7.2 Inside the Eukaryotic Cell I. The Framework of the Cell A. Cytoskeleton 1. Helps the cell move, keep its shape, & organize its parts. 2. Made up of three fibers a. microfilaments, microtubules, & intermediate fibers II. Directing Cellular Activity A. Nucleus 1. Nuclear envelope – double membrane surrounding the nucleus a. Has many small pores that allow molecules to move in & out

B. Ribosomes 1. Made up of RNA & many proteins 2. Can switch between “free” or “bound” III. Protein Processing A. Vesicles 1. small, spherical shaped sac that is formed by a membrane B. Endoplasmic Reticulum 1. System of internal membranes that moves proteins & other substances through the cell 2. The ER is connected to the nuclear envelope 3. Rough ER a. bumpy appearance under an electron microscope, bumps are ribosomes 4. Smooth ER a. has no attached ribosomes C. Golgi Apparatus 1. Modifies, sorts, & packages cell products

IV. Storage & Maintenance A. Lysosome – digest cell’s food, digest old, damaged, or unused organelles B. Central Vacuole 1. Found in plants 2. Stores water, ions, nutrients, wastes, toxins, & pigments C. Contractile Vacuole 1. Pump excess water out of the cell V. Energy Production A. Chloroplasts – uses light energy to make sugar from CO2 & water B. Mitochondria – uses energy from organic compounds to make ATP. 1. aka mitochondrion