Cell Theory and Proponents PDF

Summary

This document discusses the cell theory, including its key postulates and proponents such as Aristotle, van Helmont, Redi, Needham, Spallanzani, and Pasteur. It also details the structure and function of organelles like the nucleus, mitochondria, endoplasmic reticulum, and more. The document is well-organized, with clear explanations and diagrams.

Full Transcript

**General Biology 1/Reviewer/1^st^ Quarter** **Cell Theory and the Proponents** **Cell -The basic fundamental unit of life** **1.Cell is the simplest and smallest life form.** - **Cell is life.** **2. Cell makes up life living organisms.** - **Cell is the building blocks of life.** **...

**General Biology 1/Reviewer/1^st^ Quarter** **Cell Theory and the Proponents** **Cell -The basic fundamental unit of life** **1.Cell is the simplest and smallest life form.** - **Cell is life.** **2. Cell makes up life living organisms.** - **Cell is the building blocks of life.** **Cell Theory (Unifying Theory in Biology) -Postulates of Cell Theory** **1. Cell is the basic and fundamental unit of life.** **2. All living organisms are composed of cells.** **3. Cells arise from pre-existing cells.** **All living organisms have Cells. Biogenesis "Life can only come from another life"** **Theory of Spontaneous Generation (Abiogenesis):** **-Hypothetical process by which living organisms develop from non-living matter.** **-Persisted until 17th century** **-Proposed by Aristotle (384-322BC)** **"Life arose from non-living material if the materials contained pneuma ("vital heat")** **Evidences of spontaneous generation by Aristotle:** **1.** **Fish appeared in puddles of water 2.** **Maggots in decomposing meat** **Arguments in Spontaneous Generation:** **-Jan Babtista van Helmont (7^th^ Century)** - **Mice in rags and wheat kernels** **-Francisco Redi (1626-1697)** **Refute the idea that maggots spontaneously generated on meat left out open in the air** **Predicted preventing flies from direct contact on meat would prevent appearance of maggot** **Meat in the Jar Experiment** **-Maggots could only form when flies were allowed to lay eggs on the meat. Not a product of spontaneous generation** **-John Needham (1713-1781)** **Tries to prove spontaneous generation** **Boil broth in animal and plant matter** **-Lazzaro Spallanzani (1729-1799)** **Did not agree with Needham** **Experimented with heated broths.** **-This experiment suggested that microbes were introduced into the flask from the air** **Results contradicted Needham** **Needham's counterargument** **Needham argued that life originates from a "life force" that was destroyed during Spallanzani's extended boiling.** **Any subsequent sealing of the flasks then prevented new life force from entering and causing spontaneous generation.** **-Louis Pasteur (1825-1895)** Disproved spontaneous generation using "Swan-necked experiment" -Since no microbes can enter the flask, if there is no growth of microbes then it is impossible for life to come from any "life force" (nowhere) **DEVELOPMENT OF CELL THEORY** **CELL THEORY TIMELINE** 1\. Zaccharias Janssen- Invention of the 1^st^ microscope 2, Robert Hooke- First to discover and describe the cells. Coined the term cells Hooke used oak cork tissues Cella = small rooms -\> Cells Published his observations in his book Micrographia in 1665 3\. Antonie van Leuwenhoek- First to see living and motile cells/organisms under the microscope. Discovered bacteria, and protists -\> animalcules 4\. Matthias Jakob Schleiden- Suggested that all elements of plants are made of cells Theodore Schwann- Realized that all animals are made of cells. Became major proponents of cell theory: - Cell is the basic and fundamental unit of life - All organisms are made up of cells 5\. Rudolf Virchow- Coined the latin phrase "Omnis cellula e cellula" which means ''Cells come from pre-existing cells'' Plagiarized the idea of Robert Remak 6\. Robert Remak- Challenged spontaneous and came up with the 3^rd^ postulate "Cells come from pre-existing cells" 7\. Louis Pasteur- Disproved the theory of spontaneous generation once and for all through a swan neck flask experiment **Modern Postulates of Cell Theory** 1\. All cells have the same basic chemical composition 2\. Hereditary information (DNA) is passed on from cell to cell 3\. Energy flow occurs within the cell **Cell Structure and Organelles** Cell organelles- Subcellular structures which are separated internally into numerous membranous compartments. "Little organ" **-Non-Membrane Bound Organelles** Function: Maintain Cell Integrity Protection Support Movement **Plasma/Cell Membrane** Serves as barrier separating the inside and outside of the cell Phospholipid bilayer structure Described as fluid mosaic Protection of Cell Amphipatic which means: Prevents unwanted and toxic molecules from coming in Prevents entrance of foreign materials and pathogens **SELECTIVELY PERMEABLE** Only allows the passage of specific molecules an inhibits others. **MAINTENANCE FOR THE CELLULAR ENVIRONMENT** Cell Recognition and signaling. Cell membrane contains cell receptors (proteins and carbohydrates) which is used for recognition of other cells and molecules, identification, send signals, and communication. **Cell Wall (Plants Only)** Made up of Cellulose A rigid **SEMI-PERMEABLE** outer layer of **PLANT CELLS** For protection, shape, and structural support of plants **Cytoplasm** Clear, semi fluid space Site for metabolic reactions Houses organelles Flexible cellular framework composed of: **-Microtubules** Made up of **tubulin proteins.** For structural support and organization Movement of cell (Flagella and Cilia) Transport of organelles Movement of chromosomes during cell division **-Microfilaments** Made up of **actin proteins** Help maintain shape Engulfing and secretion via cell membrane Assist in cell movement Contraction of cell **-Intermediate Filaments** Made up of **mixed proteins** Support Holds and keep organelles in place **Cilia and Flagella** Elongated structures made of microtubules Cilia- Hair like structure For locomotion and food collection Flagella- Whip like structure Mainly for locomotion **Centrosomes** Composed of spindle-fibers, centrioles, and microtubules **-Membrane Bound Cell Organelles** Function: Maintain Cell Function Manufacturing Processing Energy Transport **Nucleus "Control Center"** -Spherical -double-membrane(bilayer) -Stores genetic material (DNA: chromatin) -Pre-assembly points for ribosomal units -Ribosomes transcript mRNA which passes through **[nuclear pore]** to proteins which are responsible for cellular functions DNA (genetic info) mRNA PROTEINS **NUCLEOLUS** Site for production and assembly of ribosomes **Endoplasmic Reticulum "Manufacturing and transport center"** -Complex labyrinth (cisternae) -branches out to cytoplasm -membrane-bound (bilayer) -continuous with nucleus **Rough ER** -storage for proteins and enzymes -synthesize proteins -attachment site for ribosomes **Smooth ER** \- synthesizes, manufactures modify and transports lipids \- Steroid metabolism \- No ribosomes -Transports macromolecules -Aids in the detoxification of wastes and harmful chemicals **Golgi Apparatus "Delivery and Packaging Center"** -Stacks of disk-like membranes (cisternae) -Modifies, sorts, and packages proteins and lipids (mostly from ER) for transport to target destinations **Vesicles "Transporting Organelles"** -bud off from the cisternae of ER and Golgi -membrane-bound (bilayer) sacs -contain enzymes or secretory products -transport manufactures materials -storage -site for digestion **ENDOMEMBRANE SYSTEM** **Nucleus ERGolgiPlasma Membrane** Collection of organelles that help modify each other. **Mitochondria "Powerhouse of the Cell"** -elongated organelle -membrane-bound (bilayer) -membrane-bound (bilayer) Site for cellular respiration: converts energy from food (glucose) to energy (ATP) Cellular respiration review (article) \| Khan AcademyATP = energy currency of the cell Inner layer is the site for cellular respiration Folding increases surface area of production of ATP -\> more energy!! **Chloroplast** ONLY IN PLANTS -oval-shaped organelle -membrane-bound (bilayer) Site for photosynthesis: converts light energy into chemical energy (sugar) ![Photosynthesis: Step by Step Guide (Experiments Included)](media/image2.jpeg) **Lysosome** -membrane-bound (bilayer) sphere -contains hydrolytic enzymes (hydrolases) Digestion/ breaking down of wastes, obsolete/damaged cell parts, unwanted materials inside the cell and other materials for secretion or recycling. -Sends signaling enzymes if the cell should undergo APOPTOSIS/ Cell death **Peroxisome** -contains catalytic enzymes (catalase) Metabolizes lipids (fatty acids) and amino acids through oxidation Detoxify poisons (eg reactive oxygen species, H202) **Vacuole "Water storage center"** Animals: small and numerous Plants: one and large Protists: Contractile -membrane surrounded sac (single membrane) -occupies huge portion of the plants Storage site of water, food and other compounds **Provides shape and structural support for plant cells** **Water fills the vacuole until it becomes [turgid]**

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