Cells PDF

Cells 6.4 ALL ORGANISMS HAVE CELLS THAT SPECIALISE  In this topic, you will learn that all cells can be broken into two groups, prokaryotes and eukaryotes. prokaryotic cells (bacteria) do not have organelles or a nucleus. eukaryotes have a nucleus and different organelles that ar...

Cells 6.4 ALL ORGANISMS HAVE CELLS THAT SPECIALISE  In this topic, you will learn that all cells can be broken into two groups, prokaryotes and eukaryotes. prokaryotic cells (bacteria) do not have organelles or a nucleus. eukaryotes have a nucleus and different organelles that are used to divide them into Kingdoms  Key Points:  prokaryotic cell: primitive single-celled organism that has no nucleus.  eukaryotic cell: complex cell that contains a nucleus and membrane- bound organelles.  Prokaryotes and eukaryotes: Cells are classified into two main groups: prokaryotic cells and eukaryotic cells. 1- Prokaryotic cells belong in the kingdom Monera. They are the most primitive cellular forms on Earth and are unicellular (single cells). They are much simpler than eukaryotic cells and do not have many of the organelles described in the previous topic. For example, they have no nucleus and their genetic material (DNA) is found free in the cytoplasm. Prokaryotes include all the bacteria found on Earth. 2- Eukaryotic cells are more complex cells and are found in organisms from each of the other four kingdoms – Animalia, Plantae, Fungi and Protista. Eukaryotic cells keep their genetic material in a nucleus and have the membrane- bound organelles. Most eukaryotes are multicellular.  Plant cells When we look at whole organism plants and animals, it’s fairly easy to see that they are different. However, once microscopes started to become more powerful, scientists could see differences between the individual plant and animal cells. Plant cells use their chloroplasts to photosynthesise and need cell walls to provide structure. Many plant cells also store their nutrients in large vacuoles (large spaces surrounded by a membrane)  Fungal cells Fungi such as mushrooms are often mistaken for a type of plant. Using a microscope, scientists are able to see that fungal cells are different from plant cells. For example, fungal cells don’t have chloroplasts, so they cannot photosynthesise, and they don’t have large vacuoles filled with liquid. Instead of making their own glucose, fungi such as mushrooms need to absorb their nutrients from the soil.  Protists Protists (Kingdom Protista) are a mixed group of organisms that are mostly unicellular (the whole organism is made up of just one cell). Many live in water, some are photosynthetic (they make their own food, like plants), some eat other organisms and some cause diseases. Depending on where it lives and its food sources, a protist’s shape or structure will have evolved to suit its environment.  Animal cells Single-celled or unicellular organisms, such as bacteria, are made of one cell only. Multicellular organisms, like us, are made of more than one cell and often many billions of cells. The different cells in a multicellular organism communicate and work together to produce a functioning organism. Their different roles in the body mean they have different sizes and shapes. All animal cells have a nucleus and organelles, but no chloroplast or cell wall. https://www.oxforddigital.com.au/goto/OB599/resources/TR-OB599- B01-0028-resource-120.html?idp=1dzvrpmt