B2 Cell Division Flashcards
What does the nucleus contain?
Chromosomes made of DNA.
What are chromosomes made of?
DNA.
What happens during the cell cycle?
The genetic material is doubled & 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 followed by cell division.
What happens to a cell in stage 1 before it divides?
It needs to grow and increase the number of sub-cellular structures such as ribosomes & mitochondria. The DNA replicates to make two copies of each chromosome.
What happens to the nucleus during mitosis?
One set of chromosomes is pulled to each end of the cell & the nucleus divides.
What happens in stage 3 of the cell cycle after mitosis?
The cytoplasm & cell membranes divide to make two identical cells.
Why is cell division by mitosis important?
Needed for growth and development of multicellular organisms.
What is a stem cell?
An undifferentiated cell which is able to differentiate and divide to form lots of cells of the same type.
What are meristems?
Plant stem cells that can differentiate into any type of plant cell throughout the life of the plant.
What can plant stem cells be used for?
The can be used to make clones of plants quickly and economically.
What are the advantages of embryonic stem cells?
Can develop into most other types of cels, each cell divides every 30 minutes, low chance of rejection & painless.
What are the disadvantages of embryonic stem cells?
Cause death to the embryo, unreliable and the embryos can’t give consent.
What are the advantages of adult stem cells?
Permission can be given to collect stem cells and they are safe.
What are the disadvantages of adult stem cells?
Risk of infection from operation, painful to donate stem cells and few types of cells.
Why do some scientists have concerns about the use of stem cells?
Could cause cancer.
What are the sources of adult stem cells?
Bone marrow, umbilical cord, blood & skin.
Why might stem cells from embryos be more useful than adult stem cells?
Because more types of cells.
What happens during the process of therapeutic cloning?
An embryo is produced with the same genes as the patient.
What are the advantages of therapeutic cloning?
May cure diseases, produce replacement cells, treat diabetes & paralysis. Cells unlikely to be rejected, cells and tissues of any kind can be made, many cells are produced and reduces waiting time for transplants.
What are the disadvantages of therapeutic cloning?
Potential life is killed, shortage of egg donors, may transfer viral infection, poor success rate.
Why do most organisms have an even number of chromosomes in their body cells?
Chromosome come in pairs.
