Standard 1j Preknowledge
1j) ***Students know how eukaryotic cells are given shape and internal organization by a cytoskeleton or cell wall or both.
CALIFORNIA FRAMEWORKS SUMMARY:
The cytoskeleton, which gives shape to and organizes eukaryotic cells, is composed of fine protein threads called microfilaments and thin protein tubes called microtubules. Cilia and flagella are composed of microtubules arranged in the 9 + 2 arrangement, in which nine pairs of microtubules surround two single microtubules. The rapid assembly and disassembly of microtubules and microfilaments and their capacity to slide past one another enable cells to move, as observed in white blood cells and amoebae, and also account for movement of organelles within the cell. Students can observe prepared slides of plant mitosis in an onion root tip to see the microtubules that make up the spindle apparatus. Prepared slides of white fish blastula reveal animal spindle apparatus and centrioles, both of which are composed of microtubules.