CELLS - CELL DIVISION Flashcards
(16 cards)
What are 2 uses of mitosis?
- For growth & repair of human cells
- Embryonic development
- Asexual development
What is mitosis?
The formation of 2 new identical daughter cells from an original cell
What is created through meiosis?
4 genetically unique daughter cells
- Each have half the number of chromosomes as the parent cell
What is the cell cycle?
Process of cells that divide multiple times
- Starts with a cell that has been produced by mitosis and ends with the cell ready to divide again
Where do specialized cells and stem cells move from?
From G1 into G0 (resting phase) - can be temporary
Where is majority of the cell cycle spent in?
Interphase
- Cell is growing and DNA is replicated
- DNA is uncondensed and replicated - amount of DNA is doubled
- Organelles are replicated
- Amount of ATP produced is increased as energy is required for cell division
What are 3 stages in interphase?
- G1 phase: Cell elongates and new organelles & protein are made
- S (synthesis): Cell replicates its DNA - essential before the cell can divide
- G2 phase: Cell keeps elongating & proteins needed for cell divison are made
What is mitosis?
Formation of 2 new identical daughter cells from an original cell
What is cytokenisis?
Final stage where the cytoplasm divides and 2 separate genetically identical cells are formed
- Cells will now start interphase to prepare for the next round of mitosis
Simplified explanation of what occurs in interphase
- DNA unravels and replicates
- Organelles replicate
- ATP increases
Why is mitosis necessary?
- It replaces damaged/old cells and is how organisms grow and repair
- Asexual production
EQ: Mitosis is important in the life of an organism, give 2 reasons why
CELL CYCLE
- Process of the formation of clones of white blood cells in a immune response
- Process for **growth and repair of tissues **
EQ: Meiosis occurs during the life cycle of organisms, what is the importance?
CELL CYCLE
- It creates variation by** crossing over** (non sister chromatids exchanging genes) and independent assortment.
- It creates haploid gametes, which fuse during fertilisation to produce diploid cells with a constant number of chromosomes.
EQ: What phase does DNA replication take place?
CELL CYCLE
S-phase
EQ: Using knowledge of the cell cyle, explain why some cells had 8.4 units of DNA while others had 4.2 units of DNA
CELL CYCLE
- Cells with 8.4 units of DNA would’ve went through late interphase whereas
- Cells with 4.2 untis of DNA would’ve went through early interphase
EQ: Cells lining the intestine complete the cell cycle in a short time, explain an advantage of this
CELL CYCLE
It can replace damaged cells quickly
