B2 - Cell Division Flashcards
Chromosomes are found in….
Pairs
D. Meiosis
2 stage process of cell division that reduces the chromosomes of daughter cells. It is involves in making gametes for sexual reproduction
How many chromosomes do you have?
46 - 23 pairs
Stages of the cell cycle:
1: longest. Grows bigger-increases mass, replicate DNA form 2 copies of each chromosome. Increase number of sub-cellular structures (eg. Mitochondria)
2: mitosis - each set of chromosomes are pulled to a different end of cell = nucleus divides.
3: cytoplasm and cell membranes divide to form 2 identical daughter cells.
When do most types of animal cells differentiate?
At an early stage of development.
D. Differentiation.
The process where cells become specialised for a certain function.
D. Zygote?
When the egg and sperm fuse.
2 types do stem cells?
Embryonic and adult
Where are adult stem cells from?
Bone marrow
Uses of stem cells in humans?
• Treatment of paralysis and spinal injuries
• Treatment of diabetes
• Restoration of eyesight
• Bone damage and cartilage
• Heart damage after a heart attack
Uses of stem cells in plants?
• Clones of the mature plant can be grown very quickly and economically
• Large numbers of rare plants can be produced - save from extinction?
• Produce large quantities of cloned plants with disease resistance
Problems with embryonic stem cells?
• Most come from aborted embryos or spare embryos from fertility treatment
• As embryo cannot give permission it’s a violation of human rights
• Developments are slow, expensive and hard to control
• May cause cancer
• Trigger an immune response
How are scientists overcoming ethical issues with embryonic stem cells?
Taking them from the umbilical cord and amniotic fluid.
Advantages of embryonic stem cells? (4)
- Wont be rejected by patient
- Many cells can be produced
- reduce waiting time for organ transplants
- Cells and tissues of any type could be produced
D. Allele?
a version of a particular gene
