Describe the structure of nucleosomes.

Explain how the two strands of the DNA double helix are held together.

There are multiple tandem repeats of nucleotide segments of DNA found in the non-coding DNA between genes. Outline how tandem repeats are used for DNA profiling.

Explain what happens in a person when they develop type I diabetes.

State how type I diabetes should be treated to avoid harmful health consequences of the condition.

a unit of DNA wound/coiled around 8 histone proteins / octamer;

1. hydrogen bonding between nucleotides / bases;
2. complementary base pairs;
3. adenine-thymine and cytosine-guanine form base pairs (between the two strands with H-bonding);
4. 2 bonds between A and T, while 3 bonds between C and G;

OWTTE

Full names required for c and d though use ecf.

1. tandem repeats (at one locus) vary in number of times sequence repeats / represent different alleles for one locus;
2. DNA sample cut by restriction enzymes into fragments;
3. samples of DNA are amplified at specific genetic sites with PCR;
4. the fragments are separated by their size/number of repeats with gel electrophoresis;
5. fluorescent/radioactive label attached to different tandem repeats;
6. data from several loci at one time uniquely identify individuals / like a fingerprint, combinations of alleles are specific to an individual;
7. comparisons/similarities between fragment patterns to determine paternity/evidence match to a suspect’s profile / other example of comparison/similarity;

OWTTE

1. insulin is necessary to control/regulate blood glucose concentrations
   OR
   insulin is necessary for the cells to take up glucose (for energy);
2. insufficient insulin is made by the pancreas
   OR
   autoimmune response/antibodies destroy the (β) cells of the pancreas that make insulin;
3. reduced uptake of glucose from the blood / glucose accumulates in the blood / elevated blood glucose levels;

“sugar” is NOT accepted in place of glucose. However, this should only be penalized once; i.e., utiltize ECF.

1. inject insulin / monitoring blood glucose / devices that release insulin;
2. decrease consumption of sugars/CHO / diet modification;
3. increase exercise;
4. keep weight in healthy range;

The structure of a nucleosome was correctly described for many, but some did not mention the number of histones.

There was a noticeable number of blank answers with respect to this question about using tandem repeats as the foundation of DNA profiling. Others had a good idea about PCR and gel electrophoresis, but many didn't mention restriction enzymes and did not clearly understand that patterns are compared.

This question about blood sugar regulation was well done by most. This was a question where the use of general terms rather than specific terms led to lost marks. For example, sugars instead of glucose and ‘the body’ instead of ‘the pancreas’