chapter 3 - organisation and digestion

Question 1

name the 5 levels of organisation

Answer 1

cells > tissues > organs > organ systems > organisms

Question 2

what is a tissue?

Answer 2

a group of cells with similar structures and functions

Question 3

what is an organ?

Answer 3

a group of tissues working together to perform a specific function

Question 4

function of liver in digestion?

Answer 4

it produces bile, which neutralises hydrochloric acid from, the stomach and emulsifies fat to form small droplets with a large surface area

Question 5

function of saliva in digestion?

Answer 5

lubrication to help swallowing - contains amylase to break down starch

Question 6

enzymes produced in pancreas?

Answer 6

amylase, protease and lipase

Question 7

what are enzymes?

Answer 7

protein molecules that catalyse specific reactions in organisms

Question 8

why are enzymes described as specific?

Answer 8

each enzymes only catalyses a specific reaction, because the active site only fits together with certain substrates (lock and key)

Question 9

function of amylase?

Answer 9

to break down starch into glucose

Question 10

where are amylases produced?

Answer 10

salivary glands, pancreas, and small intestine

Question 11

function of protease?

Answer 11

to break down proteins into amino acids

Question 12

where are proteases produced?

Answer 12

stomach, pancreas and small intestine

Question 13

function of lipase?

Answer 13

to break down lipids into fatty acids and glycerol

Question 14

where are lipases produced?

Answer 14

pancreas and small intestine

Question 15

factors that affect rate of activity of an enzyme?

Answer 15

temperature and pH

Question 16

what does denatured mean?

Answer 16

the shape of an enzymes active site is changed by high temperatures or an extreme pH, so it can no longer bind with the substrate

Question 17

effect of temperature on enzyme activity?

Answer 17

as temperature increases, rate of reaction increases until it reaches the optimum for enzyme activity - above this temperature enzyme activity decreases and eventually stops

Question 18

effect of pH on enzyme activity?

Answer 18

different enzymes have a different optimum pH at which their activity is greatest - at a pH much lower or higher than this enzyme activity decreases and stops

Question 19

why do different digestive enzymes have different optimum pHs?

Answer 19

different parts of the digestive system have very different pHs - the stomach is strongly acidic, and the pH in the small intestine is close to neutral