B2 - Cell Division Flashcards
Chromosomes are found in….
Pairs
What is mitosis?
One division of a diploid parent cell to produce two genetically identical diploid daughter cells for growth and repair
What is meiosis
Two division of a diploid parent cell to produce four genetically non-identical haploid daughter cells for the formation of gametes.
How many chromosomes do you have?
46 (games have 23 ceach)
Stages of the cell cycle:
1) Before a cell can divide it needs to grow and increase the number of sub-cellular structures (ribosomes and mitochondria). DNA replicates to form two copies of each chromosome.
2) In mitosis one set of chromosomes is pulled to each end of the cell and the nucleus divides.
3) Finally the cytoplasm and cell membranes divide to form two identical 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 to protect from extinction?
- Crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for
farmers.
Problems with embryonic stem cells?
- Potential harm to embryo
- Ethical objections: As embryo cannot give permission it’s a violation of human rights
- Most come from aborted embryos or spare embryos from fertility treatment
- 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)
- Low chance of being 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
D. Cytokinesis?
the dividing of the cell at the last stage of mitosis
D. Chromosome?
a thread-like structure carrying genetic material
D. Mitosis?
Asexual cell division where 2 identical cells are formed
D. Chromatids?
duplicate chromosomes produced during mitosis
What is the function of stem cells from embryos?
Stem cells from human embryos can be cloned and made to
differentiate into most different types of human cells.
What is the function of stem cells from adult bone marrow?
Stem cells from adult bone marrow can form many types of cells including blood cells.
What is the function of stem cells from the meristem of plants?
Meristem tissue in plants can differentiate into any type of plant cell, throughout the life of the plant.
