BIOL1003 Lecture Notes - Lecture 10: Centromere, Pangenesis, Afrocentrism
The chromosome
• It was observed under the first microscopes that all organisms were made of cells
• It was also observed that al cells have black dots in them. This was called the nucleus
• Dividing cells scramble all their internal bits and them put them together again
• The nucleus breaks up to form dark easily stainable coloured bodies- chromosomes
• Chromosomes can only be seen during cell division
The gene
• Mendel hypothesised a factor that conveys traits from parent to offspring
• Darwin used the phrase ‘pangenesis’
• shortened o ‘pangen’
Genes and chromosomes
• Through the observation of cell division and mapping of chromosomal bands he
determined that they correlated to inherited traits, Morgan established in 1910 that
genes can be found on chromosomes
• He had no idea what chromosomes were made out of
Chromosome
• It is a condensed form of proteins and nucleus acids carrying genetic information,
visible only during cell division
Chromatin
• When the cell is not dividing: it is relaxed, spread out in the nucleus and called
chromatin. It is still made of nucleus acids and proteins but looks different
•
•
• metrocentric- centromere in the middle, afrocentric chromosome- centromere is
severely offset from the middle, telocentric- centromere at the very end of the
chromosome
Caryotype
• Description of chromosomes in an organism
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Document Summary
The chromosome: it was observed under the first microscopes that all organisms were made of cells, it was also observed that al cells have black dots in them. This was called the nucleus: dividing cells scramble all their internal bits and them put them together again, the nucleus breaks up to form dark easily stainable coloured bodies- chromosomes, chromosomes can only be seen during cell division. The gene: mendel hypothesised a factor that conveys traits from parent to offspring, darwin used the phrase pangenesis", shortened o pangen". Chromosome: it is a condensed form of proteins and nucleus acids carrying genetic information, visible only during cell division. Chromatin: when the cell is not dividing: it is relaxed, spread out in the nucleus and called chromatin. It is still made of nucleus acids and proteins but looks different: metrocentric- centromere in the middle, afrocentric chromosome- centromere is severely offset from the middle, telocentric- centromere at the very end of the chromosome.