Abjad P

JEJAK MAHASISWA	..:: KAMUS BIOLOGI JEJAK MAHASISWA ::..															Dibuat 12/19/2011
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Glosarium ini diambil dari Buku Biologi Campbell | Jejak Mahasiswa

P site

Peptidyl-tRNA site; the binding site on a ribosome that holds the tRNA carrying a growing polypeptide chain.

pacemaker

A specialized region of the right atrium of the mammalian heart that sets the rate of contraction; also called the sinoatrial (SA) node.

paedogenesis

(pee-doh-JEN-eh-sis) The precocious development of sexual maturity in a larva.

paedogenesis

(pee-doh-JEN-eh-sis) The precocious development of sexual maturity in a larva.

paleontology

(PAY-lee-un-TOL-uh-jee) The scientific study of fossils.

Pangaea

(pan-JEE-uh) The supercontinent formed near the end of the Paleozoic era when plate movements brought all the land masses of Earth together.

paraphyletic

(PAR-uh-FY-leh-tik) Pertaining to a taxon that excludes some members that share a common ancestor with members included in the taxon.

parasite

(PAR-uh-site) An organism that absorbs nutrients from the body fluids of living hosts.

parasitism

A symbiotic relationship in which the symbiont (parasite) benefits at the expense of the host by living either within the host (endoparasite) or outside the host (ectoparasite).

parasympathetic division

One of two divisions of the autonomic nervous system; generally enhances body activities that gain and conserve energy, such as digestion and reduced heart rate.

parathyroid glands

Four endocrine glands, embedded in the surface of the thyroid gland, that secrete parathyroid hormone and raise blood calcium levels.

parazoa

(PAR-uh-ZOH-uh) Members of the subkingdom of animals consisting of the sponges.

parenchyma

(pur-EN-kim-uh) A relatively unspecialized plant cell type that carries most of the metabolism, synthesizes and stores organic products, and develops into more differentiated cell types.

parthenogenesis

(PAR-then-oh-JEN-eh-sis) A type of reproduction in which females produce offspring from unfertilized eggs.

partial pressure

The concentration of gases; a fraction of total pressure.

passive transport

The diffusion of a substance across a biological membrane.

pattern formation

The ordering of cells into specific three-dimensional structures, an essential part of shaping an organism and its individual parts during development.

pedigree

A family tree describing the occurrence of heritable characters in parents and offspring across as many generations as possible.

pelagic zone

(pel-AY-jik) The area of the ocean past the continental shelf, with areas of open water often reaching to very great depths.

peptide bond

The covalent bond between two amino acid units, formed by condensation synthesis.

peptidoglycan

(PEP-tid-oh-GLY-kan) A type of polymer in bacterial cell walls consisting of modified sugars cross-linked by short polypeptides.

perception

The interpretation of sensations by the brain.

perennial

(pur-EN-ee-ul) A plant that lives for many years.

pericycle

(PAIR-eh-sy-kul) A layer of cells just inside the endodermis of a root that may become meristematic and begin dividing again.

periderm

(PAIR-eh-durm) The protective coat that replaces the epidermis in plants during secondary growth, formed of the cork and cork cambium.

peripheral nervous system

The sensory and motor neurons that connect to the central nervous system.

peristalsis

(PAIR-is-TAL-sis) Rhythmic waves of contraction of smooth muscle that push food along the digestive tract.

peroxisome

(pur-OKS-eh-some) A microbody containing enzymes that transfer hydrogen from various substrates to oxygen, producing and then degrading hydrogen peroxide.

petiole

(PET-ee-ole) The stalk of a leaf, which joins the leaf to a node of the stem.

pH scale

A measure of hydrogen ion concentration equal to -log [H⁺] and ranging in value from 0 to 14.

phage

(fage) A virus that infects bacteria; also called a bacteriophage.

phagocytosis

(FAY-goh-sy-TOH-sis) A type of endocytosis involving large, particulate substances.

pharynx

(FAH-rinks) An area in the vertebrate throat where air and food passages cross; in flatworms, the muscular tube that protrudes from the ventral side of the worm and ends in the mouth.

phenetics

(feh-NEH-tiks) An approach to taxonomy based entirely on measurable similarities and differences in phenotypic characters, without consideration of homology, analogy, or phylogeny.

phenotype

(FEE-nuh-type) The physical and physiological traits of an organism.

pheromone

(FAIR-uh-mone) A small, volatile chemical signal that functions in communication between animals and acts much like a hormone in influencing physiology and behavior.

phloem

(FLOH-um) The portion of the vascular system in plants consisting of living cells arranged into elongated tubes that transport sugar and other organic nutrients throughout the plant.

phosphate group

(FOS-fate) A functional group important in energy transfer.

phospholipids

(FOS-foh-LIP-ids) Molecules that constitute the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail.

photic zone

(FOH-tik) The narrow top slice of the ocean, where light permeates sufficiently for photosynthesis to occur.

photoautotroph

(FOH-toh-AW-toh-trohf) An organism that harnesses light energy to drive the synthesis of organic compounds from carbon dioxide.

photoheterotroph

(FOH-toh-HET-ur-oh-trohf) An organism that uses light to generate ATP but that must obtain carbon in organic form.

photon

(FOH-tahn) A quantum, or discrete amount, of light energy.

photoperiodism

(FOH-toh-PEER-ee-od-iz-um) A physiological response to day length, such as flowering in plants.

photophosphorylation

(FOH-toh-fos-for-uh-LAY-shun) The process of generating ATP from ADP and phosphate by means of a proton-motive force generated by the thylakoid membrane of the chloroplast during the light reactions of photosynthesis.

photorespiration

A metabolic pathway that consumes oxygen, releases carbon dioxide, generates no ATP, and decreases photosynthetic output; generally occurs on hot, dry, bright days, when stomata close and the oxygen concentration in the leaf exceeds that of carbon dioxide.

photosynthesis

The conversion of light energy to chemical energy that is stored in glucose or other organic compounds; occurs in plants, algae, and certain prokaryotes.

photosystem

The light-harvesting unit in photosynthesis, located on the thylakoid membrane of the chloroplast and consisting of the antenna complex, the reaction-center chlorophyll a, and the primary electron acceptor. There are two types of photosystems, I and II; they absorb light best at different wavelengths.

phototropism

(FOH-toh-TROH-piz-um) Growth of a plant shoot toward or away from light.

phylogeny

(fih-LOJ-en-ee) The evolutionary history of a species or group of related species.

phylum

A taxonomic category; phyla are divided into classes.

phytoalexin

(fy-toh-ah-LEK-sin) An antibiotic, produced by plants, that destroys microorganisms or inhibits their growth.

phytochrome

(FY-tuh-krome) A pigment involved in many responses of plants to light.

pilus

(PILL-us) (plural, pili) A surface appendage in certain bacteria that functions in adherence and the transfer of DNA during conjugation.

pineal gland

(PIN-ee-ul) A small endocrine gland on the dorsal surface of the vertebrate forebrain; secretes the hormone melatonin, which regulates body functions related to seasonal day length.

pinocytosis

(PY-noh-sy-TOH-sis) A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.

pith

The core of the central vascular cylinder of monocot roots, consisting of parenchyma cells, which are ringed by vascular tissue; ground tissue interior to vascular bundles in dicot stems.

pituitary gland

(pih-TOO-ih-tair-ee) An endocrine gland at the base of the hypothalamus; consists of a posterior lobe (neurohypophysis), which stores and releases two hormones produced by the hypothalamus, and an anterior lobe (adenohypophysis), which produces and secretes many hormones that regulate diverse body functions.

placenta

(pluh-SEN-tuh) A structure in the pregnant uterus for nourishing a viviparous fetus with the mother's blood supply; formed from the uterine lining and embryonic membranes.

placental mammal

A member of a group of mammals, including humans, whose young complete their embryonic development in the uterus, joined to the mother by a placenta.

placoderm

(PLAK-oh-durm) A member of an extinct class of fishlike vertebrates that had jaws and were enclosed in a tough, outer armor.

plankton

Mostly microscopic organisms that drift passively or swim weakly near the surface of oceans, ponds, and lakes.

plasma cell

A derivative of B cells that secretes antibodies.

plasma membrane

The membrane at the boundary of every cell that acts as a selective barrier, thereby regulating the cell's chemical composition.

plasma

(PLAZ-muh) The liquid matrix of blood in which the cells are suspended.

plasmid

(PLAZ-mid) A small ring of DNA that carries accessory genes separate from those of a bacterial chromosome.

plasmodesma

(PLAZ-moh-DEZ-muh) (plural, plasmodesmata) An open channel in the cell wall of plants through which strands of cytosol connect from adjacent cells.

plasmogamy

The fusion of the cytoplasm of cells from two individuals; occurs as one stage of syngamy.

plasmolysis

(plaz-MOL-eh-sis) A phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall when the cell loses water to a hypertonic environment.

plastid

One of a family of closely related plant organelles, including chloroplasts, chromoplasts, and amyloplasts (leucoplasts).

platelet

A small enucleated blood cell important in blood clotting; derived from large cells in the bone marrow.

pleated sheet

One form of the secondary structure of proteins in which the polypeptide chain folds back and forth, or where two regions of the chain lie parallel to each other and are held together by hydrogen bonds.

pleiotropy

(PLY-eh-troh-pee) The ability of a single gene to have multiple effects.

plesiomorphic character

(PLEEZ-ee-oh-MOR-fik) A primitive phenotypic character possessed by a remote ancestor.

pluripotent stem cell

A cell within bone marrow that is a progenitor for any kind of blood cell.

point mutation

A change in a gene at a single nucleotide pair.

polar covalent bond

A type of covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.

polar molecule

A molecule (such as water) with opposite charges on opposite sides.

pollen grain

An immature male gametophyte that develops within the anthers of stamens in a flower.

pollination

(POL-eh-NAY-shun) The placement of pollen onto the stigma of a carpel by wind or animal carriers, a prerequisite to fertilization.

poly-A tail

During RNA processing, a nucleotide complex at the 3' end of an mRNA molecule that helps inhibit degradation and enhances translation.

polyandry

(POL-ee-AN-dree) A polygamous mating system involving one female and many males.

polygenic inheritance

(POL-ee-JEN-ik) An additive effect of two or more gene loci on a single phenotypic character.

polygyny

(pol-IJ-en-ee) A polygamous mating system involving one male and many females.

polymer

(POL-eh-mur) A large molecule consisting of many identical or similar monomers linked together.

polymerase chain reaction

(PCR) A technique for amplifying DNA in vitro by incubating with special primers, DNA polymerase molecules and nucleotides.

polymorphic

(POL-ee-MOR-fik) Referring to a population in which two or more physical forms are present in readily noticeable frequencies.

polymorphism

(POL-ee-MOR-fiz-um) The coexistence of two or more distinct forms of individuals (polymorphic characters) in the same population.

polynucleotide

(POL-ee-NOO-klee-oh-tide) A polymer made up of many nucleotides covalently bonded together.

polyp

(POL-ip) The sessile variant of the cniderian body plan. The alternate form is the medusa.

polypeptide

(POL-ee-PEP-tide) A polymer (chain) of many amino acids linked together by peptide bonds.

polyphyletic

Pertaining to a taxon whose members were derived from two or more ancestral forms not common to all members.

polyploidy

(POL-ee-ploid-ee) A chromosomal alteration in which the organism possesses more than two complete chromosome sets.

polyribosome

(POL-ee-RY-boh-some) An aggregation of several ribosomes attached to one messenger RNA molecule.

polysaccharide

(POL-ee-SAK-ur-ide) A polymer of up to over a thousand monosaccharides, formed by condensation synthesis.

population

A group of individuals of one species that live in a particular geographic area.

positional information

Signals, to which genes regulating development respond, indicating a cell's location relative to other cells in an embryonic structure.

positive feedback

A physiological control mechanism in which a change in some variable triggers mechanisms that amplify the change.

postsynaptic membrane

(post-sin-AP-tik) The surface of the cell on the opposite side of the synapse from the synaptic terminal of the stimulating neuron that contains receptor proteins and degradative enzymes for the neurotransmitter.

postzygotic barrier

(POST-zy-GOT-ik) Any of several species-isolating mechanisms that prevent hybrids produced by two different species from developing into viable, fertile adults.

potential energy

The energy stored by matter as a result of its location or spatial arrangement.

predation

An interaction between species in which one species, the predator, eats the other, the prey.

prezygotic barrier

(PREE-zy-GOT-ik) A reproductive barrier that impedes mating between species or hinders fertilization of ova if interspecific mating is attempted.

primary consumer

An herbivore; an organism in the trophic level of an ecosystem that eats plants or algae.

primary germ layers

The three layers (ectoderm, mesoderm, endoderm) of the late gastrula, which develop into all parts of an animal.primary growth Growth initiated by the apical meristems of a plant root or shoot.

primary immune response

The initial immune response to an antigen, which appears after a lag of several days.

primary producer

An autotroph, which collectively make up the trophic level of an ecosystem that ultimately supports all other levels; usually a photosynthetic organism.

primary productivity

The rate at which light energy or inorganic chemical energy is converted to the chemical energy of organic compounds by autotrophs in an ecosystem.

primary structure

The level of protein structure referring to the specific sequence of amino acids.

primary succession

A type of ecological succession that occurs in an area where there were originally no organisms.

primer

An already existing RNA chain bound to the template DNA to which nucleotides must be added during DNA synthesis.

principle of allocation

The concept that each organism has an energy budget, or a limited amount of total energy available for all of its maintenance and reproductive needs.

prion

An infectious form of protein that may increase in number by converting related proteins to more prions.

procambium

(pro-KAM-bee-um) A primary meristem of roots and shoots that forms the vascular tissue.

progesterone

(pro-JES-teh-roan) A steroid hormone secreted by the corpus luteum of the ovary; maintains the uterine lining during pregnancy.

prokaryotic cell

(pro-KAR-ee-OT-ik) A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles; found only in the domains Bacteria and Archaea.

prometaphase

The phase of mitosis in which the nuclear envelope breaks into fragments. Some of the spindle fibers reach the chromosomes and attach to protein structures at the centromeres, called kinetochores, while others make contact with microtubules coming from the opposite pole. The opposing spindle fibers move the chromosomes toward the metaphase plate, an imaginary plane equidistant from the poles.

promoter

A specific nucleotide sequence in DNA that binds RNA polymerase and indicates where to start transcribing RNA.

prophage

(PRO-fage) A phage genome that has been inserted into a specific site on the bacterial chromosome.

prophase

The first stage of mitosis, during which duplicated chromosomes condense from chromatin, and the mitotic spindle forms and begins moving the chromosomes toward the center of the cell.

prostaglandin

(PG) (PROS-tuh-GLAN-din) One of a group of modified fatty acids secreted by virtually all tissues and performing a wide variety of functions as messengers.

prostate gland

A gland in human males that secretes an acid-neutralizing component of semen.

protein kinase

An enzyme that transfers phosphate groups from ATP to a protein.

protein

(PRO-teen) A three-dimensional biological polymer constructed from a set of 20 different monomers called amino acids.

proteoglycans

(pro-tee-oh-GLY-kanz) A glycoprotein in the extracellular matrix of animal cells, rich in carbohydrate.

protoderm

(PRO-toh-durm) The outermost primary meristem, which gives rise to the epidermis of roots and shoots.

proton pump

(PRO-tahn) An active transport mechanism in cell membranes that consumes ATP to force hydrogen ions out of a cell and, in the process, generates a membrane potential.

proton

A subatomic particle with a single positive electrical charge, found in the nucleus of the atom.

protonephridium

(PRO-toh-nef-RID-ee-um) An excretory system, such as the flame-cell system of flatworms, consisting of a network of closed tubules having external openings called nephridiopores and lacking internal openings.

proton-motive force

The potential energy stored in the form of an electrochemical gradient, generated by the pumping of hydrogen ions across biological membranes during chemiosmosis.

proto-oncogene

(PRO-toh-ONK-oh-jeen) A normal cellular gene corresponding to an oncogene; a gene with a potential to cause cancer, but that requires some alteration to become an oncogene.

protoplast

The contents of a plant cell exclusive of the cell wall.

protostome

(PRO-toh-stome) A member of one of two distinct evolutionary lines of coelomates, consisting of the annelids, mollusks, and arthropods, and characterized by spiral, determinate cleavage, schizocoelous formation of the coelom, and development of the mouth from the blastopore.

protozoan

(plural, protozoa) A protist that lives primarily by ingesting food, an animal-like mode of nutrition.

provirus

Viral DNA that inserts into a host genome.

proximate causation

The hypothesis about why natural selection favored a particular animal behavior.

pseudocoelomate

(SOO-doh-SEEL-oh-mate) An animal, such as a rotifer or roundworm, whose body cavity is not completely lined by mesoderm.

pseudopodium

(SOO-doh-POH-dee-um) (plural, pseudopodia) A cellular extension of amoeboid cells used in moving and feeding.

punctuated equilibrium

A theory of evolution advocating spurts of relatively rapid change followed by long periods of stasis.