Enzymes and digestion

Question 1

What is an enzyme?

Answer 1

A protein that acts as a catalyst in biochemical reactions without being used up.

Question 2

What factors affect the rate of enzymes?

Answer 2

Temperature and pH levels.

Question 3

Briefly outline why temperature affects the enzymes activity rate

Answer 3

All enzymes have an optimal temperature that they can work at. most are around 37 degrees Celsius. This is because they core temperature is normally around this so they work best at this temperature. If the optimal temp is exceeded then this will cause the enzyme to denature.

Question 4

Briefly outline why pH levels affects the enzymes activity rate.

Answer 4

All enzymes have an optimum pH level to work at. If this level is exceeded then it can cause the enzyme to denature and to change shape meaning the enzyme won’t fit with it’s substrate any longer.

Question 5

What is the difference between egestion and excretion?

Answer 5

Egestion is the removal of faeces and undigested food. Excretion is the removal of metabolic waste for example Co2 and urea.

Question 6

Define digestion.

Answer 6

Chemical and mechanical breakdown of large insoluble molecules to small soluble ones.

Question 7

Outline what happens to the food in the mouth.

Answer 7

It is chewed, crushed, cut and torn into smaller pieces that can be mechanically digested. it is then mixed in with saliva containing salivary amylase this helps to break it down and to go down the oesophagus.

Question 8

Define absorption

Answer 8

Products of digestion moving through walls via diffusion into the blood stream.

Question 9

Design an experiment to investigate the effect of temperature on enzymes activity.

Answer 9

C- temp of the water one at 30 and another at 70 degrees.
O- volume of the starch.
R- repeat 3 times and then calculate an average
M- how long the iodine takes to turn blue black.
S- Volume of starch and the pH of the substrate.

Question 10

Design an experiment to investigate the effect of pH on enzyme activity.

Answer 10

C- the pH of the solutions
O- photopaper, whether it is the same size square or same SA
R- repeat 10 times for each pH
M- how long it takes for the photopaper to go clear/ colourless
S- temp and volume of enzymes left.