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level: Level 1

Questions and Answers List

level questions: Level 1

The chemical processes by which atmospheric nitrogen is assimilated into organic compounds, especially by certain microorganisms as part of the nitrogen cycle. ni·tro·gen fix·a·tion Related words: Nitrogen Cycle#1 Nitrogen Fixation
A chemical substance that neutralizes alkalis, dissolves some metals, and turns litmus red; typically, a corrosive or sour-tasting liquid of this kind. ac·id Related words: Base, Litmus paper#2 Acid
A substance capable of reacting with an acid to form a salt and water, or (more broadly) of accepting or neutralizing hydrogen ions. Ba-ss Related words: Acid, Ph scale#3 Base
Action intended to nullify the effects of some previous action noo-truh-luh-zey-shuh n, nyoo- Related words: Acids, Bases#4 Neutralization
Organic compound, any of a large class of chemical compounds in which one or more atoms of carbon are covalently linked to atoms of other elements. or·gan·ic com·pound Related Words: Compounds#5 Organic Compound
A chemical element (e.g., potassium, magnesium, calcium) required in large amounts for plant growth and development. mac·ro·nu·tri·ent Related Words: Micronutrients#6 Macronutrients
A chemical element or substance required in trace amounts for the normal growth and development of living organisms. mi·cro·nu·tri·ent Related Words: Macronutrients#7 Micronutrients
Any of a large group of organic compounds occurring in foods and living tissues and including sugars, starch, and cellulose. car·bo·hy·drate Related Words: Lipids, Protein, Nucleic acids#8 Carbohydrates
Any of a large group of nitrogenous organic compounds that are essential constituents of living cells; consist of polymers of amino acids; essential in the diet of animals for growth and for the repair of tissues; can be obtained from meat and eggs and milk and legumes. pro·tein Related Words: Carbohydrates, Lipids, Nucleic Acids#9 Protein
Any of a class of organic compounds that are fatty acids or their derivatives and are insoluble in water but soluble in organic solvents. lip·id Related Words: Carbohydrates, Protein, Nucleic Acids#10 Lipids
A complex organic substance present in living cells, especially DNA or RNA, whose molecules consist of many nucleotides linked in a long chain. nu·cle·ic ac·id Related Words: Carbohydrates, Proteins, Lipids#11 Nucleic Acids
The act of dispersing or diffusing something. dif·fu·sion Related Words: Osmosis, Active transport#12 Diffusion
Diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal. os·mo·sis Related words: Diffusion, Active Transport#13 Osmosis
The movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy. ac·tive trans·port Related Words: Diffusion, Osmosis#14 Active Transport
A chemical reaction in which water reacts with a compound to produce other compounds; involves the splitting of a bond and the addition of the hydrogen cation and the hydroxide anion from the water. hy·drol·y·sis Related Words: Substrate#15 Hydrolysis
The surface or material on or from which an organism lives grows or obtains its nourishment. sub·strate Related Words: Hydrolysis#16 Substrate
Any animal/insects lacking a backbone or notochord; the term is not used as a scientific classification. in·ver·te·brate Related words: Water Bodies#17 Invertebrate
A way of expressing very dilute concentrations of substances. Usually describes the concentration of something in water or soil. One ppm is equivalent to 1 milligram of something per litre of water (mg/l) or 1 milligram of something per kilogram soil (mg/kg). Par·t·s Per Mil·lion Related Words: Concentration#18 Parts Per Million (PPM)
A sudden increase in the level of acidity of surface waters (lakes, streams, and rivers) in mid‐latitude areas, caused by the melting in spring of snow that has accumulated through the winter, and stored dry fallout of acidic precipitation. S·pring Ac·id Sho·ck Related words: Greenhouse gases#19 Spring Acid Shock
A measure of the lethal dose of a toxin, radiation, or pathogen. The value of LD₅₀ for a substance is the dose required to kill half the members of a tested population after a specified test duration. Le·thal Do·se 50 Related Words: PPM#20 LD50 (Lethal Dose 50)
A gas that contributes to the greenhouse effect by absorbing infrared radiation, e.g., carbon dioxide and chlorofluorocarbons. Green·hou·se Gas·es Related words: Spring Acid Shock#21 Greenhouse gases
Refers to human activities that are adding to the warming of the atmosphere due to the greenhouse effect—the presence of gases that increases the atmosphere's retention of the heat energy of the sun. En·han·ced Green·hou·se E·ffect Related Words: Greenhouse Gases#22 Enhanced Greenhouse Effect
The long-term rise in the average temperature of the Earth's climate system. Cli·mate Ch·ange Related Words: Greenhouse Effect#23 Climate Change
Water held underground in the soil or in pores and crevices in rock. ground·wa·ter Related Words: Leachate#24 Groundwater
Water that has percolated through a solid and leached out some of the constituents. leach·ate Related Words: Groundwater#25 Leachate
The breakdown of organic matter by microorganisms, such as bacteria and fungi. Bio·de·gradtion Related Words: Phytoremediation, photolysis#26 Biodegradation
Refers to the technologies that use living plants to clean up soil, air, and water contaminated with hazardous contaminants. Phy·to·reme·diation Related words: Biodegradtion, Photolysis#27 Phytoremediation
The decomposition or separation of molecules by the action of light. Pho·tol·y·sis Related words: Biodegradation, Phytoremediation#28 Photolysis
The concentration of toxins in an organism as a result of its ingesting other plants or animals in which the toxins are more widely disbursed. Bio·mag·nific·ation Related Words: Concentration#29 Biomagnification