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32 Cards in this Set
- Front
- Back
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Cell Cycle |
• Defines changes from formation of cell until it reproduces |
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Cell Cycle Includes: |
– Interphase (subdivided into: Go, G1, S & G2) • Cell grows and carries out usual functions • Cell spends most of its time in this phase – Cell division (mitotic phase) • Divides into two cells |
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Mitotic (M) phase of the cell cycle properties |
• Essential for body growth and tissue repair |
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When/where does mitotic phase NOT occur |
Does not occur in most mature cells of nervous tissue, skeletal muscle, and cardiac muscle |
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Cell Division • Includes two distinct events: |
1. Mitosis
2. Cytokinesis |
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four stages of nuclear division (mitosis) |
• Prophase • Metaphase • Anaphase • Telophase |
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Cytokinesis |
—division of cytoplasm by cleavage furrow |
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I Passed My Anatomy Test Cheers |
-Interphase -Prophase -Metaphase -Telophase -Cytokinesis |
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Interphase |
• Period from cell formation to cell division |
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chromatin |
Nuclear material scattered and unfolded in cell |
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Three subphases of interphase |
– G1 (gap 1)—vigorous growth and metabolism • – S (synthetic) – G2 (gap 2) |
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What happens in G1? |
(gap 1)—vigorous growth and metabolism
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What happens in S subphase? |
(synthetic)—DNA replication occurs PRIOR to cell division, chromatin strands replicate |
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What happens in G2 subphase? |
gap 2 - preparation for division |
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G0 phase |
Cells that permanently cease dividing |
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What happens during Prophase? |
• Nuclear envelope fragments/breaks up • Duplicated chromosomes of two sister chromatids become visible • Centrioles move apart to opposite poles • Sister chromatids attach to spindle fiber |
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What happens during Metaphase> |
• Tubules of spindles pull on the chromosomes • Sister chromatids are aligned midway between poles called metaphase plate • Centromeres of chromosomes aligned at equator |
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What happened during Anaphase? |
• Separation of sister chromatids • Centromeres of chromosomes split simultaneously—each chromatid becomes a chromosome • Spindle tubules pull sister chromatids apart to opposite poles |
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What happens during Telophase? |
• Begins when chromosome movement stops i.e., arrives at spindle poles • Chromosomes return to threadlike form • New nuclear membrane forms • Two nuclei form • Division of cytoplasm • Forms two cells |
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What happens during Cytokinesis? |
• Two daughter cells formed or pinched apart, • Each new cell contains identical genes & chromosomes (AKA nucleus) • Each of the new cells’ nucleus is identical to original |
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Why DNA has to be replicated before cell divides? |
So daughter cell has identical genes |
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What does a cell need to replicate? |
Enzymes |
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End result of DNA replication? |
- two identical DNA molecules formed from original – During mitotic cell division one complete copy given to new cell; one retained in original cell |
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semi-conservative replication |
– Each DNA composed of one old and one new strand |
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master blueprint for protein synthesis |
DNA |
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Two steps of protein synthesis |
Transcription
Translation |
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Transcription |
• DNA information coded in mRNA |
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Translation |
• mRNA decoded to assemble polypeptides • Converts sequence of nucleic acids into amino acid sequence of proteins |
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Three Main Types of RNA |
• Messenger RNA (mRNA) • Ribosomal RNA (rRNA) • Transfer RNAs (tRNAs) |
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Role of mRNA |
– Carries instructions for building a polypeptide, involved in transcription and translation |
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role of rRNA |
– Structural component of ribosomes that is involved in translation of mRNA message |
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role of tRNA |
– Bind to amino acids and pair with bases of codons of mRNA with rRNA involved in translation of mRNA message |
