Cells
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71 terms
Terms | Definitions |
|---|---|
 cytology | a part of the broader discipline of cell biology |
| cell biology | the study of cells that incorporates aspects of biology, chemistry, and physics |
| sex cells or germ cells | the sperm of males or the oocytes of females |
| somatic cells | (soma means body) includes all the other cells in the human body |
| extracellular fluid | a watery medium surrounding a cell |
| interstitial fluid | (interstitium means something standing in between) extracellular fluid in most tissues |
| cell membrane (or plasma membrane) | surface of the cell that separates the inside of the cell from the surrounding extracellular fluid, controls the entry or elimination of ions, nutrients, and waste. Also is the first part of the cell affected by its surroundings and gives stability to tissues |
| phospholipid bilayer | makes up the cell membrane, and contains other lipids, proteins, and carbohydrates |
| integral proteins | part of the membrane itself and are commonly transmembrane proteins |
| peripheral proteins | are attached to, but are able to separate from, the membrane |
| anchoring proteins | attach the cell membrane to other structures and stabilize its position |
| recognition proteins | the cells of the immune system recognize other cells as normal or abnormal based on the presence or absence of these |
| receptor proteins | sensitive to the presence of specific extracellular molecules called ligands |
| ligands | anything from a small ion to a relatively large and complex hormone |
| carrier proteins | bind solutes and transport them across the cell membrane |
| channel | a central pore of an integral protein that forms a passageway completely across the cell membrane |
| glycocalyx | formed by the carbohydrate portions of the proteoglycans, glycoproteins, and glycolipids. Functions include lubrication and protection, anchoring and locomotion, specificity in binding, and recognition |
| cytoplasm | material located between the cell membane and the membrane surrounding the nucleus |
| cytosol | intracellular fluid that contains dissolved nutrients, ions, soluble and insoluble proteins, and waste products |
| organelles | structures suspended within the cytosol that perform specific functions within the cell |
| inclusions | masses of insoluble materials in the cytosol |
| nonmembranous organelles | not completely enclosed by membranes and all of their components are in direct contact with the cytosol |
| membranous organelles | isolated from the cytosol by phospholipid membranes, just as the cell membrane isolates the cytosol from the extracellular fluid |
| cytoskeleton | provides an internal protein framework that gives the cytoplasm strength and flexibility |
| microfilaments | as the smallest of the cytoskeletal elements, they are less than 6nm (nanometers) in diameter |
| actin | form the microfilaments |
| intermediate filaments | range from 7-11nm in diameter, and strengthen the cell and help maintain its shape, stabilize the positions of organelles, and stabilize the position of the cell with respect to surrounding cells through specialized attachment to the cell membrane |
| microtubles | hollow tubes built from the globular protein tubulin |
| tubulin | globular protein that makes up microtubles |
| thick filaments | relatively massive bundles of subunits composed of the protein myosin that can reach 15nm in diameter |
| myosin | protein that makes up thick filaments |
| microvilli | small, finger-shaped projections of the cell membrane on their exposed surfaces |
| centrioles | cylindrical structures composed of short microtubles, usually exist in pairs |
| centrosome | the cytoplasm surrounding the centrioles, the heart of the cytoskeletal system |
| cilia | relatively long, slender extensions of the cell membrane |
| basal body | anchors microtubles just beneath the cell surface |
| ribosomes | the organelles responsible for protein synthesis |
| small and large ribosomal subunits | subunits of a functional ribosome that are often separate and distinct |
| Free ribosomes | scattered throughout the cytoplasm, the proteins they manufacture enter the cytosol |
| Fixed ribosomes | attached to the endoplasmic reticulum (ER- membranous organelle), proteins are modified and packaged for secretion |
| Proteasomes | organelles that contain an assortment of protein-digesting enzymes, or proteases |
| Endoplasmic Reticulum | a network of intracellular membranes connected to the nuclear envelope, which surrounds the nucleus |
| cisternae | chambers that act as a reservoir for water |
| smooth endoplasmic reticulum (SER) | a part of the endoplasmic reticulum that contains no ribosomes |
| rough endoplasmic reticulum (RER) | functions as a combination workshop and shipping depost for proteins, rough refers to the fact that it contains ribosomes |
| transport vesicles | membranous sacs that dliver their contens to the Golgi apparatus |
| Golgi apparatus | consists of 5 or 6 flattened cisternae that modifies and packages secretions, renews or modifies the cell membrane, and packages special nzymes within vesicles for use in the cytosol |
| Secretory vesicles | contain secretions that will be discharged from the cell these vesicles will perform exocytosis (fusing with the plasma membrane to empty contents) |
| Lysosomes | special vesicles that provide an isolated environment for potentially dangerous chemical reactions |
| autolysis | a process in which enzymes rapidly destroy the cell's proteins and organelles |
| Peroxisomes | absorb and break down fatty acids and other organic compounds |
| membrane flow | a continuous exchange between the ER, Golgi apparatus, and the cell membrane |
| mitochondria | produce energy for the cell |
| cristae | numerous folds in the inner membrane of a mitochondrion |
| matrix | the surface area exposed to fluids, where the production of energy takes place, in a mitochondrion |
| glycolysis | the first step of ATP production |
| nucleus | the largest and most conspicuous structure in a cell; under a light microscope, it is often the only organelle visible |
| aerobic metabolism | the fact that mitochondrial activity requires oxygen |
| tricarboxylic acid cycle (or TCA cycle) | also known as the Krebs Cycle, is an enzymatic pathway that systematically breaks down the absorbed pyruvic acid in the presence of oxygen |
| nuclear envelope | surrounds the nucleus and separates it from the cytosol |
| perinuclear space | a narrow space between the double membrane of the nuclear envelope |
| nuclear pores | where the chemical communication between the nucleus and the cytosol takes place |
| nuclear matrix | a network of fine filaments that provides structural support and may be involved in the regulation of genetic activity |
| nucleoli | dark-staining organelles that synthesize rRNA |
| histones | proteins that make up nucleoli |
| nucleosome | complex that occurs at intervals where the DNA strands wind around the histones |
| chromatin | a tangle of loosely coiled, fine filaments that cells that are not dividing |
| chromosomes | the distinct structures of tightly coiled chromatin taht appear just before cell division begins |
| genetic code | the chemical "language" of the cell |
| gene | the functional unit of heredity and it contains all the DNA triplets needed to produce specific proteins |
| gene activation | the factors controlling the process of uncoiling the DNA prior to "reading" |
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