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Overview of the cell

Overview of the cell. Paramecium. Human Cheek Cells. Onion Cells. Biology 20. Before we could see cells. There had to be the microscope! Early lens makers (often physicists) allowed for the study of microbiology. The first people to see cells.

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Overview of the cell

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  1. Overview of the cell Paramecium Human Cheek Cells Onion Cells Biology 20

  2. Before we could see cells.. • There had to be the microscope! • Early lens makers (often physicists) allowed for the study of microbiology

  3. The first people to see cells... • Robert Hooke - He was looking at cork and noted that he saw a “great many boxes” (1665). • Anton van Leeuwenhock– observed living cells in pond water. He called these “animalcules”. (1673)

  4. The first people to see cells... • Theodore Schwann- observed that the tissues of animals had cells (1839) • MattaisSchleiden– observed that plants contained cells (1845) • Rudolf Virchow – every living thing is made up of cells (1850)

  5. The Cell Theory • Every living organism is made of one or more cells. • The cell is the basic unit of structure and function. It is the smallest unit that can perform life functions. • All cells arise from pre-existing cells.

  6. Question for you... • Why is the Cell Theory called a Theory and not a Fact?

  7. Main Points • All organisms are made up of cells. They can be: • Unicellular (1 cell) • OR multicellular (many cells) • In unicellular organisms all life functions are carried out by a single cell. • In multicellular organisms, cells specialise to perform specific functions – division of labour.

  8. Cells as seen with a microscope • Living protoplasm surrounded by surface membrane (& non-living cell wall in plants). • The living material between the nucleus and the cell surface membrane is known as cytoplasm. • Cytoplasm contains variety of cell organelles.

  9. Two main types of cells

  10. Prokaryotic Cells • Very simple cells, probably first to inhabit the earth. • Do not contain a membrane bound nucleus. Their nucleus material (DNA) lies free in a region known as nucleoid. • Example: Bacteria. DNA of bacteria is circular. • The word "prokaryote" means "before the nucleus"

  11. Eukaryotic Cells • More advanced cells. • Possess true nucleus and nucleus material are found inside the nucleus surrounded by the two membranes, i.e nucleus envelope. • Example: plant cell, animal cell.

  12. Eukaryotic Cells 4 main parts: • cell membrane - outer boundary • cytoplasm - jelly-like fluid interior • nucleus - the "control center”, contains the cell's DNA (chromosomes) • organelles - "little organs" that carry out cell functions

  13. Organelles in Animal & Plant Cells Animal Cell Plant Cell

  14. Differences in Animal & Plant Cells Found only in Animal Cells Found Only in Plant Cells • Lysosomes • Cell Wall • Chloroplasts • Chromoplasts/Amyloplasts

  15. Prokaryotic versus Eukaryotic Cells

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