Cầu tiếng Anh

Physiological adjustment to a change in an environmental factor. ā ace

Acetyl coenzyme A; the entry compound for the citric acid cycle in cellular respiration, formed from a two-carbon fragment of pyruvate attached to a coenzyme. a/ah ash ch chose ē meet e/eh bet

One of the most common neurotransmitters; functions by binding to receptors and altering the permeability of the postsynaptic membrane to specific ions, either depolarizing or hyperpolarizing the membrane. g game ī ice i hit ks box

A substance that increases the hydrogen ion concentration of a solution. kw quick ng song

The symptoms and signs present during the late stages of HIV infection, defined by a specified reduction in the number of T cells and the appearance of characteristic secondary infections. ō robe o ox oy boy s say sh shell

The discharge of hydrolytic enzymes from the acrosome, a vesicle in the tip of a sperm, when the sperm approaches or contacts an egg. th thin ū boot u/uh up

A vesicle in the tip of a sperm containing hydrolytic enzymes and other proteins that help the sperm reach the egg. z zoo primary accent

A globular protein that links into chains, two of which twist helically about each other, forming microfilaments (actin filaments) in muscle and other kinds of cells. secondary accent

A modified form of guanine nucleotide added onto the 5 end of a pre-mRNA molecule.

A model of flower formation identifying three classes of organ identity genes that direct formation of the four types of floral organs.

An electrical signal that propagates (travels) along the membrane of a neuron or other excitable cell as a nongraded (all-or-none) depolarization.

A graph that profiles the relative effectiveness of different wavelengths of radiation in driving a particular process.

Nonliving; referring to the physical and chemical properties of an environment.

The termination of a pregnancy in progress.

The amount of energy that reactants must absorb before a chemical reaction will start; also called free energy of activation.

A protein that binds to DNA and stimulates gene transcription. In prokaryotes, activators bind in or near the promoter; in eukaryotes, activators generally bind to control elements in enhancers.

A plant hormone that slows growth, often antagonizing the actions of growth hormones. Two of its many effects are to promote seed dormancy and facilitate drought tolerance.

The third stage of food processing in animals: the uptake of small nutrient molecules by an organism’s body.

The range of a pigment’s ability to absorb various wavelengths of light; also a graph of such a range.

Long-lasting immunity conferred by the action of B cells and T cells and the resulting B and T memory cells specific for a pathogen. Active immunity can develop as a result of natural infection or immunization.

The specific region of an enzyme that binds the substrate and that forms the pocket in which catalysis occurs.

The part of the ocean’s benthic zone between 2,000 and 6,000 m deep.

The movement of a substance across a cell membrane against its concentration or electrochemical gradient, mediated by specific transport proteins and requiring an expenditure of energy.

Any of a group of ancient jawed aquatic vertebrates from the Silurian and Devonian periods.

A fruit, or assemblage of fruits, in which the fleshy parts are derived largely or entirely from tissues other than the ovary.

Inherited characteristic of an organism that enhances its survival and reproduction in a specific environment. GLOSSARY

A process in which traits that enhance survival or reproduction tend to increase in frequency over time, resulting in a better match between organisms and their environment.

A vertebrate-specific defense that is mediated by B lymphocytes (B cells) and T lymphocytes (T cells) and that exhibits specificity, memory, and selfnonself recognition; also called acquired immunity.

Period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities.

A rule of probability stating that the probability of any one of two or more mutually exclusive events occurring can be determined by adding their individual probabilities.

See ATP (adenosine triphosphate).

An enzyme that converts ATP to cyclic AMP in response to an extracellular signal.

The clinging of one substance to another, such as water to plant cell walls, in this case by means of hydrogen bonds.

A connective tissue that insulates the body and serves as a fuel reserve; contains fat-storing cells called adipose cells.

One of two endocrine glands located adjacent to the kidneys in mammals. Endocrine cells in the outer portion (cortex) respond to adrenocorticotropic hormone (ACTH) by secreting steroid hormones that help maintain homeostasis during long-term stress. Neurosecretory cells in the central portion (medulla) secrete epinephrine and norepinephrine in response to nerve signals triggered by short-term stress.

A catabolic pathway for organic molecules, using oxygen (O 2 ) as the final electron acceptor in an electron transport chain and ultimately producing ATP. This is the most efficient catabolic pathway and is carried out in most eukaryotic cells and many prokaryotic organisms.

The relative number of individuals of each age in a population.

A fruit derived from a single flower that has more than one carpel.

The symptoms and signs present during the late stages of HIV infection, defined by a specified reduction in the number of T cells and the appearance of characteristic secondary infections.

Glycolysis followed by the reduction of pyruvate to ethyl alcohol, regenerating NAD and releasing carbon dioxide. Glossary

A general term for any species of photosynthetic protist, including both unicellular and multicellular forms. Algal species are included in three eukaryote supergroups (Excavata, SAR, and Archaeplastida). Glossary

A complete digestive tract, consisting of a tube running between a mouth and an anus.

A deep-sea hydrothermal vent that releases water that is warm (40–90°C) rather than hot and that has a high pH (is basic). These vents consist of tiny pores lined with iron and other catalytic minerals that some scientists hypothesize might have been the location of the earliest abiotic synthesis of organic compounds.

Any of the alternative versions of a gene that may produce distinguishable phenotypic effects.

The formation of new species in populations that are geographically isolated from one another.

A fertile individual that has more than two chromosome sets as a result of two different species interbreeding and combining their chromosomes.

The binding of a regulatory molecule to a protein at one site that affects the function of the protein at a different site.

A coiled region constituting one form of the secondary structure of proteins, arising from a specific pattern of hydrogen bonding between atoms of the polypeptide backbone (not the side chains).

A life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte; characteristic of plants and some algae.

A type of eukaryotic gene regulation at the RNA-processing level in which different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns.

Selflessness; behavior that reduces an individual’s fitness while increasing the fitness of another individual.

One of the three major subgroups for which the SAR eukaryotic supergroup is named. This clade arose by secondary endosymbiosis, and its members have membrane-enclosed sacs (alveoli) located just under the plasma membrane.

One of the dead-end air sacs where gas exchange occurs in a mammalian lung.

An agerelated dementia (mental deterioration) characterized by confusion and memory loss.

An organic molecule possessing both a carboxyl and an amino group. Amino acids serve as the monomers of polypeptides.

A chemical group consisting of a nitrogen atom bonded to two hydrogen atoms; can act as a base in solution, accepting a hydrogen ion and acquiring a charge of 1 .

An enzyme that joins each amino acid to the appropriate tRNA.

A small, toxic molecule (NH 3 ) produced by nitrogen fixation or as a metabolic waste product of protein and nucleic acid metabolism.

A member of a group of shelled cephalopods that were important marine predators for hundreds of millions of years until their extinction at the end of the Cretaceous period (65.5 million years ago).

A technique associated with prenatal diagnosis in which amniotic fluid is obtained by aspiration from a needle inserted into the uterus. The fluid and the fetal cells it contains are analyzed to detect certain genetic and congenital defects in the fetus.

A member of a clade of tetrapods named for a key derived character, the amniotic egg, which contains specialized membranes, including the fluid-filled amnion, that protect the embryo. Amniotes include mammals as well as birds and other reptiles.

An egg that contains specialized membranes that function in protection, nourishment, and gas exchange. The amniotic egg was a major evolutionary innovation, allowing embryos to develop on land in a fluid-filled sac, thus reducing the dependence of tetrapods on water for reproduction.

A protist characterized by the presence of pseudopodia.

An amoeba-like cell that moves by pseudopodia and is found in most animals. Depending on the species, it may digest and distribute food, dispose of wastes, form skeletal fibers, fight infections, or change into other cell types.

A protist in a clade that includes many species with lobeor tube-shaped pseudopodia.

A member of the clade of tetrapods that includes salamanders, frogs, and caecilians.

Having both a hydrophilic region and a hydrophobic region.

The strengthening of stimulus energy during transduction.

A structure in the temporal lobe of the vertebrate brain that has a major role in the processing of emotions.

An enzyme that hydrolyzes starch (a glucose polymer from plants) and glycogen (a glucose polymer from animals) into smaller polysaccharides and the disaccharide maltose.

A metabolic pathway that consumes energy to synthesize a complex molecule from simpler molecules.

A catabolic pathway in which inorganic molecules other than oxygen accept electrons at the “downhill” end of electron transport chains.

Having characteristics that are similar because of convergent evolution, not homology.

Similarity between two species that is due to convergent evolution rather than to descent from a common ancestor with the same trait.

The fourth stage of mitosis, in which the chromatids of each chromosome have separated and the daughter chromosomes are moving to the poles of the cell.

The structure of an organism.

The requirement that a cell must be attached to a substratum in order to initiate cell division.

Any steroid hormone, such as testosterone, that stimulates the development and maintenance of the male reproductive system and secondary sex characteristics.

A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number.

A flowering plant, which forms seeds inside a protective chamber called an ovary.

A dormant state involving loss of almost all body water.

The point at the end of an egg in the hemisphere where the least yolk is concentrated; opposite of vegetal pole.

A negatively charged ion.

Pertaining to the front, or head, of a bilaterally symmetrical animal.

A portion of the pituitary gland that develops from nonneural tissue; consists of endocrine cells that synthesize and secrete several tropic and nontropic hormones.

In an angiosperm, the terminal pollen sac of a stamen, where pollen grains containing sperm-producing male gametophytes form.

In plants, the male gametangium, a moist chamber in which gametes develop.

A member of a primate group made up of the monkeys and the apes (gibbons, orangutans, gorillas, chimpanzees, bonobos, and humans).

A protein secreted by plasma cells (differentiated B cells) that binds to a particular antigen; also called immunoglobulin. All antibodies have the same Y-shaped structure and in their monomer form consist of two identical heavy chains and two identical light chains.

A nucleotide triplet at one end of a tRNA molecule that base-pairs with a particular complementary codon on an mRNA molecule.

A peptide hormone, also called vasopressin, that promotes water retention by the kidneys. Produced in the hypothalamus and released from the posterior pituitary, ADH also functions in the brain.

A substance that elicits an immune response by binding to receptors of B or T cells.

The process by which an MHC molecule binds to a fragment of an intracellular protein antigen and carries it to the cell surface, where it is displayed and can be recognized by a T cell.

A cell that upon ingesting pathogens or internalizing pathogen proteins generates peptide fragments that are bound by class II MHC molecules and subsequently displayed on the cell surface to T cells. Macrophages, dendritic cells, and B cells are the primary antigenpresenting cells.

A symbiotic fungus whose hyphae grow through the cell wall of plant roots and extend into the root cell (enclosed in tubes formed by invagination of the root cell plasma membrane).

The general term for a surface protein, located on B cells and T cells, that binds to antigens, initiating adaptive immune responses. The antigen receptors on B cells are called B cell receptors, and the antigen receptors on T cells are called T cell receptors.

Referring to the arrangement of the sugar-phosphate backbones in a DNA double helix (they run in opposite 5 3 directions).

Specialized branching hyphae that are found in some mutualistic fungi and exchange nutrients with living plant cells.

One of two prokaryotic domains, the other being Bacteria.

One of four supergroups of eukaryotes proposed in a current hypothesis of the evolutionary history of eukaryotes. This monophyletic group, which includes red algae, green algae, and plants, descended from an ancient protistan ancestor that engulfed a cyanobacterium. See also Excavata, SAR, and Unikonta.

The part of an ocean or lake beneath the photic zone, where light does not penetrate sufficiently for photosynthesis to occur.

A bud at the tip of a plant stem; also called a terminal bud.

In plants, the female gametangium, a moist chamber in which gametes develop.

Tendency for growth to be concentrated at the tip of a plant shoot because the apical bud partially inhibits axillary bud growth.

The endodermlined cavity, formed during gastrulation, that develops into the digestive tract of an animal.

A thickened area of ectoderm at the tip of a limb bud that promotes outgrowth of the limb bud.

A member of the reptilian group that includes crocodiles, alligators and dinosaurs, including birds.

A localized region at a growing tip of a plant body where one or more cells divide repeatedly. The dividing cells of an apical meristem enable the plant to grow in length.

A vessel that conveys blood between an artery and a capillary bed.

A vessel that carries blood away from the heart to organs throughout the body.

A segmented ecdysozoan with a hard exoskeleton and jointed appendages. Familiar examples include insects, spiders, millipedes, and crabs.

A group of alveolate protists, this clade includes many species that parasitize animals. Some apicomplexans cause human disease.

The ability of some plant species to reproduce asexually through seeds without fertilization by a male gamete.

The selective breeding of domesticated plants and animals to encourage the occurrence of desirable traits.

Everything external to the plasma membrane of a plant cell, including cell walls, intercellular spaces, and the space within dead structures such as xylem vessels and tracheids.

The fruiting body of a sac fungus (ascomycete).

A member of the fungal phylum Ascomycota, commonly called sac fungus. The name comes from the saclike structure in which the spores develop.

A type of programmed cell death, which is brought about by activation of enzymes that break down many chemical components in the cell.

A saclike spore capsule located at the tip of a dikaryotic hypha of a sac fungus.

The generation of offspring from a single parent that occurs without the fusion of gametes. In most cases, the offspring are genetically identical to the parent.

The bright warning coloration of many animals with effective physical or chemical defenses.

A small, finger-like extension of the vertebrate cecum; contains a mass of white blood cells that contribute to immunity.

A channel protein in a cellular membrane that specifically facilitates osmosis, the diffusion of free water across the membrane.

One of a ribosome’s three binding sites for tRNA during translation. The A site holds the tRNA carrying the next amino acid to be added to the polypeptide chain. (A stands for aminoacyl tRNA.)

The translocation of a species to a favorable habitat beyond its native range for the purpose of protecting the species from human-caused threats.

A solution in which water is the solvent.

A member of a subgroup of the major arthropod clade Chelicerata. Arachnids have six pairs of appendages, including four pairs of walking legs, and include spiders, scorpions, ticks, and mites.

The acquired ability to associate one environmental feature (such as a color) with another (such as danger).

A cardiovascular disease in which fatty deposits called plaques develop in the inner walls of the arteries, obstructing the arteries and causing them to harden.

Association of a fungus GLOSSARY

The smallest unit of matter that retains the properties of an element. with a plant root system in which the fungus causes the invagination of the host (plant) cells’ plasma membranes; also called endomycorrhiza.

The total mass of an atom, numerically equivalent to the mass in grams of 1 mole of the atom. (For an element with more than one isotope, the atomic mass is the average mass of the naturally occurring isotopes, weighted by their abundance.)

An atom’s dense central core, containing protons and neutrons.

The number of protons in the nucleus of an atom, unique for each element and designated by a subscript.

An adenine-containing nucleoside triphosphate that releases free energy when its phosphate bonds are hydrolyzed. This energy is used to drive endergonic reactions in cells.

A complex of several membrane proteins that functions in chemiosmosis with adjacent electron transport chains, using the energy of a hydrogen ion (proton) concentration gradient to make ATP. ATP synthases are found in the inner mitochondrial membranes of eukaryotic cells and in the plasma membranes of prokaryotes.

A peptide hormone secreted by cells of the atria of the heart in response to high blood pressure. ANP’s effects on the kidney alter ion and water movement and reduce blood pressure.

A region of specialized heart muscle tissue between the left and right atria where electrical impulses are delayed for about 0.1 second before spreading to both ventricles and causing them to contract.

A heart valve located between each atrium and ventricle that prevents a backflow of blood when the ventricle contracts.

A chamber of the vertebrate heart that receives blood from the veins and transfers blood to a ventricle.

Referring to a secreted molecule that acts on the cell that secreted it.

An immunological disorder in which the immune system turns against self.

An efferent branch of the vertebrate peripheral nervous system that regulates the internal environment; consists of the sympathetic and parasympathetic divisions and the enteric nervous system.

An individual that has more than two chromosome sets that are all derived from a single species.

A chromosome that is not directly involved in determining sex; not a sex chromosome.

An organism that obtains organic food molecules without eating other organisms or substances derived from other organisms. Autotrophs use energy from the sun or from oxidation of inorganic substances to make organic molecules from inorganic ones.

A term that primarily refers to indoleacetic acid (IAA), a natural plant Glossary hormone that has a variety of effects, including cell elongation, root formation, secondary growth, and fruit growth. Glossary

A structure that has the potential to form a lateral shoot, or branch. The bud appears in the angle formed between a leaf and a stem.

A typically long extension, or process, of a neuron that carries nerve impulses away from the cell body toward target cells.

The lymphocytes that complete their development in the bone marrow and become effector cells for the humoral immune response.

One of two prokaryotic domains, the other being Archaea.

A virus that infects bacteria; also called a phage.

A form of the bacterium Rhizobium contained within the vesicles formed by the root cells of a root nodule.

Natural selection that maintains two or more phenotypic forms in a population.

A graph in which the independent variable represents groups or nonnumerical categories and the values of the dependent variable(s) are shown by bars.

All tissues external to the vascular cambium, consisting mainly of the secondary phloem and layers of periderm.

A dense object lying along the inside of the nuclear envelope in cells of female mammals, representing a highly condensed, inactivated X chromosome.

A member of one of three clades of early-diverging lineages of extant flowering plants. Examples are Amborella , water lilies, and star anise and its relatives.

A eukaryotic cell structure consisting of a “9 0” arrangement of microtubule triplets. The basal body may organize the microtubule assembly of a cilium or flagellum and is structurally very similar to a centriole.

The metabolic rate of a resting, fasting, and nonstressed endotherm at a comfortable temperature.

In a specified group of organisms, a taxon whose evolutionary lineage diverged early in the history of the group.

A substance that reduces the hydrogen ion concentration of a solution.

Elaborate fruiting body of a dikaryotic mycelium of a club fungus.

A member of the fungal phylum Basidiomycota, commonly called club fungus. The name comes from the club-like shape of the basidium.

(buh-sid -ē-um, buh-sid -ē-ah) A reproductive appendage that produces sexual spores on the gills of mushrooms (club fungi).

A type of mimicry in which a harmless species resembles an unpalatable or harmful species to which it is not closely related.

Individually, an action carried out by muscles or glands under control of the nervous system in response to a stimulus; collectively, the sum of an animal’s responses to external and internal stimuli.

The study of behavioral interactions between individuals within populations and communities, usually in an evolutionary context.

A mass of abnormal cells with specific genetic and cellular changes such that the cells are not capable of surviving at a new site and generally remain at the site of the tumor’s origin.

The bottom surface of an aquatic environment.

The communities of organisms living in the benthic zone of an aquatic biome.

One form of the secondary structure of proteins in which the polypeptide chain folds back and forth. Two regions of the chain lie parallel to each other and are held together by hydrogen bonds between atoms of the polypeptide backbone (not the side chains).

A metabolic sequence that breaks fatty acids down to two-carbon fragments that enter the citric acid cycle as acetyl CoA.

Body symmetry in which a central longitudinal plane divides the body into two equal but opposite halves.

A member of a clade of animals with bilateral symmetry and three germ layers.

A mixture of substances that is produced in the liver and stored in the gallbladder; enables formation of fat droplets in water as an aid in the digestion and absorption of fats.

A method of asexual reproduction in single-celled organisms in which the cell grows to roughly double its size and then divides into two cells. In prokaryotes, binary fission does not involve mitosis, but in singlecelled eukaryotes that undergo binary fission, mitosis is part of the process.

A common term for the two-part, latinized format for naming a species, consisting of the genus and specific epithet; also called a binomen.

A relatively small area with numerous endemic species and a large number of endangered and threatened species.

(1) The overall flow and transformation of energy in an organism. (2) The study of how energy flows through organisms.

A surface-coating colony of one or more species of unicellular organisms that engage in metabolic cooperation; most known biofilms are formed by prokaryotes.

A fuel produced from biomass.

Any of the various chemical cycles, which involve both biotic and abiotic components of ecosystems.

The scientific study of the past and present geographic distributions of species.

The use of computers, software, and mathematical models to process and integrate biological information from large data sets.

An approach to restoration ecology that uses organisms to add essential materials to a degraded ecosystem.

An internal timekeeper that controls an organism’s biological rhythms. The biological clock marks time with or without environmental cues but often requires signals from the environment to remain tuned to an appropriate period. See also circadian rhythm.

A process in which retained substances become more concentrated at each higher trophic level in a food chain.

Definition of a species as a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring but do not produce viable, fertile offspring with members of other such groups.

The scientific study of life.

The total mass of organic matter comprising a group of organisms in a particular habitat.

Any of the world’s major ecosystem types, often classified according to the predominant vegetation for terrestrial biomes and the physical environment for aquatic biomes and characterized by adaptations of organisms to that particular environment.

The use of organisms to detoxify and restore polluted and degraded ecosystems.

The entire portion of Earth inhabited by life; the sum of all the planet’s ecosystems.

The manipulation of organisms or their components to produce useful products.

Pertaining to the living factors— the organisms—in an environment.

A depressive mental illness characterized by swings of mood from high to low; also called manic-depressive disorder.

A hormonal contraceptive that inhibits ovulation, retards follicular development, or alters a woman’s cervical mucus to prevent sperm from entering the uterus.

(1) A leaflike structure of a seaweed that provides most of the surface area for photosynthesis. (2) The flattened portion of a typical leaf.

The fluid-filled cavity that forms in the center of a blastula.