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Living Organisms
- are made of cells
- egg+sperm= zygote
- these cells divide and divide
- 1-2-4-8
Always making new cells by dividing old cells/ whole life
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What is a cell?
- Cell is smallest unite of life-take it apart and its not alive
- Cell Cycle- normal process of controlled cell division
- Nucleus with DNA
- Organelles
- Communicate with other cells
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Cell Cycle
- Orderly process of growth and division into 2 cells
- G1- makes organelles, gets bigger, 8 hours
- S- the DNA is replied all 46 chromosomes are copied
- G2- more growth, getting ready to divide
- M- mitosis nucleus divides
- Cytogenesis- cell divide
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DONT CONFUSE SISTER CHROMATIDS with HOMOLOGOUS CHROMOSOMES.
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Sister Chromotids
- 2 identical copies of a chromosome connected by a centromere
- Twin
- Same alleles duplicated
- Still homologous pair
- Still code for same thing just different versions
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Homologous Chromosomes
- Carry the same genes
- Code for the same thing (gene)
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Checkpoints
- Proteins check
- Proteins decide if the cell should go on or not
- G1- Do we need new cells? Are growth factors present? Do we have sufficient nutrients? Is the cell big enough?
- STOP
- Interphase
- G2- Is the cell big enough? Was the DNA replicated correctly? If not commit suicide- apoptosis. Fix DNA if only small errors
- STOP
- Mitosis- is mitosis proceeding correctly.
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Cells Don't Have to Divide
- Nerve cells stop at checkpoint
- RBC- 20 million/sec- new ones every three months
- Kidney- wear out so divide frequently
- Live- if needed can divide. Otherwise remain in G1- only makes when needed
- Development- lots of division and apoptosis
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DNA Replication
- Interphase- DNA is copied (not actually dividing)
- Mitosis- DNA is split equally into two daughter cells
- Cytokinesis- Parent cell is cleaved in half
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Cancer
- A loss of control over the cell cycle, a failure at the checkpoint.
- Normal DNA, normal genes, normal proteins.
- Change in DNA, change in genes, change in protein
- Proteins check the cell and regulate cell cycle
- If proteins are changed because the DNA is changed they don't regulate the cell cycle
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Tumor
Abnormal mass of cells
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Benign Tumor
- (kind)
- Usually reaches a certain size then stops.
- Mole
- Does not invade tissue- sits on top of it
- Usually does not cause cancer tumors
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Malignant Tumor
- (Wicked)
- Continues to grow, does not reach a certain size and stop.
- Invades tissue.
- Not incapsulated
- Is Cancer
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Metastatsis
Some of the cells let go and move through the blood stream to another part of your body
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Mutations in three types of genes cause cancer
- Proto-oncogenes
- Oncogene
- Common oncogene
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Proto-Oncogene
- (Before Cancer Gene)
- Genes that code for proteins that stimulate cell division
- Normal genes that everyone has
- Operate at G1
- Makes cell cycle go
- Makes growth factor receptor, bunch of things for sending cells on
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Oncogene
- Cancer gene
- Mutated proto-oncogene
- Stimulates division when normal proto-oncogene would not
- Stuck accelerator
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Common Oncogene
is BRAF- also HER2- receptor acts as if gf there when its not
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Tumor Suppressor Gene
- Normal genes that code for proteins that inhibit cell division
- Operate at G2 checkpoint
- Stopping cell division (broken pedal)
- Mutated tumor suppressor (broken break pedal)
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Stability Genes
- Operate at G2 and Mitosis checkpoint
- To repair damage, proteins cut out wrong DNA and puts correct DNA in
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Mutations and Cancer
- It takes more than one mutation in a single cell to cause cancer
- Stability gene- mechanic
- Stability genes keep mutations to a minimum and when they are inactive mutations in other genes occur at a higher rate
- Mutations turn off normal contact inhibition gene
- Mutations turn off angiogenesis gene (blood new creation)
- Turns off telomerase gene- (end of chromosomes)
- Look in notes!
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Hereditary Cancer
- 5-10%
- Dont inherit cancer you inherit the chance to get cancer (cancer risk)
- Occurs in first degree relatives (blood)
- All other cancer is called spontaneous cancer- not inherited
- Bilateral- both lungs
- Recurrent- because all the other cells still have the one mutated gene
- Inherited at a young age
- Older you get the more likely you will get it except past 80
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Causes of Cancer
- May take 20 years after exposure before you find it
- Carcinogen causes cancer
- Chemicals- cigarette, diet (not sure how)
- Radiation- uv light from sun, naturally occurring gas called radon- lung cancer, melanoma- deadly skin cancer
- Viruses- 4 we know cause cancer in humans, most viruses that cause cancer in lab animals don't cause cancer in humans. -HPV causes cervical cancer. -Hepatitis B and C causes liver cancer. -Lymphocytotrophic virus, human t cell leukemia, AIDS patients- Epstein barr virus, hodgkins lymphoma AIDS patients
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Detection of Cancer
- Pain and Scars
- Lump
- Biopsy- when they find some the suspicious take a chunk of the body to find cells
- Proteins
- PSA levels get high when you have prostate cancer- protein found in urine.
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Getting Rid of Cancer- Surgery
- Take out cancer, if they can reach it
- Have to be able to remove some tissue the cancer is in
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Getting Rid of Cancer- Chemotherapy
- 1. Targets rapidly moving diving cells- cancer cells, hair cells, lining of mouth, red blood cells, skin cells
- 2. Anti-Angiogenesis Drugs- (blood new) If you can stop new blood cells from forming you can stop cancer from growing. Tumor needs angiogenesis to grow.
- 3. Anti-Telomerase Drug- (caps that protect end of chromosomes) Clinical trials, keeps cells from being immortal
- 4. Rational Drugs- Test cancer and test drugs against it. Trying to make a drug to just affect cancer cells
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Getting Rid of Cancer- Radiation
- Damages cells in high doses kills cells
- Used with shallower cancers
- Cancers where you have to go through another organism
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Getting Rid of Cancer- Biotherapy
- Immune system- patrol body- looking for things that are non-self
- Goal is to get the immune system to see cancer cells as non-self cells
- If you can do this your immune system would get rid of it
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Getting Rid of Cancer- Monoclonal Antibodies
- Form of biotherapy
- Take a mouse genetically engineer it so it makes human antibodies
- Human cells into a mouse which then makes anti bodies against itself
- Then take antibodies and inject it into cancer patient
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