The growth rate of three children was measured. The growth rate of the hGH-deficient child who did not receive daily hGH injections was $2.5\,\text{cm year}^{-1}$. The growth rate of the hGH-deficient child who received daily hGH injections was $10.0\,\text{cm year}^{-1}$ in the first year after treatment began. The growth rate of the child who is not hGH-deficient was $5.0\,\text{cm year}^{-1}$. Calculate the percentage increase in growth rate of the hGH-deficient child treated with hGH injections compared with the child who is not hGH-deficient. Show your working.
Name the kind of enzyme that cuts plasmid DNA and the kind of enzyme that makes cDNA from hGH mRNA.
Identify and explain two features of plasmids that make them suitable as vectors for carrying hGH cDNA into Escherichia coli cells.
In 1985, several cases of a rare brain disease were identified in people who had been treated many years earlier with hGH taken from pituitary glands. From 1985 onwards, it was decided that only recombinant hGH should be used to treat patients. Explain the advantages of making human therapeutic proteins, such as hGH, by recombinant DNA technology.
hGH is among many proteins in the body whose secretion or production is controlled by a person's sleep-wake pattern. The sleep-wake pattern describes, within a $24$ hour day, when a person is asleep and when they are awake. Pattern 1 means asleep at night and awake during the day, while pattern 2 means asleep during the day and awake at night. Researchers used microarray analysis to find which genes have altered expression because of a person's sleep-wake pattern. They collected mRNA from a group of people with sleep-wake pattern 1 and from the same group of people after their sleep-wake pattern had been changed to pattern 2. A summary of the results is shown in Table 3.1. (i) Describe how changing the sleep-wake pattern from pattern 1 to pattern 2 affects the number of genes expressed. (ii) Explain how eukaryotic genes can be switched on and off, for example, at certain times of day. (iii) Explain how bioinformatics can help to identify whether the genes whose expression is changed by moving from pattern 1 to pattern 2 are important to health.