October 15, 2008
Check Your Recall Questions
1. Nerve cells often have long, threadlike extensions that transmit electrical impulses from one part of the body to another. Epithelial cells that line the inside of the mouth are thin, flattened, and tightly packs, an arrangement that enables them to protect underlying cells.
2. The three major parts of a cell are the nucleus, cytoplasm, and cell membrane.
3. The nucleus directs the overall cell activities by housing the genetic material. The cytoplasm surrounds the nucleus, and the cell membrane determines which substances enter and leave the cell and it also oversees how cells interact.
4. An organelle is a specialized structure within the cytoplasm that performs specific functions.
1. A selectively permeable membrane is a membrane that controls which substances enter and leave the cell.
2. The cell membrane is composed of mostly lipids, proteins, and a small amount of carbohydrates.
3. The endoplasmic reticulum provides a vast tubular network that transports molecules from one cell part to another. The endoplasmic reticulum also participates in the synthesis of proteins and lipid molecules.
4. The Golgi apparatus refines, packages, and delivers proteins synthesized on ribosomes associated with the ER.
1. A mitochondrion is an elongated, fluid-filled sac that has an outer an inner layer and is the major site where energy is transformed into adenosine triphosphate through chemical reactions.
2. Lysosomes destroy worn cellular parts and they break down nutrient molecules or foreign particles.
3. Microtubules are built of tubulin and are three times the size of microfilaments which are built of actin and provide cell mobility.
4. Structures composed of microtubules are centrosome, cilia, and flagella.