Ch. 13-14
What are differences between cell plates and cleavage furrows?
Cell plates occur in plant cells and cleavage furrows are only in animal cells.
What is hemizygous?
Characterized by having one or more genes without allelic counterparts. Pertaining to a diploid cell with only one copy of a gene instead of the usual two copies
What are the differences between chromatin and chromosomes?
Chromatin is unfolded, uncondensed, extended DNA while chromosomes are condensed DNA. Chromosomes are condensed chromatin and chromatin is unfolded chromosomes.
What occurs during prophase I of meiosis that is so important?
DNA is exchanged.
Who is Nancy Wexler?
Discovered the gene that causes Hungtinon's disease.
Who is T.H. Morgan?
Discovered the role that chromosomes play in heredity.
What are sex chromosomes? Give examples.
Either of a pair of chromosomes, usually designated X or Y, in the germ cells of most animals and some plants, that combine to determine the sex and sex-linked characteristics of an individual, with XX resulting in a female and XY in a male in mammals. Red/Green color blindness.
Name the subphases of interphase and describe what occurs during each subphase.
G1: This is the first growth phase. The cell synthesizes proteins and produces cytoplasm organisms. S: This is the synthesis phase. The cell grows while it copies its chromosomes. G2: This is the second growth phase. The cell begins the assembly of the spindle.
What is epistasis? Name an example of epistasis.
Gene expression at one locus alters expression of a gene at another locus. Pigment gene.
What is the purpose of mitosis?
produces the cells of the body. When they split they produce identical cells with a complete set of DNA. They are exactly like their parents. It only has one division and that leads to two cells.
What is the purpose of meiosis?
produces the gametes or the "sex cells" such as sperm and eggs. Meiosis goes through two divisions, one in meiosis 1 and one in meiosis 2. In the end, it results in four cells and each cell only contains half of the genetic material. At fertilization male and female gametes come together to form a new being with half of its mothers genes and half of its fathers.
Name an example of a human disorder due to a deletion.
smith-magenis
What are examples of human diploid cells?
somatic cells
What is the Law of Segregation?
the principle, originated by Gregor Mendel, stating that during the production of gametes the two copies of each hereditary factor segregate so that offspring acquire one factor from each parent.
What are spindle fibers?
the structure that separates the chromosomes into the daughter cells during cell division
What is binary fission?
the subdivision of a cell (or body, population, or species) into two or more parts and the regeneration of those parts into separate cells (bodies, populations, or species).
Name examples of human disorders due to aneuploidy in autosomes.
trisomy or down's syndrome.
Give examples of homozygous recessive genotypes.
tt
Are the progeny cells of mitosis haploid [1n] or diploid [2n]?
two diploid
What are examples of incomplete dominance?
Red and White flowers forming Pink flowers.
Name an example of co-dominance.
Red and White flowers forming Red and White spotted flowers.
Name examples of human traits [not disorders] that are recessive.
Square shaped face. Cleft in chin. Straight hairline.
Name an example of a human disorder that exhibits incomplete dominance.
Tay-sachs.
Who is Gregor Mendel?
The "father of genetics". Came up with the Law of Segregation and the Law of Independent assortment.
What is the metaphase plate?
The plane of the spindle approximately equidistant from the two poles along which the chromosomes are lined up during mitosis or meiosis. Also termed the equator.
What is the norm of reaction?
The range of a phenotype.
What is a polygenic trait? Give an example.
When many genes affect one phenotype. Skin color.
Name examples of human traits [not disorders] that are dominant.
Widows peak. Oval shaped face. Long eye lashes.
Who is Mary Lyon?
X-chromosome inactivation.
What is a centrosome?
an organelle that serves as the main microtubule organizing center (MTOC) of the animal cell as well as a regulator of cell-cycle progression
What is the Law of Independent Assortment of Chromosomes?
for every pair of unit factors, each of them would assort independently into the newly formed gametes.
Are the progeny cells of meiosis I haploid [1n] or diploid [2n]?
four haploid
What are differences between gamete cells and somatic cells?
gametes produce somatic cells.
What is a Barr body?
An inactive X-chromosome.
Co-dominance
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Complete Dominance
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Describe what the following alterations of chromosomes are: deletion; inversion; reciprocal translocation; and duplication
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Incomplete Dominance
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Name a sex-linked trait in the fruit fly.
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Name examples of sex-linked disorders in humans.
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Name examples of sex-linked traits that are not disorders in humans.
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Name the 4 methods of studying the fetus during pregnancy. Which has the least risk to mother and baby?
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Name the three ways variation of the species occurs due to sexual reproduction.
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What DNA is inherited extranuclearly and maternally?
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What are cyclins and cyclin dependent protein kinases [Cdks] and how do they provide internal control of cell division?
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What are growth factors and how do they provide external control of cell division?
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What are homologous chromosomes? Name the three characteristics that defines homologous chromosomes.
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What are linked genes?
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What are sex-linked [a.k.a. X-linked] traits?
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What are sister chromatids?
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What are the differences between kinetochore microtubules and non-kinetochore microtubules?
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What are the differences between the following terms: benign tumor; cancer and metastasis.
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What are the hallmarks of each of the subphases of mitosis?
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What is a karyotype? What does it show us?
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What is a wildtype organism vs. a mutant?
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What is anchorage dependency? Do normal cells have this characteristic?
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What is density-dependent inhibition? Do transformed cells have this characteristic?
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What is genomic imprinting?
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What is the difference between transformed cells vs. cancer cells?
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What is the restriction point in the cell cycle?
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Where is the centromere?
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Why do humans appear to tolerate extra X and Y chromosomes?
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What is an example of an aneuploid number of chromosomes?
21, 18, 13
In humans, what is the haploid number of chromosomes?
23
In humans, what is the diploid number of chromosomes?
46
Name an example of multiple alleles.
ABO blood group.
Name examples of human disorders that are recessive.
Achondroplasia
What are alleles?
An allele is an alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome. These DNA codings determine distinct traits that can be passed on from parents to offspring. The process by which alleles are transmitted was discovered by Gregor Mendel and formulated in what is known as Mendel's law of segregation.
What is an autosome?
Any chromosome not considered as a sex chromosome, or is not involved in sex determination. It occurs in pairs in somatic cells and singly in sex cells (gametes).
What are genes?
Genes are segments of DNA located on chromosomes. Genes exist in alternative forms called alleles. Alleles determine distinct traits that can be passed on from parents to offspring. The process by which genes are transmitted was discovered by Gregor Mendel and formulated in what is known as Mendel's law of segregation.
What human cells are haploid?
Hair and eye color.
Name examples of human disorders that are dominant.
Huntington's
Where is the centrosome in an animal cell?
It directly surrounds the cytoplasm surrounding the centrioles.
What are pleiotropic effects? Give a gene that shows pleiotropic effects.
One gene that has multiple phenotypes. Sickle Cell (can treat/prevent malaria)
What is the difference between phenotype and genotype?
Phenotype is the part you can see. Genotype is genetic code.
What are multifactorial traits?
Phenotypes determined by genes and environment.
Name the subphases of mitosis and describe what occurs during each subphase.
Prophase (a) The chromosomes shorten and thicken. (b) Centrioles move to opposite poles of the cell. (c) Spindle fibers, made of microtubules, are constructed to extend from the centrioles toward each pair of sister chromatids. The spindle apparatus consists of kinetochore and nonkinetochore microtubules. (d) Each chromosome is duplicated and the copies remain attached together and are called sister chromatids. They remain attached to one another at a region of the chromosome called the centromere. (e) The nuclear membrane dissolves. (f) After the nuclear membrane dissolves, the spindle fibers can attach to the sister chromatids. Special structures at the centromere region called kinetochores provide a place of attachment for kinetochore microtubules. Nonkinetochore microtubules overlap those from the opposite pole. (2) Metaphase (a) During late prophase chromatids begin to move toward the cell equator (metaphase plate). (b) At metaphase the chromatids are aligned at the equator. (c) The kinetochores of sister chromatids face opposite poles so that each sister chromatid is attached to kinetochore microtubules from opposite ends of the cell. (3) Anaphase (a) Chromatids begin to move apart, toward opposite poles. (b) Once separated, the chromatids are again called chromosomes. (c) By the sliding past one another of nonkinetochore microtubules, the cell elongates. (4) Telophase (a) Nonkinetochore microtubules elongate the cell further. (b) The chromosomes reach opposite poles of the cell and become less tightly coiled. (c) Spindle fibers dissolve. (d) Nuclear membrane reforms at each end of the cell. (e) Cytokinesis has begun.
Give examples of heterozygous genotypes.
Tt
What is a dihybrid cross?
a cross between F1 offspring (first generation offspring) of two individuals that differ in two traits of particular interest
What is a monohybrid cross?
a cross between parents who are heterozygous at one locus; .
What is asexual reproduction?
a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy reduction, or fertilization
What is polyploidy?
a term used to describe cells and organisms containing more than two paired (homologous) sets of chromosomes
Name examples of human disorders due to aneuploidy in sex chromosomes.
monosomy causes turner's syndrome.
What is a test cross?
used to determine if an individual exhibiting a dominant trait is homozygous or heterozygous for that trait. Put more simply test crosses determine the genotype of an individual with a dominant phenotype.