Genetic Disease

Description

Flashcards on Genetic Disease, created by Raheem Chaudhry on 01/04/2018.
Raheem Chaudhry
Flashcards by Raheem Chaudhry, updated more than 1 year ago
Raheem Chaudhry
Created by Raheem Chaudhry over 6 years ago
2
0

Resource summary

Question Answer
Describe the different types of genetic mutations. [6 marks] Insertions, Deletions, Substitutions. Substitutions can be 'missense' or 'nonsense' mutations. Insertions and deletions can be frameshift mutations. Plus: Splice shifts (intron/exon site lost).
Describe nonsense-mediated mRNA decay. [2] Cellular mechanisms detect that mRNA is improper (due to nonsense or splice shift) and degenerate mRNA before protein product can be formed.
Briefly outline the Gene-to-Protein pathway. [3] Gene --Transcription--> Primary mRNA --splicing--> Mature mRNA --Translation--> Protein
Effects of different types of mutations. [4] Loss-of-function Gain-of-function Dominant-negative (loss-of-function) Gene-dosage affecting
Define "Loss-of-Function" mutations and give a pathological example. [2] Where the gene product has reduced or none of normal function e.g. Duchenne Muscular Dystrophy (DMD).
What is the role of dystrophin? [2] It links the cell with the matrix of the myofilament. Found in the sacrolemma.
What sort of mutation is most likely to cause Duchenne Muscular Dystrophy? [1] Frameshift mutation
Inheritance of Duchenne Muscular Dystrophy. [1] X-linked recessive
What is Gower's Sign? [1] Where the patient has to use their hands and arms to "walk" up their body from a squatting position due to lack of hip and thigh muscle strength.
Describe "Gain-of-Function" mutations. [2] Where the gene product acquires a new, abnormal function. However, only the specific mutation that gives the product its new function will result in the clinical phenotype.
Give an example of a "gain-of-function" mutation resulting in a pathological condition. [2] HTT gene mutation results in Huntington's Disease.
Describe the specific mutation in Huntington's Disease and its affect. [6] Expanded and unstable CAG repeats in exon 1 of the HTT (huntingtin) gene. A normal allele will have 9-35 CAG repeats but an affected allele will have 36-100 CAG repeats. This results in a polyglutamine tract in the protein causing the protein to aggregate + cause neuronal death.
Define "dominant-negative" mutations. [2] A mutation where the mutant gene product not only loses its own function but also prevents other gene products from functioning correctly.
Explain how Osteogenesis Imperfecta is an example of the dominant-negative effect. It is a mutation in Type I collagen. It has mild and lethal phenotypes depending on whether the mutated alpha chain is incorporated into the collagen. The alpha chain mutation affects bone and collagenous structures.
What is the "gene dosage effect"? Give an example of the effect in pathology. Where the mutation varies the level of gene product. An example is Down's Syndrome (additional Chromosome 21).
Show full summary Hide full summary

Similar

IB Biology Topic 4 Genetics (SL)
R S
Fluid and Electrolyte Imbalances
D R
Infectious diseases
Clare Yu
Proteins
Ifeoma Ezepue
DNA structure and replication
Ifeoma Ezepue
Malignancies
Mark George
General epi flashes
Sno
The Biological basis of Heart Disease
Andrea Leyden
General Pathoanatomy Final MCQs (401-519)- 3rd Year- PMU
Med Student
Biology - B1 - AQA - GCSE - Keeping Healthy and Defending Against Infection
Josh Anderson
Biology AQA 3.1.5 The Biological basis of Heart Disease
evie.daines