Equal masses of fat are mixed with equal lipase concentrations at 37 °C. A has large droplets at pH 3; B has large droplets at pH 8; C has small droplets at pH 8. This lipase works best near pH 8.
.1
Explain why B should digest fat faster than A.
[2 marks]
.2
Explain why C should be faster than B and relate this to bile.
[2 marks]
6 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
Two plants grow under the same bright, warm conditions. One has plentiful water; the other has dry soil and closes many stomata.
Explain how closing stomata helps the dry-soil plant but can limit its growth.
[6 marks]
6 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
A clinic considers transferring two embryos instead of one. Two-embryo transfer may increase pregnancy probability per transfer, but also increases the chance of multiple pregnancy.
Evaluate the use of two-embryo transfer. Include scientific, practical and ethical considerations.
[6 marks]
4 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
Plant tissue gains 4% mass at 0.20 mol/dm³ sugar and loses 4% at 0.40 mol/dm³. Assume a linear relationship between these points.
.1
Estimate the concentration giving zero net mass change.
[2 marks]
.2
Explain what zero net change means and how to improve the estimate.
[2 marks]
6 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A class plans to investigate how light intensity affects photosynthesis using pondweed, a lamp, a ruler, a water bath and a gas-collection syringe.
Plan an investigation that produces valid, repeatable rate comparisons.
