Cell differentiation notes
description
Transcript of Cell differentiation notes
![Page 1: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/1.jpg)
Cell Cycle & Differentiation
Chapter 3
Unit 1
![Page 2: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/2.jpg)
The Cell Cycle
• A set of events that occur during a cell’s lifetime– From the time a cell is “born” until it divides– Cycle is repeated for each cell– Includes:
• Growth• Preparation• Division
![Page 3: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/3.jpg)
The Cell Cycle
![Page 4: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/4.jpg)
The Cell Cycle
• Consists of three major stages:– Interphase*
– Mitosis*
– Cytokinesis
• *Each of these are broken into several distinct phases
![Page 5: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/5.jpg)
The Cell Cycle
• Interphase– Cell’s spend about 90% of the cycle in here– Broken down into three phases
• Gap 1 • Synthesis• Gap 2
![Page 6: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/6.jpg)
Interphase
• Gap 1– AKA “Growth” 1– Cells in this phase are growing in size– Producing lots of ATP– Dividing and reproducing cell organelles
![Page 7: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/7.jpg)
Interphase
• Synthesis– Cells in this phase are copying all the DNA
found in the nucleus– Synthesis is referring to the building of new
DNA molecules– Necessary to ensure that both cells that
result from division have 100% of DNA
![Page 8: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/8.jpg)
Interphase
• Gap 2– AKA “Growth” 2– Cells in the phase are checking to make
sure their DNA has been replicated correctly
– Check to make sure organelles are copied
![Page 9: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/9.jpg)
The Cell Cycle
• Assuming everything is ready at the G2 phase, the cell will proceed to division– Cell division in humans is called mitosis– Has four phases
• Prophase• Metaphase• Anaphase• Telophase
![Page 10: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/10.jpg)
Mitosis
• Prophase– Pro- means first– DNA thickens into chromosomes
• Remember, it has been replicated.• Look like X’s• Each side of the X is called a chromatid
– Nuclear membrane dissolves
![Page 11: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/11.jpg)
Prophase
![Page 12: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/12.jpg)
![Page 13: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/13.jpg)
Mitosis
• Metaphase– Meta- means middle– Spindle Fibers form
• Attach to centromere of chromosome• Move chromosomes to cell’s equator
– Centrioles found at opposite ends of cell
![Page 14: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/14.jpg)
Metaphase
![Page 15: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/15.jpg)
Mitosis
• Anaphase– Spindle Fibers shorten, pulling
chromosomes in half• Sister chromatids split apart• Chromatids move toward opposite sides of cell• ***Chromatids are now called chromosomes
![Page 16: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/16.jpg)
Anaphase
![Page 17: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/17.jpg)
Mitosis
• Telophase– Chromosomes reach the cell’s poles– Two new nuclei form…one around each
set of chromosomes at opposite ends– Chromosomes unwind– Spindle fibers dissolve
![Page 18: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/18.jpg)
Telophase
![Page 19: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/19.jpg)
Cytokinesis
• The final stage of cell division
• Literally means “cytoplasm divides”– Cell pinches in half– The “pinch” is called
a cleavage furrow
![Page 20: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/20.jpg)
Differentiation
• Humans are conceived when a sperm and egg unite, forming a single-celled zygote
• Zygotes are unspecialized
• When we are born, we have more than 260 specialized cell types
• How??? Differentiation
![Page 21: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/21.jpg)
Differentiation
• Cells specialize by differentiating into certain cell types– They turn off parts of DNA that they don’t
need– Use only the parts of DNA that are needed
to become a specific cell– *Cells that are specialized generally
can’t change and become other cell types
![Page 22: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/22.jpg)
Differentiation
• Stem Cells– Unspecialized cells that can can become
ANY type of cell in the body– Stem cells found in every organ in body– Stimulated to divide when…
• Growth is needed• Damage needs to be repaired
![Page 23: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/23.jpg)
Differentiation
• When a stem cell divides…– Two cells are produced through mitosis– One cell is a new stem cell (unspecialized)– One cell is called a progenitor cell
• Somewhat specialized• Will divide many more times, with each
daughter cell become more and more specialized
– *Cells “decide” to become specialized at the end of the G1 phase of cell cycle
See Page 69 in textbook!!!
![Page 24: Cell differentiation notes](https://reader034.fdocuments.us/reader034/viewer/2022042613/54737456b4af9f980a8b52ab/html5/thumbnails/24.jpg)
Apoptosis
• Defined as programmed cell death– Happens at the end of G1 in cell cycle– Occurs for many reasons
• Sculpting organs from overgrown tissue in the fetus
• Removes webbing between fingers as fetus• Destroys skin cells following a sunburn