Paper 1 - Mitosis / Tumours Flashcards
(18 cards)
What is a tumour ?
A lump of cells caused by rapid cell division
What are cancer cells ?
Cells undergoing uncontrollable cell division
When is mitosis / cell division required ?
-when an organisms grows
-when an organism becomes damaged and needs new cells for repair
-organisms like bacteria reproduce asexually
It is important that any cells produced contain genetic information that is identical to the parent cell.
What are the 3 stages of the cell cycle?
Interphase
Mitosis
Cytokinesis
What occurs during interphase ?
- cell makes extra subcellular parts
- DNA replication occurs
- the copies of the chromosomes stay attached to each other forming an ‘X’ shape. -> diploid have two sets of chromosomes
What happens during mitosis?
Cell splits, two identical daughter cells produced.
What happens during prophase?
Nucleus starts to break down and spindel fibres appear.
What happens during metaphase?
By the end of metaphase, chromosomes lined up on the spindel fibres along the middle of the cell - (equator)
What happens during anaphase ?
Chromosome copies are separated and moved to opposite ends of the cell on spindel fibres
What happens during telephase?
A membrane forms around each set of chromosomes to form Nuclei.
What happens during cytokinesis ?
A cell surface membrane forms to separate the two cells. (Cellulose cell walls formed in plants)
What happens during asexual reproduction, what does it rely on ?
- Relies on mitosis
- Offspring are genetically identical to parents
- Faster than sexual reproduction
- Does NOT produce variation
Examples of asexual reproduction
Strawberry plants, using runners - stems that run along the ground, potatoes use tubers.
Aphids (animal) can asexually reproduce.
What are the two types of tumors ?
Tumour a group of cancerous cells -> damage or even death
Benign and malignant.
What is a benign tumour / features ?
- grows slowly
- usually grow within a membrane so can be easily removed
- do not invade other parts of the body.
What Is a malignant tumour / features ?
- grows quickly
- invade neighbouring tissues and can spread to other parts of the body through the bloodstream.
- as the tumour grows, cancer cells can detach and form secondary tumours in other parts of the body. Divide and invade surrounding tissue -> METASTASIS
What is a carcinogen ?
Chemicals and other agents that result in cancer.
-cause cancer by damaging DNA, cause mutations to occur -> several mutations required to cause cancer -> more likely as we age.
Risk factors for cancer
- Industrial and environmental factors at work (chemical carcinogens eg. Cigarette + ionising radiation eg. Ultraviolet causing skin cancer from the sun)
- lifestyle factors - large fat or salt intake
- genetic factors
- viruses linked to cancer being spread through sexual intercourse.
