Active Transport Across A Cell Membrane example essay topic

1. Active transport- The movement of a chemical substance through a gradient of concentration or electrical potential in the direction opposite to normal diffusion, requiring the expenditure of energy: active transport across a cell membrane. 2. Cell- The smallest structural unit of an organism that is capable of independent functioning, consisting of one or more nuclei, cytoplasm, and various organelles, all surrounded by a semi permeable cell membrane. 3.

Cell membrane- The semi permeable membrane that encloses the cytoplasm of a cell. 4. Cell theory- a theory in biology that includes one or both of the statements that the cell is the fundamental structural and functional unit of living matter and that the organism is composed of autonomous cells with its properties being the sum of those of its cells 5. Cell wall- a theory in biology that includes one or both of the statements that the cell is the fundamental structural and functional unit of living matter and that the organism is composed of autonomous cells with its properties being the sum of those of its cells Chloroplast- A chlorophyll-containing plastid found in algal and green plant cells.

6. Chromatin- A complex of nucleic acids and proteins, primarily histones, in the cell nucleus that stains readily with basic dyes and condenses to form chromosomes during cell division 7. Chromosome- A threadlike linear strand of DNA and associated proteins in the nucleus of eukaryotic cells that carries the genes and functions in the transmission of hereditary information. 8.

Concentration- The amount of a specified substance in a unit amount of another substance. 9. Cytoplasm- The protoplasm outside the nucleus of a cell Cytoskeleton- The internal framework of a cell, composed largely of actin filaments and micro tubules. 10.

Diffusion- The spontaneous intermingling of the particles of two or more substances as a result of random thermal motion. DNA- A nucleic acid that carries the genetic information in the cell and is capable of self-replication and synthesis of RNA. DNA consists of two long chains of nucleotides twisted into a double helix and joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine. The sequence of nucleotides determines individual hereditary characteristics. 11. Endocytosis - A process of cellular ingestion by which the plasma membrane folds inward to bring substances into the cell.

Endoplasmic reticulum- A membrane network within the cytoplasm of cells involved in the synthesis, modification, and transport of cellular materials. 12. Eukaryote- A single-celled or multicellular organism whose cells contain a distinct membrane-bound nucleus. 13. Exocytosis - A process of cellular secretion or excretion in which substances contained in vesicles are discharged from the cell by fusion of the vesicular membrane with the outer cell membrane. 14.

Facilitated diffusion- in cell biology, a process by which substances are transported across cell membranes by means of protein carrier molecules; also called facilitated transport Golgi apparatus- A network of stacked membranous vesicles present in most living cells that functions in the formation of secretions within the cell. Also called Golgi body, Golgi complex. 15. Lipid bi layer- the basic structure of a cell membrane consisting of a double layer of phospholipid molecules 16. Lysosomes- A membrane-bound organelle in the cytoplasm of most cells containing various hydrolytic enzymes that function in intracellular digestion. 17.

Micro filament- Any of the minute fibers located throughout the cytoplasm of cells, composed of actin and functioning primarily in maintaining the structural integrity of a cell. 18. Microtubule- Any of the proteinaceous cylindrical hollow structures that are distributed throughout the cytoplasm of eukaryotic cells, providing structural support and assisting in cellular locomotion and transport 19. Mitochondria- A spherical or elongated organelle in the cytoplasm of nearly all eukaryotic cells, containing genetic material and many enzymes important for cell metabolism, including those responsible for the conversion of food to usable energy. 20.

Nuclear envelope- The double-layered membrane enclosing the nucleus of a cell. 21. Nucleolus- A small, typically round granular body composed of protein and RNA in the nucleus of a cell. It is usually associated with a specific chromosomal site and involved in ribosomal RNA synthesis and the formation of ribosomes. 22.

Nucleus- A large, membrane-bound, usually spherical protoplasmic structure within a living cell, containing the cell's hereditary material and controlling its metabolism, growth, and reproduction. 23. Organ- A differentiated part of an organism, such as an eye, wing, or leaf, that performs a specific function 24. Organelle - A differentiated structure within a cell, such as a mitochondrion, vacuole, or chloroplast, that performs a specific function. 25. Osmosis- Diffusion of fluid through a semipermeable membrane from a solution with a low solute concentration to a solution with a higher solute concentration until there is an equal concentration of fluid on both sides of the membrane.

26. Phagocytosis- The engulfing and ingestion of bacteria or other foreign bodies by phagocytes 27. Prokaryote- An organism of the kingdom Monera (or Prokaryote), comprising the bacteria and, characterized by the absence of a distinct, membrane-bound nucleus or membrane-bound organelles, and by DNA that is not organized into chromosomes. Also called monera n 28.

Ribosome- A minute round particle composed of RNA and protein that is found in the cytoplasm of living cells and serves as the site of assembly for polypeptides encoded by messenger RNA. 29. Selective permeability-30. Tissue- An aggregation of morphologically similar cells and associated intercellular matter acting together to perform one or more specific functions in the body. There are four basic types of tissue: muscle, nerve, epidermal, and connective.

31. Vacuole- A small cavity in the cytoplasm of a cell, bound by a single membrane and containing water, food, or metabolic waste.