Mitosis 3201

Prophase

  1. The chromatin condenses into tightly packed chromosomes

  2. The nuclear membrane breaks down, which releases the chromosomes into the cytoplasm

  3. The nucleolus disappears

  4. One pair of cylindrical organelles, called centrioles, moves apart to opposite poles of the cell

Metaphase

  1. Spindle fibres guide the chromosomes to the equator of the cell

  2. Spindle fibres from opposite poles attach to the centromere of each chromosomes

Anaphase

  1. Each centromere splits apart and the chromatids separate from each other

  2. The spindle fibres that link the centromeres to the poles of the cell shorten

  3. As these fibres shorten, sister chromatids are pulled to opposite poles. At the same time, other microtubules in the spindle apparatus lengthen and force the poles of the cell away from one another.

At the end of anaphase, one complete, diploid set of chromosomes has been gathered at each pole of the elongated cell.

Telophase

  1. Begins when the chromatids have reached the opposite poles of the cell

  2. The chromatids begin to unwind into the longer and less visible strands of chromatids

  3. The spindle fiber breaks down

  4. A nuclear membrane forms around each new set of chromosomes, and a nucleolus forms within each new nucleus.

Cytokinesis

ANIMALS

  • In animal cells, a cleavage furrow forms in the cell membrane along the cell equator. This indentation deepens until the cell is pinched in 2.

  • Cytokinesis ends with the separation of 2 genetically identical daughter cells.

    PLANTS

  • In plant cells, they do not have centioles, but they do form spindle apparatus.

  • the cell wall of a plant cell is much stronger than the membrane of an animal cell

  • The cell wall does NOT furrow and pinch during cytokinesis in plants

    • instead a membrane called a Cell Plate forms between the two daughter nuclei.

Cancer and The Cell Cycle

Cancer : uncontrolled cell division

Quality control checkpoints are built into the cell cycle to ensure that each cell meets a certain standard.

as a cell approaches the end of the G1, the phase of rapid growth, it will go through a checkpoint known as G1/S.

The cell checks for DNA damage, this ensures that DNA synthesis in S phase will be successful. cells with undamaged DNA will pass through the checkpoint and then proceed to S phase. Damaged DNA will undergo repair but if repair isn’t possible, programmed cell death, called apoptosis.

When the checkpoint system is working correctly, it will maintain healthy cell reproduction, but sometimes genes that code for regulatory protein, which plays the role of inspector at these checkpoints, becomes altered which will produce a malfunctioning protein or no protein at all.

as a consequence uncontrolled cell division will occur, resulting in cancer

uncontrolled cell growth in cancer can result in a tumor forming, which may alter the function of normal body tissues, and is then able to invade other parts of the body. Typically, more than one change in DNA is needed to cause cancer.

CANCER THERAPIES

Surgery : removes the tumor and nearby tissue during an operation

the types and severity of side effects vary from person to person based on multiple factors :

  • location and type of cancer

  • type of cancer

  • Side effects/complications: pain, fatigue, appetite loss, swelling, drainage, infection, bruising, numbness, and bleeding

Radiation Therapy : is a cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors

at high doses, radiation therapy kills cancer cells or slows their growth by damaging the DNA. Cancer cells whose DNA is damaged beyond repair stop dividing or they die. When the damaged cells die, they are broken down and removed by the body.

Most commonly used to treat cancers of the Head & Neck, breast, Cervix, Prostate, and Eye.

Side effects of radiation therapy : Fatigue, hair loss, nausea and vomiting, skin changes, headache, blurry vision, swelling, tenderness, cough, shortness of breath, Sexual problems, fertility problems, urinary & bladder changes, diarrhea

Chemotherapy : is a drug treatment that uses powerful chemicals to kill fast-growing cells in your body.

Chemotherapy is used most often to treat cancer, since cancer cells grow and multiply much more quickly than most cells in the body.

When is chemotherapy used :

to cure the cancer without other treatments. chemotherapy can be used as the primary or sole treatment.

after other treatments, to kill hidden cancer cells. after treatments such as surgery, they might use chemotherapy to kill any cancer cells that might remain in the body, this is called Adjutant therapy.

To prepare you for other treatments. chemotherapy can be used to shrink a tumor so that you can use other kinds of therapy, like surgery and radiation.

To ease signs and symptoms. chemotherapy may help relieve signs and symptoms of cancer by killing some of the cancer cells. Doctors call this palliative chemotherapy.

side effects of chemo include : Nausea, vomiting, diarrhea, hair loss, loss of appetite, fatigue, fever, mouth sores, pain, constipation, easy bruising, bleeding.

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.

targeted therapy can be used on : breast cancer, leukemia, colorectal cancer, lung cancer, lymphomia, melanoma.

What can targeted therapy do :

  • block or turn off signals that tell cancer cells to grow and divide

  • prevent the cells from living longer than normal

  • destroys cancer cells

Side effects of targeted therapy : diarrhea, liver problems, blood clotting, slow wound healing, high blood pressure, fatigue, mouth sores, nail changes, loss of hair colour, rash and dry skin.

Hormone Therapy : is a cancer treatment that slows or stops the growth of cancer that uses hormones to grow. hormone therapy also has other names.

Hormone therapy is used to :

treat cancer. hormone therapy can lessen the chance that cancer will return or stop or slow its growth.

Ease cancer symptoms. Hormone therapy may be used to reduce or prevent symptoms in men with prostate cancer who are not able to have surgery or radiation therapy.

When its used :

  • used to treat prostate and breast cancers that use hormones to grow

  • most often used along with other cancer treatments.

Side effects for men : hot flashes, loss of interest in or ability to have sex, weakened bones, diarrhea, nausea, enlarged and tender breasts, fatigue.

Side effects for women : Hot flashes, vaginal dryness, changes in your period if you haven’t went through menopause yet, loss of interest in sex, nausea, mood changes, fatigue.

Stem cell transplant : healthy cells are placed in your body to help your bone marrow start to work properly. The new stem cells make healthy blood cells.

  • it is used when stem cells or bone marrow have been damaged or destroyed by cancer or disease.

  • used to treat some cancers such as leukemia, lymphoma, multiple myeloma, and neuroblastoma.

  • it may be used after high-dose radiation and chemotherapy to treat cancer.

How stem cell transplants work

the stem cells in the bone marrow turn into red blood cells, white blood cells, and platelets.

when these blood cells mature they move into the peripheral blood (the blood that flows through the body.)

if the bone marrow is damaged or destroyed, it can’t make normal blood cells.

in a stem cell transplant, healthy stem cells are placed in the body to help your bone marrow start to work properly. The new stem cells make healthy blood cells.

a stem cell transplant is very complex. it can take 6 to 12 months or longer for your blood counts to be back to normal and your immune system to work well.

side effects of a stem cell transplant can be very serious or even life-threatening

Side effects of stem cell transplant : low blood cell counts, infection, bleeding, anemia, veno-occlusive disease, digestive system problems, sore mouth and throat, nausea, vomiting, loss of appetite, weight loss, diarrhea.

The formation of reproductive cells

Haploid : cell with half the number of chromosomes

Meiosis : cell division that produces half the number of chromosomes

Germ cell : gamete producing cell

Gamete : are an organism’s reproductive cells, also referred to as sex cells.

Female gametes are called ova or egg cells, and male gametes are called sperm. Gametes are haploid cells, and each cell carries only one copy of each chromosome.