Part A - Questions
Q1) The cells in the epithelial lining of your gut turn over approximately every 5-6 days. Intestinal stem cells need to keep dividing to keep up with this high turnover. Are these stem cells undergoing meiosis or mitosis? Support your answer.
Q2a) What is chromosome non-disjunction?
b) At what specific stage in the cell cycle would it occur?
c) What is a human condition that is caused by chromosome non-disjunction?
Q3) A Drosophila sperm cell contains four chromosomes. How many chromosomes would be present in a spermatogonial cell about to enter meiosis? How many chromatids would be present in a spermatogonial cell at metaphase I of meiosis? How many would be present at metaphase II?
4) In what ways are the packaging of prokaryotic and eukaryotic chromosomes into living cells similar?
Part B - Questions
Q1. In a man who is heterozygous at two different loci A and B, what percentage of his sperm will have the following haploid genotypes?
a) AB
b) bA
Q2. In a family with 6 children, how many different permutations of birth order satisfy the scenario of having four boys and two girls?
Q3. A couple knows they are both carriers of an allele for the recessive Parkinson's Disease. They would like to have 4 children and want to know the likelihood that none of their children will have Parkinson's in later life. What is the probability of this outcome?
Q4. You do not have Parkinson's Disease, but your father has it. There is no history of Parkinson's Disease in your mother's family. What is the probability that you will pass on the Parkinson's allele (p) to your offspring? What assumption do you make about your mother in order to calculate this probability?
Q5. Now consider this scenario. Your father (now deceased) did not get Parkinson's disease in his old age, but his brother (your uncle) did. Now what is the probability that you are a carrier?
Q6. Same scenario as Q5, but now what is the probability that your child will be a carrier?
Part C - Questions
Q1. A man is heterozygous for a mutation in the PARK7 gene. Analysis of his genomic DNA reveals the sequence below for the coding strand. The next four questions are based on this information.
a) Say that the T at position 60 is the last base of codon 21. What two amino acids are specified at codon 23 by this man's two PARK7 alleles?
b) What type of mutation is this:
i. Insertion leading to a frameshift
ii. Deletion leading to a frameshift
iii. Point mutation leading to a silent mutation
iv. Point mutation leading to missense mutation
c) Justify your answer above.
d) How would we find out which, if either, of this man's alleles corresponded to the wild type sequence?
Q2. If the transcribed PARK7 gene is over 23 kb, why is the mature PARK7 mRNA only 902 nt long?
Q3. Below is the first 300 base pairs of the PARK7 mRNA; the following question is based on this sequence.
a) Write out the sequence of the template strand for the bold and underlined sequence above (label the ends to indicate orientation).
Q4. Below is the first 300 base pairs of the mature human PARK7 mRNA. The following questions are based on this sequence.
a) The PARK7 protein sequence starts Met-Ala-Ser-Lys-Arg-Ala. Using nucleotide numbers, identify the translational start site in the mature mRNA:
b) What is the amino acid sequence encoded by the bolded and underlined sequence?
c) Would this sequence occur in the PARK7 protein?
Assignment Files -
https://www.dropbox.com/s/k4cm6s08r0etm04/Desktop.rar?dl=0
https://www.dropbox.com/s/ovchqk9yzzo3785/Desktop2.rar?dl=0