B2.2 Organelles and compartmentalization

Compartmentalization

The separation of of cellular components into compartments by either a single or doble membrane layer.

Benefits of compartmentalization during phagocytosis

Pathogens are engulfed by the formation of vacuoles using the plasma membrane. the membranes around the phagolysosome, formed from the fusion of the hago some and lysosome, provides an isolated environment for the digestion of the pathogen & prevents the spread of enzymes into the rest of the cell’s interior

Benefits of compartmentalization

• Allows for division of labor

• Enzymes and substrates involved in the same processes can be in close proximity to each other.

• Reactions can happen faster or more efficiently

• Organelles can be moved around the cell

• Lower chance of non-specific interactions

Role of Golgi apparatus and RER on protein synthesis

The RER produces proteins to be secreted and proteins for transport in the cells. the G.A processes and packages proteins for secretion.

Transcription and translation in euka. & proka. cells

In the euka. organisms, the DNA is separated from the cytoplasm by the nuclear membrane, whereas the genetic material of prokaryotes is within the cytoplasm. in euka., transcription occurs w/i the nucleus, while translation occurs in the cytoplasm. In proka., however, both processes occur in the cytoplasm (these don’t have a nucleus). Due to this lack of separation, both transcription and translation happen simultaneously in proka., while in euka., transcription must be completed first before translation can begin. This allows post-transcriptional modification in euka.

Ribosomes are the site of translation in both euka. and proka., however, 70s ribosomes carry it out in proka., & 80s ribosomes carry out translation in euka. During transcription, mRNA is synthesized in the 5’ to 3’ direction in both euka and proka, & both involve RNA polymerase.

Formation of vesicles

Vesicles are cell structures surrounded by a lipid villager that contain substances . Vesicles can be used to transport substances around cells, to release substances from cells and take substances into cells.

Similarities and differences b/w structure of RER & G.A

• Both are made up of flattened membrane areas

• RER has ribosomes bound to the outside of it, G.A does not