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26 Cards in this Set
- Front
- Back
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Why do cells undergo mitosis? |
To allow an organism to grow, repair, and reproduce |
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Genetics |
study of heredity and variation |
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Each cell has a nucleus that contains DNA arranged in long strands called ___________. |
chromosomes |
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Chromosomes and associated proteins are also called ___________. |
chromatin |
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Gene |
A segment of DNA that codes for a particular trait |
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Locus |
Position of a gene on a chromosome |
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How many chromosomes do humans have? Arranged in how many pairs? |
46 chromosomes, 23 pairs |
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How many sets of chromosomes do human cells have? |
2 sets of chromosomes |
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Diploid (2N)
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2 sets of the same chromosomes |
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Haploid (1N) |
1 set of chromosomes (e.g. sperm/egg) |
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Polyploid |
3 or more sets of chromosomes |
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Asexual Reproduction |
The chromosomes of the parent cell are copied and the daughter cells are genetically identical.
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Sexual Reproduction |
Reproduction from the fusion of two haploid cells. the combination of the chromosomes from each parent create a genetically unique individual. |
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What is the benefit of sexual reproduction?
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Variation in offspring gives a better chance of survival in a changing environment. |
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Forms of asexual reproduction include the following: |
Budding: a small offspring emerges (buds) from the parent Vegetative reproduction: new plants grow from stolons, tubers, or adventitious roots etc... Parthenogenesis: common in plants and aphids, unfertilized eggs develop into an individual Fragmentation: in worms, plants and fungi, new individual grows from a fragment of the parent |
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Prokaryotic cells divide asexually using _______. |
binary fission |
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How much of its life does a cell spend in interphase? |
90% of its life |
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Interphase |
Growth stage: cell grows, organelles increase in number Chromosomes replicate to form sister chromatids attached at centromere Chromosomes condense and become visible In animal cells, centrioles replicate |
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Prophase |
In animal cells, centrioles move to opposite poles Spindle fibres radiate from centrioles Nuclear membrane begins to dissolve |
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Metaphase |
Spindle fibres attach to chromosomes and align them at the equator Each chromatid within the pair is attached to spindle fibres from the opposite pole |
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Anaphase |
Centromeres divide Spindle fibres shorten, pulling each sister chromatid to the opposite pole-creating a V pattern |
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Telophase |
Chromosomes reach the opposite poles Chromosomes unwind Spindle fibres disappear Nuclear envelope reforms |
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Plant cell during cytokinesis |
Vesticles gather at equator and release cell wall material to form a cell plate Cell plate becomes new cell wall and vesticle membrane forms new cell membrane |
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Animal cell during cytokinesis |
Animal cells pinch inward forming a cleavage furrow |
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Mitosis in Animal cells VS Mitosis in Plant Cells |
Animal: Cytokinesis - cleavage furrow pinches inward Centriole present Plant: A cell plate is formed down the middle of the cell, cell wall prevents pinching Modified, called an MTOC-microtubule organizing centre (spindle fibres are made of MT proteins) |
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Outcome of Mitotic Cell Division |
Each new nucleus contains an exact copy of the DNA present in the original nucleus Each new offspring cell has exactly the same number and kind of chromosome In unicellular organisms, mitosis increases the population sizes In multicellular organisms, mitosis is important for growth and repair |
