Exam-style practice (harder): Biology multiple choice quiz
14 questions. Pick an answer and you'll see why right away. Options are shuffled each attempt, and the review at the end links each missed question to the dot point to revise.
The rate of an enzyme-catalysed reaction was measured at different substrate concentrations, with and without substance X.
Substrate concentration (mM) Rate without X (units) Rate with X (units) 1 20 8 2 33 16 5 50 33 20 60 57 40 61 60 Which conclusion is best supported by the data?
E. coli is growing in a medium that contains a high concentration of tryptophan.
Which statement correctly describes the regulation of the trp operon in these conditions?
A circular plasmid is 8.0 kb long. Taking one point on the plasmid as 0 kb, it has EcoRI sites at 1.0 kb and 3.5 kb, and a BamHI site at 6.0 kb. The plasmid is cut with both enzymes and the products are separated by gel electrophoresis.
Which bands will be seen?
A desert plant opens its stomata at night. At night it fixes CO₂ into a four-carbon acid that is stored in the vacuole. During the day, with its stomata closed, CO₂ is released from the stored acid and enters the Calvin cycle in the same cells.
Which option correctly identifies the plant type and the advantage of this adaptation?
The rate of photosynthesis of a plant was measured at different light intensities at two CO₂ concentrations. Temperature was kept constant.
Light intensity (units) Rate at 0.04% CO₂ Rate at 0.10% CO₂ 100 10 10 200 18 19 400 26 34 600 27 45 800 27 48 At 0.04% CO₂, which factor is limiting the rate at 100 units and at 600 units of light?
Yeast cells are grown in a sealed flask of glucose solution with no oxygen.
Which statement correctly describes their respiration?
Scientists use CRISPR-Cas9 to cut a specific gene in a crop plant.
What determines the location in the genome where Cas9 cuts?
A forensic sample contains 10 copies of a target DNA sequence. The sequence is amplified by PCR for 20 cycles.
Assuming the DNA doubles perfectly every cycle, approximately how many copies of the target sequence will there be?
A virus has entered a person's cells and is replicating inside them.
Which statement describes how the adaptive immune response eliminates the infected cells?
A person was exposed to an antigen on day 0 and again on day 30. Their antibody concentration was measured.
Day 0 7 14 21 30 37 44 Antibody (arbitrary units) 0 5 40 20 8 400 350 Which statement best explains the response after day 30?
A storm kills 90% of a beetle population. Which beetles die is random with respect to their genotypes. In the surviving population, the frequency of one allele has changed from 0.20 to 0.45.
Which process best explains this change?
The table shows the number of amino acid differences between human cytochrome c and the cytochrome c of other species.
Species Amino acid differences from humans Chimpanzee 0 Rhesus monkey 1 Dog 11 Horse 12 Chicken 13 Yeast 44 Which conclusion is supported by this data?
A student measured the zone of inhibition around an antibiotic disc on three plates in one lesson, with the same ruler: 14, 14 and 15 mm. A student at another school, using a different brand of agar and digital calipers, obtained 14 mm and 15 mm for the same antibiotic and bacterium.
Which term best describes the agreement between the two schools' results?
A hominin fossil is found in a sediment layer between two layers of volcanic ash. Radiometric dating gives an age of 1.8 million years for the ash layer above the fossil and 2.1 million years for the ash layer below it.
What can be concluded about the age of the fossil?