A respirometer shows a germinating seed sample uses 2.4 cm³ oxygen in 8 minutes. Its mass is 3.0 g. An equal-mass boiled sample uses no measurable oxygen.
.1
Calculate oxygen uptake rate per gram in cm³ per minute per gram.
[2 marks]
.2
Explain the difference between the seed samples.
[2 marks]
4 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
An engineer wants all cells of a new plant to contain an introduced gene. Another proposal would insert the gene into just a few cells of a fully grown leaf.
.1
Explain why introducing the gene at an early developmental stage is more suitable for the first aim.
[2 marks]
.2
Explain a limitation of inserting the gene only into a mature leaf.
[2 marks]
4 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
Researchers record 48 freshwater invertebrate species at an unpolluted site and 18 at a site with low dissolved oxygen. The sites also differ in temperature and water flow.
.1
Calculate the percentage decrease in species count relative to the unpolluted site.
[2 marks]
.2
Evaluate the claim that low oxygen alone caused the decrease.
[2 marks]
4 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A transect runs from a shaded wall into a lawn. Mean plant counts per quadrat at 0, 2, 4, 6 and 8 m are 1, 3, 6, 6 and 5 respectively.
.1
Describe the pattern in the data without claiming a cause.
[2 marks]
.2
Explain how to investigate whether light accounts for the pattern.
[2 marks]
6 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
Two carriers of cystic fibrosis consider embryo screening. Screening can identify embryos with two recessive alleles, but the IVF process may not produce an unaffected embryo suitable for transfer.
