Mitosis and cancer Flashcards
Substance between cell membrane and nucleus containing organelles
Cytoplasm
One cells cell cycle starts… and ends..
- Starts when the cell forms
- Ends when as a mature cell it divides into two daughter cells
Two main phases of the cell cycle
Interphase
Mitosis
Phase in which DNA is replicated
Interphase
Chromosomes of DNA that has replicated consist of…
- Two sister chromatids
- Joined by a centromere
Two sister chromatids constitute one…
Chromosome
Features of a cell in interphase prior to mitosis
- Cell growth
- DNA replication
- More growth and preparation for cell division
A small cell versus a large cell’s surface to volume ratio
- Small cell: large surface area to volume ratio
- Large cell: small surface area to volume ratio
A small surface area to volume ration forces the cell to…
Divide into two daughter cells
Time for typical mitosis phase to take place
1-2 hours
After cell division, the fate of the daughter cells
- One often grows and divides again
- The other usually changes to form a specialized cell (tissue)
Why cells divide
Growth
Repair
Reproduction (asexual)
Region in plants where cell division occurs
- Apical meristem (tips of roots, shoots and buds)
- Lateral meristem (under bark)
Division of the cytoplasm
Cytokinesis
Mitosis
Division of the nucleus
Early prophase
- DNA becomes visible as chromosomes
- Centrosomes made of two centrioles moving towards cell poles
- Microtubule structures start to form spindle
- Nucleolus disappears
Late prophase / prometaphase
- Nuclear membrane disintegrates
- Microtubules attach themselves to the chromosomes
- Spindle apparatus formed
- Chromosomes start to move towards equator
Metaphase
- Nuclear membrane disintegrated
- Centrosomes pull on chromosomes using spindle (tug of war)
- Chromosomes lined up along equator
Anaphase
- Centromeres cleave
- Sister chromosomes split to form daughter chromosomes
- Daughter chromosomes pulled by microtubules towards opposite spindle poles
- Polar microtubules elongate cell
Telophase
- Daughter chromosomes reach opposite poles
- New nuclear membrane forms around each set
- Nucleolus reforms
(Not part of mitosis but at the same time cytokinesis occurs)
Mode of cytokinesis in animal cells
Cleavage furrow
Mode of cytokinesis in plant cells
Cell plate formed separating daughter nuclei
Cancer
A broad group of diseases involving unregulated cell growth
Cancer cells appear different to normal cells
Little cytoplasm
Multiple nuclei
Coarse chromatin
Different types of cancer
Carcinoma - epithelial tissue
Sarcoma - connective tissue
Leukemia - blood/bone marrow
Blastoma - other stem/precurser cells
Causes of cancer
Genetic (5-10%)
Tobacco (25-30%)
Diet and obesity (30-35%)
Infections (15-20%)
Radiation (10%)
Stress, lack of exercise and pollution
Types of tumor
Benign
Malignant
Benign tumors
Stay at one site
Don’t spread
Malignant tumors
Cancer cells spread
Other organs affected
Cancer metastasis
Cancer cells affect organs and tissues different from cancer origin
Cancer treatments
Surgery
Chemotherapy
Radiotherapy
Complementary therapy
Cancer surgery
Remove cancer cells with scalpel or laser
Chemotherapy
Chemicals that kill cancer cells
Chemicals that stop DNA from making new cells
Radiotherapy
Using radiation to target cancer cells
Prevent cancer by avoiding
Tobacco
Obesity
Insufficient diet
Physical inactivity
Alcohol
STI’s
Air pollution
Complementary cancer therapy
Alternative treatments not affecting each other or affecting prescribed medical treatment
Usually aim to treat or relieve symptoms
E.g. Traditional medicines
E.g. Prayer/ positive thinking techniques
Traditional medicines used to treat cancer
Cancer bush tea
African wild potato
Both believed to strengthen immune system
