cellulose fibers are embedded in other sugars and proteins barrier and contributes to plant shape

extracellular structures

• many animal cells are surrounded by extracellular matrix; collagen; embedded in gel-like glycoproteins + other proteins
• holds cells together in tissue group of cells with the same function)
• contributes to bone, cartilage, skin
• filters materials passing through different tissues
• navigates cell movements in tissue repair
• cell communication

study chemistry/recap

• 2 protons + 2 neutrons = atomic num
• atomic weight avg of mass num of isotopes in their normal occurring proportions

isotopes

• form an element with different numbers of neutrons ; different mass numbers
• some isotopes are unstable radioisotopes