B2 cell division 1 Flashcards
What is a gene?
A short section of DNA that codes for a protein/controls a characteristic
What are chromosomes?
Structures in the nucleus that carry genes
How many chromosomes are in one human body cell (a somatic cell)?
46
Chromosomes are arranged in ___ pairs in a human body cell (a somatic cell)
23
How many percent of your chromosomes have you inherited from your father?
50%
Briefly describe the cell cycle
Cell content (including DNA) is replicated, mitosis occurs to make two genetically identical cells
Define ‘mitosis’.
Cell division that produces two genetically identical daughter cells
Which type of reproduction is based only on mitosis?
Asexual
State three key importances of mitosis
Growth, repair, asexual reproduction
Briefly describe the first stage in the cell cycle.
Cell size increase, DNA and organelle replication
Briefly describe the second stage (mitosis) in the cell cycle.
Nucleus divides - One set of chromosomes is pulled to each end of the dividing cell
Briefly describe the third stage in the cell cycle.
Cytoplasm and cell membrane divides into two daughter cells
What has to happen to the cell before mitosis to ensure we can two genetically identical daughter cells?
DNA and organelles must replicate before division
Define ‘differentiation’.
The process where a cell becomes specialised/adapted to perform specific functions
Define ‘stem cell’.
Undifferentiated cell with the potential to become specialised
