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meiosis vs mitosis Cheat Sheet (DRAFT) by

Cell division, processes

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Meiosis vs mitosis

Mitosis
Meiosis
Same
2 diploid identical daughter cells
4 haploid non-id­entical daughter cells
Produces new cell
one division
two divisions
Starts with a diploid parent cell
growth and repair, asexual reprod­uction
producing gametes
Cells undergo cell replic­ation
somatic cells
germ cells
The body needs both
46 chromo­somes
23 chromo­somes
Both take place in cell nuclei
No crossing over/g­enetic recomb­ination
Crossing over (genetic variation)
Both involve cell division

Types of stem cells

Totipotent
Plurip­otent
Multip­otent
early embryo­/bl­ast­ocyst
inner cell mass of developing embryo
bone marrow­/cord blood
any type of cell/t­issue
differ­entiate many tissue types/but cannot create
differ­entiate into blood cells

What is the purpose of meiosis and mitosis?

Mitosis
Meiosis
The purpose of miosis is for growth and repair, or asexual reprod­uction.
The purpose of meiosis is to produce germ cells, games, sex cells.

Mitosis

Interp­hase:
G1: cell contents duplic­ated, S: DNA replic­ation, G2: check for error
Prophase:
Chromatin -> chromo­somes, Nuclear membrane starts to breakdown, Centrioles move to opposite ends of the cell
Metaphase:
Spindle fibers are sent out from the centri­oles, Spindle fibers attach to centro­meres, Chromo­somes line up in the middle (single file)
Anaphase:
Centro­meres break down, Spindle fibers contract, Sister chromatids pulled to opposite sides of the cell
Telophase:
Nuclear membrane reforms, Cell starts to pinch in middle, Chromo­somes -> chromatin
Cytoki­nesis:
Division of cytoplasm, 2 diploid identical daughter cells, Exact copy of genetic inform­ation

What is cancer?

Cancer cells are your cells, they are non-fu­nct­ioning cells that have had their apoptosis gene turned off
Apoptosis is programmed cell death, where a cell that isn't functi­oning will die, therefore it isn't taking recourses from functi­oning cells
Usually when these cells are present our immune system will break them down
However when the apoptosis gene is off and the cell division gene is on these cells start to contin­ually replicate at a rate that our body cannot keep up with. Lots of cells = tumour

Ethics behind stem cells

Confid­ent­iality
Voluntary partic­ipation
Risk of harm
Informed consent
It involves the destru­ction of embryos to harvest totipotent and plurip­otent stem cells (when is something living? When it has a heartbeat or the moment its cells start replic­ating?)
 

Mitosis

how does meiosis allow for genetic variation?

Crossing over
00:00 00:36 Crossing over, as related to genetics and genomics, refers to the exchange of DNA between paired homologous chromo­somes (one from each parent) that occurs during the develo­pment of egg and sperm cells (meiosis). This process results in new combin­ations of alleles in the gametes (egg or sperm) formed, which ensures genomic variation in any offspring produced.
Random fusion of gametes
which egg is released is random and which sperm that enters the egg is random therefore the alleles that are being carried by the egg and sperm and eventually the offspring were randomly selected
Random assortment of genes
the separa­tion, or assort­ment, of homologous chromo­somes is random. This means that all of the maternal chromo­somes will not be separated into one cell, while the all paternal chromo­somes are separated into another.

What are stem cells?

Stem cells are undiff­ere­ntiated cells which means they currently have no job to do in the body Stem cells can be artifi­cially modified to become a certain type of cell, for example they have grown fully functi­oning mouse hearts in a lab They also inject stem cells that have been programmed to be cartilage and ligaments into injured knees and joints.
Stem cells are catego­rised according to their ability to develop into different tissue types. Some stem cells are capable of differ­ent­iating into more different tissue types than others
Stem cells can be artifi­cially modified to become a certain type of cell, for example they have grown fully functi­oning mouse hearts in a lab
They also inject stem cells that have been programmed to be cartilage and ligaments into injured knees and joints.
 

meiosis

Interphase 1
Prophase 2
G1, S, G2
Chromatin -?> chromo­somes, Nuclear membrane starts to break down, Centrioles move to opposite ends of cell
Prophase 1
Metaphase 2
Chromatin -> chromo­somes, Nuclear membrane starts to break down, Centrioles move to opposite ends of cell
Spindle fibers are sent out from centrioles and attach to centro­meres Chromo­somes line up in the middle (single file)
Metaphase 1
Anaphase 2
Spindle fibers are sent from centrioles and attach to centro­meres, Chromo­somes line up in middle as homologous pairs (2 lines), Crossing over occurs here
Centro­meres break down Spindle fibers contract Sister chromatids pulled to ends of the cell
Anaphase 1
Telophase 2
Centro­meres break down, Spindle fibers contract, Homologous chromo­somes are pulled to opposite ends of the cell
Nuclear membrane reforms Cells start to pinch in middle Chromo­somes -> chromatin
Telophase 1
Cytoki­nesis 2
Nuclear membrane reforms, Cells start to pinch in the middle, Chromo­somes -> chromatin
Division of cytoplasm 4 non-id­entical haploid daughter cells
Cytoki­nesis 1
Division of cytoplasm, 2 non-id­entical haploid daughter cells

What is a tumour?

A tumor is a mass of cells that are taking resources from the body but giving nothing back which means the body cannot function as it should. A tumor where the cells do NOT spread is said to be benign.
A malignant tumor where the cells DO spread via the circul­atory or lymphatic systems cancer. A malignant tumor is a problem as when the cells spread they start making more tumors around the body. A tumor on the liver means the liver cannot function as it should but tumours on the liver, pancreas and stomach means all 3 of those organs cannot function as they should. Also 1 tumor is more easily treated then multiple tumours.
 

meiosis

Cancer treatments

Surgery
the goal of surgery is to remove the cancer or as much of it as possible
Chemot­herapy
uses drugs to kill cancer cells
Radiation therapy
Radiation therapy uses high-p­owered energy beams, such as X-rays or protons, to kill cancer cells. Radiation treatment can come from a machine outside your body (external beam radiat­ion), or it can be placed inside your body (brach­yth­erapy).
Immuno­therapy
Immuno­the­rapy, also known as biological therapy, uses your body's immune system to fight cancer. Cancer can survive unchecked in your body because your immune system doesn't recognize it as an intruder. Immuno­therapy can help your immune system "­see­" the cancer and attack it.
Targeted drug therapy
Targeted drug treatment focuses on specific abnorm­alities within cancer cells that allow them to survive. Targeted therapy is a cancer treatment that uses drugs to target specific genes and proteins that are involved in the growth and survival of cancer cells. Targeted therapy can affect the tissue enviro­nment that helps a cancer grow and survive or it can target cells related to cancer growth, like blood vessel cells.