Organelles II Flashcards
______ are the most dynamic cytoskeleton.
Microtubules
_____ is the protein that makes up microfilaments
Actin
Actin binds to ____ to polymerized and form microfilaments. Unpolymerized actin monomer is soluble and called ____. Polymerized actin is called ___ and forms microfilaments. _____ ____ proteins are responsible for actin changes.
ATP
G actin
F actin
Actin associated
Microfilaments have ___. It is easier for G-actin (actin monomers) to be added to the ____ end and removed from the ____ end.
Polarity
Positive
Negative
Microfilaments are usually on the _____ of the cell and interacts with the plasma membrane. They participate in the formation of specialized epithelial cell appendages, such as ____ and ___.
Periphery
Microvilli
Filopodia
_____ is a meshwork formed from microfilaments found in specialized cells.
Lamellipodium
Microfilaments form a ____ in a dividing cell.
Cleavage furrow
Numerous actin associated proteins influence microfilament organization and function. For example ____ cross links microfilaments into parallel bundles. _____ cross links filaments to allow for 3D network formation.
Fimbrin
Filamin
Microfilament-membrane linkages play a key role in cell function. _____ proteins and ____ link microfilaments to the plasma membrane. _____ links microfilaments with the plasma membranes in muscle cells
ERM
Vinculin
Dystophrin
Linking/anchoring proteins are usually _____ proteins.
Transmembrane
_____ family GTPases are master regulators of the actin cytoskeleton. They modulate the activity of numerous _____ ____ proteins, including a number of protein kinases.
Rho
Actin associated
_____ ____ polymerize to form bipolar fibers, there long tails wrap around each other in an antiparallel orientation. This allows them to pull microfilaments past each other, used in ____ contraction. Unconventional myosin’s bind to different ____ in the cytoplasm and participate in vesicular trafficking.
Type II myosins
Muscle
Cargo
What are the main functions of microfilaments?
- Support plasma membrane
- strengthens cell to cell adhesion
- support microvilli
- physically interconnects the plasma membrane, cytoplasm, extra cellular matrix, and nucleus
- Interacts with myosin
- Drives cytokinesis during cell division
_____ has GTPase activity and polymerizes into microtubules. ____ and ____ tubulin bind to form dimers which then polymerize into microtubules. The beta end forms the _____ side of the tubule and the alpha end forms the ____ side.
Tubulin
Alpha
Beta
Positive
Negative
_____ _____ is the tendency for microtubules to polymerize and depolymerize
Dynamic instability
It is easier for tubulin to add to the ____ end and be removed from the _____ end.
Positive
Negative
A _____ protects and anchors the microtubules negative end, leaving the positive end free in the cytoplasm. This is the dominant factor in the _____ of microtubules.
Centrosome
Organization
When _____ binds to the heterodimer, it will be added to the microtubule. When _____ binds to the heterodimer, it will be released.
GTP
GDP
Centrosomes are composed of _____, a short cylinder composed of 9 microtubules. The _______ _____ surrounds the centrioles, contains TURCs which nucleate microtubule polymerization.
Centrioles
Pericentriolar material (PCM)
____ ____ is a form of centrosome during cell replication.
Spindle poles