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53 Cards in this Set
- Front
- Back
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Autoploidy |
Genome doubling - multiplication of one full set of chromosomes Identical; derived from the same species Allow for growth to occur faster Problem with reproduction - too much |
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Allopolyploidy |
Combination of genetically distinct but similar chromosome sets via hybridization between two distinct but similar species |
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Polyploidy |
More than two sets of chromosomes
Sterile - problems with pairing and separation of homologous chromosomes in meiosis
Cells get terminated, not viable |
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Monoploidy |
One set of chromosomes |
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Chromosome Disjunction |
Normal seperation/moving apart of chromosomes - centromeres spilt apart and chromosomes move apart
- Anaphase of Mitosis - sister chromatids separate and move towards opposite poles of the cell - Anaphase 1 of Meiosis - homologous chromosomes move apart - Anaphase 2 of Meiosis - sister chromatids separate and move apart
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Chromosome Non-disjunction |
Failure of homologous chromosomes or sister chromatids to separate Anaphase of mitosis and meiosis 1 and 2 Leeds to uneven chromosome number Missing or extra chromosomes (N+1 or N-1) |
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Aneuploidy |
Cell has extra/missing copies of a specific chromosome
Monosomy - loss (2n-1) - abortion Trisomy - gain (2n+1) - syndrome |
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Trisomy 21 - Down Syndrome |
- Meiosis 1 - one chromosome contains both chromosomes and the other contains nothing - Meiosis 2 - two chromosomes split while the other two have nothing
- Developmentally delayed, heart defects, epicanthic fold, small jaw, protruding tongue, broad hands, transverse palmer crease, broad flat face, low set ears, poor muscle tone, weak reflexes, mental ability varies from person to person, severity changes from person to person - Increased frequency associated with increased maternal age - Link with dementia "Alzheimer's Disease" - 50+ years old |
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Trisomy 13 - Patau Syndrome |
Average life span ~6 months Large triangular nose with cleft lip and palate Neurological defects Malformation of brain and heart Polydactyly - clenched hands, extra fingers Small head and absent eyebrows Dysplastic/malformed ears Undescended/abnormal testes |
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Trisomy 18 - Edward Syndrome |
Average life span ~3 months "Elfin" appearance Clenched hands with overlapping fingers Rocker bottom feet, flexed big toe, prominent heels Severe heart and neurological problems Small mouth and jaw, short neck Back part of skull is prominent Dysplastic/malformed ears Shield chest, short and prominent sternum, wide-set nipples |
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Turner Syndrome XO |
- Short stature, wide-schist, normal IQ, webbing of the neck, ovaries fail to develop, uterus and oviducts small and immature - Female reproductive system significantly underdeveloped - Nothing wrong mentally, physically deformed only - Receive growth hormone therapy to increase stature - Receive estrogen at puberty for breast development - People that survive are miracles - largest percentage of abortion |
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Klinefelter Syndrome XXY |
Male with two X chromosomes Phenotypic features develop after puberty Breast development and female body fat distribution; normal otherwise Testosterone therapy and breast tissue removal Sterile, struggle with muscle coordination |
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Triple X Females (Trisomy X) |
- Phenotypically normal - taller than average, delayed development of speech and language skills, learning disabilities, behavioural and emotional difficulties - Hard to diagnose - female but with one extra chromosome |
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XYY Males |
Phenotypically normal - Taller than average - Delayed development of speech and language skills - Learning disabilities - Behavioural and emotional difficulties - Delayed development of motor skills - Hypotonia - weal muscle tone - Involuntary movements |
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Characteristics of Cancer Cells |
1. Lost the genetic ability yo stop dividing 2. Immortal 3. No contact inhibition 4. De-differentiated cells 5. No tissue affinity; can metastasize 6. Neo-angiogenesis 7. Transformed cells |
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Cell Cycle Regulation |
Frequency varies (muscle cells grow faster than neurons) Are a result of regulation - facilitate movement Cancer cells escape normal regulatory controls
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Cytoplasmic Signals |
Cell in S phase fused to cell in G1; G1 nucleus enters S phase; DNA replicated
Cell in M Phase fused to cell in G1; G1 nucleus begins mitosis (spindles form, chromosomes condense) even though only one chromatid is present |
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Checkpoints |
- Border - Certain things in place in order to move from one to the other - START (G1); end of G2 (G2); middle of mitosis (M) - START checkpoint very important - once it gets the go-ahead, can proceed through S phase; if it doesn't, it will delay/exit and switch to non-dividing G0 |
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Senescence |
The cell does not respond to growth stimuli anymore (most somatic cells) |
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Regulations for Cell Duplication |
1. Size of the cell 2. Enough food present 3. External stimuli |
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Internal Stop and Go Signals |
G2 - errors in S phase (replication/repair) - signal prevents - Integrity - checks if job done properly - DNA damage/mutation goes into arrest in G2 - Apoptosis - Skin cells recovered and regenerated quickly
M checkpoint - problems with spindle fibre formation (delays anaphase) - Metaphase, sees if everything's lined up properly on equator (integrity) - Ability to check, if not done properly, apoptosis |
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Apoptosis |
Cell death occurs when there is a failure to repair DNA |
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External Stop and Go Signals Growth Factors |
Proteins that diffuse through the body Bind to membrane receptors in lock and key fashion - Bloodstream - Make specific receptors have a specific affinity for a specific GF - Responds in G1 - Hormones and transcription factors |
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Enzymes - Pro-caspases |
Break down the nucleus Supposed to be inactive, damage = active Active results in the starting of apoptosis |
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Anti-apoptotic Factors
Pro-apoptotic Factors |
Do not want apoptosis to occur
Want apoptosis to occur |
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Proto-oncogenes |
Encodes growth factors Transcriptionally active in dividing tissues Allow cells to move forward through the cell cycle Become oncogenes sometimes, can become cancerous
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Oncogenes |
- Altered proto-oncogenes - Can produce too much GF or an altered GF - One mutation sufficient for cancer development - When something goes wrong, can't be controlled, uncontrolled growth - Either protein is modified or produced more frequently - gain of function of a dominant gene - Increase transcription level, produce inactive protein (hypomorphic allele) - Dominant expression - one mutant gene needed for cancer |
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Proto-oncogenes --> Oncogenes |
1. Point mutations
2. Deletion mutations
3. Chromosomal translocations that create new fusion proteins - lose fragment, create new protein - after expression, strong promoter can change (rare)
4. Chromosomal translocations that move a strong promotor upstream of a proto-oncogene so that it is inappropriately expressed - specific gene expressed at higher level
5. Gene amplification resulting in over-expression of a protein - promoter swap - duplication increases copy number - over-expression - gene copy number amplified - no apoptosis - continued growth - cancer
6. A virus can carry a photo-oncogene to a new chromosomal location - virus inserts into PO, viral regulatory elements cause over-expression |
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Viruses |
Active oncogenes, resulting in cancer Integrated into the genome Caused by negative DNA elements Regulatory elements come from virus-external affairs (cancer)
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Burkitt Lymphoma |
Large tutors found in lymph glands of face and neck Reciprocal translocation between chromosome 8 and 14 cMyc from C8 next to regulatory region of immunoglobulin genes on C14 |
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Kinases |
Activate signal transduction; affect growth
cSrc - becomes activated, functions with EGFR, activates cell cycle progression, inactivates apoptosis
Epidermal Growth Factor Receptors - growth of cells, receptor activated, results in transcription factors that impact the nucleus and transcription
CSK - becomes active when no growth factor, inactivates cSrc (changes composition, binds phosphate group) and entire function becomes inactive
CSK inactivates cSrc which activates EGF If CSK inactive, absence of EGF Allows expression at high levels Src leaves cancer - over-expression, point mutation |
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Tumor Suppressor Genes |
Encode proteins that turn off cell division Two mutations needed for cancer development Functions at checkpoints - stops cell from dividing at specific place One can compensate for the other Recessive expression - two mutant genes needed for cancer |
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Tumor Suppressor - p53 |
- Gene TP53 on chromosome 17 - In active in a normal healthy cell - Active during cellular stress (DNA damage) - transcription factor, arrests at G1 checkpoint until repaired, activates DNA repair mechanism, cell cycle restarts when repaired, apoptosis is initiated if damage irreparable - Prevents cancer - Regulation in normal cellular conditions - Guardian of the genome - integrity - Always transcribing to make protein - Binds to protein mdm2, targets and destroys proteasomes, doesn't function in absence of stress, can't perform function - A backup mechanism - ready to respond to cellular impact, enables apoptosis, prevents tumor formation - Destroyed if not needed |
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Protein Stability (p53) |
Normal cellular function - stable in cell for half the time, varies between proteins
Degradation - proteasome (destruction barrel for proteins, very small)
Ubiquitin - small proteins added onto proteins that are targeted for degradation to proteasomes then destroyed into amino acids (irreversible) |
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Loss of p53 Function |
- Inherit one copy develop tumors in early adulthood - Inability to arrest in G1, activate DNA repair, initiate apoptosis, uncontrolled cell cycle progression - Radiation (UV), chemicals, viruses - mutagens known to modify - As soon as loos of function, tumor can appear |
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CDKs |
Cyclin-dependent kinases Phosphorylate target proteins to turn 'on or 'off' Affect within the cell Play a role in transition, not needed anywhere else (no function in G1) Activity regulated within the cell Every CDK has specific cyclin |
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Cyclins |
Concentration varies in a cyclical fashion during cell cycle Bind to CDKs, change conformation activating kinase activity Proteins produced to activate CDKs Early interphase (G1) - low cyclin, low CDK level End og G2 - high cyclin, high CDK activity, phosphorylation |
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Abundance |
Amount of protein in cell is regulated Drops after it performs function, peaks CDK activity Cyclin destroyed Abundance of cyclin regulates CDK activity Link between concentration and activity to ensure movement |
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Tumor Suppressor - Retinoblastoma Protein (RB) |
- Encoded by RB1 gene on chromosome 13 - Stops other proteins from triggering DNA replication - Do not proceed to S phase - RB bind to transcription factor E2F needed for cell cycle progression - Normal growing cells - RB phosphorylated by kinase, allows cells to pass checkpoints (CDKs), phosphorylated Tb (pRB) cannot bind to inactive E2F transcription factor, E2F activates genes needed for cell cycle progression - Located in the eye, prevents DNA replication |
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Loss of RB1 gene/RB Protein Function |
Results in constitutively active E2F Uncontrolled cell cycle progression, cancer development Abnormal appearance of the retinal through pupil "white pupil" Develops "squint/cross-eyed" vision Abnormal eye development Other types of cancer |
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Human Papilloma Virus (HPV) |
-Integrates in human genome - Risk of cervical cancer (genital warts) - Two viral proteins - E6 and E7 - E6 binds and targets p53 for ubiquitin, mediates proteolysis int eh proteasome, cell cannot arrest or activate apoptosis, targets for destruction, defence mechanism taken away - E7 binds and inactivates RB, E2F is releases and active, stimulates cell cycle progression, changes folding, releases protein - Impacts the way we regulate our cell cycle - Body can normally get rid of it - Genomic DNA - virus integrates (stable), starts to express proteins E6 and E7 - Ability to hijack, duplicate, uncontrolled growth |
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BRACA 1 |
- Chromosome 17 - Encode genes needed to activate DNA repair enzyme - Tumor suppressor - implement checkpoints, stops division, impact on progression, essential for DNA repair
- Recognizes double stranded DNA breaks - Binds to it - Brings BRACA2 to the specific site - Stops checkpoint - G2 to M transition and mitosis - Aneuploidy - cancer, struggled to complete cytokinesis
- Negatively impacts oncogenes - inhibits cMyc - Positive effect on tutor suppressor genes - positively impacts RB and p53 - prevents cell cycle progression - Negatively impacts steroid hormone receptors - Activates stress response and DNA repair proteins |
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BRACA 2 |
- Chromosome 13 - Encode genes needed to activate DNA repair enzyme - Tumor suppressor - implement checkpoints, stops division, impact on progression, essential for DNA repair
- Brings repair protein RAD51, allows double stranded DNA to interact with homologous sister chromatid/chromosome - Homologous recombination - two chromatids, one serves as template to recover the other broken one - Recognizes if not lined up properly - G2 and M transition and mitosis - Aneuploidy - cancer, struggled to complete cytokinesis |
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DNA Repair |
Cell viability is compromised when there is a break Treat break so that it can go through recovery process |
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Cancer Treatment Goals |
1. Prevention 2. Cure 3. Control 4. Palliation |
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Metastasis of Cancer |
Spread to different tissues Form varieties of cancer of the body rather than in one area |
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Cancer Treatment Plans |
Main/Primary Treatment - one type is needed Combination Treatment - given together or at different times
Neoadjuvant - given before primary treatment to shrink tumor so that it's easier to treat with the primary therapy (chemotherapy, radiation)
Adjuvant - given after primary treatment to control, destroy any remaining, or reduce risk of reappearance |
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Cancer Treatment Types |
Local - specific part, limited to that area (radiation and surgery)
Systemic - bloodstream, metastatic cancer, reduce chance of reoccurrence (chemotherapy drugs)
Targeted - directly target cancer cells while sparing normal cells, biological agent |
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What are individual treatment plans based on? |
1. Type 2. Characteristics - how it came about in the first place 3. Stage - 0 - Out of control, growth starting, no invasion/spreading - 1 - Invasion - 2 - Invasion, lymph nodes, increase in inflammation - 3 - Invasion, lymph nodes, increase in inflammation - 4 - Spreading, colonization in different areas, metastasis 4. Personal situation and wishes |
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Main Cancer Treatments |
Chemotherapy Radiation Therapy Surgery Targeted Therapy (hormonal therapy, biological therapy) Stem Cell Transplant |
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Chemotherapy |
- Drugs used to stop uncontrolled cell division 1. Prevent cells from entering S phase 2. Block or stop mitosis 3. Stop neo-angiogenesis
- Antibodies - protein that matches foreign protein, specific to one - Antibodies block growth factor receptors, prevent anything else from binding - Herceptin blocks growth factor receptors in breast cancer - Breast cancer cells require estrogen, tamoxifen prevents binding of estrogen - Cells recognize foreign proteins, make specify proteins that identify these (antibodies), goes to lymph nodes/ liver, gets degraded, macrophages clean up the mess - Vinca alkaloids binds to specific sites on tubulin, inhibiting assembly of tubulin into spindles needed in mitosis (process altered), Paclitaxel makes spindle apparatus stable, prevents sister chromatids from spreading - Need microtubules to break down so the chromosomes can move apart - Tamoxifen has anti-angiogenesis properties - Some drugs block development of blood vessels, affect chemicals that cells use to signal each other - Thalamoid affects signals between cells, prevents tumor cells from signalling new blood vessels, tumor starvation
Side Effects - Hair follicle cells - baldness - Skin cells - cuts and wounds heal slowly - Digestive tract cells - nausea, mouth ulcers, bacterial infections - Blood stem cells - reduced red blood cells lead to anemia, reduced white blood cells lead to infections |
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Radiation Therapy |
- Higher dose repeatedly destroys cancer cells - Cancer cells don't have time to repair themselves, normal cells do - Very hard to destroy cancer cells without damaging normal cells - Goal - give enough radiation to destroy cancer cells in your body but not so much that normal cells can't recover - Localized Treatment - double stranded DNA breaks, prone to being killed by radiation |
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Surgery |
- Main way of removing cancer, used in combination - Remove or repair tissue - Lower the risk of developing certain types of cancer, to restore function or appearance, relieve symptoms - Treat solid tumors - Different surgical techniques and procedures |
