1.4 - Cell Division Flashcards
Why do all Multicellular Organisms require a continuous supply of new Cells?
- Growth
- Development
- Repair
What are the 3 Stages of the Cell Cycle?
- Growth
- DNA Replication + Mitosis
- Division (Cytokinesis)
What happens in the Growth stage of The Cell Cycle?
- The Cell Grows in Size.
- The number of sub-cellular structures (e.g. Mitochondria & Ribosomes) Increase.
What happens in the DNA Replication Stage? (M)
- The DNA is Duplicated
- So each new cell has a full set of DNA.
How is the DNA placed in a Cell that is not Dividing?
- Spread out into Long Strings.
When a Cell starts to Prepare for Division, what happens to the DNA?
- DNA Condenses into Chromosomes.
What are Chromosomes?
- Coiled up packets of DNA.
What does the DNA in Chromosomes contain?
- A large number of Genes.
- These control the Development of different Characteristics.
What are the two copies of Chromosomes called?
- A ‘Pair’.
- One copy is from mother, other copy is from father.
How many Chromosomes do Humans have?
- 23 Pairs
- 46 Singular
When each Chromosome is Duplicated what happens?
- Each Duplicate stays attached to the original, forming an X Shape.
What is each half of the Duplicated Chromosome called?
- An Arm
What happens when a Cell is ready to Divide?
1 ) All of the Cell’s Chromosomes line up along the centre of the Cell.
2 ) Cell fibres from both sides of the cell attach to their respective half of each Chromosome.
3 ) Cell fibres pull the arms of the Chromosomes to opposite sides of the cell (Poles).
4 ) The Chromosomes are broken in half into two separate arms.
What happens during the final stage of The Cell Cycle (Cytokinesis)?
- The Cell Membrane and Cytoplasm pull apart forming two genetically identical Daughter Cells.
What is the Definition of Binary Fission?
The Process by which Prokaryotic Organisms Divide and Reproduce.
