Cell: Activities.

- Activity 4:

· Search what procaryotic and eucaryotic cells have in common.

- Both have DNA as their genetic material (it’s DNA that tells cells what kind of cells they should be).

- Both are covered by a cell membrane.

- Both contain RNA.

- Both are made from the same basic chemicals: carbohydrates, proteins, nucleic acid, minerals, fats and vitamins.

- Both have ribosomes (the structures on which proteins are made).

- Both regulate the flow of the nutrients and wastes that enter and leave them.

- Both have similar basic metabolism (life processes) like photosynthesis and reproduction.

- Both require a supply of energy.

- Both are highly regulated by elaborate sensing systems ("chemical noses”) that make them aware of the reactions within them and the environment around them.

· What are the differences?

- Structural Differences

Eukaryotic cells contain two important things that prokaryotic cells do not: a nucleus and organelles (little organs) with membranes around them.

- DNA arrangement

Although both eukaryotic and prokaryotic cells contain DNA, the DNA in eukaryotic cells is held within the nucleus. In prokaryotic cells, the DNA floats freely around in a unorganized manner.

- Size

Eukaryotic cells are, on average, ten times larger than prokaryotic cells.

- Cell wall diferents

Prokaryotic cells have a cell wall composed of peptidoglycan (amino acid and sugar). Some eukaryotic cells also have cells walls, but none that are made of peptidoglycan.

- Age differences

- 4.6 billion years ago the Earth was formed
- 3.5 billion years ago the first life arose: prokaryotic bacteria
- 1.5 billion years ago eukaryotic cells arose
- 0.5 billion years ago the Cambrian explosion – multi-celled eukaryotes arose
- 3 million years ago our earliest ancestors, the hominids, appeared