| Date | May 2017 | Marks available | 4 | Reference code | 17M.3.SL.tz0.14 |
| Level | Standard Level | Paper | Paper 3 | Time zone | time zone 0 |
| Command term | Discuss | Question number | 14 | Adapted from | N/A |
Question
State the typical pH range found in the mouth.
State the typical pH range found in small intestine.
Discuss the role of enzymes in digestion.
Markscheme
Mouth:
5.5 to 7.5✔
Small intestine:
6.0 to 8.0✔
enzymes are a class of proteins that support biochemical reactions / speed up/catalyse reactions✔
enzymes are secreted by salivary glands/ stomach / pancreas / liver / small intestine✔
digestive enzymes are essential for the breakdown of carbohydrates / fats / proteins into small absorbable molecules✔
digestive enzymes are secreted in an inactive form and are only activated at the site of function to protect the secretion organs from any damaging, premature enzymatic action✔
enzymes work most efficiently when the environment is optimal in temperature ‹37° C › and pH value✔
without enzymes the process of digestion would be a long and inefficient process, with energy not being supplied at an appropriate rate✔
