Glossary+of+Terms

__Key Terms and Definitions__
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 * __Abiotic:__** non-living factors of the Earth which affect the ability of living organisms to survive in an environment. These can include both physical and chemical factors.


 * __Alleles:__** Two alleles for each gene are inherited, one from each parent. They can be dominant or recessive, and two alleles code for the gene that is inherited.


 * __Alteration of generations__**: third type of life cycle exhibited by plants and some species of algae


 * __Amino acid__**: one of 20 different monomers that makes up a polypeptide


 * __Amniocentesis:__** A technique for testing the genotype of a fetus that is in it's 14th-16th week of pregnancy. It can determine if the fetus has Tay-Sachs disease


 * __Anthers:__** the sac at the end of the stamen


 * __Apomixis:__** plants that produce seeds without their flowers having to be fertilized.

__**Asexual reproduction**__: a single individual is the sole parent and passes copies of all its genes on to its offspring.


 * __ATP (adenosine triphosphate):__** It releases free energy, when the phosphate is broken down and the energy is absorb by the chemical reaction


 * __Autosomes__**: all chromosomes besides the X and Y chromosomes

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 * __Bundle-sheath cells:__** Tightly packed sheaths around the veins of the leaf.

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 * __C3 plants:__** First organic product of carbon fixation is a 3-C compound


 * __C4 plants:__** Serve as introduction to the Calvin Cycle with an alternative mode of the carbon fixation that forms a four- carbon compound as its first product


 * __Calvin Cycle:__** Part of Photosynthesis. Makes sugar.


 * __Carbon fixation:__** Making the carbon into organic compounds.


 * __CAM/crassulacean acid metabolism:__** Mode of carbon fixation


 * __Carotenoids:__** Has various shades of yellow and orange.


 * __Catalyst:__** substance that increases the rate of a reaction without being consumed.


 * __Cerebrum__**: the largest part of the brain, it has right and left hemispheres and is divided into motory and sensory areas.


 * __Character:__** A feature passed to offspring (ex.hair color)

__**Chiasmata**__: X-shaped regions that represent a crossing of nonsister chromatids, which are two chromatids belonging to separate but homologous chromosomes


 * __Chlorophyll a:__** The major and an important pigment


 * __Chlorophyll b:__** An accessory pigment (yellow-green) that helps absorb light and transfer energy to chlorophyll a.


 * __Chromosome:__** A gene-carrying structure found in the nucleus of cells. It includes one long DNA molecule and sometimes protein and RNA. (More about [|chromosomes])

__**Clone:**__ (1) A lineage of genetically identical individuals or cells. (2) In populare usage, a single individual organism that is genetically identical to another individual. (3) As a verb, to make one or more genetic replicas of an individual or cell.


 * __Codominance:__** This is when a hybrid offspring shows both traits of the parents.


 * __Codon__**: triplet of nucleotides on an mRNA molecule that codes for one amino acid (see [|codon chart])

__**Complete Dominance:**__ Phenotypes of the heterozygote and dominant homozygote are indistinguishable.


 * __Crossing Over__**: the exchange of genetic material between nonsister chromatids.


 * __Cyclic electron flow:__** An alternative path that the photoexcited takes.


 * __Cyclic Photophosphorylation:__** When the Cyclic flow generates ATP

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 * __Daughter Cell__**: A cell that will result from the replication and division of a single parent cell.

__**Dihybrid cross**__: two heterozygous pairs VS. the same two heterozygous pairs. Example: GgNn x GgNn. It represents two individual crosses that happen independently of one another.

__**Diploid cells**__: the zygote and all other cells having two sets of chromosomes.

__**Dominant allele:**__ A trait that is fully expressed in an organism's appearance.


 * __Double fertilization:__** when two sperm cells with different cells of the embryo sac unite.


 * __Down Syndrome:__** This disorder is a result of the alteration of chromosome numbers. In Down Syndrom, there are 47 chromosome with trisomy of the 21st chromosome. Characteristics include facial features, short structure, heart deffects, and metal redardation.

__**DNA**__: deoxyribonucleic acid; DNA is made up of the nucleotides A, C, T, G and takes the shape of a [|double helix]
 * DNA is located in the nucleus of eukaryotic cells
 * contains all the genetic information of an organism


 * __DNA Polymerase__**: An enzyme that catalyzes the elongation of new DNA at a replication fork by the addition of nucleotides to the existing chain.


 * __Duchenne Muscular Dystrophy:__** A sex linked disorder most commen in men, it is characterized by progressive weakening of the muscles and loss of coordination.

media type="custom" key="18439" __**Electroporation**__: a short electrical pulse is added to a solution with cells which creates tiny, non-permanant holes in the plasma membrane of the cells.


 * __Emergent properties:__** properties of life.


 * __Endosperm:__** a food-storing tissue.


 * __Epistasis:__** A gene that changes the expression of a different gen. (the mouse fur example in the book, page 250)

__**Eukaryote:**__ organisms with a complex cell or cells, where the genetic material is organized into a membrane-bound nucleus or nuclei- Animals, plants, fungi or protists are examples of eukaryotes.

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 * __F1 Generation:__** First generation of offspring following the P generation (parents)


 * __F2 Generation:__** Generation of offspring following the F1 generation

__**Fertilization (syngamy):**__ the union of gametes.

__**Frameshift mutation:**__ the insertion or deletion of nucleotides that may alter the reading frame of a genetic message


 * __Fragmentation:__** separating the parent plant into parts that can grow again


 * __Frederick Griffith Experiment__**: this was the experiment done with mice and heat killed and normal bacteria. When normal (S) bacteria was injected into a mouse it died, but when (R) bacteria was injected into the mouse it lived. Then when heat killed (S) bacteria was injected into the mosue it lived. However when heat killed (S) bacteria and (R) bacteria was injected to a mouse it died. This experiment showed that the (R) bacteria was genetically transformed with the heat killed (S) bacteria which killed the mouse.

media type="custom" key="18442" __**Gametes**__: reproductive cells


 * __Gene:__** A piece of DNA that codes for the production of a trait

F1 generation: 1st filial generation; hybrids. F2 generation: 2nd filial generation; 3:1 ratio.
 * __Generations__**: P generation: 1st parent generation; true breeding.


 * __Genetic code:__** organization of neucleotides in DNA molecules that carries genetic information

__**Genetics**__: the scientific study of heredity and hereditary variation


 * __Genomics__**: studying genomes and genes using DNA sequencing.

__**Genotype:**__ the resulting offspring of a cross in alleles, which are the letters (ex. AA, Aa, aa)


 * __Glyceraldehyde 3-Phosphate (G3P):__** The calvin cycle produces this 3-carbon sugar.

__**Guttation:**__ the loss of liquids from ends of vascular tissues at the margins of leaves.

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 * __Haploid cell__**: a cell with a single chromosome set


 * __Helicase__**: enzyme that unwinds the double helix at the replication fork, seperating the two old strands


 * __Hemophilia:__** A sex linked disorder characterized by the absence of a certain protien required for blod to clot; many people die from this disorder by bleeding to death even from a small scratch


 * __Heredity:__** the transmission of traits from one generation to the next


 * __Heterozygous:__** alleles that are different


 * __Hierarchy:__** A rank given to something, one thing above the other

__**Homologous chromosomes (homologues**__): the chromosomes that make up a pair


 * __Homozygous:__** alleles that are the same


 * __Hybridization:__** the mating, or crossing, of two different varieties of species. Mendel's breeding experiment in which he crossed pollinated two contrasting, true-breeding pea varieties (purple flowered plants and white flowered plants) is an example of hybridization.

__**Huntington's Disease:**__ This is caused by a very lethal dominant allele, that attacks the nervous system. It isn't detected untill the he/she is 35-45 years old.


 * __Human Genome:__** It consists of about 30,000 gnes and 3 billion base pairs.

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 * __Incomplete Dominance:__** This when instead of a hybrid having two possible results, it has a third result which is a mix between the original possiblities. (A red flower and a white flower breed and with incomplete dominance a third possiblity could be pink, instead of just white or red). **//__In__//**complete - **//__In__//**termediate.

__**Initiation**__: the initial site of the RNA polymerase attachment; the promoter region
 * includes the start codon

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 * __Karyotype__**: an organizational technique for chromosomes of a cell. They are organized according to number, size, and type.


 * __Klinefeltner's Syndrome (XXY):__** This disorder caused by the alteration of chromosome numbers affects only males. Altough they are born with male sex organs, the testes are abnormally small and the man is sterile.

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 * __Law of segregation:__** Mendel's first law of the two, establish that allele pairs seperate during the process of gamete formation and randomly reforming during the fusion process of gametes at fertilization.


 * __Law of independence assortment:__** The second law of Mendel's stating that each allele pair segregates on its own during the formation of gamete; this applies to two traits in a gene is located on different pairs of homologous chromosomes

__**Life cycle**__: the generation-to-generation sequence of stages in the reproductive history of an organism, from conception to production of its own offspring


 * __Light reaction:__** The second stage of photosynthesis. Converts solar energy to chemical energy.


 * __Locus:__** A location where a gene is specifically located on a segment of a chromosome

media type="custom" key="18448" __**Meiosis**__: cell division


 * __Mendel, Gregor:__** Considered by some to be the "father of modern genetics." By comparing the traits found in the P, F1, and F2 generations of peas, Mendel tracked heritable characteristics and was able to prove that the inheritance of traits follows particular laws.


 * __Mesophyll:__** It is the tissue in the interior of the leaf


 * __Mesophyll cells:__** Between the bundle sheath and the leaf surface


 * __Missense mutations:__** base pair substitution that alters the codon, though the codon still works because it codes for the same amino acid.

__**Monohybrid cross**__: heterozygous pair VS. same heterozygous pair. example: Aa x Aa


 * __Monosomy X (Turner's Syndrome):__** This disorder caused by the alteration in chromosome numbers only affects females. Even though the females are born with sex organs, they do not mature at adolescence and secondary sex characteristics fail to develope.


 * __mRNA__** (messenger RNA): single stranded nucleic acid that serves as a messenger between DNA and ribosomes
 * carries a copy of the genetic code from the nucleus to the cytoplasm


 * __Multiple alleles:__** More then two alleles in any given population. (ex.human blood types)


 * __Multicellular organism:__** An organism with more than one cell.

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 * __NADP+:__** Stores the energized electrons


 * __Noncyclic electron flow:__** The predomiant route


 * __Noncyclic photophosphorylation:__** ATP synthesis, it is driven by light energy


 * __Nonsense mutation:__** a type of mutation that changes an amino acid codon to be one of the stop codons, this creates a shorter and usually non-functional protein.


 * __Neurons:__** Nerve impulses that tells your body what to move is transmitted to this specialized cell.

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 * __Okazaki Fragments:__** Short segments of the lagging strand.

media type="custom" key="18451" __**P Generation:**__ Parental, or parent generation


 * __Pedicel:__** the stalk holding the flower to the plant.


 * __Pedigree:__** A family tree drawn with symbols to show inheritance patterns for specific phenotypes.


 * __PEP carboxylase:__** An enzyme forming the 4 carbon molecule, oxaloacetate.


 * __Phenotype__**: an organism's physical traits.


 * __Photophosphorylation:__** By adding the a phosphate group to ADP it generates ATP (its a process)


 * __Photosystems:__** These are the light-harvesting units of the thylakoid membrane
 * **__Photosystem I__** and **__Photsystem II:__** participates in light reactions, but different in the reaction center. they are in order the way they were discovered.


 * __Pleiotropy__** //__(PLY-eh-troh-pee)__**:**// A gene with many effects. (ex. sickle cell anemia)


 * __Point mutation__:** a change in one or a few base pairs in a single gene


 * __Poly(A) tail__**: sequence of up to 200 A (adenosine) nucleotides added to the 3' end of a newly formed RNA molecule


 * __Polypeptide__**: a polymer (chain) of many amino acids linked together by peptide bonds


 * __Population:__** Groups of species that lives in the same area.


 * __Primary electron acceptor:__** A specialized molecule.


 * __Primase:__** An enzyme that forms RNA nucleotides to make the primer.

__**Prokaryotes:**__ organisms without a cell nucleus (= karyon), or any other membrane-bound organelles.


 * __Protenoids:__** polypeptides produced by abiotic means.


 * __Protists:__** are a diverse group of organisms, comprising those eukaryotes that can not be classified in any of the other kindoms.

__**Protobionts:**__ aggregates of abiotically produced molecules.


 * __Punnet Square__**:formula used to figure out the possible outcomes of a new generation


 * __Purines__**: include the two bases, adenine and guanine, classified for their two organic rings


 * __Pyrimidines__**: include the two bases, cytosine and thymine, which have a single carbon ring

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 * __Quantitative Characters (polygenic inheritance):__** This is a heritance of genes depending on environment, such as skin or hair color.

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 * __Reaction center:__** Where the first light-driven chemical reaction of photosynthesis occurs


 * __Recombinant DNA__**: DNA that has genes from two different sources


 * __Receptacle__**: the enlarged end of the pedicle.


 * __Recessive allele:__** A trait that has no noticeable effect on an organism's appearance.

__**Restriction enzyme**__: cuts up pieces of DNA.

__**RFLP(restriction fragment length polymorphisms)**__: Difference in DNA sequence on homologous chromosomes that result in different patterns of restriction fragment lengths


 * __Ribosome__**: composed of a large and a small subunit, an organelle that is the site of protein synthesis

__**Ribozyme:**__ is an RNA molecule that catalyzes a chemical reaction..


 * __Rubisco/RuBP carboxylase:__** An enzyme in the calvin cycle.


 * __Rule of Addition:__** The probability of an event that can possibly happen in 2 or more different ways, is the sum of each probability.


 * __Rule of Multiplication:__** A method used to decide the probability that 2 or more different events will come together.

media type="custom" key="18454" __**Sex chromosomes**__: the X and Y chromosomes

__**Sexual reproduction**__: two parents give rise to offspring that have unique combinations of genes inherited from the two parents


 * __Silent mutations:__** have no effect on the encoded protein, the base pairs may switch but the same protein is created.

__**Solute:**__ Substance that is dissolved in a solution.

__**Solution:**__ Liquid mixture of two or more substances.

__**Solvent:**__ Dissolving agent of a solution, dissolves solute.


 * __Somatic cell__**: Any of the cells of a plant or animal except for reproductive cells

__**Spores**__: meiosis in the sporophyte produces haploid cells

__**Sporophyte**__: the multicellular diploid stage


 * __Stomata/stoma:__** Pores on the bottom of the leaf, in which CO2 enters.


 * __Stromatolites:__** banded domes of sedimentary rock that are strikingly similar to layered mats formed today in salt marshes and some warm-ocean lagoons by colonies of bacteria and cyanobacteria


 * __Synapse:__** the space between the axon and dendrite where neurotransmitters travel between.

__**Synapsis**__: process where the during prophase I of meiosis, th eduplicated chromosomes pair with their homologues

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 * __TATA box__**: sequence of DNA that promotes the initial binding of transcription factors to DNA


 * __Terminator__**: Sequence of RNA that stops transcription

__**Tetrad**__: the four closely associated chromatids of a homologous pair.

__**Trait:**__ A genetically determined characteristic; Traits can be physical or behavorial.

__**Transcription**__: the process through which the DNA code is copied onto RNA
 * see [|animation]

__**Translation**__: the process of using the RNA code to produce a polypeptide
 * by transferring amino acids within the cytoplasm to ribosome, tRNA translates mRNA code


 * __Transpiration:__** the evaporation of water from the plant surface.


 * __Trisomy X (XXX):__** This disorder is caused by the alteration of chromosome numbers, with an extra X chromosome. People effected by trisomy X are women, however they are completely normal and cannot be distinguished from other normal females other than the Karyotype (XXX).


 * __Water potential:__** the potential energy of water molecules, it is which way the water will move.

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 * __Visible light:__** the color that is reflected which the human eye can see.

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 * __Zygote__**: the cell that is developed by the joining of two gametes.