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30 Cards in this Set
- Front
- Back
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Fertilization
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combination of gametes (sex cells) toform a single celled zygote
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Eggs
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female gametes; relatively large; cytoplasmcontains yolk, RNA, ribosomes, mitochondria
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Sperm
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–male gametes; relatively small; usually use aflagellum for mobility
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Activation
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takes place in the zygote,caused by fertilization of the egg -Cell increases rate of metabolism -Plasma membrane changes to blockfertilization by a second sperm -Cytoskeleton rearranges cytoplasm to allowfor differentiation of daughter cells |
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Differentiation
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process in which cellsbecome specialized in form and function Ex: muscle cell, skin cell, nerve cell All cells contain a full set of an organism’sgenes (DNA) Proteins determine which genes are turned“on” and “off” in individual cells Only genes that are turned “on” aretranscribed and translated into proteins forthe cell |
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Morphogenesis
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process in whichdifferentiated cells organize into tissues and organs. __________of gastrula into an organism involves: Coordinated movement of cells and tissues Changing cell shapes Folding/splitting cell layers Genetically timed cell death of certain cells |
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Stem cells
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undifferentiated cells that mayform a variety of different types of cells(genes have not been turned “on” or “off”) Two types of _______cells: -Embryonic -Adult |
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Embryonic stem cells
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“pluripotent”; mayform any type of cell in the body Ex: embryo cells prior to gastrulation |
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Adult stem cells
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“somatic stem cells”;somewhat differentiated, but may still forma variety of types of cells for a specific tissueor organ Ex: bone marrow cells |
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Cleavage
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period of cell division after fertilization thatproduces a small ball of many cells (blastula)
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Gastrulation
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process in which the blastula cells moveinto three distinct layers to form a hollow ball of cellscalled a gastrula
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3 Primary Germ Layers in the Gastrula
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Ectoderm Endoderm Mesoderm |
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Ecotoderm
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outer layer of the gastrula that forms skin,nervous system, and related structures
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Endoderm
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– inner layer of the gastrula that forms a tubeto become the lining of the digestive system
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Mesoderm
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middle layer of the gastrula that forms theskeleton, muscles, heart, blood, and other internal organs
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Body plan
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the generalshape of the organism;first visible duringgastrulation
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Notochord
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formed bythe mesoderm; rod oftissue develops into partof the backbone Determines dorsal-ventral and anterior-posterior directions |
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Neural tube
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formed by the ectoderm on thedorsal side of the notochord; becomes thebrain, spinal cord, and nerves
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Metamorphosis
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series of changes that transforms alarva into an adult Larva – juvenile form capable of feeding Ex: tadpoles, caterpillars, maggots |
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Homeotic Genes (aka Hox Genes)
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control process ofsegmentation (division of the body into various sections) First discovered in fruit flies, later found in other animals Each gene controls the development of one bodysegment Genes are arranged in order of body segments |
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Homeobox
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the 180 base pair DNA sequence found ineach homeotic gene Each ___________sequence codes for the formation of ahomeodomain (portion of the protein that binds to the DNAto regulate the transcription of important genes) |
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homeodomain
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(portion of the protein that binds to the DNAto regulate the transcription of important genes)
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Asexual Reproduction
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single parent produces geneticallyidentical offspring (clones) Ex: prokaryotes (bacteria) and single celled eukaryotes use Ex: fungi (spores), some plants (buds, runners, fragmentation,process called Binary Fission Asexual reproduction allowsthe zygote to form amul.cellular organism |
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Clone
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genetically identical organisms or cells Occur naturally through asexual reproduction aswell as through genetic engineering |
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Diploid cells (2n)
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carry a double set ofchromosomes (one pair of each type) Somatic cells (body cells) |
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Haploid cells (n)
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carry one set of chromosomes(one of each type) Gametes (sex cells) |
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Homologouschromosomes
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indiploid organisms; apair of the same typeof chromosome -Similar in structure -Contain same types ex: eye color, haircolor, etc - May contain differentforms of a gene ex: blue eyes v.brown eyes |
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Sexual Reproduction
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two different parents’ haploid gametescombine during fertilization to form a unique diploid zygote In sexual reproduction, eachdiploid parent produceshaploid gametes Sexual reproduction allowsthe diploid organism to formits own haploid gametes |
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Meiosis
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process of cell division in which diploid parent cells formunique haploid gamete cells
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-Cells divide twice during meiosis, but the chromosomes are notduplicated after the first division -Meiosis distributes a random mixture of chromosomes to eachgamete to produce genetically unique cells -Homologous chromosomes pair up side by side (tetrads) duringthe first meiotic division, often exchanging corresponding piecesof DNA (crossing-over) which increases genetic variety ofgametes |
