MCB Lecture 30 Cytosol Flashcards
Describe the membrane structure of organelles
Single lipid bilayer from the same design plan
Describe the cytosol
It is the interior of the cell membrane
The cell is very crowded, so there is not much cytosol
Describe the design plan of organelles, and what this means for transport between them
The organelles have the same design plan. This means that one organelle can turn into another by budding and forming vesicles.
Also, transport between organelles is simple: vesicular transport
Extracellular space is topologically equivalent to …
The lumen of organelles
Describe how molecules are transported between organelles
Budding and fusion of vesicles
Which organelles have two lipid Bilayers?
Nucleus, mitochrondria, chloroplasts
Describe the evolution of a nucleus
DNA was present in the cytosol (like prokarya), then it became surrounded by a membrane that split off from the plasma membrane
The nuclear intermembrane space is continuous with …?
The rough endoplasmic reticulum
The nuclear innermembrane space is continuous with …?
The cell cytosol
Describe the evolution of mitochondria
An aerobic bacterium was engulfed by the cell into a vesicle. It has remained in this vesicle
Which proteins are involved with the cytoskeleton?
Motor proteins
The structure itself, eg. actin
Which proteins are associated with the nucleus?
Transcription factors, spliceosome
Which proteins are associated with the cell membrane?
Transporters
Receptors
Channels
Which proteins are associated with the mitochondria?
The complexes on the inner membrane involved with the electron transport chain
Which proteins are associated with the endoplasmic reticulum?
Ribosomes
Translocators
Chaperones
Which proteins are associated with the Golgi apparatus?
Many enzymes for all the modifications that go on
Which proteins are associated with the lysosomes?
Lysosomal enzymes
Which proteins are secreted?
Eg. Insulin, collagen
Where does protein synthesis begin?
On a ribosome in the cytosol
What are the two challenges of protein trafficking?
- Access to a compartment
2. Targeting to a compartment
What are the three mechanisms of transport of molecules around the cell?
- Gated
- Transmembrane transport
- Vesicular transport
Where does gated transport occur?
Nucleus <-> cytosol
Where does transmembrane transport occur? What does it require?
From the cytosol to the mitochondria, peroxisomes and ER
Where does vesicular transport occur?
Between organelles
