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53 Cards in this Set
- Front
- Back
centromere
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primary constriction
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karyotype
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is an assemblage of metaphase chromosomes of an individual arranged in pairs according to the order of descending length and position of the centromere.
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metacentric chromosome
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is one that has a centrally located centromere and chromosome arms with approximately equal length.
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submetacentric chromosomes
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have centromeres located close to the center of the chromosome, but he chromosome arms are distinctly unequal in length.
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acrocentric chromosomes
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have centromeres located much nearer one end than the other, resulting in chromosome arms that are decidedly unequal in length.
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telocentric
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no human chromosomes have centromeres on the end(telocentric), thus having only one arm.
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secondary constrictions
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human chromosomes that usually represent the site of ribosomal RNA genes.
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satellites
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short, distal, chromosomal portions.
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region
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an area of a chromosome between two major landmarks such as centromere, conspicuous band, or chromosome end.
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bands
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within each region are numbered starting with the band closest to the centromere and proceeding toward the end of each chromosome arm.
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syndrome
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a complex of symptoms that may include aneuploidies with morphological, physiological, and psychological deviations form normal.
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DNA molecules have areas that
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are not genes, called junk DNA.
Junk DNA is thought to play important roles in cellular metabolism and inherited diseases. |
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RFLP Analysis
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is one of the original processes used to create a DNA profile.
Restriction Fragment Length Polymorphism. |
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Restriction Enzymes
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enzymes that cut the DNA molecule at specific sites
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Gel Electrophoresis
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A process that separates fragments of DNA.
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Gel
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is a thin sheet of gelatin supported by a glass plate with electrodes atached at both ends.
One end of the gel has a positive charge and the other end has a negative charge. DNA fragments are attracted to the positive end of the gel plate. Smaller, lighter fragments migrate more easily through the gel and therefore travel farther in a given time period than larger, heavier fragments. |
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Molecular probes
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small pieces of DNA that use the base-pairing rule to locate and bind only to the fragments that will be used to form the DNA profile.
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X-ray film
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photographs the sheet of DNA bands.
the only bands visible on the developed film are those that have been labeled with molecular probes. |
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DNA Restriction Analysis
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is a method that uses bacterial enzymes known as restriction endonucleases or restriction enzymes to reveal exact nucleotide sequences.
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Restriction Map
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can be produced with the information obtained through the use of restriction enzymes that cut DNA molecules, such as circular viral DNAs, into specific fragments.
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bacteriophage
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a virusthus infects bacteria.Particular forms such as lambda are used as vectors for cloning DNA.
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bp(base pair)
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a pair of complementary nitrogeneous bases in a DNA molecule; also the unit of measurement for DNA sequences.
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cathode
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the negative electrode from which electrons are emitted; opposite of the anode.
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endonuclease
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a class of enzymes that degrades DNA and/or RNA molecules that cleave bonds linking adjacent nucleotides
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evolution
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is a change in the genetic composition of a population.
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evolution results
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from a change in the frequency of the alleles in the gene pool produced by one or more of the following factors:
mutation, gene flow, natural selection, genetic drift, or nonrandom mating. |
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mutation
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the naturally occurring mutations of genes and chromosomes produce variation in the gene pool.
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gene flow
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the frequency of alleles in the gene pool may change due to the immigration of emigration of organisms.
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natural selection
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the impact of the environment on the survival and reproduction of genotypes within the population is a major force in changing the frequency of alleles.
Selection is always on the phenotypes, but the genetic effect is on the genotypes. |
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genetic drift
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the frequency of alleles in the gene pool may change by pure chance.
It is a significant evolutionary mechanism in small populations only. |
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nonrandom mating
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If there is a mating preference for a certain combination of alleles, the frequency of alleles in a population will change.
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Castle-Hardy-Weinberg (CHW) law or Equilibrium
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states that in the absence of forces that change gene frequencies, the frequencies of the alleles in a population will remain constant from generation to generation.
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CHW equation
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p2 + 2pq + q2 = 1
p2 = the frequency of TT individuals(homozygous dominants) 2pq= the frequency of Tt individuals(heterozygotes) q2 = the frequency of tt individuals (homozygous recessives) |
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systematics
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the classification of organisms and groups of organisms.
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species
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are groups of actually or potentially interbreeding natural populations, which are reproductively isolated form other such groups.
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Chromosomes are arranged by:
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size,
location of centromere |
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Chromosomal Alterations
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Errors during meiosis lead to abnormalities
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deletion
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Chromosomes
Lose a piece |
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translocation
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Chromosomes Recombine with a non-homologous chromosome
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Errors during recombination (Meiosis I)
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can result in some chromosomal abnormalities.
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Chromosomal aberrations fall into three general categories:
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Translocation/Chromosomal Breaks
Deletion Fragile site |
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Polyploidy
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presence of additional sets of chromosomes
Common in plants Lethal in most animals |
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Aneuploidy
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presence of extra chromosome or an absence of one
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Trisomy
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“three bodies” – having one extra chromosome
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Monosomy
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missing a chromosome
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Meiotic nondisjunction causes
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the gain or loss of single chromosomes
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Aneuploid Condition:
Trisomy 21 |
Down Syndrome
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Aneuploid Condition:
Trisomy 18 |
Edwards Syndrome
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Aneuploid Condition:
Trisomy 13 |
Patau Syndrome
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Chromosome Breaks
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Spontaneous breaks due to errors in DNA replication & errors in crossing-over
Environmental factors: UV light, Radiation, Viruses, Chemicals Cri du Chat: Caused by partial deletion of Chromosome 5 Infant’s cry sound like a cat. Speech problems after infancy. abnormal glottis & larynx |
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Sex Chromosome Aneuploidy
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is more common than Autosome Aneuploidy
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Turner Syndrome
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Female (45 total chromosomes, 1 sex chromosome (X))
Only monosomy that is Not lethal Abnormalities: don’t develop normal at time of puberty, underdeveloped breasts, rudimentary ovaries Infertile: do Not ovulate or menstruate Treatment: Hormone supplements can help these women lead normal lives. |
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Fragile Sites
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Fragile X Syndrome: normally CGG is repeated 50 times; in fragile X, up to 1000 times
Makes a very thin physical region of the chromosome. Results in range of mental retardation and behavioral problems Occurs in both sexes; most females with fragile X are heterozygous |