B3 (Orginisation and the digestive system)

Question 1

What is a cell?

Answer 1

The building blocks of life.

Question 2

What is a tissue?

Answer 2

A group of cells.

Question 3

What is a organ?

Answer 3

A group of tissues.

Question 4

What is an organ system?

Answer 4

A group of organs.

Question 5

What is an organism?

Answer 5

A group of organ systems.

Question 6

What is the main function of the digestive system?

Answer 6

To digest food and absorb the nutrients obtained from digestion.

Question 7

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

Answer 7

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

Question 8

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

Answer 8

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

Question 9

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

Answer 9

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

Question 10

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

Answer 10

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

Question 11

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

Answer 11

Absorbs water from undigested food, producing faeces.

Question 12

What is the role of enzymes in the digestive system?

Answer 12

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

Question 13

How does the shape of an enzyme affect its function?

Answer 13

Enzymes have a specific active site which is complimentary to their substrate.

Question 14

What is metabolism?

Answer 14

The sum of reactions in an organism.

Question 15

What types of metabolic reactions do enzymes catalyse?

Answer 15

• 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 carbohydrates to glucose.

Question 16

What is the lock and key hypothesis of enzyme function?

Answer 16

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

Question 17

How does the temperature affect enzyme action?

Answer 17

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

Question 18

How does pH affect enzyme function?

Answer 18

The optimum pH for most enzymes is 7 (apart from protease sin the stomach) . If the pH is too extreme, the shape of the active site may be altered and the enzyme may no longer work.

Question 19

What is the role of carbohydrases in the digestive system?

Answer 19

Carbohydrases break down carbohydrates into monosaccharides and disaccharides. Amylase breaks down starch into maltose, and Maltese breaks down maltase

Question 20

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Answer 20

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