Mitosis Flashcards
Interphase
G1 -cells undergoes rapid growth
S- centrosomes divide
G2- ribosomes and mitochondria are evenly distributed
Prophase
- chromosomes start to condense
- nuclear membrane disintegrates
- spindle forms between centrioles
- centrioles migrate to opposite poles
Metaphase
- chromosomes line up along equator
- chromosomes attach to spindly fibres by centromeres
Anaphase
- spindle fibers shorten
- chromatids pulled to opposite poles
- chromosomes sperate
Telophase
- chromosomes form groups at each pole
- chromosomes uncoil and become less visible
- nuclear envelope forms around each group of chromosomes
Mitosis
DNA replicates
difference between mitosis and meiosis
MITOSIS
- everywhere throughout cell (somatic cells)
- cell division
- 2 diploid, identical daughter cells produced
- form of asexual reproduction
- 46 chromosomes
- 1 cycle
MEOISIS
- sexual reproduction ( only in sex cells)
- 23 chromosomes
- 4 haploid, unique daughter cells produced
- 2 cycles
what is the control checkpoint
-step of cell cycle where cycle is checked for repairs or damage of DNA before preceding to mitosis
steps of the cell cycle
INTERPHASE: G1, S, G2
Checkpoint
MITOSIS
CYTOKENISIS
what are CYCLINS
a family of proteins that control the progression of cells through the cell cycle
process of CYCLINS
- Cells cannot progress to the next stage of the cell cycle unless a specific cyclin reads its threshold
- cyclins bind to enzymes called cylin-depedent kinases =
- these kinases then become active and attach phosphate groups of other proteins in the cell
- the attachment of phosphate triggers the other proteins to become active and carry out tasks (specific to one of the phases of the cell cycle)
what are kinases
family-related enzymes
correlation…
does not mean causation
types of tumor formations
- Mutagens
- Oncogenes
- Metastasis
what are mutagens
carcinogenic chemicals (cancer causing), high energy radiation e.g X-rays of lungs
what are oncogenes
genes that have mutated that can cause cancer
what is metastasis
movement of cells from a primary tumor to set up a secondary tumor (CANCER SPREADS THROUGHOUT BODY)
what are the features of a cancer cell (tumor)
- cancer cells do not differentiate into a specialist cell type
- a cancer cell is parasitic, taking nutrients from a surrounding cells by forming large numbers of blood vessels to supply it
- a cancer cell undergoes uncontrolled division
what are risk factors
anything that increase a change of developing a disease
-are correlational but not casual
e.g international travel= risk factor for malaria
cause= parasite in mosquitos
- smoking is a major risk for cancer
What does epidemiology mean
the study of people
difference between reliability and validity
RELIABILITY- the consistency of findings
VALIDITY- measuring what you set out to measure
what is lung cancer
- biggest cause for cancer-related deaths
- 90% of cases caused by smoking
- mos cases due to uncontrolled growth of epithelial cells living in the airway (cancer arising from the cells are called carcinomas)
symptoms of lung cancer
- shortness of breath
- coughing
- loss of weight
- nausea
timeline of the progression the smoking is the causation for lung cancer
- RICHARD DOLL AND AUSTIN BRADFORD (1950)
investigate 17000 men and women in London
find: risk of developing lung cancer increases in proportion to the amount smoked - BRITISH MALE DOCTORS INVESTIGATION (1950-2001)
- study of British male doctors health and smoking habits
found:
- lifelong smokers died, on average, 10 years earlier than non smokers
- the earlier smokers stopped smoking ,the more chance they have of avoiding reduced life expectancy .
