Cell Division And Cell Life Cycle Flashcards
Interphase- Synthesis (S)
The 2nd stage of interphase. This is when the DNA is replicated. The DNA is loosely organized in this stage.
Interphase-Gap 1 (G1)
The 1st stage of interphase. During this time the cell increases in size, and organelles increase in number.
Interphase-Gap 2 (G2)
The 3rd stage of interphase. The cell continues to grow.
Mitosis- Prophase (P)
1st step of mitosis. The DNA condenses into chromosomes. The nucleus breaks down. The centrioles begin to move to opposite sides of the cell, spindle fibers begin to form.
Mitosis- Metaphase (M)
2nd stage of mitosis. Spindle fibers attach to the centromere of the chromosomes which are in the center of the cell.
Mitosis- Anaphase (A)
3rd stage of mitosis. The chromosomes split into sister chromotids. The spindle fibers begin to shorten, pulling the sister chromatids to opposite sides of the cell.
Mitosis- Telophase (T)
4th stage of mitosis. Nuclear membranes start to form, chromosomes begin to uncoil, and spindle fibers fall apart.
Why do cells divide?
They need to efficiently diffuse materials (let then move in/out of the cell) AND they need to prevent DNA overload.
Cytokinesis-Animal Cell
The cytoplasm pinches, creates 2 new daughter cells, both are identical twins.
Cytokinesis- Plant Cell
Cell plate forms, forming a new cell wall
Homologous Chromosomes
Chromosomes that have the same structure, contain the same genes. One comes from each parent.
Crossing over
The exchange of chromosome segments between homologous chromosomes. This occurs during prophase 1.
Asexual reproduction (Binary fission)
The creation of offspring from a single parent and does not involve the joining of gametes. Produces two, roughly equal cells.
Sexual reproduction
The fusion of two gametes, resulting in offspring that are a mixture of both parents.
Meiosis
Makes diploid cells into haploid cells. Produces gametes. Creates genetic diversity. DNA does NOT replicate after Meiosis 1. In Meiosis 1 homologous pairs seperate, in Meiosis 2, chromosomes separate like in Mitosis.
