ch 6 - a tour of the cell
Order by
78 terms
Terms | Definitions |
|---|---|
 light microscope | visible light is passed through the specimen and then through glass lenses which light is refracted in such a way that the image of the specimen is magnified as it is projected; types: bright field, phase-contrast, fluorescence, confocal |
| organelles | membrane-enclosed structures within eukaryotic cells |
| electron microscope | focuses a beam of electrons through the specimen or onto its surface; hundredfold improvement over standard light microscope; SEM and TEM |
| scanning electron microscope (SEM) | used for detailed study of the topography of a specimen; creates 3D image of cells |
| transmission electron microscope (TEM) | used to study the internal structure of cells; specimen stained; |
| cell fractionation | a centrifuge is used to take cells apart and separate major organelles and other sub cellular structures from one another; process is by spinning the test tubes at high speeds |
| prokaryotic cells | lack a true nucleus and other membrane-enclosed organelles of the eukaryotic cell; much simpler in structure; include bacteria and archaea; |
| eukaryotic cells | protists, fungi, animals and plants are composed of eukaryotic cells; most DNA is contained in the double membrane bound nucleus |
| cell components | all cells are bounded by the plasma membrane, have cytosol, chromosomes, and ribosomes |
| cytosol | inside all cells there is a semifluid, jellylike substance called cytosol in which subcelluar components are suspended |
| cytoplasm | in eukaryotic cells, this term refers only to the region between the nucleus and the plasma membrane |
| plasma membrane | selective barrier that allows passage of enough oxygen, nutrients and wastes to service the entire cell |
| cytoskeleton | reinforces cells shape; functions in cell movement; components are made of protein. includes microfilaments, intermediate filaments, microtubules |
| ribosomes | complexes that make proteins; free in cytosol or bound to rough ER or nuclear envelope |
| golgi apparatus | organelle active in synthesis, modification, sorting, and secretion of cell products |
| peroxisome | organelle with various specialized metabolic functions; produces hydrogen peroxide as a by-product, then converts it to water |
| mitochondrion | organelle where cellular respiration occurs and most ATP is generated |
| centrosome | region located near the nucleus where the cells microtubules are initiated; contains a pair of centrioles |
| flagellum | motility structure present in some animal cells, composed of a cluster of microtubules within an extension of the plasma membrane |
| endoplasmic reticulum | network of membranous sacs and tubes; active in membrane synthesis and other synthetic and metabolic processes; composed of rough er and smooth er |
| nucleus | composed of: nuclear envelope, nucleolus and chromatin; contain most of genes(DNA) in eukaryotic cell |
| nuclear envelope | double membrane enclosing the nucleus; perforated by pores; continuous with ER |
| nuclear lamina | a netlike array of protein filaments that maintains the shape of the nucleus by mechanically supporting the nuclear envelope |
| nucleolus | nonmembranous structure involved in production of ribosomes; a nucleus has one or more nucleoli; synthesizes rRNA from instructions in DNA |
| chromosome | structures of DNA that carry the genetic information |
| chromatin | material consisting of DNA and proteins; visible in a dividing cell as individual condensed chromosomes |
| in animal but not plant cells | lysosomes, centrosomes with centrioles, and flagella |
| in plant but not animal cells | chloroplasts, central vacuole, cell wall and plasmodesmata |
| cell wall | outer layer that maintains cells shape and protects cell from mechanical damage; made of cellulose, other polysaccharides and protein |
| plasmodesmata | cytoplasmic channels through cell walls that connect the cytoplasms of adjacent cells |
| chloroplast | photosynthetic organelle; converts energy of sunlight to chemical energy stored in sugar molecules |
| endomembrane system | composed of: nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, various kinds of vesicles and vacuoles and plasma membrane; membranes of this system are related either through direct physical continuity or by the transfer of membrane segments as tiny vesicles |
| functions of endomembrane system | synthesis of proteins, transport of proteins into membranes and organelles or out of the cell, metabolism and movement of lipids, and detoxification of poisons |
| smooth ER | enzymes of smooth ER are important in the synthesis of lipids, detoxify drugs and poisons(esp. in liver cells), stores calcium ions |
| rough ER | studded with ribosomes; membrane factory for the cell; makes membrane phospholipids |
| glycoproteins | proteins that have carbohydrates covalently bonded to them |
| transport vesicles | vesicles in transit from one part of the cell to another |
| golgi apparatus | "warehouse" for receiving, sorting, shipping, and even some manufacturing; consist of stacks of flattened sacs (cisternae) not physically connected |
| "cis" face of golgi apparatus | "receiving department" of golgi. located near ER |
| "trans" face of golgi apparatus | "dispatches vesicles"; gives rise to vesicles that pinch off and travel to other sites |
| lysosome | digestive organelle where macromolecules are hydrolyzed; digest materials taken into the cell |
| phagocytosis | carried out by lysosomes: engulfing smaller organisms or food particles; macrophages (white blood cells that engulfs and destroy bacteria) |
| food vacuoles | formed by phagocytosis |
| contractile vacuoles | pump excess water out of the cell, thereby maintaining a suitable concentration of ions and molecules inside the cell |
| central vacuole | develops by the coalescence of smaller vacuoles; plays a major role in growth of cells by enabling the cell to become larger with a minimal investment in new cytoplasm |
| mitochondria | sites of cellular respiration, the metabolic process that uses oxygen to generate ATP by extracting energy from sugars, fats, and other fuels |
| chloroplasts | membranes divide space into 3 compartments: inter membrane space, stroma and thylakoid space. found in plants and algae; sites of photosynthesis; convert solar energy to chemical energy by absorbing sunlight and using it to drive the synthesis of organic compounds such as sugars from carbon dioxide and water |
| endosymbiont theory | theory states that an early ancestor of eukaryotic cells engulfed an oxygen-using non photosynthetic prokaryotic cell. eventually, the engulfed cell formed a relationship with the host cell in which it was enclosed, becoming an endosymbiont; over the course of evolution, the host cell and its endosymbiont merged into a single organism, a eukaryotic cell with a mitochondrion |
| cristae | foldings in mitochondrion |
| mitrochrondrial matrix | enclosed by the inner membrane |
| thylakoids | in chloroplasts; membranous system in the form of flattened, interconnected sacs |
| granum | stacks of thylakoids |
| stroma | fluid outside the thylakoids that contains the chloroplast DNA and ribosomes as well as many enzymes |
| plastids | family of closely related plant organelles; amyloplast: a colorless organelle that stores starch(amylose), particularly in roots and tubers; another is the chromoplast, which has pigments that give fruits and flowers their orange and yellow hues |
| peroxisome | a specialized metabolic compartment bounded by a single membrane; contain enzymes that removes hydrogen atoms from various substrates and transfer them to oxygen producing hydrogen peroxide as a by-product. |
| cytoskeleton | network of fibers extending throughout the cytoplasm; composed of 3 types of molecular structures: microtubules, microfilaments, and intermediate filaments |
| microtubules | hollow tubes; functions: maintenance of cell shape, guide organelle movement, and separate chromosomes in dividing cells |
| microfilaments | two intertwined strands of actin; functions: maintenance of cell shape, changes in cell shape, muscle contraction, cytoplasmic streaming, cell motility, and cell division |
| intermediate filaments | fibrous proteins supercoiled into thicker cables; functions: maintenance of cell shape, anchorage of nucleus and certain other organelles, and formation of nuclear lamina |
| centrioles | 9 sets of pairs of centrioles located within centrosome |
| basal body | structurally similar to a centriole; anchors a microtubule assembly of a cilium or flagellum |
| dyneins | In cilia and flagella, a large motor protein extending from one microtubule doublet to the adjacent doublet. ATP hydrolysis drives changes in dynein shape that lead to bending of cilia and flagella. |
| actin | a globular protein |
| cortex | outer cytoplasmic layer of a cell semisolid consistency |
| myosin | A type of motor protein that associates into filaments that interact with actin filaments to cause cell contraction. |
| cytoplasmic streaming | a circular flow of cytoplasm within cells that speeds the distribution of materials within the cell |
| primary cell well | a young plant first secretes a realtively thin and flexible wall |
| middle lamella | a thin layer rich in sticky polysaccharides called pectins |
| secondary cell wall | between plasma membrane and primary cell wall; has a strong and durable matrix that affords the cell protection and support |
| extracellular matrix (ECM) | The meshwork surrounding animal cells, consisting of glycoproteins, polysaccharides, and proteoglycans synthesized and secreted by the cells. |
| collagen | forms strong fibers outside cells; accounts for 40% of total protein in human body |
| proteoglycans | A large molecule consisting of a small core protein with many carbohydrate chains attached, found in the extracellular matrix of animal cells. A proteoglycan may consist of up to 95% carbohydrate. |
| fibronectin | An extracellular glycoprotein secreted by animal cells that helps them attach to the extracellular matrix. |
| integrins | In animal cells, a transmembrane receptor protein with two subunits that interconnects the extracellular matrix and the cytoskeleton. |
| plasmodesmata | An open channel through the cell wall that connects the cytoplasm of adjacent plant cells, allowing water, small solutes, and some larger molecules to pass between the cells. |
| tight junctions | prevent fluid from moving across a layer of cells |
| desmosomes | "anchoring junctions" function like rivets, fastening ells together in strong sheets. attach muscle cells to each other in a muscle. |
| gap junctions | "communicating junctions" provide cytoplasmic channels from one cell to an adjacent cell; necessary for cell communication |
First Time Here?
Welcome to Quizlet, a fun, free place to study. Try these flashcards, find others to study, or make your own.