Instructions Johnathon and April are both pre-medical students working at a phys
ID: 193937 • Letter: I
Question
Instructions Johnathon and April are both pre-medical students working at a physician's office over the summer with Dr. Targaryen. Both are extremely curious about how minute mutations in different genes can lead to significant disorders and diseases that can debilitate otherwise healthy individuals. As the summer winds to an end Dr. Targaryen calls Johnathon and April into his office to give them a special project. A patient (herein referred to as Patient X) has just come into the office exhibiting some interesting symptoms. He has a good idea of what it is, but he'd like to see if Johnathon and April can figure it out and determine how they would confirm their diagnosis. Patient X is small in stature (just under 5 feet tall). He's a male who has been found to be infertile and develops severe skin lesions after being in the sun. He also has a distinctive high pitched voice and a narrow face. There also appears to be a learning disability and he may be developing diabetes already. Although Patient X is still relatively young (age of 16), initial tests indicate he has developed several tumors in his colon and lungs. Johnathon and April get to work and after several hours produce a preliminary diagnosis including several ways with which to test if their diagnosis was correct. A number of these methods are based on DNA sequence at specific genes Their diagnosis was in fact correct and Dr. Targaryen was extremely excited. Both Johnathon and April left the physician's office with a renewed sense of curiosity and drive to become medical professionals. (Hint: for the sake of this case study, you may want to focus on DNA repair and replication genes)Explanation / Answer
Que 7
Ans:
Several members of the same family were diagnosed with same kind of cancer when they were unusually young. The following is the most likely explanation for this phenomenon. It is possible that the individuals with the cancer have: inherited a mutation in a gene required for mismatch repair.
Explanation:
- In fact, affected individuals in some families with a history of early onset of colon cancer have been found to carry mutations in mismatch repair genes.
Que 8
Ans:
The following statements about sequence proofreading during DNA replication is FALSE: The exonuclease activity cleaves DNA in 5' to 3' direction.
Explanation:
- 3' to 5' exonuclease activity cleaves DNA strands to remove incorrect base pairs.
Que 9.
Ans:
Human being with the inherited disease xeroderma pigmentosum have serious problem with lesion on their skin and often develop skin cancer with repeated exposure to sunlight. Type of DNA damage not recognized in the cells of these individuals is: ultraviolet irradiation damage.