B2-cell division Flashcards
what is cell division used for?
What is cell division used for:
To grow
To replace dead/damaged cells
To repair tissue
what is the first phase of the cell cycle
The cells expand (grow) - they duplicate the chromosomes, the organelles and the cytoplasm
what is the sencond stage of the cell cycle
what happens in prophase
In prophase DNA condenses into chromosomes spindle fibres attach to the centres of the chromosomes
what happens in metaphase
In metaphase the spindle fibres line the chromosomes up at the equator of the cell
what happens in anaphase
in anaphase the spindle fibres contract separating the sister chromatids and pull them to the poles of the cell
what happens in telephase
In telophase the nuclear membrane forms, and the cell membrane starts to cleave
what is a stem cell
A stem cell = an undifferentiated/unspecialised cell that can differentiate
where is stem cells in plants located?
Unspecialised cells are formed in meristems - active regions in the stems and the roots
what does cloning mean
Cloning = producing identical offspring
what is a zygote
Zygote = fertilised egg cell
what are adult stem cells
Adult stem cells = undifferentiated cells of an organism that produce many more cells of the same type
why are there ethical reasons to using embryonic stem cells
Others say as an embryo cannot give permission, using it as a violation of human rights
Religious beliefs mean they cannot accept interference with process of human reproduction
what can pateints do to reduce rejection of stem cells
Treating an unrelated person with adult stem cells an trigger an immune response, SO the patient may need to take immunosuppressants
what are immuno-suppressants
IMMUNO - SUPPRESSANTS - drugs that SUPPRESS the immune system
