Mutations Flashcards
What is the effect of substitution mutation?
1 silent mutation —-no change in protein due to redundancy in the genetic code
2 missense mutation —— alteration in amino acid sequence of a protein
3 nonsense mutation _____introduction of underdeveloped stop codon
What is the impact of insertion mutation?
Causes a frameshift mutation altering the entire downstream reading frame often resulting in non-functional protein
What is the effect of deletion mutation?
Like insertion deletion also typically causes a frameshift mutation on this it cures in multiples of three nucleotide
What are neutral mutations?
Neutral mutations are mutations that have no observable effect.
Why do many mutations have no observable effect?
Many mutations have no observable effect due to redundancy in the genetic code, occurrence in non-coding regions, or lack of significant structural or functional change in the resulting protein.
What is a silent mutation?
A silent mutation is a type of mutation that does not change the resulting protein due to redundancy in the genetic code.
What are non-coding regions?
Non-coding regions are parts of the DNA, such as introns or regulatory DNA, that do not impact gene expression.
What is Sickle Cell Anaemia?
Sickle Cell Anaemia is a genetic disorder caused by a substitution mutation in the gene that codes for the ß-globin chain of haemoglobin (HBB gene).
What type of mutation causes Sickle Cell Anaemia?
A single base substitution occurs in the HBB gene on chromosome 11.
What change occurs in the HBB gene that leads to Sickle Cell Anaemia?
The codon GAG (glutamic acid) changes to GTG (valine), resulting in the production of abnormal haemoglobin called haemoglobin S (HbS).
How does HbS differ from normal haemoglobin?
HbS molecules are less soluble than HbA and tend to stick together under low oxygen conditions.
What is the effect of HbS on red blood cells?
HbS causes haemoglobin to polymerize, distorting red blood cells into a characteristic sickle shape.
What are the consequences of sickle-shaped red blood cells?
Sickle-shaped cells are less flexible, leading to blockages in small blood vessels (vaso-occlusion) and have a shorter lifespan (10-20 days vs. 120 days for normal RBCs), leading to anaemia.
What are common symptoms of Sickle Cell Anaemia?
Common symptoms include fatigue and weakness (due to anaemia) and pain crises (caused by blocked blood flow).
What causes cystic fibrosis?
A recessive mutation in the CFTR gene.
What does CFTR stand for?
Cystic Fibrosis Transmembrane Conductance Regulator.
What is the main effect of cystic fibrosis on mucus production?
Leads to the production of thick, sticky mucus.
What body systems are affected by cystic fibrosis?
Gaseous exchange, digestive, and reproductive systems.
What is the probability of producing a child with cystic fibrosis if both parents are carriers?
25% chance.
What is the probability of producing a child with cystic fibrosis if only one parent is a carrier?
0% chance.
How does healthy CFTR function in the lungs?
Regulates the movement of chloride ions, creating an osmotic gradient that keeps mucus thin.
What effect does mutated CFTR protein have on the lungs?
Impaired chloride ion transport leads to thick, sticky mucus.
What are the consequences of thick mucus in the lungs due to cystic fibrosis?
Blocks airways, inhibits ciliary action, leads to chronic lung infections and difficulty breathing.
What can chronic lung infections from cystic fibrosis lead to over time?
Respiratory failure.
How does healthy CFTR function in the digestive system?
Regulates movement of chloride ions and water, ensuring digestive enzymes are secreted into the small intestine.
Fill in the blank: Cystic fibrosis is a genetic disorder caused by a _______.
recessive allele.
What role does CFTR play in the pancreas?
CFTR helps ensure that digestive enzymes are secreted into the small intestine
What effect does defective CFTR have in Cystic Fibrosis?
Thick mucus blocks the ducts of the pancreas, preventing digestive enzymes from reaching the small intestine
What is a consequence of the blockage of digestive enzymes in Cystic Fibrosis?
Malabsorption of nutrients, leading to poor growth and malnutrition
What is steatorrhea?
Fatty stools due to undigested fats
What long-term effects can chronic malnutrition have in individuals with Cystic Fibrosis?
Poor bone health and weight loss
What is the role of CFTR in the reproductive system?
CFTR is involved in the secretion of fluids in male and female reproductive organs
How does CFTR function in males?
CFTR helps with the production of seminal fluid
How does CFTR function in females?
CFTR aids in the production of cervical mucus
What is a common cause of male infertility in individuals with Cystic Fibrosis?
Bilateral absence of the vas deferens
What effect does thick mucus have on the vas deferens in males with CF?
It obstructs the vas deferens, preventing sperm from reaching the semen
Do women with Cystic Fibrosis retain the ability to conceive?
Yes, but they may experience fertility issues
What challenge does thick mucus pose for women with Cystic Fibrosis regarding fertility?
It can make it more difficult for sperm to reach the egg
What is the role of the CFTR protein?
The CFTR protein is a chloride ion channel located in the cell membrane.
How does the CFTR protein affect ion transport?
It allows chloride ions to move out of the cell.
What is the effect of chloride ion movement on water?
The movement of chloride ions creates an osmotic gradient, causing water to follow.
How does CFTR function maintain mucus consistency?
This maintains the balance of water in mucus, keeping it thin and mobile, which aids in proper mucus clearance from the lungs and other organs.
What happens when the CFTR protein is mutated?
A mutation in the CFTR gene results in a malfunctioning or absent CFTR protein.
What is the consequence of disrupted ion transport due to mutated CFTR?
The chloride ions cannot move out of the cell properly, or the CFTR protein is unable to function correctly.
What is the impact of impaired chloride ion movement on mucus?
Without chloride ion movement, water is not drawn out, leading to thick, sticky mucus.
What complications arise from thick mucus caused by mutated CFTR?
The thick mucus clogs airways in the lungs, impairing gas exchange and causing breathing difficulties. It also blocks ducts in the pancreas, leading to malabsorption of nutrients.
What is the key function of healthy CFTR?
Regulates chloride and water transport, maintaining normal mucus consistency.
What are the consequences of mutated CFTR?
Leads to impaired chloride ion transport, resulting in thick, sticky mucus and related complications.
