The very first level of classification...
'karyote' = 'kernal' or 'seed'
- The main difference between prokaryotes and eukaryotes is the presence/absence of a nucleus.
- The "kernal" is referring to the nucleus.
- Pro means before (before the nucleus)
- Eu means with (with a nucleus)
Prokaryotes
Figure: a) generalsised diagram of a prokaryotic cell, b) a line diagram of a prokaryotic cell.
Split into TWO domains: Archaea and Bacteria
Size 1–10 µm in length and 0.2–2.0 µm in diameter
Cytoplasm is made up of cytosol fluid together with cell organelles.
Ribosomes build up (synthesise) proteins from amino acids
Genetic material in a single circular chromosome.
Split into TWO domains: Archaea and Bacteria
Size 1–10 µm in length and 0.2–2.0 µm in diameter
Cytoplasm is made up of cytosol fluid together with cell organelles.
Ribosomes build up (synthesise) proteins from amino acids
Genetic material in a single circular chromosome.
- Direct contact with the cytoplasm – no nuclear membrane.
- Carry instructions for protein synthesis
- May contain extra numerous small rings of DNA, called plasmids. These can reproduce independently of the main chromosome.
- These extra pieces of DNA often provide the cell with some genetic advantages e.g. antibiotic resistance.
Eukaryotes
Split into:
Size 10–100mm in length and 0.2–2.0mm in diameter.
Membrane-bound organelles in separate compartments
Cytoplasm is made up of cytosol fluid and cell organelles
Ribosomes build (synthesise) proteins from amino acids
Has specialized structures such as the endoplasmic reticulum is where protein is modified and transported.
Membrane-bound nucleus contains DNA
- One Domain: Eucarya
- 4 Families: Animals, Plants, Fungi, Protists
Size 10–100mm in length and 0.2–2.0mm in diameter.
Membrane-bound organelles in separate compartments
Cytoplasm is made up of cytosol fluid and cell organelles
Ribosomes build (synthesise) proteins from amino acids
Has specialized structures such as the endoplasmic reticulum is where protein is modified and transported.
Membrane-bound nucleus contains DNA