Term
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Definition
-Cell's informational unit
-Made of DNA |
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Term
| What are the phases of eukaryotic cell cycle? |
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Definition
Interphase:
-G1: Growth and prep for S
-S: DNA/Protein synthesis, chromosome duplication
-G2:increase protein synthesis
M Phase:
-Mitosis: Nuclear division
-Cytokineses: Cytoplasm divides |
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Term
| Describe a duplicated chromosome |
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Definition
-Consists of pair of sister chromatids containing identical DNA sequences
-Centromere: constricted region, joins sister chromatids
-Kinetochore: protein to which microtubules bind, attached to centromere |
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Term
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Definition
-DNA and Protein
-Makes up chromosomes |
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Term
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Definition
| -Allow DNA sorting into daughter cells |
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Term
| How is DNA organized into prokaryotic cells? |
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Definition
-Circular DNA molecules
-DNA replication begins at single site on bacterial DNA |
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Term
| What is the structure of eukaryotic chromosomes? |
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Definition
Nucleosome:
-histone(protein) bead wrapped in DNA
-Organized into coiled loops
-Held together by scaffolding proteins |
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Term
| What is the process and significance of mitosis? |
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Definition
-Mitosis preserves chromosome number in Eukaryotes
-Identical chromosomes are distributed to each pole of the cell, and a nuclear envelope forms around each set |
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Term
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Definition
-Chromatin condenses into duplicated chromosomes(pair of sister chromatids)
-Nuclear envelope beings to disappear
-Mitotic spindle begins to form |
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Term
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Definition
-Spindle microtubules attach to kinetochore of chromosome
-Chromosomes being to move toward cells midplane |
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Term
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Definition
-Chromosomes align on cells midplane(metaphase plate)
-Mitotic spindle is complete
-Microtubules attach kinetochore of sister chromatids to opposite poles of cell |
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Term
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Definition
-Sister chromatids separate and move to opposite poles
-Each former chromatid is now a chromosome |
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Term
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Definition
-Nuclear envelope reform
-Nucleoli appear
-Chromosomes uncoil
-Spindle disappears
-Cytokinesis begins |
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Term
| How is the cell cycle controlled? |
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Definition
-Cyclin-dependent kinases (CDKS) are protein kinases that control cell cycle.
-Cyclins are regulating proteins levels fluctuate during cell cyle. |
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Term
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Definition
Single parent:
-offspring have identical hereditary traits
Mitosis:
-basis for eukaryotic asexual reproduction |
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Term
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Definition
-Meiosis produces gametes
-2 haploid sex cells (gametes) fuse to form a single diploid zygote |
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Term
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Definition
-Chromosomes are paired (homologous chromosomes)
-Similar in length, shape, other features
-Carry genes affecting same trait |
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Term
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Definition
-Contains only one member of each homologous chromosome pair
-N |
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Term
| What is the process and significance of meiosis? |
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Definition
-One diploid cell divides two times yielding 4 haploid n cells
-Sexual life cycles in eukaryotes require meiosis
-each gamete contains half the # of chromosomes in parent cell |
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Term
| What are the phases of meiosis? |
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Definition
Meiosis 1
-prophase 1
-metaphase 1
-anaphase 1
Meiosis 2(Just like mitosis)
-prophase
-prometaphase
-metaphase
-anaphase
-telophase |
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Term
| What happens in prophase 1 of meiosis? |
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Definition
-Homologous chromosomes join by crossing over.
-Nonsister chromatids exchange segments of DNA strands which results in genetic recombination. |
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Term
| What happens in metaphase 1 of meiosis? |
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Definition
| The tetrads line up on metaphase plate |
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Term
| What happens in anaphase 1 of meiosis? |
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Definition
| Chromosomes separate and distribute to different nuclei. |
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Term
| What is the result of meiosis 1? |
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Definition
| Each nucleus contains haploid number of chromosomes. |
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Term
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Definition
-Single nuclear division
-2 daughter cells genetically identical to each other and to original cell
-No synapsis of homologous chromosomes |
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Term
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Definition
-2 successive nuclear divisions form 4 (n) cells
-Synapsis of homologous chromosomes occurs during prophase 1
-Increases genetic variability |
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Term
| What are the 2 types of animal cells? |
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Definition
-Somatic cells (diploid) are produced by mitosis
-Gametes(haploid) are produced by meiosis aka gametogenesis |
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Term
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Definition
Alternation of generations:
-SPOROPHYTE (multicellular 2n) forms haploid spores by meiosis
-spores divide by mitosis to form GAMETOPHYTE(multicellular n) which produces gametes by mitosis
-2 haploid gametes fuse to form diploid zygote which divides by mitosis to produce new diploid sporophyte. |
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Term
| How do simple eukaryotes reproduce? |
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Definition
-May be haploid (produced by mitosis)
-Only diploid stage is the zygote (2n) which undergoes meiosis to restore the haploid state
-introduces some variation |
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