Lecture Five Flashcards
What is the cytoskeleton’s function?
It maintains the cell shape and the position of the organelles. It can rapidly assemble and disassemble, making it dynamic. This allows rapid changes in cell shape. Even though it is highly dynamic it still produces stability.
What are the 3 main components of the cytoskeleton?
Microtubules, intermediate filaments, microfilaments
What are microtubules made of and what is their function?
They are made of tubulin filaments, and is a cylindrical shape. They resist compression which allows them to maintain the cell shape. They are also used for cell motility in flagella and cilia. They are also used as ‘tracks’ for ATP powered motor proteins.
What are intermediate filaments made of and what is their function?
They are made of various proteins, and are supercoiled into cables. They are less dynamic than microtubules and microfilaments, and are used for more permanent structures that maintain cell shape and anchors organelles.
What are microfilaments made of and what is their function?
They are made of a double chain of actin, which can form either linear strands or 3-D networks. They resist tension, and make the cell shape less fluid (maintaining cell shape). Interactions between actin and motor proteins such as myosin support cell movement. This allows for muscle contraction.
What are the three cell joins?
Tight junctions, desmosomes, gap junctions
What are tight junctions?
Tight junctions hold neighbouring cells together, and can form a continuous seal. This prevents the movement of fluid across cell layers.
What are desmosomes?
Desmosomes are an anchoring junction, which provide attachments between sheets of cells. It is connected into the cell with intermediate filaments.
What are gap junctions?
Gap junctions are a connection that provides cytoplasmic contact between two cells. This means that small and large molecules can pass between the cells, which allows for rapid intercellular communication.
What type of protein is the ECM mostly made of? Why is it so good? Where are they?
Glycoprotein collagen, it resists tension. They are embedded in the proteoglycan complex matrix.
What are proteoglycans and what do they do?
They are proteins with lots of sugar chains, and has a jelly like consistency. They trap water, which resist compression.
What is a protein that attaches cells to the ECM?
Fibronectins
What is the membrane protein that connects the ECM to the cytoskeleton?
Integrins
