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48 Cards in this Set
- Front
- Back
What does cell need to do before it can divide?
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the genome (chromosomes) must be copied
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What is mitosis?
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the process by which somatic cells divide, forming two daughter cells, that contain the same diploid number of chromosomes.
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chromosomes consist of?
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two sister chromatids that are attched by a centromere
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mitosis is the divison of what?
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the nucleus
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what is cytokinesis?
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the division of the cell's cytoplasm.
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What happens to the chromosomes during the cell cycle?
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they are doubled, then mitosis reduces them back to a diploid of 46 chromosomes.
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What is meiosis?
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the daughter cell of the has half the chromosomes (23). happens in the ovaries and testies and makes gametes
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what is the mitotic phase?
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it is 10% of the cell cycle that consist of mitosis and cytokinesis.
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what is interphase?
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90% of the cell cycle, consisting of G1 phase, s phase, and G2 phase.
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how does interphase prepare for division?
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-increases in volume
-duplicates cell organelles -replicates histones,and other protein associated with DNA |
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Prophase
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chromatin becomes tightly coiled. the nucleoli disappear, and mitotic spindle of microtubules extend from the centrosomes and form in the cytoplasm.
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Prometaphase
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nuclear envelope begins to fragment. Spindle begin to attach to chromosomes. Chromsomes have further condensed. each two chromatids from a chromosome now has kinetochore at its centromere region.
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metaphase
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centrioles have now migrated to poles in the cells. Chromosomes line up at equator. All kinetochores have attached to a microtubule.
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what is a spindle?
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all microtubules together.
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Anaphase
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sister chromatids begin to seperate and pull apart. at the end, both ends have an equal amount set of chromatids.
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Telophase
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nuclear envelope re-forms around chromatids at both ends.the chromatid fibers become less dense in the chromosomes. cytokinesis begins, and forms 2 new cells.
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what is a cleavage furrow?
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this pinches off as two new cells are being made.
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what do kinetochores to microtubules?
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they are equipped with proteins that walk up microtubules, breaking off tublin subunits as they go. theis shortens the microtubules and effectively reels in the chromatids.
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what does the cell cycle contol system do?
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moves the cell through stages by a number of checkpoints, which tells a cell to conintue dividing or stop.
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why is the G1 phase checkpoint the most important checkpoint?
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because this is the check point the go-ahead check point and will most liekly finish the cycle once the check point gets the okay.
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what is G0?
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this is the non-dividing checkpoint for when G1 does not have permission.
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kinases
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proteins that control the cell cycle.
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when are the only time the kinases activate?
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when they are connected to a cyclin protein.
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what is the name for the kinases that only activate with cyclin proteins?
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cyclin-dependent kinases (Cdk)
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how is the activity of cyclin and Cdk through the cell cycle?
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their levels simultaneously rise and fall.
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Maturation-promoting factor or MPF
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it is a Cdk that triggers the cell to go from G2 phase into M phase.
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compare mitosis to meiosis
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-mitosis has two 46 chromsome dught cells and meiosis has 23.
- mitosis is made to make identical cells, and meiosis is meant to pass on genetic information to offspring. |
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Heredity
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the tranmission of traits from one generation to the next
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Genetics
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the study of heredity and variation
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Variation
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genetic differences between siblings and other members of the same species.
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Genes
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are segments of DNA, and the basic unit of heredity that are transmitted from one generation to the next.
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gametes
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reproductive cell that transmitt genes from one generation to the next
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locus
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the location of a gene on the chromosome
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Asexual reproduction
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a form of reproduction in which a single parent is involved in passing on all it's genes to its offspring
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Sexual reproduction
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two individuals contribute genes to their offspring. causes greater genetic variation.
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life cycle
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the generation-to-generation sequence of stages in reproductive history of an organism.
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somatic cells
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any cells in the body that are not gametes
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karyotype
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to a picture of a set of chromosomes, arranged in pairs of homologous from largest to smallest
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homologous chromosomes
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are chromosome that carry the genes that control the same trait.
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what are the human sex chromosomes
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X and Y
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autosomes
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nonsex chromosomes
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haploid cells
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gametes that carry half the chromosomes of a diploid cell
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fertilization
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a combination of a sperm and a egg cell. one haploid gamete from each parent fuse.
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zygote
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the results of fertilization
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diploid
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a zygote and all somatic cell of an organism are these.
also known as 2n |
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Meiosis
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the process by which, in course of gamete production, the chromosomes id halved so haploid gametes are formed.
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what is the sexual life cycle for humans and most animals?
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meiosis occurs during gamete production and the diploid zygote divdes by mitosis; making a diploid multicellular organism.
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what sexual life cycle does plant, some protists and aglae?
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after gametes fuse to form the diploid zygote, meiosis occurs to prduce haploid cells. these cells divde by mitosis, forming a haploid, multicellular organism.
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