Cytoskeleton Flashcards
What is the cytoskeleton?
A network of filaments providing structural integrity to the cell
The cytoskeleton is used for…
…transportation within the cell
The cytoskeleton allows movement of …
… the cell and cellular projections
What is the cytoskeleton responsible for?
cellular polarity
The cytoskeleton is not always…
…permanent, can be rapidly remodelled even within permanent structures
Protofilaments are made up of …
…smaller subunits
protofilaments are built by…
…repetitive assembly of small soluble proteins
Protofilaments are weak…
…non-covalent interactions between monomers
Polymerisation and depolymerisation can be used to …
…do mechanical work
Distribution and behaviour regulated by …
…associated ‘accessory proteins’
Protofilaments are controlled by…
…extracellular and intracellular signals
Filaments are made of …
…protofilaments
Lateral bonds between protofilaments hold …
…filaments together
Arrangement depends on …
…the filament type
The eukaryotic cytoskeleton has …
…three major components
The eukaryotic cytoskeleton has three major components which are:
Microfilaments
Microtubules
Intermediate filaments
What colour are microfilaments?
Red
What colour are Microtubules?
Green
Narrowest type of microfilament?
7nm diameter
Microfilaments are …
…Actin monomers (G-actin), globular polypeptide
Microfilaments are polymers of…
…F-actin
Microfilaments are ATP/ADP…
…binding sites
How do microfilaments assemble?
Assemble head to tail, giving polarity
Two parallel protofilaments in a…
…right-handed helix
Microfilaments are crosslinked by …
…accessory proteins to form bundles, or networks
Polymerisation of microfilaments initiated by …
…actin related proteins (ARP)
Plus end of microfilaments gains more …
…monomers than it loses
Minus end of microfilaments loses …
…more monomers than it gains
Microfilaments have a […] structure, known as […]
Microfilaments have a DYNAMIC structure, known as TREADMILLING
ARPs found at …
…end of actin polymers, and can bind to side of other fibres, creating a web.
Examples of parallel bundles of microfilaments?
Microvilli
Muscle
Examples of mesh of microfilaments?
Lamellepodia
Actin-myosin interactions cause…
…contraction of the ring, resulting in separation of daughter cells.
Villi and Fibrin link …
…the actin fibres into tight bundles of 20-30 fibres
Myosin I connects…
… the actin to the plasma membrane
What is attached to the end of microfilaments?
A cap of proteins is attached to the end of microfilaments.
Actin microfilaments run…
…the entire length and support each microvillus
Cross linking actin-binding proteins link…
…microfilaments to eachother and to the plasma membrane