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30 Cards in this Set
- Front
- Back
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nHomologouschromosomes |
¨Chromosomesthat pair up during meiosisnOnecame from each parentnContainthe same genes |
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How are chromosomes, DNA, and genes related? |
nEachisone long DNA molecule¨A geneis a short region of the moleculeEachchromosome can have > 1,000 genes |
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nAutosomes |
¨The “other” 22 pairs of homologous chromosomes ֨. |
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nSexchromosomes |
¨Females have 2 X chromosomes (XX) ¨Males have X and Y (XY) nY is very small nHas few genes |
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nDiploid |
¨Two copies of each chromosome (somatic cells) nHomologous pair ¨Paternal & maternal homologue in each cell ? |
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nHaploid |
¨Only one copy of each chromosome (reproductive cells) nHomologous pairs are split A |
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nPhenotype |
qExpression of a genetic trait qWhat you see |
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nGenotype |
qGenetic make up qThe actual genes on the chromosomes |
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Why are mutations important? |
Ultimate source of variation |
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nMutation: |
¨Change in DNA that makes up a gene |
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nMutationscan be |
¨ Harmful ¨ Beneficial ¨ Neutral |
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nDifferentalleles arose from |
a mutation ¨e.g., everyone had brown eye until blue eyes arose through mutation nNote this is not a real example, just made it up. |
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nHomozygote— |
same two alleles (AA or aa) |
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An allele, or allel, |
is one of a number of alternative forms of the same gene or same genetic locus. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation. However, most genetic variations result in little or no observable variation. |
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nHeterozygote— |
two different alleles (Aa) |
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nGenotype |
nGenotype—the genetic makeup qTheactual genes on the chromosomes |
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nPhenotype— |
observable characteristics qExpressionof a genetic traitqWhatyou see |
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nDiploid |
¨Two copies of each chromosome (somatic cells) nHomologous pair ¨Paternal & maternal homologue in each cell ? |
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nnHaploid |
¨Only one copy of each chromosome (reproductive cells) nHomologous pairs are split |
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nJohann “Gregor” |
Mendel is considered the father of genetics nPublished his work in 1866 nWork wasn’t accepted or even reallydiscovered until 1900 |
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¨Pgeneration— |
parent generation |
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¨F1generation— |
first generation |
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¨F2generation— |
second generation |
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Summaryof Mendel’s Concepts. Alternativeversions of genes (i.e.,alleles) cause |
variation in inherited traits C |
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1.Offspringinherit ). |
one allele from each parent. |
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1.Anallele is dominant if it |
has exclusive control over the phenotype of an organism when paired with a different allele. |
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1.Twocopies of a gene separate in meiosis and |
end up in different gametes. |
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1.Gametesfuse without regard |
to which alleles they carry. e |
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alleles |
nDifferent versions of a given gene |
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nHuman blood groups |
¨Three alleles of one gene nIA: A type sugar nIB: B type sugar ni: neither A or B +( |
