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Cell Cycle Interphase, Mitosis, Cytokinesis, and Cancer Cell Division • One cell divides into 2 new identical daughter cells. • Chromosomes carry the genetic information (traits) of the cell How many Chromosomes are in each of your cells? Single Chromosome Diploid Cells A full set of chromosomes Haploid Cells A half set of chromosomes Normal Karyotype Abnormal Karyotype Gene Expression • Cell differentiation occurs because cells have the ability to turn off most genes and only work with the genes necessary for the cell to do its specific job. Cell Size Limitations • Surface area to volume ratio – Cell transport – Cellular communication Cell Division • Prokaryotes: binary fission • Eukaryotes: cell cycle Cell Cycle Made of three parts 1. Interphase 2. Mitosis 3. Cytokinesis Interphase Spindle forming Centrioles Nuclear envelope Chromatin Interphase Centromere Chromosomes (paired chromatids) Prophase Cytokinesis Spindle Centriole Telophase Nuclear envelope reforming Centriole Individual chromosomes Anaphase Metaphase Interphase • The time in between cell divisions when cells grow; longest part of the cell cycle. Interphase -broken into 3 different parts: 1. G1 - First Growth The cell grows in size and increases # of organelles 2. S - Synthesis DNA replicates during this time Happens rapidly 3. G2 - Second Growth Increase the size of the cell again and increase the # of organelles again Mitosis Prophase Spindle forming Centrioles Nuclear envelope Chromatin Interphase Centromere Chromosomes (paired chromatids) Prophase Cytokinesis Spindle Centriole Telophase Nuclear envelope reforming Centriole Individual chromosomes Anaphase Metaphase Mitosis • Prophase – Longest phase of mitosis – Early prophase: • Chromatin coils up into visible chromosomes • Sister chromatids are exact copies of each other Mitosis • Prophase – Late Prophase: • The nucleus begins to disappear • Centrioles move to opposite ends of the cell • Spindle fibers form between the centrioles Prophase (centrioles) Metaphase Spindle forming Centrioles Nuclear envelope Chromatin Interphase Centromere Chromosomes (paired chromatids) Prophase Cytokinesis Spindle Centriole Telophase Nuclear envelope reforming Centriole Individual chromosomes Anaphase Metaphase Mitosis • Metaphase – Chromosomes attach to the spindle fibers by their centromeres. – Chromosomes line up in the middle of the cell. Spindle Anaphase Spindle forming Centrioles Nuclear envelope Chromatin Interphase Centromere Chromosomes (paired chromatids) Prophase Cytokinesis Spindle Centriole Telophase Nuclear envelope reforming Centriole Individual chromosomes Anaphase Metaphase Mitosis • Anaphase – Centromeres split – Chromatid pairs separate and pull apart to opposite sides of the cell Telophase Spindle forming Centrioles Nuclear envelope Chromatin Interphase Centromere Chromosomes (paired chromatids) Prophase Cytokinesis Spindle Centriole Telophase Nuclear envelope reforming Centriole Individual chromosomes Anaphase Metaphase • Telophase – Chromosomes uncoil – Nuclear membrane reappears – A new membrane starts to form between the two new nuclei Mitosis Cytokinesis Spindle forming Centrioles Nuclear envelope Chromatin Interphase Centromere Chromosomes (paired chromatids) Prophase Cytokinesis Spindle Centriole Telophase Nuclear envelope reforming Centriole Individual chromosomes Anaphase Metaphase Cytokinesis • Cytoplasm divides • In Animals: cell membrane pinches in to form a furrow • In Plants: a cell plate is created to form a new cell wall Cytokinesis Cell Cycle Regulation Checkpoints: or stop lights are the quality control mechanism Cell Cycle Regulation Apoptosis: programed cell death; occurs when a cell does not pass quality control Cell Cycle Regulation Cancer: uncontrolled cell division; when apoptosis doesn’t happen Control of the Cell Cycle • Cancer can: –Interfere with normal processes –Spread to other tissue (metastasize) –Crowd out healthy tissue Control of the Cell Cycle • Cancer cells often have an abnormal shape Control of the Cell Cycle – Cancer may be cause by many factors called carcinogens: • Environmental • Smoking • Pollution • Radiation • Viral Infections