Genetics Ch 2

An inherited form of migraine is caused by mutation in a gene that encodes a sodium channel in neurons. What is a sodium channel?

A sodium channel is a protein-lined opening in a plasma membrane that regulates the movement of sodium into and out of cells.

Distinguish between: a bacterial cell and a eukaryotic cell, interphase and mitosis, mitosis and apoptosis, rough ER and smooth ER, microtubules and microfilaments, stem cell and a progenitor cell, totipotent and pluripotent

Bacterial cell and eukaryotic cell: A bacterial cell is usually small and lacks a nucleus and other organelles. A eukaryotic cell contains membrane-bound organelles, including a nucleus, that compartmentalize biochemical reactions. Interphase and mitosis: During interphase, cellular components are replicated. During mitosis, the cell divides, distributing its contents into two daughter cells Mitosis and apoptosis: Mitosis increases cell number. Apoptosis eliminates cells. Rough ER and smooth ER: Rough ER is a labyrinth of membranous tubules, studded with ribosomes that synthesize protein. Smooth ER is the site of lipid synthesis. It is a membranous labyrinth but lacks ribosomes. Microtubules and microfilaments: Microtubules are tubules (hollow) of tubulin pairs and microfilaments are solid rods of actin. Both form the cytoskeleton. Stem cells and progenitor cells: A stem cell has greater developmental potential than a progenitor cell. Totipotent and pluripotent: A totipotent cell can differentiate as any cell type; a pluripotent cell's fates are more restricted.

Give the function of each organelle: lysosome, rough ER, nucleus, smooth ER, Golgi apparatus, mitochondrion, peroxisome.

Lysosome: dismantles debris Rough ER: protein synthesis Nucleus: houses DNA Smooth ER: lipid synthesis Gogli apparatus: processes secretions Mitochondrion: energy extraction Peroxisome: detoxification

How do stem cells maintain their populations within tissues that consist mostly of differentiated cells?

Stem cells maintain their populations because mitosis produces a daughter cell that differentiates, as well as one that "self-renews," remaining a stem cell