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Biology Unit 1
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Term | Definition |
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Anaphase | the stage of mitosis or meiosis when chromosomes are split and the sister chromatids move to opposite poles of the cell. |
Catalyst | a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change. |
Cell Theory | a scientific theory which describes the properties of cells. These cells are the basic unit of structure in all organisms and also the basic unit of reproduction. |
Chromatin | a complex of macromolecules found in cells, consisting of DNA, protein and RNA. |
Cilia | an organelle found in eukaryotic cells. |
Activation Energy | the minimum energy that must be input to a chemical system with potential reactants to cause a chemical reaction. |
Benedict's Solution | A solution of sodium citrate, sodium carbonate, and copper sulfate that changes from blue to yellow or red in the presence of reducing sugars, such as glucose. |
Biuret Reagent | an aqueous solution of biuret (allophanamide) treated with cupric sulfate and sodium hydroxide. In the presence of protein, this blue solution will change color to pink-purple. |
Compound Light Microscope | an optical instrument for forming magnified images of small objects, consisting of an objective lens with a very short focal length and an eyepiece with a longer focal length, both lenses mounted in the same tube. |
Cytokinesis | the physical process of cell division, which divides the cytoplasm of a parental cell into two daughter cells. |
Exocytosis | a process in which an intracellular vesicle (membrane bounded sphere) moves to the plasma membrane and subsequent fusion of the vesicular membrane and plasma membrane ensues. |
Flagella | organelles defined by function rather than structure. |
Fluid Mosaic Model | A model that describes the structure of cell membranes. In this model, a flexible layer made of lipid molecules is interspersed with large protein molecules that act as channels through which other molecules enter and leave the cell. |
Golgi Apparatus | an organelle found in most eukaryotic cells. |
Electron Microscope | a type of microscope that uses a beam of electrons to create an image of the specimen. It is capable of much higher magnifications and has a greater resolving power than a light microscope, allowing it to see much smaller objects in finer detail. |
Isomer | molecules with the same chemical formula but different chemical structures. |
Polar | having electrical or magnetic polarity. |
Hydrogen Bond | the electrostatic attraction between polar molecules that occurs when a hydrogen (H) atom bound to a highly electronegative atom such as nitrogen (N), oxygen (O) or fluorine (F) experiences attraction to some other nearby highly electronegative atom. |
Hypertonic | having a higher osmotic pressure than a particular fluid, typically a body fluid or intracellular fluid. |
Hypotonic | having a lower osmotic pressure than a particular fluid, typically a body fluid or intracellular fluid |
Interphase | the phase of the cell cycle in which the cell spends and performs the majority of its time. Then, in preparation for cellular division, it increases in size. |
Isotonic | denoting or relating to a solution having the same osmotic pressure as some other solution, especially one in a cell or a body fluid. |
Lysosome | an organelle in the cytoplasm of eukaryotic cells containing degradative enzymes enclosed in a membrane. |
Macromolecules | a molecule containing a very large number of atoms, such as a protein, nucleic acid, or synthetic polymer. |
Microfilament | a small rodlike structure, about 4–7 nanometers in diameter, present in numbers in the cytoplasm of many eukaryotic cells |
Microtubule | a microscopic tubular structure present in numbers in the cytoplasm of cells, sometimes aggregating to form more complex structures. |
Nucleolus | a small dense spherical structure in the nucleus of a cell during interphase. |
Polymer | a substance that has a molecular structure consisting chiefly or entirely of a large number of similar units bonded together |
Substrate | the surface or material on or from which an organism lives, grows, or obtains its nourishment. the substance on which an enzyme acts. |
Plasma Membrane | a microscopic membrane of lipids and proteins that forms the external boundary of the cytoplasm of a cell or encloses a vacuole, and that regulates the passage of molecules in and out of the cytoplasm. |
Prokaryote | a microscopic single-celled organism that has neither a distinct nucleus with a membrane nor other specialized organelles. |
RNA | a polymeric molecule. It is implicated in various biological roles in coding, decoding, regulation, and expression of genes |
Selective Permeability | one that allows certain molecules or ions to pass through it by means of active or passive transport. |
Telophase | the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed. |
Transport Protein | a protein that serves the function of moving other materials within an organism. |
Vacuole | storage bubbles found in cells. They are found in both animal and plant cells but are much larger in plant cells. |