 | Term | Definition |
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cell |
basic functional unit of all living things |
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plasma membrane (cell membrane) |
bounds the cell and encloses the nucleus and cytoplasm; Separates internal metabolic events from the external environment and controls the movement of materials into and out of the cell. This is a double phospolipid membrane(lipid bilayer) w/ the polar hydrophilic head forming the 2 outer faces and the nonpolar hydrophobic tails pointing toward the inside of the membrane. |
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cytoplasm |
consists of specialized bodies called organelles suspended in a fluid matrix |
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cytosol |
consists of wter and dissolved substances such as proteins and nutrients. |
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peripheral proteins |
proteins that may attach loosely to the inner and outer surface of the cell membrane. |
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integral proteins |
proteins that may extend into the cell membrane and appear at both surfaces (transmembrane proteins). Like phospholipids, these are amphpathic, w/ the hydrophobic regions embedded in the membrane and the hydrophilic regions exposed to the aqueous solutions bordering the membrane |
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fluid mosaic model |
the mosaic nature of scattered proteins w/in a flexible matrix of phospholipid molecules describes this |
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phospholipid membrane |
(p/c) is selectively permeable. Only small, uncharged, polar molecules (such as H20 and CO2) and hydrophobic molecules (nonpolar molecules like O2 and lipid-soluble molecules such as hydrocarbons) freely pass across the membrane. In contrast, large polar molecules (such as glucose) and all ions are impermeable |
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Proteins |
(p/cm) has different functions: channel, transport, recognition/glycoX, adhesion, electron transfer |
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Channel proteins |
proteins that provide passageways through the membrane for certain hydrophilic (water-soluble) substances such as polar and charged molecules |
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Transport proteins |
proteins that spend energy (ATP) to transfer materials across the membrane. When energy is used for this purpose, the materials are said to be actively transported and the process is called active transport |
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Recognition proteins |
proteins that distinguish the identity of neighboring cells. These proteins are glycoproteins b/c they have short polysaccharide chains (oliosaccharides) attached. The oligosaccharide part of the glycoprotein protrudes from the surface of the membrane like an antenna |
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Adhesion proteins |
proteins that attach cells to neighboring cells or provide anchors for the internal filaments and tubules that give stability to the cell |
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Receptor proteins |
protein providing binding sites for hormones or other trigger molecules. In response to the hormone or trigger molecule, a specific cell response is activated |
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Electron transfer proteins |
proteins that are involved in trasferring electrons from one molecule to another during chemical reactions |
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Cholesterol |
(p/cm) molecules distributed throughout the phospholipid bilayer provde some rigidity to the plasma membranes of Animal Cells. In Plant cells, related substance (Sterols) provide a similar function |
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glycocalyx |
(p/cm) is a carbohydrate "coat" covering the outer face of the plasma membrane. It conissts of various oligosaccharides (short polysaccharide chains) that are attached to membrane phospholipids (glycolipids) and proteins (such as glycoproteins/recognition). This provides markers for cell-cell recognition |
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Organelles |
are bodies w/in the cytoplasm that serve to physically separate the various metabolic reactions that occur w/in cells. EX: nucleus, ribosome, ER, Golgi apparatus, lysosomes, peroxisomes, mitochondria, chloroplasts, microtubules, flagella/cilia) |
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Nucleus |
Contains DNA which is spread out w/in nucleus as a threadlike matrix - cromatin. When the cell begins to divide, crhromatin condenses into rod-shaped bodies called - chromosomes; made up of 2 long DNA molecules and histone. The histones- serve to organize the lengthy DNA, coiling it into bundles - nucleosomes. Also visible w/in This are one or more nucleoli - concentrations of DNA in the process of making ribosomes. This also serves as the site for the separation of chromosomes during cell division. |
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Ribosome |
subunits that are manufactured in the nucleus and consist of RNA molecules and proteins. In the cytoplasm, This assist in the assembly of amino acids into proteins |
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Endoplasmic Reticulum (ER) |
consists of stacks of flattened sacs involved in the production of various materials. When ribosomes present, (rough X) creates glycoproteins by attaching polysaccharide groups to polypeptides as they are assembled by the ribosomes. (Smooth X) w/o Ribosomes - is responsible for the synthesis of lipids and hormones, esp in cells that produce these substances for export from the cell. In livercells, Smooth X breakdown: toxins, drugs, and toxic by-products from cellular reactions |
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Golgi apparatus |
group of flattened sacs arranged like a stack of bowls. Function - to modify and package proteins and lipids into vesicles (small spherical shaped sacs) outside suface of this. Vesicles often migrate and relase their contents to the outside of the cell |
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lysosome |
are vesicles from a Golgi apparatus that contain digestive enzymes. the break down of food, cellular debris, and foreign invaders sac as bacteria. This does NOT occur in plant cells. |
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Peroxisomes |
are organelles that break down various substances. During the breakdown process, O2 combines w/hydrogen to form toxic hydrogen peroxide (H2O2), which converts to H2O. These are common in liver and kidney cells where they break down toxic substances and in photosynthesizing plant cells. |
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Mitochondria |
carry out aerobic respiration, a process in which energy (in the form of ATP) is obtained from carbs |
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Chloroplasts |
carry out photosynthesis, the platn process of incorporating energy from the sunlight into carbs |
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Microtubules, intermediate filaments, microfilaments |
3 protein fibers that are innvolved in estlshing the shape of or in coordinating movements of the cytoskeleton - the internal structure of the cytoplasm |
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Microtubules |
protein fiber (made of tubulin) and provide support and motility for cellular activities. They are found in the Spindle Apparatus (guides the movement of chromosomes during cell division), and in flaggella and cilia, structures that project from the plasma membrane to provide motility to the cell. |
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Intermediate filaments |
protein fiber that provides suppor for maintaining the shape of the cell |
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Microfilaments |
protein fiber (made of actin) and are involved in cell motility. They are found in muscle cells and in cells that move by changing shape, such as phago-cytes (white blood cells that wander throughout the body attacking bacteria) |
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Flagella and cilia |
are structures that protrude from the cell membrane and make wavelike movements. F - long and few C - short and many; Structurally - consists of microtubules arranged in a "9+2" array-nine pairs |
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Centrioles and basal bodies act as Microtubule Organizing Centers (MTOCS) |
where microtubules orinated from |
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Cell walls |
Found in plants, fungi, protists, and bacteria. They develop outside the plasma membrane and provide support for the cell. In plants, This consists mainly of cellulose - a polysaccharide of B-glucose) These of fungi- cellulose or chitin Chitin-modified polysaccharide differing from cellulose in that one of the hydroxyl groups is replaced by a group containing nitrogen |
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Vacuoles and Vesicles |
fluid filled |
