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Cell divison - Coggle Diagram
Cell divison
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-Cyclin levels rise and fall, depending on which cycle the cell is in
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a phase, and broken down towards the end of the
phase, which signals the cell to move on
During the cell cycle, a cell grows, prepares for division, and then divides to form 2 daughter cells. They spend most of their time in interphase.
Prophase-DNA condenses, organizes, and chromosome structure appears, protein strands appear from centrosomes
Metaphase- Microtubules attach to chromosomes, line up in the middle
Anaphase- chromosomes separate, through shortening of microtubules attach to kinetochores, poles move further (move away)
Telophase-nuclear membrane repairs around both sets of chromosomes, 2 cells formed by cytokinesis
There are 3 phases of interphase, G1, S, and G2
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G1 checkpoint- cell resources get checked by P53. cells stay in this stage until cyclins bind to CDKs to move on to the next stage (cell size, nutrients, growth factors, and DNA damage)
G2 checkpoint- checks for DNA damage, DNA replication completion
M checkpoint- MPF checks spindle and chromosomes to make sure they're connected properly and ensure cells can complete mitosis ( checks for chromosomal attachment to spindle at metaphase)
P53- activates DNA repair, holds the cell in G1 to repair the cell, and triggers apoptosis if the cell is beyond repair
DNA replication
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Free nucleotides are attracted to exposed bases on the loose strands of DNA ( so that DNA polymerase can come in and join the base pairs together )
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-Cells need to divde because due to food, water, and oxygen used up in the cell, it can die if it gets too big
-The information is used to build molecules needed for growth, as it gets bigger the information in the DNA remains the same. So if it grew too big it would face an information crisis.
Cancer is caused by rapid cell division
Oncogenes (an altered form called proto-oncogenes) are responsible for promoting cell growth but when mutated can promote tumor formation or growth
Tumor suppressor genes control apoptosis and cell growth
Both copies of the gene need to be mutated thus recessive
-Mismatch-repair genes are DNA repair genes that correct these naturally occurring spelling errors in the DNA but when these genes are altered or mutated, mismatches (mistakes) in the DNA remain