Exam 3 Part 2

Question 1

myosin I

Answer 1

actin dependent, mediates contraction, moves vesicles, and allows contraction of the membrane
moves to + end, hops along actin or hops to move the actin

Question 2

myosin II

Answer 2

involved in actin mediated contractions (muscle cells)

2 myosin heads walk along 2 actin filaments to move the actin

Question 3

sarcomeres

Answer 3

contracile units of muscle

myosin pulls actin filaments together

Question 4

myofibrils

Answer 4

bundle of sarcomeres

Question 5

contraction of muscle

Answer 5

ATP binds to myosin head, hydrolysis of ATP causes myosin head to move (power stroke)

Question 6

sacroplasmic reticulum

Answer 6

holds Ca2+ in muscle cells

Question 7

plasma membrane of muscle cells

Answer 7

close to the sarcomeres

Question 8

regulation of contraction

Answer 8

tropomyosin blocks the myosin-binding site on actin, Ca2+ changes actin’s conformation and kicks off tropomyosin so that myosin can bind to actin to contract

Question 9

extracellular matrix

Answer 9

provides tensile strength, structural suppor, flexibility, shock absorption, cue for cell growth/development

Question 10

collagen

Answer 10

ECM tensile strength, diverse family of proteins, 25% of all protein in body

Question 11

procollagen

Answer 11

precursor to collegen made in cells, then exported to matrix

Question 12

fibroblast cell

Answer 12

makes protcollagen and organizes collagen around itself in layers

Question 13

cells and the matrix

Answer 13

cells shape the matrix and align collagen fibers

Question 14

fibronectin

Answer 14

bridge between collagen and the cell
binds to collage and integrin
integrin transpans the membrane and anchors the collagen fiber to actin in the cell