Cells and Organelles 1 Flashcards
What is the function of the plasma membrane?
Encloses the cell
What are the two different types of cells?
Eukaryotes
Prokaryotes
Describe prokaryotic cells
They are bacteria
All processes in cytosol, no internal membranes, nucleus absent
What three categories can eukaryotes organelles be sorted into?
Protein expression
Secretion pathway
Uptake and degradation
How is DNA packaged in prokaryotes?
In a nucleoid
No nuclear envelope
How is DNA packaged in eukaryotes?
Double membrane- nuclear envelope
How does mRNA in eukaryotes pass from the nucleus through the nuclear envelope?
Via nuclear pores
Where is mRNA decoded and proteins made on?
Specialised factories called ribosomes
What is DNA packaged as?
With histones to form chromatin
What are the two forms of chromatin?
Euchromatin and heterochromatin
What is the difference between euchromatin and heterochromatin?
Most active genes found in euchromatin
Heterochromatin is more dense
What is the function of ribosomes?
Decode mRNA message and convert it to linear polypeptides
Where are ribosomes made?
In the nucleolus
What two things can happen when a ribosome begins protein synthesis?
Can begin protein synthesis in the cytosol
Recognise a signalling gene moving the mRNA and ribosome to the ER where it binds to be apart of the RER
What is the function of the RER?
Main site of membrane synthesis in the cell
What is the main pathway of secretion?
RER to Golgi to Secretion/plasma membrane
What is the function of the Golgi?
Modifies lipids/proteins- grows sugar chains on proteins/adds phosphate to some proteins
Sorts and packages cargo into distinct vesicles for export to other organelles
What carries the cargo from the RER to the Golgi?
Vesicles
What are the functions of the RER?
Site of membrane synthesis
Modifies proteins- adds sugar chains
Quality control- monitors correct folding
Signals stress- when secretion is blocked
What is the structure of the Golgi?
Golgi complex is made of stacks of flattened sacs
What process is used to secrete proteins outside the cell?
Exocytosis
