The Cell Heba Al-Tamimi 

Discovery of Cells The first scientist to look at cells under a microscope was the English scientist Robert Hooke

Common feature in all cell: Plasma membrane :the border of cell and function to regulate passage of materials into and out of cell Nucleus :region contain genetic material Cytoplasm :the components enclosed by the plasma membrane

Two Cell types Prokaryotic Cells do not have an organized nucleus surrounded by an envelope and are relatively small (1-10 um) compose two domains Eubacteria and Archaebacteria Eukaryotic Cells are much larger and have an organized nucleus enclosed by a nuclear envelope Eukarya forms 4 kingdoms :the animals ,plants ,protists and fungi

Common ancestor Archaea Eubacteria Eukaryota Protista Kingdom Fungi Kingdom Plant Kingdom Animal

Eubacteria (Prokaryotes)

Three fundamental bacterial cell shapes Cocci Bacilli Spirilli Exe 4-1 Three fundamental bacterial cell shapes Cocci Bacilli Spirilli

bacteria in yoghurt Exe 4-2 Yogurt is a nutrient-rich culture of lactic acid bacteria such as lactobacillus These bacteria live on lactose (milk sugar) and converts milk to yogurt To observe bacteria in yogurt the following procedure is employed Place a very small amount of yogurt on slides by using tooth pick , spread yogurt by using other slide (smear) Add one drop of methylene blue to the yogurt and place the cover slip Observed under microscope

Cyanobacteria Photosynthetic prokaryotes Live in aquatic environment Exe 4-3 Photosynthetic prokaryotes Live in aquatic environment E.x : Anabaena Is filamentous organism and each filament is composed of long chains of greenish cells

Eukaryotic cells The nucleus is separated from the rest of the protoplasm by a double membrane (nuclear envelope)

Human cheek cells (animal cell) Exe 4-4 The lining inside your mouth is composed of many cell layers that serve to protect your body by forming a barrier

Human skin cells (animal cells) Exe 4-5 Microscope

Onion epidermal cells The onion is an underground ,storage structure made up of thickened modified leaves called scales.

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