Eukaryotic Chromosomes are made of DNA that wrap around histone proteins. These will be packed together to form chromatin which is the basic structure of the nucleosome. During prophase, these chromatin will condense to form chromosomes visible under a light microscope. Prokaryotic chromosomes are considered to be naked because there are no proteins used.
Gene: factor that controls the characteristic of the offspring passed on from the parent
Allele: a form of the gene that can differ from other alleles by one or a few bases. Alleles for the same gene will occupy the same locus
Gene Mutation: Changes experienced by the sequence of nucleotides (gene) that code for DNA. Mutations can be caused by mutagens such as radiation, chemicals or by mistakes during cell replication
Point Mutation: A single nucleotide is replaced with another
Insertions: addition of one or more nucleotides
Deletion: removal of one or more nucleotides
Gene duplication/deletion: large segments of the chromosome are replicated or deleted
Inversion: chromosomes are found to be rotated 180 degrees
Translocation: parts of the chromosome are moved to another chromosome
Many mutations will only cause minor differences, but others can be extremely noticeable. New characteristics can be made with mutations, some harmful others beneficial.
Sickle Cell Anaemia is the result of a single base that has been changed to alter a mRNA codon found in transcription. The mRNA codon will code for a different amino acid and the formation of a different protein as well. The protein alters the structure of hemoglobin and red bloods into a sickle shape
The structure of the hemoglobin renders it insoluble and can no longer effectively carry oxygen. Patients will feel more tired due to the lack of oxygen. The sickle shaped blood cells can create blood clots that can cause many problems. These blood cells will also die more quickly resulting in a low red blood cell count. Sickle cell anaemia will only occur in people who are homozyous for the codominant allele. Those that are heterozygous will be resistant to malaria because of the one sickle cell allele.
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