Lec. 7: cytoskeleton, mitochondria, chlorplasts, ECM, peroxisomes Flashcards
1
Q
Cytoskeleton
A
- A network of fibers, extending throughout cytoplasm
- Provide structural support
- Motility (interaction with motor proteins) for movement
- Not static (can assemble/disassemble)
and nucleus for IF
2
Q
Difference between (MT, MF) and IF
A
MT and MF have a + and - end and can rapidly assemble and disassemble while IF are more stable
3
Q
Microfilaments
Location, structure, how it works, assembly-dissasembly, functions
A
- Two intertwined strands of actin with solid rods
- In the cytoplasmic mesh
- Subunits added to positive end, Subunits subtracted at negative end
- Cell shape, intracellular transport over SHORT distances with myosin
- Cell motility (crawling)
- Contraction of muscle: actin and myosin
4
Q
Intermediate filaments
Shape, Function, Location
A
- supercoiled into thick cables
- Cell shape, resist tension
- In nucleus
- Cell and nuclear anchorage
- formation of nuclear lamina
5
Q
What is the result of lamin mutations
A
- Accelerated aging in humans due to alterations in nuclear disassembly and assembly during division, abnormal nucleus, and defective chromosomal organization
6
Q
Microtubules
Structure and Function
A
- hollow cylindrical rods
- made of tubulin dimers (polar)
- Cytoplasmic tubules grow out from centrosome (+ end grows)
- Cell shape and organization
- Track for movement for LONG DISTANCES
- required interaction with motor proteins (kinesins move toward + end of MT and dyneins move toward - end of MT)
7
Q
Microtubules in cilia and flagella
A
ATP energy required
- Function in movement of appendages
- Can move cells from one place to another or move fluid over tissue
8
Q
Extracellular matrix
A
- Animal tissues have a complex ECM made of glycoproteins (secreted by cells) such as collagen fibers
- Integrins in the plasma membrane link ECM proteins such as fibroconectin with the cellular cytoskeleton facilitating crosstalk between cell and environment
9
Q
Mitochondria/chloroplasts
Roles, location,
A
- Responsible for energy transformation in cell
- Enclosed in membranes but NOT part of cell’s endomembrane system
- Can grow and reproduce within cell
- Location not static (move around cytoplasm using cytoskelton)
Mitochondria in ALL eukaryotic cells, choroplasts only in plant cells
10
Q
Peroxisomes
A
- Membrane bound organelle formed by proteins and lipids
- break down fatty acids and detox alcohol/poisons
- byproduct is H2O2 (hydrogen peroxide) which is toxic and converts it to H2O