Cells
are surrounded by cell membrane-layered structure made up of
lipids&proteins-lipoprotein,called plasmalemma.Electrostatic
attraction,selectively permeable
Firmness
is due to turgor pressure(water pushing out),the strength of cell
wall,efficiency of adjacent cell placement.Wall is microfibrils embedded by
pectin to matrix
Pectin
is most easily affected.It consists of galacturonic acid&little rhamnose.If
acid is ester matrix is weaker.When heated pectin becomes H2O soluble
Animal
muscles
Skeletal(normal),cardiac(heart),smooth(surrounds
organs)
Connective
tissue proteins contributing to structure are collagen(polypeptide chains in
triple helix that stand side by side to form fibrils)and elastin(can roll like
ball)
Each
muscle fibre consist of myofibrils |actin(I)myosin(A)actin|zline|sacromere|
A-thick
filaments of myosin polymer(connected to Z by titin),I-thin filaments of actin
When
animal dies rigor mortis occurs,so it is allowed to stand couple of
days(tenderisation due to enzyme calpain or added papain(found in fruits)