What do eukaryotic chromosomes form the basic structure of?
The nucleosome and packed together to form chromatin
What are eukaryotic chromosome consist of?
DNA wrapped around histone proteins
Eukaryotic chromosomes consist of DNA packed around histone proteins which is packed together to form chromatin- what does chromatin do during prophase and what does this allow?
Chromatin will supercool and condense during prophase which forms chromosomes that can be visualised under microscope
Eukaryotic Has had DNA wrapped around proteins prokaryotic have?
Nothing wrapped around it=’naked’
Definition of a gene
Unit of inheritance
Section of DNA that codes for protein
Definition of an allele
Different versions of the same gene
Definition of genome
Whole genetic information of an organism
Definition of gene mutation
Change in the nucleotide sequence of a section of DNA coding for a particular feature
What is the cause of sickle cell anaemia? And what does it do?
-base substitution mutation is a change of a single base sequence of DNA
What does base substitution result in?
A change in a single mRNA condon during transcription
In sickle cell anaemia what is the codon that is changed to result in the disease?
The 6th codon for the beta chain of haemoglobin is changed from GAG to GTG
The change of GAG to GTG goes what regarding S.C.A?
Causes a change in mRNA codon (GAG to GUG) resulting in a single amino acid change of glutamic acid to valine (Glu to Val)
So what does DNA change to?
What does mRNA change to?
What does amino acid change to?
All regard sickle cell anaemia
DNA = GAG to GTG
mRNA= GAG to GUG
Amino acid= Glu to Val
What does the amino acid alter?
Regarding sickle cell anaemia
Alters shape of haemoglobin –> forms fibrous, insoluble strands–> red blood cells adopt a sickle cell shape
What are the 3 bad consequences of sickle cell anaemia?
- insoluble haemoglobin chat effectively carry oxygen= weakness, shortness of breath and tiredness
- sickle cells may accumulate in the capillaries and form clots, blocking blood supply to vital organs and causing health problems
- causes anaemia (low RBC) as cells are destroyed more rapidly than normal RBC
Who does sickle cell anaemia occur in? One is one benefit of being a carrier?
- it occurs in individualsb who have 2 copies of the co-dominant sickle cell allele
- heterozygous carriers have increased resistance to malaria