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65 Cards in this Set
- Front
- Back
The nuclei of normal human cells carry ___ pairs of chromosomes for a total of ____
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23; 46
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What are the unmatched pairs of chromosomes in humans?
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In males, the X and Y chromosomes
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How many chromosomes do children born with Down syndrome have?
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47
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Down syndrome has an extra #____ chromosome
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21
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aberrant
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deviating from the ordinary, usual, or normal type
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trisomy 21
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Down syndrome; gives rise to an abnormal phenotype
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Phenotypic symptoms of trisomy 21?
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wide skull that is flatter than normal at the back, an unusually large tongue, learning disabilities caused by the abnormal development of the hippocampus, a propensity to respiratory infections and heart disorders, rapid aging, and leukemia
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propensity
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a natural inclination or tendency
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chromosomes are the cellular organelles responsible for transmitting ___________
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genetic information
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chromosome theory of inheritance
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chromosomes are the carriers of genes;
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_____ is responsible for the formation of gametes
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meiosis
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gametes
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eggs or sperm
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zygote
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the fertilized egg
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What process is responsible for multicellularism?
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mitosis
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parcel
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a part, portion, or fragment.
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A ______ error gives rise to an egg or sperm carrying an extra ________, causing Down syndrome
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meiosis; chromosome 21
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When was the chromosome theory of inheritance proposed?
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1902
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The scientific name for the fruit fly?
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Drosophila melanogaster
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gametogenesis
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process including both meiotic and mitotic division, by which specialized germ cells multiply and differentiate into gametes
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Who discovered spermatozoa?
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Anton van Leeuwenhoek
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discrete
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apart or detached from others; separate; distinct
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What does the word "chromosome" mean?
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colored bodies
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mitosis
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nuclear division followed by cell division that results in two daughter cells containing the same number and type of chromosomes as the original parent cell
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What does "mitos" mean?
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"thread"
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What does "-osis" mean?
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formation or increase
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meiosis
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The kind of nuclear division that generates egg or sperm cells containing half the number of chromosomes found in other cells within the same organism
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cytologist
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a scientist who uses microscope to study cell structure
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haploid
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gametes and other cells that carry only a single set of chromosomes
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diploid
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zygotes and other cells carrying two matching sets
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What's the shorthand symbol for a haploid cell?
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n
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What's the shorthand symbol for a normal diploid cell?
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2n
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In humans, 2n = _____
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46
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In humans, n = ________
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23
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In drosophila, 2n = ____, n = ____
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8;4
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Are most body cells haploid or diploid?
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diploid
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sister chromatids
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the two identical halves of a chromosome attached at the centromere
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metacentric
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the centromere is approximately in the middle
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acrocentric
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the centromere is very close to one end
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metaphase chromosomes can be classified by __________
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centromere position
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homologous chromosomes may also be called
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homologs
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homologous chromosomes are:
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chromosomes that match in size, shape, and banding
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How is a karyotype produced?
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taking images of stained chromosomes and arranging them in homologous pairs of decreasing size
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autosomes
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the 44 matching chromosomes within humans
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the two unmatched chromosomes in humans are called:
why? |
The sex chromosomes; they determine sex of the individual
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What's the smallest chromosome?
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autosome 21
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What is the probability that Down syndrome comes from the mother?
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80%
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amniocentesis
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surgical procedure for obtaining a sample of amniotic fluid from the amniotic sac in the uterus of a pregnant woman by inserting a hollow needle through the abdominal wall, used in diagnosing certain genetic defects or possible obstetric complications.
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prenatal
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previous to birth or to giving birth
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sex chromosomes provides the basis for:
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sex determination
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astride
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with a leg on each side of; straddling
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What's the ratio of sex determination?
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1:1
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What's notable about the chromosomes of someone with Klinefelter syndrome
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they're XXY
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If you're XXY, you have:
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Klinefelter syndrome
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Klinefelter syndrome symptoms:
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these males are typically tall, thin, and sterile; may also be mentally retarded
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If you're XO, you have
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Turner syndrome
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symptoms of Turner syndrome:
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these females are sterile, lack secondary sex characteristics (e.g., pubic hair), short stature, webbed necks
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An OY individual:
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dies
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What determines sex in fruit flies?
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the ratio of X chromosomes to autosomes (instead of the presence of Y)
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Will a human XYY individual survive?
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Yes, and will be normal or nearly so
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Is XX = female, XY = male universal?
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No!
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In C. elegans, XO individuals are:
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male
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In birds and butterflies, ZZ = ___ and ZW = ___
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male; female
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In anemone fish, sex determination is caused by:
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age; young adults are male, older adults are female
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heterogametic sex
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the gender producing different types of gametes: XY, XO, or ZW
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