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General Biology lab Lab 4 The Cell (Part A( Definition • The word cell comes from the Latin word "cella", meaning "small room". • The cell – is the basic unit of all living things • They are often referred to as "the building blocks of life". Characteristics Of Cell Several characteristics that are common to all cells, such as the presence of a cell membrane, Cytoplasm, DNA, Ribosomes, not all cells are the same. Cells arise from other cells through cellular division. Cells carry genetic material passed to daughter cells during cellular division. All organisms are composed of one or more cells. Prokaryotic cell Eukaryotic cell Smaller and simpler Bigger and complex The nuclear material is not envelope by nuclear membrane Genetic material is enclosed by nuclear membrane . Lack of many organelles Contain organelles Eubacteria and Archeabacteria Plant , Animal , Fungi and protists Single cell Multicellular Ribosomes 70s 10 µm in size 30s +50s Ribosomes 80s 100 µm in size 40s+60s Bacteria – are microscopic, single celled prokaryotic cells. Habitat of bacteria – Bacteria can be found virtually everywhere. – They are in the air, the soil, and water, and in and on plants and animals • Some bacteria cause disease, but most are actually helpful. • Because of their small size, it is impossible to see details inside bacterial cell with the light microscope. • Shape of bacteria 1. Rods 2. Sphere 3. Spirals • They generally consist of • Plasma membrane : – The laminar structure that surrounds the cytoplasm of all cells . • DNA – This single chromosome is located in a region of the cell called the nucleoid • Ribosomes – This organelle is where the last stages of protein synthesis take place. • Flagella – Some bacteria also have tail-like structures called flagella help bacteria move. • Cell wall – made of peptidoglycan ,keeps the cell from exploding if it absorbs too much water. The flagella are attached to it. • The cytoplasm – The region located between the plasma membrane and the nucleus. It contains fluid with organelles. Bacteria in yogurt Kingdom Protista • Include protozoa and algae . • protozoa – Protozoa in Greek mean first animal . – Unicellular eukaryotes – Include Rhizopoda , Euglenozoa , Ciliphora . Rhizopoda (Amoeba) Amoeba Microscopic single celled(Unicellular) organisms that possess pseudopods. Habitat of Amoeba Free living organism found in fresh water . Amorphous cell is a type of cell or organism which has the ability to alter its shape. Lacks a rigid outer cell wall . The nucleus in the center of the cell . Movement – Move by pseudo pods (false feet) – Pseudo pods are the temporary protrusion formed by streaming of cytoplasm . Nutrition – Pseudopods can also be used to engulf food in a process called phagocytosis Euglenozoa (euglena) Euglena • Genus of single-celled flagellate protists • that possess eye spot (photoreceptor) is located near the site flagellum. • Movement – Move by flagellum (it is a long, thin, whip-like projection that is used for locomotion). • Nutrition – This genus can be both autotrophic and heterotrophic (Mixotrophic ). – These cells contain chloroplasts for photosynthesis and they may also engulf food by phagocytosis when light not available Ciliphora (paramecium) • Is a genus of unicellular ciliated protozoan • Known as “slipper animalcules” • Have two nucleolus Habitat of paramecium • Paramecia are widespread in freshwater, brackish, and marine environments and are often very abundant in ponds. • Movement – Paramecia propel themselves by whiplash movements of their cilia. – Cilia : hair-like structures which are arranged in tightly spaced rows around the outside of their body • Nutrition – They get their nutrients through phagocytosis.