ex22q Flashcards
Explain why the karyotype is indicative of Down syndrome and what has most likely happened
Down syndrome is caused by trisomy 21. The karyotype shows an extra copy of chromosome 21 attached to another chromosome, likely due to a Robertsonian translocation involving chromosome 21 and another acrocentric chromosome.
Explain how a translocation event may lead to cancer and give a relevant example
Chromosomal translocations can disrupt gene function by rearranging gene segments, often creating fusion genes that lead to uncontrolled cell growth. An example is the Philadelphia chromosome, where the translocation between chromosomes 9 and 22 produces a BCR-ABL fusion gene that is oncogenic in chronic myelogenous leukemia.
Explain two possible mutational events responsible for the differences in the amino acid sequence (positions 291-300) in individuals A and B
Possible mutations could include a single nucleotide polymorphism (SNP) causing a missense mutation, changing one amino acid to another, or a frameshift mutation due to insertion or deletion that alters the downstream amino acid sequence.
List at least five characteristics of apoptotic cells
Characteristics of apoptotic cells include cell shrinkage, chromatin condensation, membrane blebbing, formation of apoptotic bodies, and externalization of phosphatidylserine.
Briefly describe the three pathways of apoptosis and their main features
The intrinsic pathway is activated by internal signals (like DNA damage), leading to mitochondrial outer membrane permeabilization and cytochrome c release. The extrinsic pathway is triggered by external ligands binding to death receptors, activating caspases. The granzyme pathway involves cytotoxic T cells delivering granzymes that directly activate caspases.
In what way can insufficient and excessive apoptosis be involved in disease? Mention a few examples
Insufficient apoptosis can lead to cancer by allowing abnormal cells to survive and proliferate, while excessive apoptosis can contribute to degenerative diseases like Alzheimer’s by causing premature cell death.
What is the current understanding of the mechanism behind Roux-en-Y Gastric Bypass (RYGB) surgery-induced type 2 diabetes remission?
The surgery alters the gut anatomy and hormone responses, enhancing GLP-1 and PYY levels, which increase insulin secretion and sensitivity, and decrease glucagon levels, collectively improving glucose homeostasis and often leading to diabetes remission.
Describe how we can use knowledge from Roux-en-Y Gastric Bypass (RYGB) surgery-induced T2D remission in developing molecular medicine for T2D
This knowledge can guide the development of drugs that mimic the hormonal effects of the surgery, such as GLP-1 agonists or DPP-4 inhibitors, to enhance insulin secretion and action without surgery.
Describe the essential differences between chemotherapy, targeted therapy, and immune therapy
Chemotherapy non-specifically targets rapidly dividing cells, targeted therapy aims at specific molecular targets involved in cancer growth, and immune therapy enhances the immune system’s ability to fight cancer.
List the main limitations of chemotherapy, targeted therapy, and immune therapy
Chemotherapy’s limitations include severe side effects and resistance development. Targeted therapy may not be effective if the cancer lacks the specific targets or develops resistance mechanisms. Immune therapy can be ineffective in some patients and may cause severe immune-related adverse effects.
Name and describe the major differences between the two types of brain strokes and highlight possible treatment strategies for each type
Ischemic stroke is caused by a clot obstructing blood flow, treated with thrombolytics or mechanical thrombectomy. Hemorrhagic stroke results from a blood vessel rupture in the brain, managed by controlling blood pressure and surgical intervention.
Describe why the circle of Willis is important in protecting the brain
The circle of Willis is a circular network of arteries that provides multiple pathways for blood flow to the brain, ensuring collateral circulation and protecting against ischemic stroke in the case of arterial blockage.
