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23 Cards in this Set
- Front
- Back
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The Phenotype for a character most commonly observed in natural populations is called the...
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Wild type
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Why is the trait of a wild type character in an organism called the mutant phenotype?
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Because, such as the white eyed fly in the typically red-eyed fruit fly, the mutant phenotype usually originated from a mutation of the wild type alle
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Duchenne muscular distrophy and hemophilia are both good exampled of..
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Recessive sex-linked traits
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When a female X-chromosome (sex chromosome) is inactivated, what does it form and why does it form this?
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It forms a condensed "Barr body" on the inside of the nuclear envelope; if forms this bc if one X chromosome wasn't inactivated, then twice the proteins would be created in females than in males, etc.
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What can happen when Carr bodies form in females who are heterozygous for a recessive sex-linked trait?
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They can exhibit mosaicism, in which some cells with the recessive X exhibit this trait and those with the dominant X do not exhibit the trait; e.g., spotted sweat formation in the skin of some women
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T/F: If one specific X chromosome in women forms a Barr body, then all the cells that form from mitosis of that cell will have the same chromosome form a Barr body as well
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True
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How are specific X chromosomes inactivated to form Barr bodies?
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CH3 (methyl) groups are added to them
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What locates genes on a chromosome with respect to chromosomal features, such as a stained bands?
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A cytogenic map
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When homologs fail to separate during Meiosis I or sister chromatids do not separate during Meiosis II, what is this called?
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Nondisjunction
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Aneuploidy is a condition in which...
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A zygote has an abnormal number of a chromosome, whether it be too many or not enough
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What does it mean when a aneuploid zygote is monosomic for a certain chromosome?
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It is missing one copy of a particular chromosome (trisomy is an added one to the homolog pair)
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T/F: Polyploids (having multiple sets of the same chromsomes instead of two, like human diploid cells) are usually more normal than aneuploids (having one too many or one too few of a chromosome).
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True
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What are the products of nonreciprocal crossing over?
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One chromosome that has deletion and the other with duplication
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What is deletion?
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When a chromosomal fragment is lost
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What is duplication?
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When a segment is repeated (ABCBCBCDEF)
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What is inversion?
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When an entire segment of a chromosomal sequence is reversed (AB(FEDC)G)
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What is translocation?
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When a fragment of a chromosome is taken off and added to a completely different, nonhomologous chromosome. Can be reciprocal or nonreciprocal.
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Cri du Chat rusults from...
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Deletion
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Leukemia is caused by...
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A large translocation in cells that will become WBCs
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Variation in phenotype depending on whether an allele is inherited from the mother or father is called...
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Genomic imprinting
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T/F: Especially in genomic imprinting, adding methyl groups can silence or especially active genes to imprint.
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True
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Why don't extranuclear genes in chloroplasts or mitochondira exhibit Mendelian genetics?
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Because they are not replicated or transmitted to daughter cells in the same fashion that nuclear DNA is
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The products of the mitochondrial genes help make up the...
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Protein complexes that make up the ETP
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