GB1 The Cell Theory.pptx

Cell Theory LEARNING COMPETENCIES: ✓ Explain the postulates of the cell theory (STEM_BIO11/12-Ia-c-1) ✓ Describe the structure and function of major and subcellular organelles (STEM_BIO11/12-Ia-c-2)  A theory is a set of propositions describing the operation and causes of natural phenomen...

Cell Theory LEARNING COMPETENCIES: ✓ Explain the postulates of the cell theory (STEM_BIO11/12-Ia-c-1) ✓ Describe the structure and function of major and subcellular organelles (STEM_BIO11/12-Ia-c-2)  A theory is a set of propositions describing the operation and causes of natural phenomena. Cell theory describes where the term “cell” and the other basic information about the cell came from.  basic unit Cell is the _____________ of life. It is the building block of all organisms. Unicellular organisms include bacteria, protists, and yeast. For example, a paramecium is a slipper-shaped, unicellular organism found in pond water. It takes in food from the water and digests it in organelles known as food vacuoles. Nutrients from the food travel through the cytoplasm to the surrounding organelles, helping to keep the cell, and thus the organism, functioning. unicellular Multicellular organisms are composed of more than one cell, with groups of cells differentiating to take on specialized functions. In humans, cells differentiate early in development to become nerve cells, skin cells, muscle cells, blood cells, and other types of cells. multicellular Their structure is related to their function, meaning each type of cell takes on a particular form in order to best serve its purpose. Nerve cells have appendages called dendrites and axons that connect with other nerve cells to move muscles, send signals to glands, or register sensory stimuli. Outer skin cells form flattened stacks that protect the body from the environment. Muscle cells are slender fibers that bundle together for muscle contraction.  But, even the life of a very huge multicellular organism begins with a single cell – a sperm cell and an egg cell. How are these concepts about the cell made known? Hans and Zacharias Janssen Dutch inventors, made the first simple microscope in 1590. Robert Hooke An Englishman, gave the term “cell” for the box-like structures observed in a cork tissue under the microscope in 1667. Anton van Leeuwenhoek Around 1675, a Dutch naturalist, observed sperm cells, red blood cells, bacteria, and other microscopic organisms in rainwater after his invention of a more powerful microscope. A nucleus was observed within some of the red blood cells. Matthias Schleiden A German botanist studied plant structures under a microscope. In 1838, he stated that all plants are composed of cells. Theodore Schwann In 1839, it was concluded that all animals are composed of cells. a German zoologist. He studied animal tissues.  Schleiden and Schwann Proposed that all living things are made up of cells. 20 years later Rudolf Virchow in 1855, Rudolf Virchow, a German biologist, observed dividing cells during his work. Such observation made him conclude that all living cells come from preexisting cells. Eventually, unifying all the discoveries and other advanced studies conducted, the cell theory was formulated stating that: 1. All living things are structurally made up of cells. 2. The cell is the fundamental unit of life. 3. Cells come from the division of preexisting cells. ACTIVITY TIME Thank you for Listening and Active Participation! Biology gives you a brain and life turns it into a mind. - Jeffrey Eugenides-