Lecture 4 Flashcards
What is the role of the Endoplasmic reticulum
To synthesise proteins.
What are the two parts of the Endoplasmic reticulum? How can we differentiate them
Smooth ER and Rough ER.
The rough ER has ribosomes that make it look rough
What does the smooth ER do?
Metabolizes carbohydrates
Lipids synthesis for membranes
Detoxification of drugs and poison
Stores calcium
What are the functions of the Rough ER
Involved in protein synthesis
Secreted and membrane bound proteins enter the lumen and are processed by the rER. (and the rest of the endomembrane system) for release from the cell or retention on the cell membrane
What is the lumen?
The space inside of the rough ER
What are the functions of the Golgi complex
Receives, modifies, sorts and ships proteins arriving from the rER
Glycosylation
Produces polysaccharides which may also be
secreted from the cell e.g. pectin &
hemicellulose
What is the Golgi complex
A series of flattened sacks or membrane enclosed areas and associated vesicles
Where do vesicles arrive and leave from the Golgi complex?
Vesicles from endoplasmic
reticulum arrive at the cis face
Vesicles will then fuse with the Golgi
Processed vesicles will leave at the trans face
Why do we say the Golgi has polarity
Because it has two sides to it, a cis side and a trans side
What is glycolysation?
Adding or modifying carbohydrates on a protein
How is adding or modifying carbohydrates on a protein important?
To ensure proteins are equipped to work to their best function.
Eg. Cell recognition or other functions
How does the Golgi complex sort proteins
They add molecular markers to direct proteins to the correct vesicles before “budding” from the trans face
What is a vesicle?
A membrane bound bubble
What are liposomes
Liposomes are artificial vesicles that can be used for drug and vaccine delivery
What is exocytosis? Is this a bulk transport or a membrane trasnport?
The process of releasing stuff out of the cell. This is a type of bulk transport
What are the two types of Exocytosis
Constitutive exocytosis
Regulated exocytosis
What is Constitutive exocytosis
Releases ECM proteins
What is Regulated exocytosis
Releases hormones and neurotransmitters. This only happens on demand
What is Endocytosis
The taking up of molecules and particulate matter outside the cell and bringing them in at the plasma membrane. This is a bulk transport
What is phagocytosis
Cells ‘eating’
What is a pseudopodium and what is its function
It is a ‘fake arm’ that wraps around target particles. This encloses them to form a phagocytic vacuole which is digested by the lysosomes
What is pinocytosis
cell ‘drinking’. The uptake of extracellular fluid containing various solutes such as protein and sugars.
THIS UPTAKE IS NON-SELECTIVE
How do cells facilitated more selective pinocytosis?
Through receptor-mediated endocytosis. This is a specialised form of pinocytosis.
What do receptor proteins do in receptor-mediated pinocytosis
They are used to selectively capture the required solute.
This is useful as it may be present at low concentrations in the Extracellular fluid
