Genetics & SCD Flashcards
Brief overview of Meiosis and Introduction to genetics and sickle cell anemia
What is a Gene?
A Gene is a heritable factor that controls a specific characteristic such as eye or hair color.
What does a Gene consist of and where is it located on the chromosome?
A Gene consists of a length of DNA in the shape of a double helix. It occupies a position on the chromosome called the locus.
What is an allele?
Alleles are different variants of the same gene.
What is a Genome?
The Genome is the total genetic material in a organism, cell or organelle.
What is genetic mutation?
Genetic mutation is the permanent change in the sequence of base pairs in DNA that makes up a Gene.
What is an example of genetic mutation?
Some Manx cats are examples of genetic mutations. Some Max cats were born tailless due to genetic mutation.
Explain the difference between Prokaryote and Eukaryote chromosomes.
Prokaryote chromosomes are circular due to not having free ends called telomeres. They are located in the nucleoid area, and are attached to the cell. Prokaryote chromosomes contain small loops of DNA called plasmids, but they DO NOT contain protein.
In Eukaryote chromosomes, there is usually more than one chromosome. The chromosomes are found in the nucleus and are linear. Eukaryote chromosomes contain BOTH protein and DNA.
What is a Gene pool?
A Gene pool is the total of the genes carried by individuals of a population.
What is sickle cell Anemia?
a severe hereditary form of anaemia in which a mutated form of haemoglobin distorts the red blood cells into a crescent shape at low oxygen levels. It is commonest among those of African descent.
Explain the consequence of a base substitution mutation in relation to the processes of transcription and translation, using the example of sickle-cell anemia. (What mutation causes sickle cell Anemia?)
Sickle-cell anemia is caused by a base substitution mutation in the HBB gene. The hemoglobin protein responsible for delivering oxygen to the body is mutated in the beta chain out of the two alpha and beta chains. Instead of 6th amino acid being GAG, it is GTG, which causes the amino acid to be valine instead of glutamic acid.. This change causes hemoglobin to distort red blood cells into a sickle shape. These cells block capillaries, reducing oxygen delivery and causing the symptoms of sickle-cell anemia.
What are the symptoms of SCD?
The symptoms of sickle cell anemia are acute anemia such as physical fatigue, vision loss, lack of oxygen that is serve enough to damage heart and kidney, and swelling of hands and feet.
What are the selective advantages of SCD?
SCD is mainly common in African-Americans. African-Americans are also prone to Malaria; however, Plasmodium cannot reproduce in Erythrocytes, meaning that carriers of Sickle Cell are less prone to Malaria. This is a huge advantage to those in West Africa, as it means they have reduced chances of contracting Malaria.
How can you test to see if a fetus will have SCD?
Amniocentesis and Chorionic Villius sampling.
Is there a cure for SCD?
Yes, but they are risky. Treatments include blood/stem cell treatments and bone marrow transplant.
What is the purpose of Meiosis?
Produce Gametes.
