IB MYP Biology Biochemistry and Enzymes
IB myp 4-5 Biology – Practice Questions- All Topics
Topic : Biochemistry and Enzymes
Topic :Metabolism– Weightage : 21 %
All Questions for Topic : Nutrition,Digestion,Biochemistry and enzymes,Movement and transport,Diffusion,Osmosis,Gas exchange,Circulation,Transpiration and Translocation,Homeostasis
Question: IB MYP Biology biochemistry
Predict what will happen to lactose in the intestines of adults who do not produce the enzyme lactase.
▶️Answer/Explanation
Ans: Lactose is not digested (by human enzymes/digestive juices); bacteria/microbes in the gut digest the lactose.
Question:
Explain how lactase secretion in adulthood could have become common in populations that keep cattle or other mammals and drink their milk.
▶️Answer/Explanation
Ans: Adults that continue to secrete lactase into adulthood have an advantage; they are better nourished on a diet containing milk; they avoid harmful effects of lactose intolerance; they are healthier so produce more children; their children inherit the trait of secreting lactase in adulthood.
Question (5 marks)
In order for enzymes to effectively control reactions in the human body, the temperature must remain constant in the range \(36.5^{\circ} \mathrm{C}\) to \(37.5^{\circ} \mathrm{C}\). Explain why enzyme-based reactions in the body are dependent on the temperature not moving outside this range.
▶️Answer/Explanation
Ans:
enzymes have an optimum temperature
too cold and reactions do not occur fast enough
too hot and enzymes change shape
and no longer function
Correct use of a term from the list:
active site; denature; catalyze; lock and key; substrate