Mitosis

Three stages of interphase

G1, S, G2

What happens in the S phase

DNA is replicated - each chromosome replicates into two identical sister chromatids, which are joined together by a centromere

Apart from DNA replication, what happens in interphase

Cell grows, volume of cytoplasm doubles, cell replicates organelles and synthesises proteins

What happens in prophase

• Chromosomes condense and become visible

• Centrioles replicate and move to poles

• Nuclear membrane disintegrates

• Nucleolus disappears

What happens in metaphase

• Spindle fibres form and form the spindle

• The spindle fibres attach to the chromosomes using the centromeres

• Chromosomes align along the equator of the cell

What happens in anaphase

• Spindle fibres shorten and contract

• Centromere divides

• Sister chromatids are pulled towards the poles

What happens in telophase

• Chromosomes reach poles and become indistinct

• Nuclear envelope reforms

• Nucleolus reforms

• Spindle disintegrates

How do drugs treating cancer usually work

• Prevent DNA from replicating

• Inhibit metaphase in mitosis by interfering with spindle formation

Cytokinesis

Division of the cytoplasm

How to bacteria reproduce

Binary fission

What does binary fission involve

• Replication of circular DNA and plasmids

• Cell membrane begins to grow between the two DNA molecules and begins to pinch inwards, dividing the cytoplasm into two

• A new murein cell wall forms between the two molecules of DNA, dividing the original cell into two identical daughter cells, each with a single copy of the circular DNA and a variable number of copies of plasmids

Differences between DNA in eukaryotic cells and prokaryotic cells

Eukaryotic DNA is linear (not circular), longer, and associated with histone proteins

Name for non-condensed, histone-associated DNA

Chromatin