Animal Tissues, organs And Systems

Question 1

What is the main function of the digestive system?

Answer 1

To digest food and absorb the nutrients obtained from digestion

Question 2

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

Answer 2

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

Question 3

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

Answer 3

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

Question 4

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

Answer 4

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

Question 5

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

Answer 5

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

Question 6

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

Answer 6

Absorbs water from undigested food, producing faeces

Question 7

What is the role of enzymes in the digestive system?

Answer 7

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

Question 8

How does the shape of an enzyme affect its function?

Answer 8

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

Question 9

What is metabolism?

Answer 9

The sum of all the reactions in a cell or an organism

Question 10

What types of metabolic reactions do you enzymes catalyse?

Answer 10

-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 11

What is the lock and key hypothesis of enzyme function?

Answer 11

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

Question 12

How does temperature affect enzyme action?

Answer 12

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 and the enzyme becomes denatured, so it can no longer catalyse the reaction. The optimum temperature is around 37 degrees

Question 13

How does pH affect enzyme function?

Answer 13

The optimum pH for most enzymes is 7 (apart from proteases in 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 14

Where are carbohydrates, proteases and lipases produced in the body?

Answer 14

Carbohydrates: amylase- salivary gland and pancreas; maltase- small intestine
Proteases: pepsin- stomach; others- pancreas and small intestine
Lipases: pancreas and small intestine

Question 15

What is the role of carbohydrases in the digestive system?

Answer 15

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

Question 16

What is the role of proteases in the digestive system?

Answer 16

Proteases break down proteins into amino acids

Question 17

What is the role of lipases in the digestive system?

Answer 17

Lipases break down lipids into fatty acids and glycerol

Question 18

How are the products of digestion used?

Answer 18

They are used to build bigger molecules such as carbohydrates and proteins. Glucose is used as a substrate in respiration

Question 19

Where is bile made and stored in the body

Answer 19

Bile is made by the liver and stored in the gallbladder

Question 20

What is the role of bile in the digestive system?

Answer 20

Bile is an alkaline substance which neutralizes 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

Question 21

What is the heart?

Answer 21

An organ that pumps blood around the body

Question 22

What is the purpose of the circulatory system?

Answer 22

Carries oxygen and other useful substances to bodily tissues, and removes waste substances

Question 23

How does the double circulatory system work?

Answer 23

One pathway carries blood from the heart to the lungs- where the gaseous exchange of oxygen and carbon dioxide take place
One pathway carries blood from the heart to the tissues

Question 24

Where does blood pumped by the right ventricle go?

Answer 24

The lungs

Question 25

Where does blood pumped by the left ventricle go?

Answer 25

Body tissues

Question 26

Why is the double circulatory system important?

Answer 26

It makes the circulatory system more efficient- for example, oxygenated blood can be pumped around the body at a high pressure by the left ventricle

Question 27

How many chambers does the heart have and what are they called?

Answer 27

4- right atrium, right ventricle, left atrium, left ventricle

Question 28

Why is the wall of the left ventricle thicker?

Answer 28

The left ventricle has to pump to blood at a higher pressure around the whole body

Question 29

What are the four main blood vessels associated with the heart?

Answer 29

Aorta (left)- carries oxygenated blood from the heart to the body
Pulmonary vein(left)- carries oxygenated blood from the lungs to the heart
Vena cava (left)- carries deoxygenated blood from the body to the heart
Pulmanory artery (right)- carries deoxygenated blood from the heart to the lungs

Question 30

What is the purpose of valves in the heart?

Answer 30

Prevent the backflow of blood

Question 31

What is the purpose of coronary arteries?

Answer 31

Coronary arteries supply the heart muscle with oxygenated blood

Question 32

Describe the process of blood flow through the heart

Answer 32

Blood enters the right atrium via the vena cava, and the left atrium via the pulmonary vein
The atria contract, forcing blood into the ventricles and causing valves to shut
After the ventricles contract, blood into the right ventricle enters the pulmonary artery (to the lungs) and blood in the left ventricle enters the aorta (to the body)

Question 33

What is the appropriate value of the natural resting heart rate?

Answer 33

70 beats per minute