下面为大家整理的是以字母P开头的SAT2生物考试中常用词汇。掌握一定的生物词汇是备考SAT2的首要前提。所以，各位考生一定要多加重视词汇的积累，预祝各位考生考试成功。

Pancreas(胰)

A digestive organ that releases enzymes into the small intestine. Also an endocrine gland that regulates glucose levels in the blood by the release of insulin or glucagon from specialized cells called islets of Langerhans.

Parathyroid(甲状旁腺)

Four small glands embedded on the posterior surface of the thyroid gland. The parathyroid glands produce a hormone that regulates the level of calcium in the bloodstream.

Parthenogenesis(单性生殖)

Asexual reproduction in which an unfertilized gamete (usually female) produces female offspring. Parthenogenesis vastly increases the speed at which a population can grow, though it results in a loss of genetic diversity among members of the population.

pelagic zone(远洋带)

The open-ocean zone at the greatest depth in a marine habitat. This zone is divided into a photic (down to 600 feet below the water’s surface) and aphotic zone.

peptide bond(肽键)

The bond between the amino acids in a protein. Formed by dehydration synthesis.

peripheral nervous system (PNS/外周神经系统)

The pathways by which the central nervous system receives sensory information from the body and sends commands to muscles. The peripheral nervous system is divided into two halves. The sensory system brings information in from the body, while the motor system sends commands out to muscles.

Peristalsis(蠕动)

The rolling motion of smooth muscle that moves food along the alimentary canal. Includes the passage from the esophagus to the stomach, the churning action of the stomach, and the passage through the small intestine.

pH

A scale for measuring the presence or absence of hydrogen ions in solution. Values between 0 and 7 indicate an excess of hydrogen ions. Such solutions are called acids. Values between 7 and 14 indicate the presence of compounds that counteract the effects of hydrogen ions. Such solutions are called bases. At pH 7, solutions are neutral.

Phagocyte(吞噬细胞)

A type of white blood cell that kills invading cells by ingesting them.

Phagocytosis(吞噬作用)

A form of endocytosis in which a cell ingests a solid particle.

Phenotype(表现性)

The entire set of observable characteristics of an organism or cell; the physical traits of an organism. The genotype, together with environmental factors, defines the phenotype.

Phloem(韧皮部)

Vascular tissue composed of cells that are living at maturity; transports the products of photosynthesis throughout the plant body.

Phospholipid(磷脂)

Type of lipid found in cell membranes. Phospholipids are made up of a single hydrophilic phosphate head and two nonpolar hydrophobic lipid tails.

phospholipid bilayer(磷脂双分子层)

A double layer of phospholipid molecules that provides the structure of the cell membrane. Formed naturally from the alignment of the two layers of lipids such that their hydrophobic tails point inward toward each other and their hydrophilic phosphate heads point outward into the watery environments inside and outside of the cell.

photic zone(透光层)

Literally, zone with light. The photic zone is part of the marine pelagic zone and extends to 600 feet below the surface of the ocean. Photosynthetic plankton as well as bony fish, sharks, and whales inhabit this zone.

Photoperiodism(光周期性)

An organism’s response to the length of day and night within a 24-hour period (photoperiod); in many plants, this phenomenon determines when flowering occurs.

Photosynthesis(光合作用)

The process by which plants and other autotrophic organisms convert light energy into organic materials, such as glucose.

Phylogeny(种系发展史)

The evolutionary relationships of a genetically similar group of organisms.

Pinocytosis(胞饮作用)

Form of endocytosis during which liquids are taken into the cell through the invagination of the cell membrane.

pioneer population(先锋群体)

The first population to move into a geographic location and begin the process of ecological succession.

Pistil(雌蕊)

The female reproductive organ of the flower, composed of a stigma, style, and ovary; sometimes called the carpel.

Pituitary(垂体)

The “master” gland of the endocrine system. The pituitary releases hormones that control the other major glands of the endocrine system. Made up of the anterior and posterior pituitary. Controlled by the hypothalamus.

Placenta(胎盘)

A structure that develops in the uterus during pregnancy; filter through which the embryo gains nutrition from the mother.

Plasmids(质体)

Circular DNA molecules found in prokaryotes.

Pollen(花粉)

The male gametophyte of gymnosperms and angiosperms.

Polymer(聚合物)

A large molecule consisting of the same or similar units attached in a series, forming a chain.

Population(族群)

A group of interbreeding organisms in a particular locale exhibiting a unique set of characteristics such as patterns of growth and reproductive strategies.

Predation(掠夺)

Term that refers to one organism eating another. Predation covers both carnivorous and herbivorous consumption.

Producers(生产者)

Autotrophic organisms such as plants, plankton, and chemosynthetic bacteria that are able to synthesize organic compounds using energy from the sun or chemical reactions. Producers do not have to consume other organisms to attain energy and are the foundation of every food web.

Progesterone(黄体酮)

Hormone that prepares the uterus for embryo implantation and helps to maintain pregnancy.

Prokaryote(原核生物)

A single-celled organism that completely lacks membrane-bound intracellular organelles such as a nucleus or mitochondria; prokaryotes possess only a single circular strand of DNA. Prokaryotes are simpler than eukaryotes and arose earlier in evolutionary history. All bacteria are prokaryotes. Taxonomists group all prokaryotes into the kingdom Monera.

Prophase(前期)

The first stage of mitosis, meiosis I, and meiosis II, during which the chromosomes become visible and the centrioles move to opposite ends of the cell and begin to form the spindle.

Pseudopods(伪足)

Temporary cytoplasmic protrusions of ameboid cells that function in movement and food uptake by phagocytosis.

Punnett square(旁尼特方格)：用棋盘方式计算子2代基因型及表现形比例的方法

A pictorial method of showing the gene combinations (genotypes) of offspring that might result from an experimental genetic cross of two parents.

Pyruvate(丙酮酸)

The three-carbon end product of glycolysis. Pyruvate is the raw material of the Krebs cycle.

以上就是关于SAT2生物考试常用词汇的全面内容，是以P开头的。各位考生可以作为备考时的参考资料，希望对各位考生的SAT2考试有所帮助。

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