Cell Division Flashcards
Where are chromosomes found?
In the nucleus
What are chromosomes made of?
Genes
What is mitosis?
A type of cell division where cells divide to form two identical daughter cells.
Describe stage 1 of mitosis.
- Cell grows bigger
- DNA replicates (chromosomes replicated)
- Increase in the number of sub-cellular structures such as ribosomes and mitochondria
Describe stage 2 of mitosis.
- A complete set of chromosomes is pulled to opposite poles of the cell by spindle fibres
- The nucleus divides to form 2 nuclei
Describe stage 3 of mitosis.
- Cytoplasm and cell membrane divide to form two identical daughter cells
What is a stem cell?
An undifferentiated cell that can differentiate into one or more types of specialised cell.
Name 3 types of stem cells.
Adult stem cells, embyronic stem cells, plant meristem
Where are adult stem cells found?
Specific parts of the body in adults and children (e.g: bone marrow)
What types of cells can adult stem cells differentiate into?
Only certain types of cells (e.g: bone marrow stem cells can only differentiate into types of blood cells)
Name 2 advantages of adult stem cells.
- Less ethical issues - adults can consent to having their stem cells removed
- It is an established technique for treating diseases such as leukemia
- Relatively safe and donors recover quickly
Name 2 disadvantages of adult stem cells.
- Requires a donor - people may need to wait a while to find someone suitable
- Can only differentiate into different types of cells so can treat fewer diseases
Where are embyronic stem cells found?
Early human embyros
Name 2 advantages of embyronic stem cells.
- Can treat a wide range of diseases
- May be possible to grow whole replacement organs
- Usually no donor needed
What type of cells can embyronic stem cells differentiate into?
Any type of cell (e.g: a nerve cell or muscle cell)
Name 2 disadvantages of embyronic stem cells.
- Ethical issues - embyro destroyed, can’t consent
- Risk of transfer of viral infections to patients
- Newer treatment so less research
Where are meristem stem cells found?
Plant meristems
What types of cells can meristem stem cells differentiate into?
All types of cells - can create whole clones of plants
Name 2 advantages of meristem stem cells.
- Can prevent the extinction of rare species of plants
- Plants with desirable traits can be cloned to produce many identical clones
- Fast and low-cost production of large numbers of plants
Name 1 disadvantage of meristem stem cells.
Cloned plants are genetically identical - whole crop could be destroyed by a single disease or genetic defect
What is therapeutic cloning?
A type of cloning where cells from a patient’s body are used to create a cloned early embryo of themselves.
What are 2 advantages of therapeutic cloning?
- Stem cells from embryo can be used for medical treatments, growing new organs.
- Stem cells have same genes as patient so are less likely to be rejected.
What is the purpose of mitosis?
Growth and repair of cells, asexual reproduction
