B2: Cell Division Flashcards
How many chromosomes does body cells have and how many does gametes have?
Body cells-46 (23pairs)
Gametes-23
Stage 1 of the cell cycle
DNA is replicated to form 2 chromosomes. The cell grows and copy’s it’s internal features such as mitochondria/ribosomes.
Stage 2 of the cell cycle
Mitosis occurs and the pair of chromosomes is pulled to each end of the dividing cell. The nucleus divides.
Stage 3 of the cell cycle
The cytoplasm and cell membrane divides to form 2 identical daughter cells.
What is mitosis essential for
Mitosis is essential for growth and developing of multicellular organisms
Mitosis takes place when organisms repair itself
It occurs during asexual reproduction
Differation in animal cells
In early embryo stages of animal cells they differentiate and become specilsed such as nerve cells.
Embryonic stem cells can differentiate into any type of cell and can become specialised
Adult stem cells can only differentiate into some specialised cells but not all like embryonic stem cells can
Therputic cloning
The embryo is produced with the AMA genetic material as the patient so illnesses like paralysis can be cured easily as you don’t have to wait for a suitable donor
What’s the problem with stem cells
There is an orange ethical question as an embryo is potential life
How do plants differentiate
They can differentiate throughout their life and is done in the active site (between roots and shoots) called the meristem.
Mitosis happens there continually there
Can animal and plant cells be cloned, How?
Plants can be cloned from a tiny piece of plant tissue and can differentiate into any kind of cell, identical to the parent cells.
Animals cannot be cloned as they differentiate perminately in early life but they can artificially be cloned, either by embryo cloning or making adult stem cells into embryos and using that.
