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69 Cards in this Set
- Front
- Back
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What did Otto Hertwig observe?
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Fertilizatin oinvolved fusion of sperm and egg nuclei.
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What did Walter Flemming describe?
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Key events of the cell division process, (mitosis)
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What did Edouard von Beneden describe?
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The appearance of rodlike structures during fertilization in the horse-worm Ascaris megalocephala
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Who named chromosomes?
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Wilhelm Waldeyer
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What did Otto Hertwig observe?
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Fertilizatin oinvolved fusion of sperm and egg nuclei.
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What did Walter Flemming describe?
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Key events of the cell division process, (mitosis)
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Do chromosomes split along the latitude or longitude during mitosis?
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Longitude
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What did August Weismann deduce?
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Genetic material must be halved in the production of sperm and eggs.
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What did Edouard von Beneden describe?
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The appearance of rodlike structures during fertilization in the horse-worm Ascaris megalocephala
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What did Wilhelm Roux propose?
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Chromosomes are transmitted equally to the daughters of mitosis.
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Who named chromosomes?
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Wilhelm Waldeyer
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What are homologous chromosomes?
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Contain same genes, but may have different alleles for each gene.
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Do chromosomes split along the latitude or longitude during mitosis?
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Longitude
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Can homologous chromosomes have different alleles?
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Yes
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What did August Weismann deduce?
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Genetic material must be halved in the production of sperm and eggs.
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Are chromosomes condensed during interphase?
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No
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What did Wilhelm Roux propose?
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Chromosomes are transmitted equally to the daughters of mitosis.
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When does recombination occur?
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Meiosis I, between homologous chromosomes
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What are homologous chromosomes?
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Contain same genes, but may have different alleles for each gene.
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Describe the stages of mitosis.
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Prophase - chromosomes condense; nuclear membranes begin to break down
Metaphase - Nuclear membrane is broken down; chromosomes line up at metaphase plate. Anaphase - Sister chromatids separate Telophase - Chromosomes arrive at opposite poles; nuclear membrane re-forms |
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Can homologous chromosomes have different alleles?
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Yes
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How many chromosomes does each daughter cell have after Meiosis I?
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Half the number of diploid, but each are composed of 2 sister chromatids.
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Are chromosomes condensed during interphase?
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No
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Where are the mitosis cells from?
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Onion root tip
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Where are the meisis cels from?
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Anthers of lily buds
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When does recombination occur?
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Meiosis I, between homologous chromosomes
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Describe the stages of mitosis.
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Prophase - chromosomes condense; nuclear membranes begin to break down
Metaphase - Nuclear membrane is broken down; chromosomes line up at metaphase plate. Anaphase - Sister chromatids separate Telophase - Chromosomes arrive at opposite poles; nuclear membrane re-forms |
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How many chromosomes does each daughter cell have after Meiosis I?
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Half the number of diploid, but each are composed of 2 sister chromatids.
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Where are the mitosis cells from?
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Onion root tip
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Where are the meiosis cells from?
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Anthers of lily buds
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What are the two beakers labeled?
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HCl and Carnoy's
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What percentage is the HCl?
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18%
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Where do you place the root tips?
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Into the 18% HCl for 4 minutes
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How long do you place the root tips in the HCl?
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4 minutes
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What does the HCl do?
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Softenst the tissue in preparation for staining and squashing
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What do you do after you put the root tips in the HCl?
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Put it int Carnoy's solution for at least 4 minutes
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How long do you put the root tips in Carnoy's solution?
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4 minutes
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What does Carnoy's solution do?
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It is a fixative tat preserves the structure of the cells.
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How long can root tips remain in Carnoy's solution?
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Indefinitely
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How much of the root tip do you cut off?
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All but the last 1-2 mm atof the tip
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How can you tell the growing tip from the rest?
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It is slightly tapered and slightly whiter in color
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What objective do you start with?
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Low power, (4x or 10x)
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Describe what happens at 400x magnification.
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Light moving from air to glass or from glass to air bneds and results in loss of resolution above 400x.
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How can a magnification of 1200x be achieved?
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If the air between the lens and the slide is replaced with oil, because oil has the safe refractive index as glass, so light will not bend and become distorted
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What dictates the upper 1200x limit?
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Wavelength of the light
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What lens do you want to make sure does not come in contact with the oil immersion?
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40x
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What shooting mode do you want the camera on?
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Auto
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Do you want the flash on on the camera?
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No
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What is pollen essentially?
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Sperm
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What are the diploid cells int he anther called?
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Meiocytes
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When meiocytes undergo meiosis, what do they produce?
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Spherial tetrads, each containing 4 hpaloid cells, which then mature into pollen grains
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What type of stain do you use on the antler?
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Acetocarmine stain
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How do you smash and chop the anther?
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With the side of a dissecting needle in the pool of stain
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What will too much pressure on the meiocytes do?
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Lyce the cells and make the stages of meiosis difficult to discern
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Should you use the 100x oil immersion lens with the meiocytes?
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No, because they are large and fragile and will be crushed
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How long does mitosis usually take?
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1/2 hour to 2 hours
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When do the spindles form?
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Metaphase
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What is the region of the centromere that the spindle fibers attach to called?
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Kinetochore
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How is meiosis more complex in plants?
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Meiosis forms sports, which undergo one or more mitotic divisions to produce a haploid gametophyte organism, which produces gametes by mitotic division of a haploid nucleus; fusion ofhaploids creates a diploid zygote that developes into a sporophyte plant
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What are the five substages of prophase I in meiosis?
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leptotene
zygotene pachytene diplotene diakinesis |
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What is leptotene?
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Chromosomes first become visible as long thread-like structures'; chromomeres
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How can sister chromatids in the leptotene be distinguished?
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Electron microscop
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What are chromomeres?
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Dese granules that appear at irregular intervels along the chromosomes in
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What is zygotene?
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Synpsis of homologous chromosomes, beginning at the chromosome tips
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What are the synpased homoglous chromosomes in zygotene referred to as?
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Vialent
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What happens during pachytene?
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Condensatin of the chromosomes continues; each bivalent actually consists of a tetrad of four chromatids, but the two ister chromatids are usually juxtaposed very tightly; crossing-over takes place
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What occurs during pachytene?
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Crossing over
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What happens during diplotene?
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The synapsed chromosomes begin to separate and the diplotene chromosomes are clearly double; but the homologous chromosomes remain held together at the chiasma
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What happens during diakinesis?
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Homologous chromosomes repel each other and the segments not connected by chiasma pull apart
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