B2 - Cell Division Flashcards
What does the nucleus contain?
Chromosomes made of DNA
What happens during the cell cycle?
Genetic material is doubled and then divided into two identical cells
How many stages are there of the cell cycle?
3
What are the stages of the cell cycle?
Growth, mitosis and cytokinesis
What happens in stage 1?
- The cell grows bigger
- DNA + chromosomes replicate/duplicate
- Ribosomes and mitochondria increase
What happens to the nucleus during mitosis?
- One set of chromosomes is pulled to each end of the cell(spindle fibres)
- Nucleus divides into two
What happens in stage 3?
- Cytoplasm and cell membrane divide to form two identical daughter cells
What is a stem cell?
An undifferentiated cell that can develop into one or more types of specialised cells
What can adult stem cells do and an example?
Can differentiate into certain types of cells(e.g bone marrow, umbilical cord, blood and skin to blood cells)
What are 3 advantages of adult stem cells?
- Consent can be given
- Quick recovery for donors
- Relatively safe
What are 3 disadvantages of adult stem cells?
- Requires a donor so can take time
- Risk of infection from operation
- Only certain types of cells
What can embryonic stem cells do and an example?
Can differentiate into any specialised cells in body(egg early human embryos)
What are 3 advantages of embryonic stem cells?
- Treat wide range of diseases
- No donor needed
- Grow whole replacement of organs
What are 3 disadvantages of embryonic stem cells?
- Ethical issues - potential human life
- Viral infections
- Under-researched
What are can plant meristem do and an example?
Can differentiate into all cell types of whole plants (e.g meristem regions in the shoots)
What are 3 advantages of plant meristem?
- Rare species cloned to prevent extinction
- Large amount of disease resistant
- Fast + low cost
What are disadvantages of plant meristem?
- Genetically identical, whole crop at risk of being destroyed by one disease
Why are stem cells useful?
- May be able to help conditions such as diabetes and paralysis.
Why are there concerns about the use of stem cells?
- Could cause viral infection, cancer, ethical and religious objections
What happens during therapeutic cloning?
An embryo is produced with the same genes as the patient
What are advantages of therapeutic cloning?
- Can cure diseases
- Cells unlikely to be rejected
- Many cells produced - reduced wait time for transplant
What are disadvantages of therapeutic cloning?
- Potential life is killed, shortage of egg donors
- Viral infection
- Poor success rate
