| A | B |
|---|
| nucleus | control center that contains the genetic material |
| nuclear envelope | the second layer around the nucleus |
| nuclear pores | holes through which materials move in and out of the nucleus |
| nucleoli | site where ribosomes are assembled |
| chromatin | DNA is combined with protein and forms a loose network of bumpy threads |
| chromosomes | chromatin threads coil and condense to form dense rod like structures |
| lysosomes | bags containing powerful digestive enzymes |
| peroxisomes | membrane sacs containing powerful oxidase enzymes that use molecular oxygen to detoxify a number of harmful substances |
| free radicals | highly active chemicals with unpaired electrons that scramble the structure of proteins and nucleic acid |
| cytoskeleton | act as a cells "bones and muscles" |
| intermediate filaments | help form desmosomes and provide internal guy wires to resist pulling fores on a cell |
| microfilaments | involved in cell motility and in producing changes in a cell shape |
| microtubles | determine the overall shape of a cell and the distribution of organelles |
| centrioles | generate microtubles and during cell division direct the formation of the mitotic spindle |
| cilia | tiny hairlike projections on cell surfaces |
| flagella | long, whiplike extensions of the cell membrane on bacteria and sperm |
| cytosol | semitransparent fluid that suspends nutrients and other solutes |
| desmosomes | anchoring junctions that prevent cells from being pulled apart |
| gap junctions | allow communication through the connexons |
| tight junctions | impermeable junctions that bind cells into leakproof sheets |
| cytoplasm | cellular material outside the nucleus but inside the plasma membrane |
| endoplasmic reticulum | fluid filled canals that carry substances from one part of a cell to another |
| Golgi aparatus | stack of flattened sacs that modifies & packages proteins |
| secretory vesicles | swollen ends of the Golgi apparatus that carry proteins to the plasma membrane |
| mitochondria | convert food into ATP |
| inclusions | stored nutrients or cell products |
| microvilli | fingerlike projections that increase a cell's surface area |
| ribosomes | site of protein synthesis |
