Compartmentalization of Cells

Question 1

How did the nucleus get formed?

Answer 1

invagination? the membrane begins to increasingly enclose the chromosomes in order to protect it.

Question 2

how did the ER form?

Answer 2

invagination? as the membrane begins to enclose the chromosomes it also has membrane bound ribosomes attached that branch off inside the cell and form the ER attached to the nucleus

Question 3

how did the mitochondria form?

Answer 3

endosymbiosis. mitochondria are descended from aerobic, bacteria like cells that were engulfed into the early eukaryote via endosymbiosis.

Question 4

Horizontal gene transfer

Answer 4

gene transfer between bacteria via

1. natural transformation by released naked DNA
2. transduction by bacteriophages (viruses)
3. sexual exchange
4. phagocytosis

Question 5

is the amount of each organelle universal across all cells?

Answer 5

no. depending on cell function the amount of each organelle will vary.

Question 6

topological equivalence definition and importance

Answer 6

spaces that are equivalent in environment so that molecules can move from one space to another without having to cross a membrane. Could be explained by invaginations