Topic 3: Non-membranous organelles Flashcards
1
Q
Name 3 of the non-membranous organelles.
A
- ribosomes
- centrosomes
- cytoskeleton
2
Q
What are the function of ribosomes?
A
- sites for protein synthesis (translation)
3
Q
What are the components of ribosomes? (2)
A
- rRNA and proteins
4
Q
Where are ribosomes located?
A
- free in cytosol
- attached to the ER
5
Q
What do ribosomes that are free in cytosol do?
A
- make proteins destined for cytosol, mitochondria and nucleus
6
Q
What do ribosomes attached to the ER do?
A
- make proteins destined for all other sites
7
Q
What are centrosomes?
A
dense area of cytoplasm
8
Q
What do centrosomes contain?
A
- usually contains 2 centrioles (function uncertain - some cells lack them)
- also has the pericentriolar matrix
9
Q
What is the function of centrosomes?
A
- organizes microtubules of cytoskeleton and spindle apparatus (for cell division)
10
Q
What is the cytoskeleton and how are they formed?
A
- ALL types support cell shape and are formed from proteins
11
Q
What is the function of the cytoskeleton? (3)
A
- important in cell movement
- cell division
- movement and anchoring of organelles + proteins (e.g. receptors, enzymes)
12
Q
What are the three types of cytoskeleton??
A
- microfilaments
- intermediate filaments
- microtubules
13
Q
What are microfilaments made of and what is their size?
A
made of actin
- smaller ones
14
Q
What are the functions of microfilaments? (3)
A
- muscle contraction (with myosin)
- maintenance of cell shape and projections (e.g. microvilli)
- cytokinesis (separates cytoplasm)
15
Q
What is the composition of intermediate filaments, and what is their function?
A
- composition is tissue specific e.g. keratin
- supports the cytoplasm (scaffolding for the cell)
- note that the size of intermediate filaments is in between the other two
