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42 Cards in this Set
- Front
- Back
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Genes
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Heritable charachterisitics that are passed on from one generation to the next
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Varying version of a gene
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Alleles
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Chromosomes
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The material that carry genetic information
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Actual Genetic Distribution of Genes in an Organism
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Genotype
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Outward apperance of the Organism due to Genetic Information
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Phenotype
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Mendel's First Law
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Law Of Segregation
-Genes exist in alternate forms -An organism has two alleles for each gene -The two alleles that segregate during meiosis will result in gametes that carry only one set of those genes -Genes display DOMINANAT and RECESSIVE characterisitcs |
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Homozygous
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When the organism has two of the same alleles for the same gene
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Heterozygous
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When the organism has two different alleles for the same gene
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Monohybrid Cross
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When during a cross only one kind of trait is being studied
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Name for plants that are being studied
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P Generation
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Name of the ofspring of the P Generation
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F Generation
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What will be the genotypic results and the phenotypic results of Pp x Pp cross?
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The genotypic ratio will be 1:2:1 and the phenotypic ratio will be 3:1.
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Test crosses/Backcrosses
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When we use a plant with a known genotype and cross it with a plant with an unknown genotype and observe the distribution of the offspring to determine the unknown genotype.
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Mendel's Second Law
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Law of Independent Assortment. States that the distribution of one set of gene is indenpendent of the distribution of another set of genes
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A cross involving two different genes
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Dihybrid Cross
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Statistical Results of a Dihybrid Cross
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9 : 3 : 3 : 1 phenotype
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How do you find the liklihood of two events occuring siultaneously?
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You need to MULTIPLY the probabilites of each event occuring.
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How do you find the liklihood two event occuring at the exclusion of eachother?
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You need to ADD probabilities of each event.
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How do you determine the probability of a plant giving a gamete of a certain genotype?
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You look at the overall genotypic distribution of the gametes and take the fraction of the gamete you want over all the gametes there are.
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If one parent is homozygous and the other is heterzygous.
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If one parent is homozygous and the other is heterozygous then all the offspring, though not homozygotes, will have the trait of the homozygous parent.
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The process that leads to recombination in which there is a physical exchange of DNA between homologous chromosomes
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Crossing over
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The basis of recombination frequency
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The further genes are from the loci the greater chance there is for the genes to recombine. On the basis of these frequencies, a genetic map can be created in which the location of each gene of the chromosome is mapped.
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Map Unit
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One map unit represents the percentage of genetic recombination between two genes. One map unit means that there is a 1 percent chance of genetic recombination between two genes while a difference of 25 map units means that there is a 25 percent chance of recombination/
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Four Exceptions of Mendel's Laws
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Incomplete Dominance,
Codominance, Penetrance and Expressivity, and Inherited Disorders |
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Incomplete Dominance
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When neither of two alleles show full dominance. In this case we see a mixing of the two alleles.
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Codominance
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Two conditions must be met for this to occur. The first is that there must be a number of different codings for a gene and the second is that there must more than one gene that is dominant to a recessive gene. In these cases, both allleles are FULLY EXPRESSED. ABO bloodtype is an example of codominance.
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Penetrance
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When a gene is dominant but is not expressed we say that the gene is not FULLY PENETRANT. We quantify the degree to which a gene is penetrant by how penetrant it is.
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Expressivity
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The fact that a given gene will have a wide range of expressions even if the gene is dominant. A gene that is dominant can have no expression at all or full expression
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Cystic Fibrorsis
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The deletion of a amino acid from the chloride channel. Results in respiratory complications due to overproduction of mucus.
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Early Acting
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A recessive gene that will kill the organism before i has a chance to reproduce
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The gene for sickle cell will confer resistance to what disease?
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Malaria
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Late acting
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A lethal gene that will not express itself until later in the organisms life where they might have had the chance to reproduce and send the allele to the next generation.
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Hemizygosity
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Given that males only have one X chromosome, if there is a genetic mutation on that chromosome men will not have another chromosome to compensate for that mutation. This condition is known as Hemizygosity.
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In which sex do X linked recessive gene appear and why?
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They appear much more frequently in men do due hemizygosity
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If a mother carries an x linked recessive gene, how will the children be affected?
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None of the children will have symptoms since they all inherit one X chromosome from the mother which will compensate for the mutated gene
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Can a male pass on a sex linked gene to his sons?
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No. In order to a sex linked gene to be passe on a child it must be on the X chromosome. Fathers do not pass on the X chromosome to their children and cannot pass anything linked to their X chromosome.
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Aneuploid
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A case where a individual does not have the correct number of chromosomes
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Nondisjunction
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When the chromosomes do not disjoin during the end of meiosis I or II
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Trisomy - Monosomy
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When nondisjunction occurs in gametes, there will be two cells with one extra set of chromosomes and another set missing one set of chromosomes. If the set of gametes with the extra chromosomes fuses with an egg, that egg with have three sets on a single chromosome. This is known as Trisomy. The zygote that was created by the fusion of the gamete that was missing a chromosome results in condition known as MONOSOMY.
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Turner Syndrome
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Where a female has a XO genetic make up. Symptoms include short stature and no secondary female characteristics
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Superfemales
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Where a female has an XXX genetic make up. Symptoms include mental retardation
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Klinfelters Syndrome
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Males with an XXY genetic make up. Symptoms on this syndrome include height, female secondary sex characteristics and sterility.
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