2.2.3 Mitochondria & chloroplasts

Mitochondria structure:

Chloroplast structure:

2.2.4 The cytoskeleton & cell wall help to maintain cell shape

Centrosomes & centrioles

Cytoskeleton: support and motility

1. microtubules 微管 25nm

microtubules have hollow structures, commonly used in shaping cells, guiding movements and separating chromosomes (eg. 马达蛋白沿着微管走)

https://puui.qpic.cn/vpic_cover/q0799vsiiyu/q0799vsiiyu_hz.jpg/1280

1. microfilaments 微丝 7nm

microfilaments have twisted double chain (has monomers), it is also used for guiding movements and separating chromosomes (eg. 细胞质缢裂)

1. Intermediate filaments 中间纤维 8-20nm

Intermediate filaments are used for fixing(固定) organelles

Cell wall细胞壁

In prokaryotes, fungi(在真菌中由肽聚糖构成), some protists and plant cells(植物细胞中由纤维素构成)