

Up to a certain point, increasing temperature increases enzyme action, as molecules have a higher kinetic energy. above a certain temperature, the shape of the active site is altered is altered and the enzyme becomes denatured, so it can no longer catalyse the reaction. the optimum temperature is around 37 degrees