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14 Cards in this Set
- Front
- Back
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Explain the difference between asexual reproduction and sexual reproduction.
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sexual brings 2 gametes together, 2 parents, gametes n, inherit mixture of genes allow genetic variation.
asexual produced idential 2n daughter cells, no genetic variation |
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Describe the human life cycle. Where in the human body does mitosis and meiosis occur?
Also indicate which components are haploid or diploid. |
n gametes fuse to make a 2n, 2 parents produce progeny, parents are 2n, each parents contribute half of genetic information. ova and sperm fuse to make embryo through fertilization. gametes are haploid somatic cells are diploid
mitosis occurs in somatic cells, mieosis occurs in only in reproductive cells, |
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Describe the general sexual life cycles of animals, most algae, and plants (and some algae). Identify the
structures, processes (mitosis or meiosis), and haploid and diploid stages. |
gametes are haploid and fuse to make diploid offspring. meiosis occurs in reproductive cells, mitosis in somatic. algae are haploid.
meiosis = reproductive cells, they fuse, mitosis |
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Discuss the process of synapsis during prophase I.
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homologous chromosomes form tetrads. homologus chromosomes align gene be gene. mechanisms unknown may involve synaptonemal complex
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Draw a tetrad at metaphase I and at anaphase I when the chromosomes have clearly separated. State the
general term used to describe the process of disjoining and separating chromosomes during anaphase I of meiosis I. |
metaphase 1 tetrad in middle, anaphase 1 moving to opposite sides
disjunction segregation |
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Chromosomes displayed in a karyotype may be arranged in homologous pairs.
State three characteristics which help indicate that the homologues of each pair are similar. |
size, position of centromere, banding patterns
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Describe the main differences between mitosis and meiosis. Discuss how the resulting daughter cells of
meiosis differ from those of mitosis. |
meiosis occurs in sexually reproducing individuals, two consecutive cell divisions, produces 4 daughter cells, n, different from parent, reproductive cells.
mitosis has 2 consecutive cell divisions, produces 2 daughter cells, identical to parents, 2n, somatic cells |
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How do crossing over, independent assortment, and random fertilization contribute to genetic variation in
sexually reproducing organisms? |
They increase genetic variation, daughter cells are geneticall different from parent cells
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In addition to sexual reproduction, name another source which may generate genetic variation.
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mutations, nondisjunction
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Why is inheritable variation of great significance to Darwin's theory of evolution?
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genetic variation creates genetically diverse individuals that are more likely to adapt towards selective pressures.
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Using examples, describe the terms aneuploidy and polyploidy. How can these conditions occur?
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aneuploidy - abnormal # of xsomes, individuals have too few or too many xsomes eg n+1. from nondisjunction.
polyploidy - xsome number is greater than two complete xsome sets eg 3n (triploidy) from chance mistakes of partitioning xsomes in mitosis or meiosis |
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Using coloured pens, draw a tetrad at PI and show one chiasma. Clearly label the chromosomes and
chromatids (sister and non-sister). |
chiasma is an X shaped structure at the site of one cross over
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Differentiate between the terms "trisomy" and "triploidy".
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triplody 3n
trisomy simply 3 versions of a xsome, eg trisonomy 21 |
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Discuss each of the following conditions: Down syndrome, Klinefelter syndrome, triple X, XYY, Turner
Syndrome, chronic myelogenous leukemia , Patau syndrome, and Edwards syndrome. |
Downs - trisnomy 21, crease in hand, shorter, dumb, flat face
Klinefelter - XXY,XXXY.., sterile 1:1000, only affects males, feminine body contours triple x - XXX, usualy normal, 1:1000, variable expression XYY - jacobs, more aggressive competitive, normal intelligence and fertility, taller Turner - XO, monosomy (2n-1), short, webbed neck, barrel chest, internal organs do not mature, sterile, 1:5000 chronic myelogenous leukemia - xsomes 22 and 9 switch pieces, uncontrolled cell growth, philadelphia xsome patau syndrome - trisomy 13, dumb, cleft palate,deaf, malformed organs Edwards - trisomy 18, small newborns, low set ears, webbed neck, receding chin, organ malformations |
