Eukaryotic organelles

Eukaryotic organelles are not present in prokaryotes. For example, prokaryotes lack a nucleus; eukaryotes have a nucleus.

Organelle

Role

Membranes

Nucleus

Contain & protect DNA. Site of transcription and partial assembly of ribosomes. Nucleus is where transcription, replication, and storage of DNA occurs.

Mitochondria

Produce ATP via Krebs Cycle and oxidative phosphorylation. Mitochondria synthesize ATP. They have their own genome. According to the endosymbiotic theory of evolution, mitochondria were prokaryotes which were engulfed by a nucleated cell and a symbiosis was formed. Mitochondria are maternal, meaning that you get your mitochondria from your mother. They can therefore be used for maternal testing.

Ribosomes

Synthesize proteins

Endoplasmic reticulum

Endoplasmic reticulum is an extension of the nuclear membrane.

Rough Endoplasmic Reticulum (RER)	Synthesis & modification of secretory, membrane-bound & organelle proteins. Rough ER, via ribosomes, produces glycoproteins and new membrane material.	1
Smooth Endoplasmic Reticulum (SER)	Detoxification & glycogen breakdown in liver; steroid synthesis in gonads. Smooth ER involved in lipid synthesis and CHO metabolism.	1

Golgi Apparatus

Modification & sorting of protein, some protein synthesis. Golgi apparatus is used for packaging. If a moiety needs to be transported within our outside the cell, the golgi apparatus will prepare it. There are three kinds of Golgi appartus: cis, medial, and trans.

Lysosomes

Contain acid hydrolases which digest various substances. Lysosomes process cell waste. They have an innate pH of 2 (relatively low) and degrade nonfunctional proteins.

Peroxisomes

Metabolize lipids & toxins using H₂O₂ (peroxide). Peroxisomes enzymatically produce and degrade H₂O₂ (hydrogen peroxide).