| Macromolecules | Large polymers that are composed of many monomers. Proteins, nucleic acids, and polysaccharides are examples. |
| Macronutrients | Essential elements that are require in relatively large amounts for plant growth |
| Mass | A measure of the quatity of matter. |
| Matrix of cell | Components of the cell that lie within the plasma membrane and exclusive of the nucleus/nucleoid. |
| Meiosis | A division process that results in the formation of 4 cells that house half the number of chromosomes as the parent cell. The division reduces the number of sets of chromosomes from two sets (2N) to one set (1N). Leads ultimately to the production of gametes. Meiosis and fertilization are processes involved in sexual reproduction. |
| Mendel's factors | Alleles that are responsible for expression of a given trait. |
| Mendelian Inheritance | Transmission of genetic traits in a manner consistent with the principles discovered by Gregor Mendel. |
| Meristem | Areas of plants that contain actively dividing cells |
|
mesophyte |
plants dependant on a moderate supply of water |
| Messenger RNA | A type of RNA molecule that carries the code for synthesis of a particular protein from the nucleus to the ribosome. |
| Metabolic pathway | A sequence of chemical reactions that leads to the synthesis or breakdown of complex molecules. |
| Metabolism | The sum of chemical reactions that occur in living organisms. |
|
microclimate |
small climactic zones |
| Micronutrients | Essential elements that are require in relatively small amounts for plant growth |
| Migration | Movement of individuals or gametes (pollen grains for example) from one population to another. |
| Mitochondrion | Double membrane bound organelle in eukaryotic cells which makes ATP by the process of respiration. For this reason, mitochondrion is called the powerhouse of the cell. |
| Mitosis | Division of a cells nucleus |
| Molarity | The number of moles per 1 liter volume. |
| Molecule | The smallest particle of a compound that retains all the chemical properties of the compound. |
| Moles | A mole is equal to 6 X 100 to the 23rd number of molecules. |
| Monocot | One of the two large groups of flowering plants distinguished by the presence of of one seed leaf or cotyledons |
| Monomers | Small molecules that serve as the building blocks or subunits of macromolecules. |
| Monosaccharide | A simple sugar molecule; a sugar monomer. Glucose and fructose are two examples of simple sugars. |
| Movement | The mobility of an organism or part of an organism or the spatial displacement of parts of a stationary organisms |
| Mutant | An individual that possesses a mutation in one or more genes. Mutants may differ in appearance or physiologically from wild type individuals. |
| Mutation | A change in the DNA sequence of a gene, or chromosome. Mutations occur in very low frequency and are the means by which new alleles originate. |
|
mutualism |
symbiosis in which both organism benefit from the relationship |
| Mycelium | Tangled mass of hyphae that make up the body of a fungus. |
| Mycorrhizae | A mutualistic association between soil fungi and plant roots that help the plant absorb essential minerals and water from the soil. |
| Mycoses | Term used to refer to diseases caused by fungi. In humans mycoses include athlete's foot, ringworm, and Valley fever. Plant mycoses are prevalent and highly destructive. |
| Mycotoxins | Toxic chemicals produced by fungi including certain types of mushroom. The toxins can result in death of humans when the fungi are consumed. |
| Natural selection | The selection by environmental factors of those individuals that are best suited to reproduce in the existing evironment and selection against those individuals that are least fit. Natural selection, as proposed by Charles Darwin, accounts for evolution. |
| Negative ion | An atom that has more electrons than protons in the atomic nucleus. |
| Neutral lipid | A type of lipid that is composed of glycerol and three fatty acids that serves as a storage form of energy |
| Neutrons | Uncharged particles that are found in the nucleus of an atom. |
| Node | Region of plant stem where a leaf and lateral bud are atttached |
| NonMendelian genetics | Transmission of genetic traits in patterns that are not consistent with the principles discovered by Gregor Mendel. Includes incomplete dominance, inheritance of linked genes, and interaction of genes in controlling a given trait. |
| Nonpolar molecule | A molecule that does not have spatial charge separation because electrons are shared equally between atoms. It is possible to have a molecule that has both polar and nonpolar characteristics. |
| Nuclear matrix | The content of the nucleus exclusive of the chromosomes. Consists of semifluid substance and cytoskeletal components. |
| Nuclear membranes | Porous membranes (2) in eukaryotic cells that form the boundary of the nucleus, keeping it separate from the cytoplasm. |
| Nucleic acids | Polymers of nucleotide monomers. DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are two types of nucleic acids. |
| Nucleiod | Dense mass of DNA found in prokaryotic cells. |
| Nucleotide | The building block of nucleic acids. A nucleotide is made up of a 5C sugar (ribose or deoxyribose), a phosphate group, and one of five nitrogenous bases. |
| Nucleus | A membrane bound compartment that houses the chromosomes and the biochemical machinery for DNA replication and transcription. Found only in eukaryotic cells. |
| Nutrient Cycling | The interconversion of inorganic and organic matter. Plants use inorganic ions to make organic matter using light energy. Animals get their organic matter from plants. Plant and animal remains and wastes are decomposed by bacteria and fungi releasing inorganic ions back into the soil. |