Question

1.If a cell were entering mitosis, how would you expect the rate of elongation as a function of monomer concentration to change for microtubules, intermediate filaments, and microfilaments? Please explain your answer.

2.

1. A cell is treated with cytochalasin. What effect would you predict this would have on the rate of elongation as a function of monomer concentration for microtubules, intermediate filaments and microfilaments? Please explain your answer.

3.

1. Suppose a mutation to the gene coding for actin made the T form more stable. What would this do microfilaments? Would you expect the mutation to be harmful? Please explain your answers.

Answer 1

1.Polymerization of actin monomers into filaments in concentration dependent. Below a certain concentration, actin monomers remain as monomers, but above a certain concentration monomers start to polymerize into filaments.actin filaments, like microtubules, are polarized with the ends having different biochemical properties. The plus end is more stable and is the end at which new monomer are added, so filaments grow from their plus end.Intermediate filaments (IFs) provide tensile strength to cells, as they resist stretching. In contrast to tubulin and actin, IFs comprise a large class of proteins that are expressed in a tissue-dependent manner. IFs are not polarized and do not support transport by motor proteins.Cell division begins along the cell's equator, between the two chromosomal pole formed duringnuclear division. Microfilaments help the cell lay down new membrane and divide into two daughter cells.Microfilaments are highways for myosin proteins that motor along the length of a strand, using the cell’s energy storage molecule, adenosine triphosphate, or ATP, as fuel. Myosin movement pinches one cell into two.