Base(碱)
An ion or compound that removes H+ ions from solution. Often bases are substances that release hydroxide ions (OH–). Bases have pH values above 7. They are the opposite of acids.
Bile(胆汁)
An emulsifier of fats secreted by the liver and stored in the gallbladder for release in the small intestine.
binary fission(二分裂) ：单细胞生物进行无性繁殖的方法之一，一个个体分裂为大小大致相同的两个子个体
Asexual reproduction found in prokaryotes in which a cell divides into two equal daughter cells by a nonmitotic process.
Biomass(生物量)
The amount of living matter in a given ecosystem. Because only 10 percent of energy is transferred between trophic levels, the biomass of lower trophic levels is greater than the biomass of subsequent trophic levels: biomass of producers > biomass of primary consumers > biomass of secondary consumers > biomass of tertiary consumers.
Biome(生物社会)
A particular geographic area with a common climate and characteristic plant and animal life. There are six major terrestrial biomes and two aquatic biomes. The six terrestrial biomes are tropical rain forest, savanna, desert, temperate deciduous forest, taiga, and tundra. The two aquatic biomes are marine and freshwater. Each biome is characterized by specific climax communities.
Blood(血)
The liquid that carries nutrients and oxygen to the cells and carries carbon dioxide and nitrogenous wastes away. The liquid fluid of blood is called plasma. Red blood cells contain hemoglobin, an iron-containing protein that binds oxygen. White blood cells fight disease. Platelets clot to prevent extreme blood loss resulting from injury.
Bone(骨)
Rigid structures composed of living cells rooted in a matrix of calcium, phosphate salts, and collagen fibers. Bones are the primary component of most vertebrate skeletons.
Brain(脑)
The center of the central nervous system. The brain coordinates the processes of the body. It is composed of various distinct regions, all of which have different functions, including the cerebrum, cerebellum, medulla oblongata, and hypothalamus.
Bryophyte(苔藓植物)
A lower terrestrial plant (often a moss or liverwort) that lacks a vascular system and is dependent on environmental moisture for reproductive and nutritive functions.
Budding(萌芽)
Asexual reproductive process in which a small portion of the cell membrane and cytoplasm receive a nucleus and pinch off from the parent cell.
Buffer(缓冲液)
Solutions that resist change in pH even when acids and bases are added.
Bulb(球茎)
Roughly spherical underground bud containing additional buds that can develop asexually into new plants.
相关推荐: