Final- chapter 7-9 – Flashcards
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molecule that carries the gene sequence to ribosomes
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messenger rna
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transcription starts at a region of dna called a
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promoter
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if the dna coding sequence was cga-atc the mrna would be
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gcu uag
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in eukaryotes, what modification occurs to the mrna transcript
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the non coding intron segments are removed
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how many nucleotides compose one codon
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3
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how many different amino acids make up the genetic code for proteins
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20
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which of the following carries amino acids to ribosomes
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trna
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what specifically determines the sequence of amino acids in a polypeptide of eukaryotes
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the exons
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which of the rnas act as an enzyme
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rrna
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for eukaryotes transcription takes place in the
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nucleus
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translation stops when
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one of the three stop codons is encountered
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a gene mutation
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all of these
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frameshift mutations may involve
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insertion of one to several base pairs
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homeotic genes are in general, in control of
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formation of major body parts
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the tightley condensed non functional x chromosome is called and
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barr body
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in mitosis
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the chromosome number stays the same
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cells with two of each kind of chromosome are discribed by the term
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diploid
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animal cells divide using a contractile ring by
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pinching
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in mitosis if a parent cell has 12 chromosomes each daughter cell will have how many chromosomes
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12
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cells with two of each kind of chromosome are described by the term
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diploid
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animal cells divide using a contractile ring by
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pinching
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an accumulation of cells that divide uncontrollably is known as
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neoplasms
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an omcogene is
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a mutated gene that results in tumors
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proto oncogenes are
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normal genes that promote mitosis
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asexual reproduction
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produces clones
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sexual reproduction
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results in new combinations of genetic traits
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alternative or different forms of the same gene are called
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alleles
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which of these is a disadvantage of asexual reproduction
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less genetic diversity in offspring
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if meiosis did not occur in sexual reproducing organisms
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the chromosome number would double each generation
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a chicken somatic cell carries 78 chromosomes. a chicken sperm cell will contain how many chromosomes
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39
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crossing over is one of the most important events in meiosis because
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it produces new combinations of alleles on chromosomes
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a _____is an offspring of a cross between two individuals that breed true for different forms of a trait
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hybrid
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which of the following determines an observable trait
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genotype
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an allele is ______ if its effect masks that of a ______ allele paired with it
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dominant recessive
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in humans skin color is controlled by several genes. thus skin color is an _____ characteristic
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epistatic
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what tool do geneticists use to study the genetics of families through generations
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pedigrees
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males more commonly are affected by , linked recessive genetic disorders than are females because
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males have only on x and thus more of a chance to be recessive
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why are most x linked disorders recessive
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dominant x linked disorders are almost always fatal to the male embryo
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amniocentesis is
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used in prenatal diagnosis to detect chromosomal mutations and genetic disorders in embryos
