Questions and Answers
What term did Robert Hooke use to describe the small units he observed in cork?
Cellulae
Who first described cells?
Robert Hooke
What did Antoine van Leeuwenhoek refer to the first living cells as?
Animalcules
Which of the following scientists contributed to the Cell Theory?
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What is a defining feature of Prokaryotic cells?
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All living things are made up of cells.
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What is the function of ribosomes in a cell?
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What does the endosymbiotic theory explain?
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The ______ is the basic unit of life.
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What structure is responsible for the protection and shape of prokaryotic cells?
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Study Notes
Discovery of the Cell
- The microscope's invention was pivotal for cell discovery.
- Robert Hooke, an English physicist, first described cells in 1665 through observations of cork using his self-built microscope.
- The term "cellulae" from Latin means small rooms, which Hooke used to describe the structures he observed.
- Antoine van Leeuwenhoek, a Dutch scientist, discovered the first living cells in 1676, referring to them as "Animalcules," earning the title Father of Microbiology.
Development of Cell Theory
- Matthias Schleiden, a German botanist, concluded in 1838 that all plants consist of individual cells.
- Theodor Schwann, in 1839, reported that all animals are also made of cells.
- Rudolf Virchow, in 1855, posited that all cells arise from pre-existing cells.
- Cell Theory, established through the work of Schleiden, Schwann, and Virchow, includes:
- The cell is the basic unit of life.
- All organisms consist of one or more cells.
- All cells arise from pre-existing cells.
Modern Cell Theory
- All living things are cellular, either unicellular or multicellular.
- Cells serve as the structural and functional unit of life.
- Cell division is responsible for passing hereditary information.
- All cells share a similar basic chemical composition despite different types.
- Energy flow and metabolic processes occur within cells.
Types of Cells
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Prokaryotic Cells:
- Lack a nucleus and membrane-bound organelles.
- Typically unicellular, found in Domains Archaea and Bacteria.
- Contain a single, circular chromosome in a nucleoid region (irregular area of DNA).
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Eukaryotic Cells:
- Contain a membrane-bound nucleus and organelles, each with specific functions.
Shared Cell Components
- Plasma Membrane: Outer layer separating cell's interior from the environment.
- Cytoplasm: Jelly-like substance including cytosol and cellular structures; in eukaryotes, it's the region between the nucleus and membrane.
- DNA: Genetic material governing cell function and reproduction.
- Ribosomes: Protein synthesis machinery of the cell.
Endosymbiotic Theory
- Proposes that symbiotic relationships led to the evolution of eukaryotic cells, where one cell engulfs another benefiting both organisms.
Prokaryotic Cell Features
- Comprised of:
- Cell Wall: Provides shape and additional protection, prevents dehydration.
- Capsule: Sticky outer layer of carbohydrates aiding attachment to surfaces.
- Flagella: Whip-like structures used for movement.
- Fimbriae: Hair-like structures facilitating attachment to surfaces.
- Pili: These assist in locomotion and DNA transfer between bacteria.
- Inclusions: Non-active nutrient or pigment deposits within the cell.
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Description
This quiz focuses on the invention of the microscope and its pivotal role in the discovery of cells. Learn about key figures such as Robert Hooke and Antoine van Leeuwenhoek, who contributed to our understanding of microscopic life. Explore the historical context and impact of these discoveries on biology.
