BIO220 Exam 1:Ch.1-6
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222 terms
Terms | Definitions |
|---|---|
 theory of epigenesis | posits that an organism is derived from substances present in the egg that differentiate into adult structures during embryonic development |
| theory of preformation | stated that sex cells contain a complete miniature adult, perfect in every form, called a homunculus |
| cell theory | all organisms are composed of basic units called cells, which are derived from similar preexisting structures |
| idea of spontaneous generation | disproved idea of the creation of living organisms from nonliving components |
| idea of fixity of species | disproved notion that animal and plant groups have remained unchanged in form since the moment of their appearance on Earth |
| theory of natural selection | based on the observation that populations tend to consist of more offspring than the environment can support, leading to a struggle for survival among them. Those organisms with heritable traits that allow them to adapt to their environment are better able to survive and reproduce than those with less adaptive traits. |
| chromosome theory of inheritance | the idea put forward independently by Walter Sutton and Theodore Boveri that chromosomes are carriers of genes and the basis for the Mendelian mechanisms of segregation and independent assortment |
| genetics | branch of biology concerned with the study of heredity and variation |
| diploid (2n) | a condition in which each chromosome exists in pairs; having two of each chromosome |
| homologous chromosomes | chromosomes that synapse or pair during meiosis and that are identical with respect to their genetic loci and centromere placement (usually one maternal and one paternal in a set) |
| mitosis | a form of cellular reproduction producing two progeny cells, identical genetically to the progenitor cell, that is, the production of two cells from one, each with the same chromosome complement as the parent cell |
| meiosis | the process of cell division in gametogenesis or sporogenesis during which the diploid number of chromosomes is reduced to the haploid number |
| haploid (n) | a cell or organism having one member of each pair of homologous chromosomes. Also, the gametic chromosome number |
| mutation | any heritable change; source of all genetic variation |
| allele | alternative forms of a gene |
| phenotype | different observable features produced by different alleles |
| genotype | set of alleles for a given trait carried by an organism |
| bacteriophages (or phages) | a virus that infects bacteria, using it as the host for reproduction |
| nucleotide | building blocks of nucleic acids; a single phosphate linked to the 5' carbon of the ribose or deoxyribose sugar linked to a nitrogenous base |
| nitrogenous bases and pairing in DNA (4) | adenine, guanine, thymine, cytosine; A with T and C with G |
| transcription | process in which the nucleotide sequence in one strand of DNA is used to construct a complementary RNA sequence |
| mRNA | messenger RNA; an RNA molecule transcribed from DNA and translated into the amino acid sequence of a polypeptide |
| translation | synthesis of proteins under the direction of mRNA |
| proteins | polymers made up of amino acid monomers |
| Number of different amino acids commonly found in proteins? | 20 |
| genetic code | the deoxynucleotide triplets that encode the 20 amino acids or specify termination of translation |
| codon | a triplet of nucleotides that specifies a particular amino acid or a start or stop signal in the genetic code. 61 codons specify the amino acids used in proteins, and three codons, called stop codons, signal termination of growth of the polypeptide chain |
| tRNA | transfer RNA; recognize the information encoded in the mRNA codons and carry the proper amino acids for construction of the protein during translation |
| central dogma of genetics | DNA makes RNA which most often makes protein |
| enzymes | molecules that serve as biological catalysts, essentially causing biochemical reactions to proceed at rates necessary for sustaining life; largest category of proteins |
| restriction enzymes | cut any organism's DNA at specific nucleotide sequences, producing a reproducible set of fragments |
| vectors | In recombinant DNA, an agent such as a phage or plasmid into which a foreign DNA segment will be inserted and utilized to transform host cells |
| recombinant DNA | a DNA molecule formed by joining two heterologous molecules |
| clones | identical molecules, cells, or organisms derived from a single ancestor by asexual or parasexual methods |
| genome | complete haploid DNA content of a specific organism |
| biotechnology | commercial and/or industrial processes that utilize biological organisms or products |
| transgenic animals | animals that contain genes transferred from other animals, usually from a different species |
| DNA microarrays | an ordered arrangement of DNA sequences or oligonucleotides on a substrate (often glass) |
| gene therapy | the insertion of working copies of a gene into the cells of a person with a genetic disorder in an attempt to correct the disorder |
| genomics | the study of genomes (genomes-->the complete haploid DNA content of a specific organism) |
| proteomics | the study of the expressed proteins present in a cell at a given time |
| bioinformatics | the design and application of software and computational methods for the storage, analysis, and management of biological information such as nucleotide or amino acid sequences |
| model organisms | organisms used for the study of basic biological processes |
| gamete | a specialized reproductive cell with a haploid number of chromosomes |
| spores | produced by some bacteria, plants, and invertebrates, a unicellular body or cell encased in a protective coat. It is capable of surviving in unfavorable environmental conditions and gives rise to a new individual upon germinations. In plants, spores are the haploid products of meiosis |
| chromatin | the complex of DNA, RNA, histones, and nonhistone proteins that make up uncoiled chromosomes, characteristic of the eukaryotic interphase nucleus |
| plasma membrane | a phospholipid bilayer that surrounds a cell and serves as a barrier between the cell and its surroundings |
| cell wall | A protective layer external to the plasma membrane in plant cells, bacteria, fungi, and some protists. In plant cells, the wall is formed of cellulose fibers embedded in a polysaccharide-protein matrix |
| glycocalyx | covering over the plasma membrane, consisting of glycoproteins and polysaccharides, on most animal cells |
| eukaryotes | organisms having true nuclei and membranous organelles and whose cells demonstrate mitosis and meiosis |
| nucleus | the membrane-bound cytoplasmic organelle of eukaryotic cells that contains the chromosomes and nucleolus |
| chromosome | in prokaryotes, a DNA molecule containing the organism's genome; in eukaryotes, a DNA molecule complexed with RNA and proteins to form a threadlike structure containing genetic information arranged in a linear sequence and visible during mitosis and meiosis |
| nucleolus | the nuclear site of ribosome biosynthesis and assembly; usually associated with or formed in association with the DNA comprising the nucleolar organizer region |
| nucleolus organizer region (NOR) | areas of DNA that encode rRNA |
| prokaryotic cells | organisms lacking nuclear membranes and true chromosomes |
| nucleoid | area where genetic material is present in prokaryotic cells |
| cytoplasm | nonparticulate, colloidal material referred to as the cytosol, which surrounds and encompasses the cellular organelles |
| endoplasmic reticulum (ER) | a membranous organelle system in the cytoplasm of eukaryotic cells. In rough ER, the outer surface of the membranes is ribosome-studded; in smooth ER, it is not |
| mitochondria | generate large amounts of ATP; found in both plant and animal cells |
| chloroplast | a self-replicating cytoplasmic organelle containing chlorophyll |
| endosymbiotic theory | the proposal that self-replicating cellular organelles such as mitochondria and chloroplasts were originally free-living organisms that entered in to a symbiotic relationship with nucleated cells |
| centriole | a cytoplasmic organelle composed of nine groups of microtubules, generally arranged in triplets. Centrioles function in the generation of cilia and flagella and serve as foci for the spindles in cell division |
| spindle fibers | cytoplasmic fibrils formed during cell division that are involved with the separation of chromatids at the anaphase stage of mitosis and meiosis as well as their movement toward opposite poles in the cell |
| centromere | the specialized heterochromatic chromosomal region at which sister chromatids remain attached after replications, and the site to which spindle fibers attach to the chromosome during cell division. Also known as the primary constriction |
| Classifications of chromosomes based on centromere location (4) | -metacentric -submetacentric -acrocentric -telocentric |
| Arms of chromosomes (2) | -p arm (think "petite") is shorter and shown on top -q arm is longer and is shown below (think "q" is the letter after "p") |
| karyotype | the chromosome complement of a cell or an individual. Often used to refer to the arrangement of metaphase chromosomes in a sequence according to length and centromere position |
| sister chromatids | replica chromatids (two parts of each chromosome) that are connected by a common centromere |
| locus (pl., loci) | the site of place on a chromosome where a particular gene is located |
| biparental inheritance | one member of each homologous pair of chromosomes is derived from the maternal parent and one is derived from the paternal parent |
| sex chromosome | a chromosome, such as X or Y in humans, or Z or W in birds, which is involved in sex determination |
| zygote | single-celled fertilized egg |
| karyokinesis | nuclear division |
| cytokinesis | cytoplasmic division |
| cell cycle | events that occur from the completion of one division until the beginning of the next division |
| interphase stage of the cell cycle | interval between divisions |
| S phase | period during interphase during which replication of the DNA of each chromosome occurs |
| Stages of Interphase (4) | 1) G1-Gap 1 2) [G0 stage-cells can withdraw from the cell cycle during G1] 3) S phase 4) G2-Gap 2 |
| Events of Prophase in Mitosis (3) | 1) chromosomes coil up and condense 2) centrioles divide and move apart 3) nuclear envelope breaks down and nucleolus disintegrates |
| centrosome | area of differentiated cytoplasm just outside of the nuclear envelope where centrioles are found |
| Events of Prometaphase in Mitosis (3) | 1) Chromosomes are clearly double structures 2) Centrioles reach the opposite poles 3) spindle fibers form |
| Events of Metaphase in Mitosis (1) | Centromeres align on metaphase plate |
| metaphase plate | equatorial plane; midline region of the cell |
| kinetochore | a fibrous structure with a size of about 400 nm, located within the centromere. It appears to be the site of microtubule attachment during division |
| Events of Anaphase in Mitosis (1) | Centromeres split and daughter chromosomes migrate to opposite poles |
| daughter chromosome | name for chromatids after initiation of anaphase; formerly sister chromatids |
| Events of Telophase in Mitosis (6) | 1) Daughter chromosomes arrive at poles 2) Cytokinesis commences late telophase: 3) chromosomes uncoil to chromatin 4) nuclear envelope reforms 5) spindle fibers disappear 6) nucleolus begins to reform |
| cell plate | cell wall that is synthesized and laid down across the metaphase plate region during telophase in plant cells; becomes the middle lamella |
| cell furrow | complete constriction of the cell membrane in animal cells |
| cell division cycle (cdc) mutations | a class of cell division cycle mutations in yeasts that affect the timing and progression through the cell cycle |
| crossing over | genetic exchange between members of each homologous pair of chromosomes |
| Difference in behavior of homologous pairs in mitosis and meiosis? | In mitosis, homologous pairs of chromosomes behave autonomously during division; In meiosis, they form pairs and synapse |
| bivalent | synapsed structure including a homologous pair of chromosomes in zygotene (2nd) stage of meiosis prophase I; both members of each bivalent have replicated but the double structure is not yet visually apparent |
| tetrad | synapsed structure including a homologous pair of chromosomes that appears in pachytene (3rd) stage of meiosis prophase I, after the double structure of each homolog is evident |
| reductional division | number of centromeres is reduced by one-half; meiosis I |
| dyad | the products of tetrad separation or disjunction at meiotic prophase I; each dyad consists of two sister chromatids joined at the centromere |
| equational division | number of centromeres remains equal; meiosis II and mitosis |
| monad | the one chromosome left in each cell at the end of meiosis II after a dyad splits |
| synapsis | the pairing of homologous chromosomes at meiosis |
| Five Substages of Meiotic Prophase I | 1) Leptotene stage 2) Zygotene stage 3) Pachytene stage 4) Diplotene stage 5) Diakenesis |
| Events during Leptotene Stage of Meiotic Prophase I (2) | 1) Chromatin material begins to condense, and the chromosomes, though still extended, become visible 2) Chromomeres (localized condensations) are found along each chromosome |
| Events during Zygotene Stage of Meiotic Prophase I (4) | 1) Chromosomes continue to shorten and thicken 2) Homology search occurs 3) Synaptonemal complex begins to form 4) Paired homologs are in the form of bivalents |
| Events during Pachytene Stage of Meiotic Prophase I (3) | 1) Chromosomes continue to coil and shorten 2) Further development of the synaptonemal complex occurs 3) The double structure of each homolog is evident and paired homologs are in the form of tetrads |
| Events during Diplotene Stage of Meiotic Prophase I (2) | 1) Within each tetrad, each pair of sister chromatids begins to separate 2) Earlier crossing over is evident through chiasmata |
| chiasma (pl., chiasmata) | area where nonsister chromatids remain in contact, thought to represent a point where genetic exchange occurred through the process of crossing over |
| Events during Diakenesis of Meiotic Prophase I (4) | 1) Chromosomes pull farther apart but non sister chromosomes remain loosely associated through chiasmata 2) Terminalization occurs--chiasmata move towards the end of the tetrad 3) Nucleolus and nuclear envelope break down 4) two centromeres of each tetrad attach to the recently formed spindle fibers |
| disjunction | the separation of chromosomes during the anaphase stage of cell division |
| nondisjunction | a cell division error in which homologous chromosomes (in meiosis) or the sister chromatids (in mitosis) fail to separate and migrate to opposite poles; responsible for defects such as monosomy and trisomy |
| spermatogenesis | production of male gamete |
| oogenesis | production of female gamete |
| spermatogonium | undifferentiated diploid germ cell |
| primary spermatocyte | enlarged spermatogonium |
| secondary spermatocyte | product of first meiotic division in spermatogenesis |
| spermatids | product of second meiotic division in spermatogenesis |
| spermiogenesis | series of developmental changes that occur to spermatids |
| spermatozoa | sperm; product of spermiogenesis |
| ova (sing., ovum) | eggs |
| oogonium | diploid germ cell |
| primary oocyte | enlarged oogonium |
| first polar body | one of the products of meiosis I in oogeneis - contains half the chromosomes but little of the cytoplasm |
| secondary oocyte | product of first meiotic division in oogenesis |
| ootid | product of second meiotic division in oogenesis |
| second polar body | a small body containing the chromosomes discarded during the second meiotic division of an ovum |
| folded-fiber model | a model of eukaryotic chromosome organization in which each sister chromatid consists of a single chromatin fiber composed of double-stranded DNA and proteins wound like a tightly coiled skein of yarn |
| asexual reproduction | reproduction that does not involve the union of gametes and in which a single parent produces offspring that are genetically identical to the parent |
| autosomes | chromosomes other than the sex chromosomes. In humans, there are 22 pairs of autosomes. |
| binary fission | the division of a prokaryotic cell into two offspring cells |
| eukaryotes | organisms having true nuclei and membraneous organelles and whose cells demonstrate mitosis and meiosis |
| fertilization | process in sexual reproduction in which male and female reproductive cells join to form a new cell |
| gametogenesis | production of gametes |
| germ cells | the only cells that can undergo meiosis--spermatogonium & oogonium |
| homologues | two chromosomes that code for the same traits as itself; traits are same, but actual genes may be different |
| karyotype | the chromosome complement of a cell or individual. Often used to refer to the arrangement of metaphase chromosomes in a sequence according to length and centromere position. |
| mitotic spindle (apparatus) | the framework of microtubules that appears in cell division, and eventually attaches to and moves the chromatids apart |
| organelles | specialized structure that performs important cellular functions within a eukaryotic cell |
| prokaryotes | organisms lacking nuclear membranes and true chromosomes |
| somatic cells | all cells other than the germ cells or gametes in the organism |
| sperm cells | male reproductive cells |
| synaptonemal complex | an organelle consisting of a tripartite nucleoprotein ribbon that forms between the paired homologous chromosomes in the pachytene stage of the first meiotic division. May be essential for crossing over. |
| testcross | a cross between an individual whose genotype at one or more loci may be unknown and an individual who is homozygous recessive for the gene or genes in question |
| X-linked alleles | genes located on the X chromosome |
| Classification of chromosomes in a karyotype | 1) size 2) banding pattern 3) centromere location |
| Summary of events of 5 periods of prophase I of meiosis | 1) leptonena -- chromomeres (localized condensations) 2) zygonema -- bivalents 3) pachynema -- tetrad 4) diplonema -- chiasma 5) diakinesis -- terminalization (chiasmata move toward ends of tetrads) |
| ploidy | a term referring to the basic chromosome set or to multiples of that set |
| 2 major differences btwn mitosis & meiosis | 1) mitosis produces 2 diploid daughter cells; meiosis produces 4 haploid daughter cells 2) mitosis produces daughter cells that are genetically identical; meiosis produces daughter cells that are not genetically identical |
| 3 ways chromosomes of a karyotype are classified | 1) size 2) banding pattern 3) centromere location |
| karyokinesis | nuclear division |
| alleles | different versions of the same gene |
| homozygous | an individual with two identical alleles |
| heterozygous | an individual with two different alleles |
| genotype | the specific allele composition of an individual |
| phenotype | the outward appearance of an individual |
| What information do you get from the Punnett Square? (4) | 1) predicted phenotypic ratio 2) predicted genotypic ratio 3) the gametes that each parent can form |
| 2 reasons that the pea plant was a good choice to study | 1) existed in several varieties with distinct characteristics 2) structure allowed for easy crosses where the parents could be controlled |
| true breeding | homozygous |
| Mendel's Law of Segregation | during gamete formation, the paired unit factors (alleles) segregate randomly so that each gamete receives one or the other with equal likelihood (50% chance of each) |
| Mendel's Law of Independent Assortment | during gamete formation, segregating pairs of unit factors (alleles) assort independently of each other (maternal & paternal don't all go to the same side) |
| chi square test | statistical test to test the null hypothesis that an observed set of data is equivalent to a theoretical expectation |
| dihybrid cross | a genetic cross involving two characteristics in which the parents possess different forms (traits) of each character |
| dominance | the expression of a trait in the heterozygous condition |
| gamete | specialized reproductive cell with a haploid number of chromosomes |
| degrees of freedom | df=n-1 |
| F1 generation | first filial generation; the progeny resulting from the first cross in a series |
| F2 generation | second filial generation; the progeny resulting from a cross of the F1 generation |
| cross-fertilization | fertilization of one plant by pollen from a different plant |
| self-fertilization | fertilization in which both egg and pollen come from the same plant |
| forked-line method | breaks down multi-hybrid crosses into a series of monohybrid crosses- product rule is then applied to line of genotypes; method to solve independent assortment problems |
| parental generation | The individuals that mate in a genetic cross. Their offspring are the first filial (F1) generation. |
| hybrid | offspring of crosses between parents with different traits |
| loss-of-function allele | a mutation that causes the diminution of a specific wild-type function |
| 3 math operations to calculate probability? | 1) sum rule 2) product rule 3) binomial expansion equation |
| Calculate # of possible gamete types | = # possible alleles ^ # of genes |
| pedigree analysis | commonly used to determine the inheritance pattern of human genetic diseases |
| probability | ratio of the frequency of a given outcome to the frequency of all possible outcomes |
| product rule | the probability that 2 or more independent events will occur is equal to the product of their respective probabilities (this AND that occurs) |
| sum rule | the probability that 1 of 2 or more mutually exclusive events will occur is the sum of their respective probabilities (this OR that occurs) |
| binomial expansion | represents all of the possibilities for a given set of unordered events; ex. "What is the probability that two of a heterozygous couple's five children will have blue eyes?" |
| goodness of fit | how close the observed data are those predicted from a hypothesis |
| random sampling error | the deviation between observed and expected outcomes |
| recessive | an allele whose potential genetic expression is overridden in the heterozygous condition by a dominant allele |
| segregation | the separation of maternal and paternal homologs of each homologous chromosome pair into gametes during meiosis |
| monohybrid cross | a genetic cross involving only one character |
| strain | a group of organisms with common ancestry that has physiological or morphological characteristics of interest for genetic study or domestication |
| trait | any detectable phenotypic variation of a particular inherited trait |
| epistasis | when the expression of one gene or gene pair masks or modifies the expression of another gene or gene pair |
| essential gene | it is for something that is essential to life, so it will be a lethal gene if it is non-functional |
| extranuclear inheritance | mitochondrial and chloroplast DNA |
| gene dosage effect | The gene dosage effect refers to the relationship between the number of functioning copies of a gene and the amount of gene product produced. In order for full deficiency to occur, both alleles must be abnormal |
| gene interaction | production of novel phenotypes by the interaction of products of alleles of different genes |
| genetic anticipation | the phenomenon in which the severity of symptoms in genetic disorders increases and the age of onset decreases from generation to generation. It is caused by the expansion of trinucleotide repeats within or near a gene |
| heterozygote advantage | also called over dominance; the phenomenon in which heterozygote is more vigorous than both the corresponding homozygotes |
| imprinting | the process by which the expression of a gene depends on whether it has been inherited from a male or a female parent |
| incomplete dominance | expressing a heterozygous phenotype that is distinct from the phenotype of either homozygous parent (not blending because you can get back to homozygous in later generations) |
| incomplete penetrance | Dominant alleles that are not always expressed, often for unknown reasons. |
| lethal allele | recessive, lethal in homozygous, may produce distinct phenotype when heterozygous, example: yellow coat color in mice |
| 2 components of simple Mendelian inheritance | 1) a single gene with two different alleles 2) alleles display a simple dominant/recessive relationship |
| 2 laws of Mendelian inheritance | 1) law of segregation 2) law of independent assortment |
| mutant alleles | an allele that has been altered by mutation |
| overdominance | also called heterozygote advantage; heterozygotes have higher fitness than either homozygote |
| pleiotropy | the control of more than one phenotypic characteristic by a single gene |
| polymorphism | the existence of two or more discontinuous, segregating phenotypes in a population |
| sex-influenced inheritance | phenotypic expression that is conditioned by the sex of the individual |
| sex-limited traits | a trait that is expressed in only one sex even though the trait may not be X-linked |
| temperature-sensitive conditional allele | a conditional mutation that produces a mutant phenotype at one temperature range and a wild-type phenotype at another |
| wild-type allele | the most common observed , designated as the norm or standard |
| 2 reasons heterozygote displays wild-type phenotype | 1) 50% of the normal protein is enough to accomplish the protein's cellular function 2) the heterozygote may actually product more than 50% of the functional protein ("up-regulated") |
| ex. of incomplete dominance | pink 4 o'clock flower |
| ex. of incomplete penetrance | 60% of heterozygotes carrying a dominant allele exhibit the trait allele-->the trait has 60% penetrance |
| ex. of expressivity | a polydactyl person with a single extra finger has lower expressivity than a one with several extra fingers |
| ex. of environmental effect | as temperature increases, the number of eye facets on the drasophilia increase |
| ex. of overdominance/heterozygote advantage | heterozygotes for the sickle cell allele are more resistant to malaria |
| ex. of multiple alleles (in population) | rabbit coat color (C, cch, ch, c) |
| ex. of temperature-sensitive conditional allele | siamese cats |
| ex. of lethal gene | yellow coat color in mice is dominant phenotypically but recessive lethal (1 will make it yellow; 2 will kill it) |
| ex. of epistasis | Bombay phenotype in which the FUT1 locus masks the expression of the IA and IB locus |
| complementation test | a genetic test to determine whether or not two mutations occur within the same gene |
| ex. of complementation | 2 wingless flies have mutations on separate genes-->offspring have wings 2 wingless flies have two different mutations on the same gene-->offspring are wingless |
| ex. of sex-influences traits | pattern baldness in humans (baldness is dominant in males but recessive in females) |
| ex. of sex-limited traits | breast development in females beard growth in males |
| What is a good indication of a gene interaction? | deviations from the 9:3:3:1 ratio |
| ex. of codominance | alleles IA & IB for red blood antigens |
| codominance | condition in which the phenotypic effects of a gene's alleles are fully and simultaneously expressed in the heterozygote |
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