Technology practice questions.

A researcher enters a newly sequenced gene into a database tool such as BLAST. What is the main purpose of doing this?

• To find known sequences similar to it
• To translate the gene directly into a protein
• To physically cut the gene using enzymes
• To increase the number of copies of the gene

Answer: To find known sequences similar to it

Sequence databases let you compare a query sequence against stored sequences to find matches, which suggests gene function or evolutionary relationships; they do not translate, cut or copy DNA.

In a quantitative investigation of breathing, what does a spirometer allow a researcher to measure?

• Lung volumes and rate of breathing
• The oxygen content of pond water
• The pH of blood in an artery
• The rate of sweating during exercise

Answer: Lung volumes and rate of breathing

A spirometer records the volume of air moved in and out of the lungs over time, giving quantitative data on lung volumes and breathing rate.

A student enters sixty measurements into a spreadsheet and uses a built-in function to obtain the standard deviation. What must be checked before the value is trusted?

• That the selected cells hold the measurements and nothing else
• That the measurements have first been sorted into rank order
• That the mean has been calculated in the row directly above
• That the values are expressed to the same number of decimals

Answer: That the selected cells hold the measurements and nothing else

A selection that reaches one row too far picks up a heading or a blank and silently changes the answer, which is the commonest spreadsheet error in a practical report. Sorting and rounding change nothing about the result.

A computer model of a population predicts a plateau that the real population never reaches. What is the appropriate response?

• Examine the model's assumptions and revise it
• Repeat the field measurements until they agree
• Report the modelled values as the expected result
• Discard the field data as unreliable and start again

Answer: Examine the model's assumptions and revise it

A model is a simplification held up against reality, and a mismatch is information about the model rather than a fault in the observations. Adjusting the data to fit the prediction inverts the whole relationship between the two.

A newly determined gene sequence is deposited in a public database rather than kept within the laboratory that produced it. What is the main scientific benefit?

• Anyone can compare it with sequences from other species
• The laboratory is credited whenever the sequence is used
• The sequence is protected against being altered or lost
• Other laboratories are prevented from repeating the work

Answer: Anyone can compare it with sequences from other species

A sequence acquires most of its meaning by comparison, so its value grows with the number of sequences it can be set against. Repetition by others is a benefit of openness rather than something to be prevented.

A student logs the temperature of a compost heap every second for two weeks. What is the main drawback of that choice of interval?

• An enormous file is produced that adds no information
• The probe wears out long before the two weeks are up
• The readings become less accurate as the file grows
• Short intervals prevent any trend from being detected

Answer: An enormous file is produced that adds no information

The interval should be short enough to capture how fast the variable actually changes, and a compost heap does not change measurably in a second. Over-sampling costs storage and processing time without improving the record.