BIOL1003 Lecture Notes - Barramundi, Allosome, Aneuploidy
Mendelian genetics
The idea that everything was made up of cells was discovered rather early. It was also
observed that cells have a universal trait... They have something in the middle and
something on the outside. The nucleus and the cell wall or membrane.
When looking at cells for long enough there was some weir action occurring in the nuclei...
This was the first sign that the nucleus is important. They found that the nucleus breaks up
into easily stainable coloured bodies: chromosomes (legit means coloured bodies). These
chromosomes are only present during cell division
The GENE:
Mendel hypothesized that there was a factor that conveys traits from parents to off spring
(1860's)
Darwin used the phrase pangenesis
Shortened to Pangen in 1880 (pangen: the smallest particle representing one hereditary
characteristic.
The term gene was first used in 1909, which was used to describe one fundamental unit of
hereditary
Hunt Morgan (1910) discovered that genes can be found on chromosomes ... But he had no
idea what chromosomes where made of :(
He found this out by working on fruit fly's, where he was breading every strain separately
(eg blue eyes, white eyes etc.) and then he would squash them and look at their
chromosomes (fruit fly chromosomes bloat thus made it easier to see... He wouldn't be able
to see it with human chromosomes....
He stained the chromosomes with silver which reflected back electrons in electron
microscopes. This showed the gene bands. He then realised that a correlation with these
traits and the bands (genes)!!!
Ultimately a chromosome is a condensed form of proteins, and nucleic acids carrying
generic info... Visible ONLY during cell division...But what happens to chromosomes when
cells aren't dividing? It is relaxed and spread out and is called chromatin (the genetic
material when it is unwounded and spread through out the nucleus) . It is still made of
nucleic acid and proteins but just looks different as it is spread out.
Categorising chromosomes :
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
The idea that everything was made up of cells was discovered rather early. It was also observed that cells have a universal trait They have something in the middle and something on the outside. The nucleus and the cell wall or membrane. When looking at cells for long enough there was some weir action occurring in the nuclei This was the first sign that the nucleus is important. They found that the nucleus breaks up into easily stainable coloured bodies: chromosomes (legit means coloured bodies). These chromosomes are only present during cell division. Mendel hypothesized that there was a factor that conveys traits from parents to off spring (1860"s) Shortened to pangen in 1880 (pangen: the smallest particle representing one hereditary characteristic. The term gene was first used in 1909, which was used to describe one fundamental unit of hereditary. Hunt morgan (1910) discovered that genes can be found on chromosomes
