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 and then divided into 2 identical cellls
How many stages are there of the cell cycle?
3
What are the stages of the cell cycle?
Growth, mitosis, 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 and mitochondria. The DNA replicates to make 2 copies of each chromosome
What happens to the nucleus during mitosis?
1 set of chromosomes is pulled to each end of the cell and the nucleus divides
What happens in stage 3 of the cell cycle after mitosis?
The cytoplasm and cell membrane divide to make 2 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 can 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?
They 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 cells, each cell divides every 30 minutes, low chance of rejection and painless
What are the disadvantages of embryonic stem cells?
Cause death to the embryo, unreliable and the embryos cant 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?
Become 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 and paralysis
Cells unlikely to be rejected
Cells and tissues of any type can be made
Many cells are produced
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?
Chromosomes come in pairs
