NESA Biology Questioning and Predicting
3 sample questions with marking guides and sample answers
Most vinegar flies have wild type (reddish-brown) eyes. However, some mutants have white eyes and cannot see. Biologists conducted a laboratory experiment to compare the fitness of flies with wild type and white eyes.
Which of the following is the best hypothesis for the experiment?
Is there a difference in the fitness of flies with wild type and white eyes?
There is a difference in the fitness of flies with wild type and white eyes.
If flies cannot see, then they will have reduced fitness.
Do flies that cannot see have reduced fitness?
Thalassemia is a genetically inherited disorder that affects the haemoglobin of blood. Two types of thalassemia are alpha (α) and beta (β). One of the treatments of both types of thalassemia involves drugs that are administered to help remove excess iron from the blood. A research team wanted to investigate the effectiveness of the different modes of delivery of these drugs.
The team set up an investigation to compare the drugs in injectable form with the orally ingested form. The team conducted their investigation on a sample of 53 beta (β) thalassemia sufferers. The participants were divided into four groups. The participants in each group had daily treatments lasting one month. The groups were:
Group A – 14 participants who received the injectable drug
Group B – 13 participants who received an inactive injectable drug
Group C – 13 participants who received the orally ingested drug
Group D – 13 participants who received an inactive oral drug.
Propose an hypothesis for the study described above.
Why were both groups B and D required for this study?
Identify a variable that was controlled in the study.
Describe the data the researchers would need to collect and when they should collect the data.
Outline the cause of alpha (α) and beta (β) thalassemia and identify what makes each type of thalassemia different.
Alpha (α) and beta (β) thalassemia display the same inheritance pattern but can have differing effects on the gene pool of a population. Justify this statement.
In 2009, the University of California discovered a mutated gene that has been shown to produce naturally short sleepers. The gene was found in a family who all normally went to bed around 11 pm and woke up naturally around 5 am. The mutated gene, known as DEC2, is believed to affect the circadian rhythm and results in people who don't need as much sleep as the average person.
If researchers wanted to further investigate the link between the DEC2 gene and sleep, they would need to set up an experimental study.
DEC2 is a gene mutation. How do gene and chromosomal mutations differ?
In the study, the mutation was found in several family members. What does this tell you about where the original mutation occurred? Justify your response.
Mutations can be caused in several ways. For each of the three ways stated below, describe how they may produce new mutations.
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Mutagens:
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DNA replication:
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Cell division:
Propose a possible hypothesis for the study.
In the study, what would the control group consist of, and what purpose would it have?
A mutation, such as the DEC2 gene, could be favourable to the human population. Explain how a favourable gene like this could lead to changes in allele frequencies of a gene pool.