B2 - Cell Division Flashcards
(16 cards)
Why must cells divide?
Growth, repair and replacement of cells
What is in the nucleus of a cell?
Chromosomes
How many chromosomes do human, adult, body cells contain?
46 (23 pairs)
What happens in the first stage of the cell cycle?
- Cell grows and increases the number of sub-cellular structures
- DNA replicates to form two copies of each chromosome
What happens in the second stage of the cell cycle? (after organelles double)
- One set of chromosomes is pulled to either end of the cell
- Nucleus divides
What happens in the final stage of the cell cycle? (after nucleus divides)
- Cytoplasm and cell membranes divide to form two identical cells
What is mitosis?
The division of cells to form two identical daughter cells
What is a stem cell?
An undifferentiated cell that can produce specialised cells and more stem cells
What are the uses of embryonic stem cells?
They can be cloned and made to differentiate into most different human cells
What are the uses of stem cells from adult bone marrow?
They can form many types of cells
What are the uses of meristem tissue?
It can differentiate into any type of plant cell
What conditions can be treated with stem cells?
Diabetes and paralysis
What is therapeutic cloning?
When an embryo is produced with the same genes as the patient
What is the point of therapeutic cloning?
Stem cells from the embryo won’t be rejected by the patient as they have the same genes
What are objections to using stem cells?
- Risk of viral infection
- Ethical objections
- Religious objections
Why would plants be cloned?
- To save a rare species from extinction
- To replicate crops with special features - disease resistance
