In the previous lesson you where expected to be able to draw and label animal, plant and bacterial cells. Now, its time to add the functions of the organelles...

You have to know the structure of a prokaryotic cell and the structure and function of a Eukaryotic cell (you must be able to compare and contrast the differences between prokaryotic & eukaryotic cells too).

Eukaryotic cells are more complex than prokaryotic cells, and include all animal and Plant cells. Eukaryotic cells have different Organelles, e.g True nucleus, larger ribosomes, and mitochondria… on the other hand Prokaryotes (bacteria) are smaller and simpler than Eukaryotes with no membrane bound organelles.

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Eukaryotes have membrane bound organelles, where important cellular functions take place. You’ll need to know the structure and function of a generalised plant cell, a generalised animal cell and a few examples of specialised animal cells like sperm, liver and muscle.

The Nucleus

The nucleus contains the genetic information of the cell in multiple strands of DNA and protein (chromosomes). The nucleus contains genes that control the eukaryotic cell.

The nucleus: contains DNA. Key functions are – replication, cell division, & protein synthesis. 

In a eukaryotic cell its DNA is linear & attached to proteins called histones.

Ribosomes: “Site of protein synthesis” - Small & dense structure NO membrane.

Mitochondria are found in almost all eukaryotic cells and are responsible for generating most of the ATP (energy currency).

Specialised cells: - sperm cell, red blood cell, muscle cell and liver cell. These specialised cells are very active and require lots of energy. so, they have many mitochondria which provides the ATP (energy currency) generated from cellular respiration.

Plant cells ad a few additional things you need to know...

Chloroplasts are the sites of photosynthesisand are found only in the cells of plants and green algae - which have chloroplasts.

Chloroplasts are where photosynthesis occurs, and chloroplasts contain a green substance called chlorophyll.

Inside the plant cell is a permanent vacuole containing cell sap – a weak solution of sugars and salts.

The cell wall a tough, flexible, (sometimes fairly rigid) layer, located external to the cell membrane.

So you know what a Prokaryote is (a cell without a true nucleus).

Did you know that Prokaryotes are Bacteria?

Biologist like to classify and categorise things... and a Prokaryotic cell is just the biological classification for all bacterial cells. So, all bacteria are prokaryotes and all prokaryotes are bacteria! 

Bacteria (prokaryotes) are single celled organisms.

For example: Escherichia coli (E. coli) is a species of bacteria that is commonly found living in the intestines of people and animals. E. coli is a single cell, which is "rod" shaped. Under certain conditions E. coli can become pathogenic (which means it has the potential to cause disease). 

So, a pathogen is an organism that can cause disease - and the pathogenic strains of E. coli cause food poisoning and diarrhoea (sometimes called travellers diarrhoea)

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