Ms. Aseel Samaro Understanding Unicellular Organisms

 They both move by rotating and disturbing the fluid around them  Some bacteria move by whipping and rotating their flagella (their tail- like structure)  This is similar to how the propeller on speedboat motor works.

 Unicellular organisms are made up of just one cell.  They carry out all the life processes needed to exist independently. Unicellular Organisms

They differ from each other in: Their structure How they feed How they move Unicellular organism

 Some have developed tiny hairs to help them move, so they can find food or escape from predators.  Some are themselves predators and will devour other unicellular organisms. Unicellular organism / How they move

 Algae are ­plant-­like unicellular organisms containing chloroplasts and make their own food. ­  Animal-­like unicellular organisms take in food through their cell membrane.  ­Fungus-­like unicellular organisms are called yeasts. They have a cell wall but cannot make their own food Unicellular organism / How they feed

List three ways unicellular organisms differ from each other. They may have either: Tails Tiny hairs Chloroplasts.

An amoeba can carry out all life processes

Name Two different unicellular organisms 1.Algae 2.yeasts

Unicellular organisms can be classified into two main groups: Prokaryotes Eukaryotes. Eukaryotes. Prokaryotes

 Prokaryote means ‘before life’ – prokaryotes are thought to be the first organisms to live on Earth.  They do not have a nucleus, and their genetic material floats within the cytoplasm.  They can be up to 200 times smaller than eukaryotes. Prokaryotes

 Bacteria are examples of prokaryotes: 1.They come in different shapes and sizes 2.Live in different environments 3.Have a range of food sources Some bacteria take in chemicals from their environment, such as iron and sulfur, and use these as food Others contain chlorophyll and use sunlight to make their own food many can absorb nutrients from their environment. 4.Bacteria can be found in extreme conditions, from ­under-­sea volcano vents to places with temperatures are below freezing.

A bacterium has no nucleus and no mitochondria.

Eukaryotes contain a nucleus, surrounded by a nuclear membrane. They also contain many organelles ( which prokaryotes do not ), including: Mitochondria Chloroplasts vacuoles. Examples of eukaryotes are: Euglena (a type of algae containing chloroplasts) Yeast Amoeba Paramecium The last two are types of protozoa. Eukaryotes

 Eukaryotes can be up to 200 times bigger than prokaryotes and often have external features to help them to survive.  Amoeba can move around because its cytoplasm can flow  Paramecium has cilia that beat and enable it to move  Euglena has a flagellum, or tail, to enable it to move Eukaryotes

A parameciumEuglena

How does euglena get its food?  It contains chloroplasts to make its own food using sunlight  it has a tail to help it move towards the light.

Summarise, in a table, the main similarities and differences between unicellular organisms.

SimilaritiesDifferences All have a cell membrane ProkaryotesEukaryotes All have cytoplasmDo not have a nuclear membrane Have a nuclear membrane All contain genetic materialSmallbig All can live independentlyDo not have chloroplastHave chloroplasts Do not have mitochondriaHave mitochondria