cytoskeleton Flashcards
what is a cytoskeleton and it’s function
- it is a network of protein polymers that:
- provide mechanical support for the cell to maintain shape
- involved in cell movement and cell division.
- the cytoskeleton protein are made up of thousands of subunits and are characterised as DYNAMIC (always assembling and disassembling)
- used as a transport network - moves organelles and vesicles around inside of the cell
- gives cells it’s structure: cells make tissues therefore also giving tissue structure
what are the three types of cytoskeleton polymers
- actin filaments
- intermediate filaments
- microtubules
where are actin filaments found and structure of actin filaments
- concentrated beneath the cell membrane and are everywhere in the eukaryotic cells
- narrow
- flexible
- highly organised and form cytoplasmic extensions eg. microvilli
what processes is actin involved with
- phagocytosis
- cytokinesis (splitting of a cell into two during cell division)
- muscle contraction
monomer and polymer of actin
- monomer: G (globular) actin
- polymer: F (filamentous) actin
actin and myosin work together
what does myosin do
- myosin proteins are molecular motor proteins
- that use ATP to generate force along actin filaments, allowing muscle contraction
examples of intermediate filaments
- keratin
keratin forms the top layer of skin along with hair
function and structure of intermediate filaments
- made up of high tensile strength ‘rope like’ filaments
- widely distributed
- mechanical strength
- helps with tissue structure
what is a heteroploymer and type 1 and type 11 keratin protein
- heteropolymer - made up of two or more proteins that come together to form the polymer
type 1 and type 11 - particular type that tell you where you are in the body and what’s cells are doing eg. differentiation status
three step process of immunohistochemistry
- incubate section of tissue with an antibody to a particular protein
- primary antibody binds to antigen
- secondary antibody binds to primary antibody
- enzyme linked to secondary antibody converts substrate to a coloured product
- tells u where the protein is in the tissue
keratin mutation
- mutation in keratin 14 or keratin 5
- keratin is involved in structure of cells and tissue therefore a mutation can lead to cell tissue fragility
- leads to blistering
function and structure to microtubules
- hollow, rigid polymers of tubule and provide cell with the strongest resistance to compression
- built of two different types of protein
- long and straight - one end attached to centromere
- each cell organisation fo microtubules differ and have a huge role in mitosis and and reorganise to form the mitotic spindle along with the microtubule - dependent motor proteins (dynein)
what are cilia and flagella made from and function
- long bundles of microtubules and molecular motors
- cilia moves mucus and debris out of the airway - the motor and tubules generate that force
what are molecular motors
- proteins - enzymes that generate force and ‘walk’ along microtubules
- kinesins and dyneins are examples of molecular motors that use microtubules
- requires atp
how do actin and microtubules work together
- they work together in cell migration and cell division
- microtubules have an influence on assembly of actin and can be bound together by linker protein
- indirect signalling between each other
- microtubules pulls chromosomes apart and actin contracts to separate the two cells
