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39 Cards in this Set
- Front
- Back
How is hereditary material carried in the human body? |
chromosomes |
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genes |
functional units of heredity consisting of DNA sequences that code for specific amino acids and thus for formation of specific proteins |
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chromosomes |
classified by structure and banding pattern |
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homologous pairs |
chromosomes common to both sexes |
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alleles |
alternative form of a gene, one member of a pair |
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homozygous |
If both alleles are the same, they and the organism are homozygous with respect to that gene. |
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heterozygous |
When the alleles of a pair are heterozygous, one is dominant and the other is recessive. |
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karyotype |
number and appearance of chromosomes in the nucleus of a eukaryotic cell |
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crossing over |
exchange of genetic material between homologous chromosomes that results in recombinant chromosomes |
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phenotype |
observable physical or biochemical characteristics of an organism |
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genotype |
genetic makeup of a cell, an organism |
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mitosis |
leads to the production of two daughter cells identical in chromosome number to the parent cell |
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meiosis |
leads to the production of four daughter cells, but each containing only half the number of chromosomes of the parent cell |
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single gene-inheritance |
autosomal, x-linked, complex |
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dominant trait |
the trait is expressed if the dominant allele is present on at least one of the pair chromosomes |
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recessive trait |
can be expressed only when the allele responsible for that trait is present on both chromosomes or when the dominant allele is not present (ex: x-linked genes in the XY male) |
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Why do recessive traits become more common with consanguineous matings? |
recessive characteristic can only be seen in the children of a heterozygous parent |
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consanguineous |
between relatives |
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x-linked traits |
genes on the x chromosome |
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examples of x-linked traits |
red-green color blindness, hemophilia A, hemophilia B, Duchenne muscular dystrophy, Becker's mescular dystrophy, Coffin-Lowry syndrome, Blue cone monochromacy, Barth syndrome |
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Testicular development of the indifferent gonad occurs regardless of whether viable _______ _______ are present. |
germ cells |
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However, the germ cells must be present for the ____________ to differentiate. |
ovaries |
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multifactoral inheritance |
due to the interaction of genetic and environmental factors |
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Multifactoral inheritance includes traits such as __________ and ____. |
height, BP |
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Multifactoral disorders include birth defts such as |
neural tube defects, some congenital heart defects, congenital dislocated hips, cleft lip and palate, pyloric stenosis |
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developmental disorder |
error in meitotic division |
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In the case of formation of gametes with a trisomy or monosomy, one gamete will have 24 chromosomes and the other will have only ____. |
22 |
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Nondisjunction is more likely to occur during the recombination that takes place during the first ___________ division. |
meiotic |
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trisomy |
presence of an extra chromosome |
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monosomy |
one member of a pair of chromosomes is missing |
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mosaicism |
When mitotic nondisjunction occurs later in development some cell lines have an abnormal number. |
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What are the possible results of non-disjunction of the sex chromosome? |
Klinefelter syndrome, extra Y chromosome, Tuner syndrome |
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translocation |
occur following breaks in one or more chromosomes, genetic material is transferred from one chromosome to another |
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A balanced translocation occurs when chromosomes exchange pieces and no genetic material is ______. |
lost |
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If material is gained or lost, that is considered an _________ ___________. |
unbalanced translocation |
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Those with unbalanced translocations may have multiple __________. |
anamolies |
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__________ _____________ is due to translocations, most commonly between chromosomes 14 and 21. |
Down syndrome |
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Depending on which combination of 21 and 14 chromosomes are transferred to the gametes, this individual can produce normal, carrier, monosomic, or _________ offspring. |
trisomic |
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Down syndrome is due to _______________, most commonly between chromosomes 14 and 21. |
translocations |