Some Bacteria undergo Endosymbiosis making more complex cells
4000 Billion Years ago the first living cells existed
Over time changes occur to the ancient Bacteria and Archaebacteria
Simple Bacteria still exist
At some stage a Bacteria absorbed another bacteria but did not digest it
This was the Endosymbiosis event
This occured 2500 Million Years ago
Endosymbiosis gave rise to individual organelles within a cell
This allowed more complex life-forms to evolve
Fistly Protists - Single celled organisms that contain organelles
Change continues to drive Evolution
More Complex cells are Larger
These new more complex cells are larger than bacteria, as seen in the picture below of a bacteria next to a Red Blood Cell, and in the YouTube clip of a White Blood Cell chasing Bacteria. This is also shown in the sizes in micrometers of the cell sizes for each of 4 Kingdoms in the picture further below
Bacteria vs Plant Cells vs Animal Cells
T
he image to the side has bacterial cell way larger than it should be compared to the other two relatively huge cell
The simple Bacteria is referred to as a Prokaryote
Only Archaea and Bacteria are Prokaryotes
The complex Animal and Plant cells (as well as Protists and Fungi) are Eukaryotes
The inclusion of organelles resulted in longer lived cells capable of greater complexity of life
Notice the number of organelles that both animal cells and plant cells have
Notice also the differences
Everything an animal cell has, a plant cell also has, however, plant cells have things that animal cells don't. This is because of photosynthesis and amino acid synthesis
Plants are autotrophes -this means they make their own food - all they need is Carbon Dioxide, Water and Sunlight - this makes Glucose and Oxygen
Using the Carbon from the Glucose, they can then make every single other biological molecule, including Simple and Complex Carbohydrates, Lipids, Nucleotides and all of the Amino Acid
Animals on the other hand, need to eat living things in order to get their food. These living things could be other Animals or Plants
The term 'essential amino acids' is a misnomer - all amino acids are essential - however human cells can make some of these from other materials - the essential amino acids are essential for us because we can not make them - we need to eat them - It is plants that make them - This is called Amino Acid Synthesis
A few relevant and interesting clips