Cell Theory PDF

Cell Theory LEARNING COMPETENCY: Explain the postulates of the cell theory STEM_BIO11/12-Ia-c-1 What is cell theory??? Why is it considered a foundational concept in biology??? Cell Theory: –Fundamental principle in biology that describes the properties and characteristics of cells. –...

Cell Theory LEARNING COMPETENCY: Explain the postulates of the cell theory STEM_BIO11/12-Ia-c-1 What is cell theory??? Why is it considered a foundational concept in biology??? Cell Theory: –Fundamental principle in biology that describes the properties and characteristics of cells. – Fundamental scientific theory of biology according to which cells are held to be the basic units of all living tissues. Three fundamental principles of Cell Theory: –1. All living organisms are composed of one or more cells –2. The cell is the basic unit of structure and function in living organisms –3. cells arise from a pre-existing cells through cell division -Cell theory applies to all forms of life.. From a single – celled bacteria to a complex multi-cellular organisms like plants and animals -explains how organisms grow, develop, and function - its principles are essential for fields-genetics, biochemistry, and molecular bio-dses and tx devt and innovations. -framework for research-guides research and studies relating to cell structure and mechanisms - continuity of life- inheritance, development,and evolution Who were the key scientists involved in the development of cell theory, & what were their contributions???  Cell Theory –In a 1665 publication called Micrographia, experimental scientist Robert Hooke coined the term “cell” (from the Latin cella, meaning “small room”) for the box-like structures he observed when viewing cork tissue through a lens. In the 1670s, Van Leeuwenhoek discovered bacteria and protozoa. Later advances in lenses and microscope construction enabled other scientists to see different components inside cells. By the late 1830s, botanist Matthias Schleiden and zoologist Theodor Schwann were studying tissues and proposed the unified cell theory, which states that all living things are composed of one or more cells, that the cell is the basic unit of life, and that all new cells arise from existing cells. PRACTICE!!!  LEARNING COMPETENCIES: 1.Describe the structure and function of major and subcellular organelles STEM_BIO11/12-Ia-c-2 2.Distinguish prokaryoticand eukaryotic cells according to their distinguishing features STEM_BIO11/12-Ia-c-3 3.Classify different cell types (plant/animal tissues) and specify the function(s) of each STEM_BIO11/12-Ia-c-4 Cells fall into one of two broad categories: prokaryotic and eukaryotic. –The predominantly single-celled organisms of the domains Bacteria and Archaea are classified as prokaryotes (pro- = before; - karyon- = nucleus). – Animal cells, plant cells, fungi, and protists are eukaryotes (eu- = true). OVERVIEW Components of Prokaryotic Cells A prokaryotic cell is a simple, single-celled (unicellular) organism that lacks a nucleus, or any other membrane-bound organelle. Prokaryotic DNA is found in the central part of the cell: a darkened region called the nucleoid (Figure 1) Figure 1. This figure shows the generalized structure of a prokaryotic cell. The cell wall acts as an extra layer of protection, helps the cell maintain its shape, and prevents dehydration. -Unlike Archaea and eukaryotes,bacteria have a cell wall made of peptidoglycan, comprised of sugars and amino acids, and may have a polysaccharide capsule The capsule enables the cell to attach to surfaces in its environment. –Some prokaryotes have flagella, pili, or fimbriae. Flagella are used for locomotion, while most pili are used to exchange genetic material during a type of reproduction called conjugation. Eukaryotic Cell –A eukaryotic cell is a cell that has a membrane- bound nucleus and other membrane-bound compartments or sacs, called organelles, which have specialized functions. eukaryotic means =“true kernel” or “true nucleus,” alluding to the presence of the membrane-bound nucleus in these cells. “organelle” means “little organ,” and, as already mentioned, organelles have specialized cellular functions, just as the organs of your body have specialized functions. All cells share four common components: –1) a plasma membrane, an outer covering that separates the cell’s interior from its surrounding environment; – 2) cytoplasm, consisting of a jelly-like region within the cell in which other cellular components are found; –3) DNA, the genetic material of the cell; and –4) ribosomes, particles that synthesize proteins. MAJOR SUBCELLULAR ORGANELLES Cell Structure and Functions 1. Cell Membrane - Separates cell from external environment; controls passage of organic molecules, ions, water, oxygen and wastes into and out of the cell 2. Cytoplasm -Provides structure to cell; site of many metabolic reactions; medium in which organelles are found 3. Nucleolus -Location of DNA 4. Nucleus - Cell organelle that houses DNA and directs synthesis of ribosomes and proteins 5. Ribosomes - Protein synthesis 6. Mitochondria - ATP production or cellular respiration 7. Peroxisomes -Oxidizes and breaks down fatty acids and amino acids and detoxifies poisons 8. Vesicles and Vacuoles - Storage and transport; digestive function in plant cells 9. Centrosome - Unspecified role in cell division in animal cells; organizing center of microtubules in animal cells 10. Lysosomes -Digestion of macromolecules; recycling or worn out organelles 11. Cell wall - Protection, structural support and maintenance of cell shape 12. Chloroplast - Photosynthesis 13. Endoplasmic reticulum - Modifies proteins and synthesizes lipids 14. Golgi apparatus - Modifies, sorts, tags, packages and distributes lipids and proteins 15. Cytoskeleton - Maintains cell‘s shape, secure organelles on specific positions, allows cytoplasm and vesicles to move within the cell, and enables unicellular organisms to move independently 16. Flagella - Cellular locomotion 17. Cilia - Cellular locomotion, movement of particles along extracellular surface of plasma membrane, and filtration PRACTICE!!!! 1. Control center, stores DNA 2. Center of the nucleus, produces ribosomes 3. Controls passage of organic molecules, ions, water, oxygen and wastes into and out of the cell. 4. Provides structure to cell; gel-like fluid in which organelles are found 5. ―Powerhouse of the cell‖, releases energy from food 6. Small structures for protein synthesis 7. Modifies proteins and synthesizes lipids 8. Modifies, sorts, tags, packages and Distributes lipids and proteins 9. Garbage disposal, digestion of macro- molecules; recycling or worn out organelles 10. Storage and transport; digestive function in plant cells. 11. Site of photosynthesis, trap sunlight to make food 12. Protection, structural support and maintenance of cell shape Direction: Using a Venn Diagram or Tabular form show the difference between a plant cell and animal cell. ASSIGNMENT! PERFORMANCE TASK: Direction: Construct a 3D model of a plant/animal cell using indigenous or recyclable materials and label the parts.