Understanding Unicellular Organisms Ms Aseel Samaro They both

Understanding Unicellular Organisms Ms. Aseel Samaro

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

Unicellular organism They differ from each other in: üTheir structure üHow they feed üHow they move

Unicellular organism / How they move § 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 feed § 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

List three ways unicellular organisms differ from each other. They may have either: üTails üTiny hairs üChloroplasts.

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. Prokaryotes

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.

§ 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 üSome bacteria take in chemicals from their environment, such as iron and sulfur, and use these as food üOthers contain chlorophyll and use sunlight to make their own food ümany 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: üMitochondria üChloroplasts üvacuoles. Examples of eukaryotes are: üEuglena (a type of algae containing chloroplasts) üYeast üAmoeba üParamecium 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 http: //www. youtube. com/watch? v=7 p. R 7 TNz. J_p. A http: //www. youtube. com/watch? v=N 9 p. Ccf. Gia. B 0 http: //www. youtube. com/watch? v=f. I 7 n. EWUjk 3 A

A paramecium Euglena

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.

Similarities Differences All have a cell membrane Prokaryotes Eukaryotes All have cytoplasm Do not have a nuclear membrane Have a nuclear membrane All contain genetic material Small big All can live independently Do not have chloroplast Have chloroplasts Do not have mitochondria Have mitochondria