Essential Biology Terms
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dankauffman on July 27, 2011
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291 terms
Terms | Definitions |
|---|---|
 energy | The capacity to perform work |
| kinetic energy | Energy that is actually doing work |
| conservation of energy | The principle that energy can neither be created nor destroyed |
| potential energy | Stored energy |
| heat | The amount of energy associated with the movement of the atoms and molecules in a body of matter |
| entropy | A measure of disorder |
| chemical energy | Energy stored in the chemical bonds of molecules; a form of potential energy. |
| calorie | The amount of energy that raises the temperature if 1 g of water by 1 degree C |
| ATP | the main energy source for cells |
| energy coupling | the use of energy released from an exergonic reaction to drive an endergonic reaction |
| metabolism | the sum total of all the chemical reactions thats occur in organisms |
| enzyme | A protein that serves as a biological catalyst, changing the rate of chemical reaction without itself being changed in the process |
| activation energy | The amount of energy that reactants must absorb before a chemical reaction will start |
| substrate | A specific substance on which an enzyme acts |
| active site | The part of an enzyme molecule where a substrate attaches |
| induced fit | the interaction between a substrate molecule and the active site of an enzyme |
| enzyme inhibitor | A chemical that interferes with an enzyme's activity |
| feedback regulation | A method of metabolic control |
| Breathing | The alteration if inhalation and exhalation |
| Cellular Respiration | The aerobic harvesting of energy from food molecules |
| Glycolysis | the multistep chemical breakdown of a molecule of glucose into two molecules of pyruvic acid |
| Krebs Cycle | another name for the Citric Acid Cycle |
| Electron Transport Chain | A series of electron carrier molecules that shuttle electrons during the redox reactions that release energy used to make ATP |
| ATP | Adenosine triphosphate , The main energy source for cells |
| ATP synthase | A complex (cluster) of several proteins found in a cellular membrane |
| ADP | Adenosine diphosphate, a molecule composed of of an adenine and two phosphate groups |
| NADH | (electron carrier) a molecule that carries electrons from glucose and other fuel molecules and deposits them at the top of an electron transport chain |
| FADH2 | another electron carrier |
| Fermentation | The anaerobic harvest of food by some cells |
| Lactic Acid Fermentation | The conservation of pyruvate to lactate with no release of carbon dioxide |
| Alcohol Fermentation | the conservation of the acid produced by glycolysis to carbon dioxide and ethyl alcohol |
| Obligate anaerobe | An organism that cannot survive in the presence of oxygen |
| Obligate aerobe | An that cannot survive without oxygen |
| Facultative anaerobe | A microorganism that makes ATP by aerobic respiration if oxygen is present |
| Chemical equation for cellular respiration | C6H12O6 + 6 O2 --> 6 CO2 + 6 H2O + ATP |
| Molecular formula for glucose | C6 H12 O6 |
| Acetyl CoA | the entry compound for the Krebs cycle in cellular respiration |
| Reduction | The gain of electrons by a substance involved in a redox reaction |
| Oxidation | The loss of electrons from a substance involved in a redox reaction |
| H+ | Hydrogen ion |
| Autotroph | an organism that makes its own food |
| heterotroph | an organism that cannot make its own organic food molecules and must obtain them by consuming other organisms or their organic products |
| mitochondria | An organelle in eukaryotic cells where cellular respiration occurs |
| cristae | A fold of the inner membrane of a mitochondria |
| matrix | The thick fluid contained within the inner membranes of the mitochondria |
| Photosynthesis equation | 6 H2O + 6 CO2 ---> C6H12O6 + 6 O2 |
| Photon | A fixed quantity of light energy |
| Stoma (stomata) | A pore surrounded by guard cells in the epidermis of a leaf |
| Mesophyll | The green tissue in the interior of a leaf |
| Thylakoid (s) | one of a number of disk-shaped membranous sacs inside a chloroplast. |
| Chlorophyll a | A green pigment in chloroplasts that participates directly in the light reactions |
| Chloroplast (s) | An organelle found in plants and photosynthesis protists |
| Wavelength | The distance between crests of adjacent waves |
| Electromagnetic spectrum | The full range of radiation, from the very short wavelengths of gamma rays to the very long wavelengths of radio signals |
| Stroma | A thick fluid enclosed by the inner membrane of a chloroplast |
| Granum (grana) | A stack of hollow disks formed of thylakoid membrane in a chloroplast |
| Photosynthesis | The process by which plants, autotrophic protists, and some bacteria use light energy to make sugars and other organic food molecules from carbon dioxide and water |
| Reaction Center | In a photosystem in a chloroplast, the chlorophyll a molecule and the primary electron acceptor that trigger the light reactions of photosynthesis |
| Calvin Cycle | The second of two stages of photosynthesis; |
| NADPH+ | oxidized electron carrier |
| NADP+ | oxidized electron carrier |
| CAM plant | A plant that uses crassulacean acid metabolism, an adaptation for photosynthesis in arid conditions |
| C3 plant | A plant the uses the calvin cycle for the initial steps that incorporate CO2 into organic material |
| C4 plant | A plant that prefaces the calvin cycle with reactions that incorporate CO2 into four-carbon compounds |
| Redox reaction | a chemical reaction in which electrons are lost from one substance (oxidation) and added to another (reduction) |
| Cell Division | the reproduction of a cell |
| Mitosis | the division of a single nucleus into two genetically identical daughter nuclei |
| Gap 1 | the chromosome gets ready for the S Phase |
| Gap 2 | each chromosome in the cells consists of two identical sister chromatids, and the cell is preparing to divide |
| S Phase | DNA synthesis, chromosome duplication |
| Interphase | the period of time in a eukaryotic cell cycle when the cell is not actually dividing |
| Prophase | The first stage of meiosis, during which duplicated chromosomes condense to form structures visible with a light microscope and the mitotic spindle forms and begins moving chromosomes toward the center of the cell |
| Metaphase | The second stage of mitosis. During metaphase, all the cell;s duplicated chromosomes are lined up at an imaginary plane equidistant between the poles of the mitotic spindle |
| Anaphase | The third stage of mitosis, beginning when sister chromatids separate from each other and ending when a complete set of daughter chromosomes has arrived at each of the two poles of the cell |
| Telophase | The last stage of of mitosis, during which daughter nuclei form at the two poles of a cell |
| Cytokinesis | The division of the cytoplasm to form two separate daughter cells. |
| Cleavage | the pinching of the plasma membrane to split it in two |
| Chromosome | A threadlike, gene-carrying structure found in the nucleus of a eukaryotic cell |
| Chromatin | The combination of DNA and proteins that constitute chromosome |
| Autosome | A chromosome not directly involved in determining the sex of an organism |
| Sex Chromosome | A chromosome that determines whether an individual is male or female |
| Sister chromatid | One of the two identical parts of a duplicated chromosome in a eukaryotic cell |
| Centriole | A structure in an animal cell, composed of microtubule triplets |
| Haploid | Containing a single set of chromosomes (n) |
| Diploid | Containing two sets of chromosomes (homologous pairs) in each cell (2n) |
| Gametic cell | a sex cell |
| Homologous chromosomes | The two chromosomes that make up a matched pair in a diploid cell |
| Meiosis 1 | splits tetrads into 2 sets of homologous pairs |
| Meiosis 2 | separates the homologous pairs into chromosomes so that they can go to each new gamete |
| Phases of Meiosis 1 | Prophase 1, Metaphase 1, Anaphase 1, Telophase 1 |
| Phases of Meiosis 2 | Prophase 2, Metaphase 2, Anaphase 2, Telophase 2 |
| Crossing over | the exchange of segments between chromatids of homologous chromosomes during prophase 1 of meiosis |
| Tetrad | A paired set of homologous chromosomes, each composed of sister chromatids |
| Chiasma | point where two chromatids cross |
| Nondisjunction | AN accident of meiosis or mitosis in which a pair of homologous chromosomes or a pair os sister chromatids fail to separate at anaphase |
| Chromosome abnormalities | abnormal cell division |
| Independent Assortment | A general rule in inheritance that when gamets form during meiosis, each pair of alleles for a particular characteristic segregate independently |
| Segregation | A general rule in inheritance that individuals have two alleles for each gene and that when gametes form by meiosis, the two alleles separate, and each resulting gamete ends up with only one allele of each gene` |
| Random Fertilization | random combination of chromosomes |
| Gregor Mendel | studied the inheritance of certain traits in pea plants (known as the father of genetics) |
| True-breeding | referring to organisms for which sexual reproduction produces offspring with inherited traits identical to those parents |
| self fertilization | the fusion of sperm and egg that are produced by the same individual organism |
| gene | A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA (or RNA) |
| allele | An alternative form of a gene |
| locus/loci | The particular site where a gene is found on a chromosome |
| incomplete dominance | A type of inheritance in which the phenotype of a heterozygote (Aa) is intermediate between the phenotypes of the two types of homozygote (AA and aa) |
| co-dominance | The expression of two different alleles of a gene in a heterozygote |
| hybrid | The offspring of parents of two different species or of two different varieties of one species |
| F1 cross | Cross between two F1 generations |
| F1 generation | the offspring of two parental individuals |
| P generation | Parental generation |
| F2 generation | the offspring of two F1 generation |
| gamete | A sex cell (a haploid egg or sperm) |
| punnett square | A diagram used in the study of inheritance to show the results of random fertilization |
| monohybrid cross | An experimental mating of individuals differing at one genetic locus |
| dihybrid cross | An experimental mating of individuals differing in two genetic loci |
| karyotype | A display of micrographs of the metaphase chromosomes of a cell, arranged by size and centromere position |
| sex chromosomes | A chromosome that determines whether an individual is male or female |
| autosomes | A chromosome not directly involved in determining the sex of an organism |
| test cross | The mating between an individual of unknown genotype for a particular characteristic and an individual that is homozygous recessive for that same characteristic |
| pedigree | A family tree representing the occurrance of heritable traits in parents and offspring across a number of generations |
| recessive allele | In a heterozygous individual, the allele that has no noticeable effect on the phenotype |
| Autosomal recessive disorders | example: sickle cell anemia |
| dominant alleles | In a heterozygote the allele that determines the phenotype with respect to a particular gene |
| co-dominant alleles | the expression of two different alleles of a gene in a heterozygote |
| blood types | A, B, AB, O |
| sickle cell anemia | A genetic disorder in which the red blood cells have abnormal hemoglobin molecules and take on an abnormal shape |
| sex-linked genes | A gene located on a sex chromosome |
| nondisjunction | An acident of meiosis or mitosis in which a pair of homologous chromosomes or a pair of sister chromatids fail to separate at anaphase |
| Deoxyribonucleic acid | (DNA) the genetic material that organism inherit from their parents |
| Ribonucleic acid | (RNA) A type of nucleic acid consisting of nucleotide monomers with a ribose sugar and the nitrogenous bases A, C, G, and U |
| bacteriophage | A virus that infects bacteria (also called a phage) |
| nucleotide | An organic monomer consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group. |
| nitrogenous base | An organic molecule that is a base and tat contains the element nitrogen |
| pentose sugar | The sugar of a nucleotide |
| phosphate group | A functional group consisting of a phosphorus atom covalently bonded to four oxygen atoms |
| purine/pyrimidine | they make up 2 groups of nitrogenous bases |
| Adenine (A) | A double-ring nitrogenous base found in DNA and RNA |
| guanine (G) | A double-ring nitrogenous base found in DNA and RNA |
| cytosine (C) | A single-ring nitrogenous base found in DNA and RNA |
| thymine (T) | A single-ring nitrogenous base found in DNA |
| uracil (U) | A single-ring nitrogenous base found in RNA |
| base pairing | DNA - A=T, G=C.....RNA - A=U, G=C |
| hydrogen bonding | bond connecting the nitrogenous bases (A, T, G, C) |
| James Watson and Francis Crick | Men who discovered the double helix shape of DNA |
| Rosalind Franklin | Woman who generated x-ray images of DNA, she povided Watson and Crick with key data about DNA |
| The double helix | the form of native DNA |
| histone | A small basic protein molecule associated with DNA |
| chromatin | A threadlike, gene-carrying structure found in the nucleus of a eukaryotic cell |
| nucleosome | An organic monomer consisting of five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group |
| DNA polymerase | An enzyme that assembles DNA nucleotides into polynucleotides using a preexisting stand of DNA as a template |
| RNA polymerase | An enzyme that links together the growing chain of RNA nucleotides during transcription, using a DNA stand as a template |
| promoter | A specific nucleotide sequence in DNA, located at the start of a gene |
| terminator | A special sequence of nucleotides in DNA that marks the end of a gene |
| messenger RNA (mRNA) | The type of ribonucleic acid that encodes genetic information from DNA and conveys it to ribosomes, where the information is translated into amino acid sequences |
| ribosomal RNA (rRNA) | The type of ribonucleic acid that, together with proteins, makes up ribosomes |
| transfer RNA (tRNA) | A type of ribonucleic acid that functions as an interpreter in translation |
| transcription | The synthesis of RNA on a DNA template |
| translation | the synthesis of a polypeptide using the genetic information encoded in an mRNA molecule |
| genetic code | the set of rules giving the correspondence between codons in mRNA and amino acids in proteins |
| codon | A three-nucleotide sequence in mRNA that specifies a particular amino acid or polypeptide termination signal |
| start codon AUG | On mRNA, the specific three nucleotide sequence (AUG) to which an initiator tRNA molecule binds, starting translation of genetic information |
| Exon | In eukaryotes, a coding portion a of gene |
| Intron | In eukaryotes, a non-expressed (noncoding) portion of a gene that is excised from the RNA trnascript |
| Splicing | Reducing the RNA strand, and getting rid of the exons and introns and capping the ends |
| Anticodon | On a tRNA molecule, a specific sequence of three nucleotides that is complementary to a codon triplet on mRNA |
| Amino acid | Serves as the monomer of proteins |
| Polypeptide chain | A chain of amino acids linked by peptide bonds |
| ribosome | A cell organelle consisting of RNA and protein organized into two subunits and functioning as the site of protein synthesis in the cytoplasm |
| gene | A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA |
| protein | A biological polymer constructed from amino acid monomers |
| mutation (insertion/deletion) | A change in the nucleotide sequence of DNA |
| frameshift mutation | genetic mutation caused my insertion or deletion of nucleotides |
| mutagen | A chemical or physical agent that interacts with DNA and causes a mutation |
| point mutation | mutation that causes the replacement of of nucleotide with another |
| Evolution (microevolution) | Genetic change in a population or species over generations; all the changes that transform life on earth |
| the voyage of the beagle | a book written by Charles Darwin about evolution |
| gene pool | All the genes in a population at any one time |
| natural variation | the selection of genetic variations by how they effect the organism's chances of survival or reproduction |
| fitness | The contribution an individual makes to the gene pool of the next generation relative to the contribution of other individuals in the population |
| survival of the fittest | Natural selection conceived of as a struggle for life in which only those organisms best adapted to existing conditions are able to survive and reproduce. |
| adaptation | inherited characteristic that enhances an organism's ability to survive and reproduce in a particular environment |
| hardy-weinberg equilibrium | the principle that the shuffling of genes that occurs during sexual reproduction, by itself, cannot change the overall genetic makeup of a population |
| selection pressures | Those factors that influence the direction of natural selection |
| directional selection | Natural selection that acts in favor of the individuals at one end of a phenotypic ratio |
| natural selection | Differential success in reproduction by different phenotypes resulting from interactions with the environment |
| descent with modification | what we define evolution as |
| stabilizing selection | Natural selection that favors intermediate variants by acting against extreme phenotypes |
| gene flow | The gain or loss of alleles from a population by the movement of individuals or gametes into or out of a population |
| genetic drift | A change in the gene pool of a population due to chance |
| bottleneck effect | genetic drift resulting from a drastic reduction in population size |
| founder effect | Random change in the gene pool that occurs in a small colony of a population |
| Speciation | The formation of new species |
| macroevolution | Evolutionary change on a grand scale, encompassing the origin of new taxonomic groups, evolutionary trends, adaptive radiation, and mass extinction |
| Pre-zygotic isolation mechanisms | A reproductive barrier that impedes mating between species |
| post-isolation mechanisms | A reproductive barrier that operates should interspecies mating occur and form hybrid zygotes |
| reproductive isolation mechanisms | A biological feature of a species that prevents it from interbreeding with other species even when populations of the to species live together |
| biological species concept | The definition of a species as a population or group of populations whose members have the potential in to interbreed and produce fertile offspring |
| mouth | An opening through which food is taken into the body |
| pharynx | Where the nose and the mouth meet |
| amylase | (saliva) enzyme in the mouth that starts chemical digestion |
| esophagus | the channel through which food passes through in a digestive tract |
| stomach | A pouch-like organ in a digestive tract that grinds and churns food and may store it temporarily |
| liver | the largest organ in the body, it performs diverse functions such as producing bile, preparing nitrogenous wastes for disposal, and deoxifying poisonous chemicals in the blood |
| bile | A solution of salts secreted by the liver that emulsifies fats and aids in their digestion |
| gall bladder | An organ that stores bile and releases it as need into the small intestine |
| pancreas | releases pancreas juice (enzymes) into the small intestine for chemical digestion |
| small intestine | the longest section of the alimentary canal. It absorb nutrients out of food |
| villi | surface of the small intestine to have more surface area for absorption |
| microvilli | smaller villi on the villi of the small intestine |
| large intestine | The tubular portion of the alimentary canal between the small intestine and the anus |
| rectum | the terminal portion of the large intestine, where feces are stored until they are eliminated |
| peristalsis | Rhythmic waves of contraction of smooth muscles. it propels food through the digestive tract |
| mechanical digestion | The physical breakdown of food into smaller pieces, as by chewing |
| chemical digestion | the breakdown of food molecules through the action of enzymes into small molecules that can be absorbed by the body |
| stomach acids | pepsin and chyme |
| pepsin | an enzyme present in gastric juice that begins the hydrolysis of proteins |
| chyme | semifluid mass of partly digested food expelled by the stomach |
| alimentary canal | a digestive tract consisting of a tube running between a mouth an an anus |
| atria | A heart chamber that receives blood from the veins |
| ventricles | A heart chamber that pumps blood out of the heart |
| pulmonary valve | A blood vessel that conveys blood from a lung to the heart |
| AV valve | valve between the atria and ventricle |
| inferior vena cava | A large vein that returns 02-poor blood to the heart from the lower part of the body |
| superior vena cava | A large vein that returns 02-poor blood to the heart from the upper body and head |
| aortic valve | valve between the left ventricle and the aorta |
| pulmonary arteries | a large blood vessel that conveys blood form the heart to a lung |
| pulmonary veins | a blood vessel that conveys blood from a lung to a heart |
| pulmonary circuit | one of two main blood circuits conveys blood between the blood and the heart |
| veins | a vessel that returns blood to the heart |
| artery | A vessel that carries blood away from the heart to other parts of the body |
| capillaries | a microscopic blood vessel that conveys blood between an artery and a vein |
| pacemaker | The SA node; maintains the heart's pumping rhythm |
| AV node | A region of specialized muscle tissue between the heart's right atrium and right ventricle |
| blood pressure | The force that blood exerts against the walls of the blood vessels |
| diastole | The stage of the heart cycle in which the heart muscle is relaxed, allowing chambers to fill with blood |
| systole | the contraction stage of the heart cycle, when the heart chambers actively pump blood |
| blood | a type of connective tissue with a fluid matrix called plasma in which blood cells are suspended |
| red blood cells | A blood cell containing hemoglobin, which transports 02 |
| plasma | the liquid matrix of blood in which the blood cells are suspended |
| hemoglobin | An iron-containing protein in red blood cells that reversibly binds 02 and transports it to body tissues |
| white blood cells | A blood cell that functions in defending the body against infections and cancer cells |
| platelets | small anuclear cells in blood |
| lungs | an internal sac, where gases are exchanged between inhaled air and the blood |
| alveoli | One of the millions of tiny sacs within the lungs where gas exchange occurs |
| trachea | the windpipe |
| bronchioles | a thin breathing tube that branches from a bronchus within a lung |
| bronchus | one of a pair of breathing tubes that branch from the trachea into the lungs |
| epiglottis | flap the covers the trachea when food is coming down |
| diaphragm | The sheet of muscle separating the chest cavity from the abdominal cavity |
| breathing | The alteration of inhalation and exhalation |
| inhalation | oxygen coming into the body |
| exhalation | CO2 going out of the body |
| gas exchange | O2 diffuses with CO2 |
| heart | The chambered muscle organ that pumps blood received from the veins into the arteries |
| myocardium | involuntary muscle found in the walls of the heart |
| puberty | physical change in which a child's body matures to an adult's body capable of reproduction |
| sexual reproduction | the creation of offspring by the fusion of two haploid sex cells (gametes), forming a diploid zygote |
| asexual reproduction | the creation of offspring by a single parent, without the participation of sperm and egg |
| penis | THe copulatory structure of male mammals |
| testis | The male gonad, produces sperm and, in many species reproductive hormones |
| epididymis | A long coiled tube into which sperm pass from the testis and re stored until mature and ejaculation |
| vas deferens | part of the male reproductive system that conveys sperm away from the testis |
| scrotum | A ouch of skin outside the abdomen that houses a testis; functions in cooling sperm |
| prostate | A gland in human males that secrete an acid-neutralizing component of semen |
| bulbourethral gland | one of two small exocrine glands present in the reproductive system of human males |
| seminal vesicle | a gland in males that secretes a fluid component of semen that lubricates and nourishes sperm |
| urethra | A duct that conveys urine from the urinary bladder to the outside |
| seminiferous tubules | a coiled sperm-producing tube in a testis |
| ejaculation | discharge of semen from the penis |
| semen | the sperm-containing fluid is ejaculated by the male during orgasm |
| sperm | a male gamete |
| ovaries | the female gonad, which produces egg cells and reproductive hormones |
| fallopian tubes | tube from the ovaries to the uterus |
| uterus | in the reproductive system of a female, the organ where the development of young occurs (the womb) |
| vagina | Part of the female reproductive system between the uterus and the outside opening |
| cervix | the neck of the uterus, which opens into the vagina |
| follicle | a cluster of cells surrounding, protecting, and nourishing a developing egg cell in the ovary, also secretes estrogen |
| ovulation | the release of an egg cell from an ovarian follicle |
| menstrual cycle | the hormonally synchronized cyclic buildup and breakdown of the endometrium |
| corpus luteum | a small body of endocrine tissue that develops from an ovarian follicle after ovulation, secretes progesterone and estrogen during pregnancy |
| fertilization | the union of the nucleus of a sperm cell with the nucleus of an egg cell, producing a zygote |
| zygote | the fertilized egg, which is diploid, that results from the union of sperm cell nucleus and an egg cel nucleus |
| implantation | event that occurs early in pregnancy in which the embryo adheres to the wall of uterus |
| placenta | the organ that provides nutrients and oxygen to the embryo and helps dispose of its metabolic wastes |
| umbilical cord | a structure containing arteries and veins that connects a developing embryo to the placenta of the mother |
| estrogen | one of the several chemically similar steroid hormones secreted by the gonads |
| progesterone | a steroid hormone secreted by the corpus luteum of the ovary |
| testosterone | An androgen hormone that stimulates an embryo to develop into a male and promotes male body features |
| LH | luteinizing hormone |
| FSH | follicle stimulating hormone |
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