Bio Midterm
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Created by:
zozart1421 on January 12, 2011
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261 terms
Terms | Definitions |
|---|---|
 Molecule | The smallest unit of a compound; composed of atoms covalently bonded to one another. |
| Element | A substance composed of atoms that are chemically identical, alike in their number of protons. |
| Atom | The smallest particle of an element that retains the properties of that element. |
| Subatomic | Referring to small particles that make up atoms, including electrons, protons, and neutrons. |
| Electron | A negatively charged particle that occurs in charge distribution. |
| Proton | A particle bearing a positive electrical charge found in the nuclei of all atoms. |
| Neutron | A subatomic particle carrying no electrical charge. |
| Electron shell | The arrangement of electrons around an atom's nucleus according to the energy they contain; electrons with the least energy are in the shell closest to the nucleus, and those with more are in shells farther from the nucleus. |
| Isotope | One of multiple forms of an element having the same atomic number but a different atomic mass. |
| Chemical bond | The attraction between two atoms resulting from the sharing or transfer of outer electrons. |
| Chemical reaction | Change in chemical bonds that produces one or more new substances. |
| Cell | The basic living unit. |
| Law of conservation of matter | The law stating that matter can be neither created nor destroyed; does not hold true at the subatomic level. |
| Activation energy | The energy necessary to start a chemical reaction. |
| Ion | An atom or a molecule that has either gained or lost one or more electrons, giving it a positive or negative charge. |
| Ionic bond | A chemical bond formed by the attraction between oppositely charged ions. |
| Covalent bond | A chemical bond formed by two atoms sharing a pair of electrons. |
| Hydrogen bond | A weak attraction between hydrogen atoms and oxygen, nitrogen, or fluorine atoms; holds together the strands of DNA in their double helix. |
| pH scale | A scale from 0 to 14 reflecting the concentration of hydrogen ions in solution; a number less than 7 denotes acidic conditions, and a number greater than 7 denotes basic conditions. |
| Acidic | Having a pH of less than 7, reflecting more dissolved hydrogen ions than hydroxide ions. |
| Basic | Alkaline; having a pH greater than 7, reflecting more dissolved hydroxide ions than hydrogen ions. |
| Organic | Refers to compounds that are made up of carbon atoms and other elements; originally thought to be associated only with living things. |
| Macromolecule | A large, complex molecule. |
| Carbohydrate | An organic compound made of carbon, hydrogen, and oxygen, with the hydrogen and oxygen atoms in a 2:1 ratio; examples are sugars, starches, and cellulose. |
| Monosaccharide | A simple sugar with three to seven carbon atoms in its carbon skeleton. |
| Disaccharide | A double sugar composed of two chemically bonded simple sugars. |
| Polysaccharide | A complex carbohydrate composed of many simple sugars bonded in a chain; for example starch and cellulose. |
| Lipid | A fat, an oil, a wax, or a fat-like compound that usually has fatty acids in its molecular structure; an important component of the plasma membrane. |
| Protein | An organic compound composed of one or more polypeptide chains of amino acids; most structural materials and enzymes in a cell are these. |
| Amino acid | An organic compound composed of a central carbon atom to which are bonded a hydrogen atom, an amino group (-NH₂), an acid group (-COOH), and one of a variety of other atoms or groups of atoms; the building block of polypeptides and proteins. |
| Peptide bond | A covalent chemical bond formed between two amino acids; bonds the amino group of each amino acid to the carboxyl group of the next. |
| Polypeptide | A long chain of chemically bonded amino acids. |
| Primary structure | The first level of organization of a protein or nucleic acid; refers to the specific sequence of amino acids or nucleotides. |
| Secondary structure | In proteins, the shape of a folded polypeptide chain; results from hydrogen bonds between adjacent parts of the molecule. |
| Tertiary structure | The three-dimensional folded structure of a polypeptide or protein molecule. |
| Hydrophobicity | The tendency to repel water; substances that are hydrophobic are non-polar and cannot hydrogen bond to water. |
| Quaternary structure | The shape of a complex protein defined by the three-dimensional arrangement of its polypeptide subunits. |
| Nucleic acid | DNA or RNA; a polymer of nucleotides important in encoding instructions for cell processes. |
| Nucleotide | A subunit of DNA or RNA composed of a 5-carbon sugar, a nitrogen-containing base, and a phosphate group. |
| RNA | Ribonucleic acid; a nucleic acid similar to DNA but having the sugar ribose rather than deoxyribose and uracil rather than thymine as one of the bases. |
| DNA | Deoxyribonucleic acid; the hereditary material of most organisms; a nucleic acid composed of deoxyribose sugar, phosphate groups, and four nitrogen-containing bases. |
| Chemical energy | Energy stored in the structure of molecules. |
| Free energy | Energy that is available to do work. |
| Nutrient | A substance that supports the growth and maintenance of an organism. |
| Heterotroph | An organism that obtains carbon compounds from other organisms. |
| Autotroph | An organism that forms its own food molecules from abiotic materials. |
| Photosynthesis | The process by which cells use light energy to make organic compounds] from inorganic materials. |
| Photoautotroph | An organism that derives energy from light and forms its own organic compounds from abiotic carbon sources. |
| Chemosynthesis | A biochemical pathway that uses energy from the oxidation of inorganic substances to drive the formation of organic molecules. |
| Cell respiration | The series of chemical reactions by which a living cell breaks down carbohydrates and obtains energy from them. |
| Producer | An autotroph; any organism that produces its own food. |
| Consumer | A heterotroph; an organism that feeds on other organisms or on their organic wastes. |
| Decomposer | An organism that lives on decaying organic material, from which it obtains energy and nutrients. |
| Food web | The overlapping food chains of an ecosystem. |
| Abiotic | Referring to a physical or nonliving component of an ecosystem. |
| Biotic | Relating to a living component of an ecosystem. |
| Ecosystem | A biological community and its abiotic environment. |
| Habitat | Type of place where an organism lives. |
| Biosphere | The outer portion of Earth-air, water, and soil-where life is found. |
| First law of thermodynamics | The law derived from the principle of the conservation of energy stating that energy can be neither created nor destroyed, but it can be transferred or transformed. |
| Law of conservation of energy | The law stating that energy can be neither created nor destroyed, only changed from one form into another. |
| Second law of thermodynamicds | The law stating that energy transfers and transformations increase the entropy of the universe. |
| Entropy | A measure of the degree of disorganization of a system, that is, how much energy in a system has become so dispersed that it is no longer available to do work. |
| Enzyme | A protein or part-protein molecule made by an organism and used as a catalyst in a specific biochemical reaction. |
| Catalyst | A chemical that promotes a reaction between other chemicals by reducing the energy required to activate the reaction; may take part in the reaction but emerges in its original form. |
| Active site | The portion of an enzyme that attaches to the substrate through weak chemical bonds. |
| Substrate | A molewcule on which enzymes act. |
| Metabolism | The sum of all the chemical changes taking place in an organism. |
| Synthesis | The process of building chemical compounds from smaller components by means of chemical reactions. |
| Decomposition | The process of breaking substances down into smaller chemical units. |
| Oxidation | The loss of electrons from a substance in a chemical reaction. |
| ATP | Adenosine triphosphate; a compound that has three phosphate groups and is used by cells to store energy and to fuel many metabolic processes. |
| ADP | Adenosine diphosphate; the compound that remains when a phosphate group is removed from ATP, releasing energy. |
| Digestion | The process by which food breaks down into molecules that an organism can absorb or use. |
| Extracellular digestion | The breakdown of nutrient molecules outside of cells. |
| Intracellular digestion | The breakdown of nutrients within a cell. |
| Ingestion | The process of taking a substance from the environment, usually food, into the body. |
| Saliva | Liquid secreted in the mouth; begins mechanical and chemical digestion. |
| Epiglottis | Flap of cartilaginous tissue at the base of the tongue in mammals; prevents food from entering the trachea, the airway to the lungs, during swallowing. |
| Peristalsis | The rhythmic waves of contraction of the smooth muscle that pushes food through the digestive tract. |
| Salivary amylase | An enzyme in saliva that begins digestion of starch; converts starch to disaccharides. |
| Gastrin | A digestive hormone secreted by the stomach lining; stimulates the secretion of fluid by gastric glands in the stomach. |
| Pepsin | A protein-splitting enzyme secreted by the gastric glands of the stomach. |
| Pepsinogen | The inactive form of pepsin. |
| Trypsin | An enzyme in pancreatic juice that breaks down protein molecules. |
| Bile | A secretion of the liver stored in the gallbladder and released through a duct to the small intestine; breaks large fat droplets into smaller ones that enzymes can act on more efficiently. |
| Lipase | A fat-digesting enzyme. |
| Villi | A fingerlike projection of the small intestine that increases surface area for absorption of digested foods. |
| Capillary | A microscopic blood vessel penetrating the tissues and consisting of a single layer of cells that allows exchange between the blood and tissue fluids. |
| Cytoplasm | The entire contents of the cell, except the nucleus, bounded by the plasma membrane. |
| Transport protein | A protein that plays a role in the active or passive movement of specific substances through cell membranes. |
| Selectively permeable | Of membranes, allowing some substances to cross and preventing others from crossing. |
| Glycoprotein | A protein linked to a sugar or polysaccharide; component of receptor molecules on the outer surface of cells. |
| Glycolipid | A lipid covalently linked to a sugar or polysaccharide; an important part of animal cell membranes. |
| Diffusion | The movement of a substance down its concentration gradient from a more concentrated area to a less concentrated area. |
| Concentration gradient | A difference in the concentration of a substance over a distance. |
| Osmosis | The movement of water (or another solvent) through a selectively permeable membrane from a solution with a lower concentration of solutes to one with a higher concentration of solutes. |
| Turgor | A cell's swelling against its cell wall caused by the pressure of the cell's contents. |
| Passive transport | The diffusion of a substance through a biological membrane. |
| Active transport | The movement of a substance through a biological membrane against a concentration gradient. |
| Facilitated diffusion | The spontaneous passage of molecules and ions, bound to specific carrier proteins, across a biological membrane down their concentration gradients. |
| Endocytosis | The cellular uptake of materials in which the plasma membrane surrounds and engulfs extracellular materials. |
| Exocytosis | The release of macromolecules from a cell by the fusion of vesicles with the plasma membrane. |
| Alveoli | Air sacs in a lung. |
| Cuticle | The waxy outer layer covering the surfaces of most land-dwelling plants, animals, and fungi. |
| Stomates | ... |
| Transpiration | ... |
| Homeostasis | ... |
| Ammonia | ... |
| Nephrons | ... |
| Kidneys | ... |
| Urinary system | ... |
| Urine | ... |
| Ureter | ... |
| Urinary bladder | ... |
| Urethra | ... |
| Glomerular capsule | ... |
| Glomerulus | ... |
| Aldosterone | ... |
| Feedback regulation | ... |
| Antidiuretic hormone | ... |
| Chemoautotrophs | ... |
| Pigments | ... |
| Chloroplast | ... |
| Chlorophyll | ... |
| Light reactions | ... |
| Calvin cycle | ... |
| NADP | ... |
| ATP synthetase | ... |
| Rate | ... |
| Photoinhibition | ... |
| Limiting factors | ... |
| Photorespiration | ... |
| Bundle sheath | ... |
| CAM | ... |
| Cell respiration | ... |
| Aerobic | ... |
| Anaerobic | ... |
| Glycolysis | ... |
| Krebs cycle | ... |
| NAD | ... |
| Electron transport system | ... |
| FAD | ... |
| Pyruvie acid | ... |
| Lactate | ... |
| Lactic-acid fermentation | ... |
| Mitochondria | ... |
| Coenzyme A | ... |
| Cytochromes | ... |
| Facultative aerobes | ... |
| Obligate anaerobes | ... |
| Obligate aerobes | ... |
| Hydrolysis | ... |
| Cell theory | ... |
| Prokaryotes | ... |
| Eukaryotes | ... |
| Nucleus | ... |
| Nucleoid | ... |
| Plasmids | ... |
| Flagella | ... |
| Organelles | ... |
| Cell wall | ... |
| Nucleoli | ... |
| Cytosol | ... |
| Cytoskeleton | ... |
| Ribosomes | ... |
| Endoplasmic reticulum | ... |
| Golgi apparatus | ... |
| Lysosomes | ... |
| Vacuoles | ... |
| Centrioles | ... |
| Cilia | ... |
| Colonies | ... |
| Epidermis | ... |
| Tissue | ... |
| Organs | ... |
| Systems | ... |
| Lignin | ... |
| Xylem | ... |
| Phloem | ... |
| Tracheids | ... |
| Vessel elements | ... |
| Cohesion | ... |
| Adhesion | ... |
| Sieve tubes | ... |
| Arthropods | ... |
| Open circulatory system | ... |
| Closed circulatory system | ... |
| Atria | ... |
| Ventricles | ... |
| Arteries | ... |
| Capillaries | ... |
| Veins | ... |
| Cardiac cycle | ... |
| Actin | ... |
| Myosin | ... |
| Z-line | ... |
| Erythrocytes | ... |
| Hemoglobin | ... |
| Leukocytes | ... |
| Macrophages | ... |
| Plasma | ... |
| Lymphatic | ... |
| Coagulate | ... |
| Platelets | ... |
| Fibrin | ... |
| Cell cycle | ... |
| Mitosis | ... |
| Interphase | ... |
| G₁ | ... |
| S | ... |
| G₂ | ... |
| M | ... |
| G₀ | ... |
| Restriction point | ... |
| Nuclear division | ... |
| Cytokinesis | ... |
| Replication origins | ... |
| DNA polymerase | ... |
| Replisome | ... |
| Mutation | ... |
| Mutagenic | ... |
| Excision repair | ... |
| Sister chromatids | ... |
| Centromere | ... |
| Chromosome segregation | ... |
| Aneuploid | ... |
| Spindle poles | ... |
| Kinetochore | ... |
| Metaphase | ... |
| Metaphase plate | ... |
| Anaphase | ... |
| Telophase | ... |
| Cyclins | ... |
| Cell-cycle arrest | ... |
| Cancer | ... |
| Messenger RNA | ... |
| Transcription | ... |
| Translation | ... |
| Ribosomal RNA | ... |
| Transfer RNA | ... |
| Genetic code | ... |
| Codon | ... |
| Anticodon | ... |
| Hormone | ... |
| RNA polymerase | ... |
| Introns | ... |
| Exons | ... |
| Splicing | ... |
| Signal sequence | ... |
| Viruses | ... |
| Bacteriophage | ... |
| Lysogenic | ... |
| Data | ... |
| Theory | ... |
| Hypotheses | ... |
| Uniformitarianism | ... |
| Natural selection | ... |
| Specie | ... |
| Adaption | ... |
| Variation | ... |
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