A lipid bi-layer membrane can be described as a “fluid mosaic”, with free lateral diffusion and almost no unassisted flipping. What are the features of lipids and lipid bi-layers that contribute to these characteristics?

Question 9 [10 marks / 10 minutes]
Suppose there are two different mutant alleles of the same gene. Sequence analysis shows that both alleles are single nucleotide substitutions, and that different nucleotide positions within the gene are affected in each allele. Phenotypic analysis shows that one allele is a null allele, and the other is dominant negative (antimorphic).
Explain what this information reveals about the two mutations. Give a hypothesis for how these two mutant alleles could show such markedly different effects. [10 marks]

Question 11 [10 marks / 10 minutes]
For the mutations in the 5’ UTR of the trp operon given below, explain the effect on expression of the trp operon relative to wildtype (increased, decreased, or unchanged).
Assume medium levels of tryptophan, such that TrpR (repressor) is inactive and attenuation is active.
a) A mutation in region 2 such that it cannot bind with region 3. [4 marks]
b) A mutation in region 4 such that it cannot bind with region 3. [4 marks]
c) Insertion of T-A basepairs immediately after region 3, such that uracils are transcribed. This insertion does not change the stem-loop formation properties of regions 1, 2, 3 or 4. [2 marks]

1. Unbeknownst to Joe, his bout of enteritis severely injures his pancreas and he unknowingly has developed type 1 diabetes. Describe the disease progression that Joe went through before diagnosis and how he was treated.

2. Describe how caloric excess excess leads to disease

1. Briefly describe three ways that insulin is stimulated? A direct response to high glucose is not an acceptable answer.

2. What is the clinical relevance of detecting glucose in the urine?

1. what is a virus?
What are the causes of the common cold?

Most vitamins are cofactors or coenzymes. What happens if we do not consume enough vitamins in our diet (specifically to the enzymes that use them)?

Several international students have performed a glucose tolerance test as part of a scientific study of lactase persistence. Here are the results:

1. Draw line graphs (all on the same grid) to show this data visually. Use a different color for each person.

2. Based on your graph, divide these students into two groups.

3. Imagine that the same test had been done on these individuals as babies. What do you predict the shape of the graph would be like? EXPLAIN your reasoning.

4. When someone takes a blood glucose test, they are usually asked to fast for twelve hours before the test. Why do you think this is done?

5. Would it be a mistake to consider blood glucose level a proxy data? EXPLAIN.

Assuming 1.5 ATP per FADH, 2.5 ATP per NADH in mitochondria, compare approximately how many ATP equivalents would be generated from the complete oxidation of 12-carbon worth of

a. saturated fatty acid

b. sugar (e.g. glucose)

Show work (possibly drawing out the cycle).

Which of the following is a type of genetic modification? Select ALL that apply.

**3.Which of the following are components of the disarmed plasmid used to create transformant plants? Select ALL that apply.

Which of the following is not a risk factor for hypertension?

. A student cut three identical slices from a potato. She determined the mass of each slice. She then placed them in labeled beakers and added a different solution to each beaker. After 30 minutes, she removed each potato slice from its solution, removed the excess liquid with a paper towel, and determined the mass of each slice. The change in mass was calculated and the results are shown in the data table below.

Change in Mass of Potato in Different Solutions: Initial Mass 17.0 grams, 17.6 grams , 16.4 grams / Final Mass 22.0 grams ,17.6 grams ,15.8 grams

Identify the process that is responsible for the change in mass of each of the three slices. _Explain why the potato slice in beaker 1 increased in mass._________

Question 8 [14 marks / 14 minutes]
Design mutations of hypothetical protein-coding genes:
a)Design a null mutation where the site of the mutation is outside the Open Reading Frame (ORF).Explain how your mutation fits the definition of a null mutation. [5 marks]
b)What type of mutagen could generate your null mutation? Explain.[2 marks]
c)Design a mutation that is not a null allele. Explain the consequence of your mutation for thefunction of the protein. [5 marks]
d)What type of mutagen could generate your second mutation? Explain.[2 marks]

Orangutans are an endangered species in their natural environment (the islands of Borneo and Sumatra), so a captive-breeding program has been established by using orangutans currently held in zoos around the world. One component of this program is cytogenetic research. This research has shown that orangutans from the two islands have different forms of chromosome 2. Before this cytogenetic difference became known, some matings were carried out between animals from different islands, and 14 hybrid progeny are now being raised in the breeding program.

1. What term/s describe the difference/s between these chromosomes?

2. Draw the chromosomes 2 pairing of such a hybrid individual, during the first meiotic prophase.

3. In 40% of meioses, there will be a crossover somewhere in the region between bands p1.1 and q1.2. Draw the chromosomes 2 gametes that would result from a meiosis in which a single crossover occurred within band q1.1.

4. What fraction of the gametes produced by a hybrid orangutan will give rise to viable progeny, if only these chromosomes differ between the parents?