Chromosomes and mitosis

What are chromosomes?

Coiled up legnths of DNA molecules

What do chromosomes contain?

A nucleus with DNA (genetic information) inside. These control the development of different characteristics.

How many chromosomes do body cells usually have?

2: one from the mother and one from the father

What are diploid cells?

cells containing 23 pairs of chromosomes

What are Haploid cells?

Cells containing 46 pair of chromosomes

What is the Cell Cycle?

The processes where cells divide to produce new cells.

Which processes do Eukaryotics and Prokaryotics use to divide?

Eukaryotes: Mitosis

Prokaryotes: Binary Fission

What happens during the Prophase?

• Chromosomes condense, making them visible - replicates the DNA

• Nuclear envelope (the membrane around the nucleus) breaks down

• centrioles (a type of protein) starts forming spindle fibres

• The cell grows in size and increases the amount of subcellular structures such as mitochondria and ribosomes.

What happens during the Metaphase?

• Spindle fibres attach to the centromere of the chromosomes

• The chromosomes align in the middle of the cell.

What happens during the Anaphase?

• When the cell splits, they become sister chromatids

• spindle fibres contracts

• centromeres divide

• Sister chromatids are pulled to opposite ends of the cell

What happens during the Telophase?

• Chromatids become uncondensed - they are not visible anymore

• nuclear membrane forms around the chromosomes - these become the nuclei

• cell membrane form around the nuclear memebrane

• The cytoplasm divides during cytokinesis (the process of dividing cytoplasm) and cell surface membrane separates the two cells.

What is produced during Mitosis?

Two identical daughter cells.