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Transcript
Human History Becomes More a Race Between Education and Catastrophe H. G. Wells A View of the Cell Discovery of Cells Robert Hooke- English physicist, used a microscope to observe many things, including thin slices of cork (1665) What he saw, he called “cells” because they reminded him of small rooms in a monestary The Hookemeister Hooke needed some help The microscope made it possible for Robert Hooke to make his observations The first compound microscope was invented in about 1590 by a Dutch spectacle maker named Zacharias Janssen In the late 1600’s, Anton van Leeuwenhoek developed a much more powerful compound microscope (could magnify up to 200 times) first to see and describe bacteria, yeast, plants, the teeming life in a drop of water, and the circulation of blood corpuscles in capillaries I use Vidal salon products to keep my hair long and lovely Cell Theory Biologists Build a Theory The invention of the microscope led to many advances in the study of science. By the 1830’s, many biologists were using the microscope as their chief investigative tool. Contributors to the cell theory Mathias Schleiden- botanist, found that plant parts he examined were made of cells. Made generalization, “all plants are made of cells” Contributors to the cell theory Theodor Schwann- studied animals, his microscope investigations of animal parts led him to generalize that all animals are made of cells. He later proposed, “all organisms are made of cells Contributors to the cell theory Rudolf Virchow- German doctor, said that new plant cells arise only from existing plant cells and new animal cells arise only from existing animal cells The ideas of these 3 men make up what is now called the Cell Theory The Three Principles of the Cell Theory Cells are the basic units of all life All organisms are made of one or more cells All cells arise from existing cells Micro = 0.000001 or millionth Nano= 0.000000001 or billionth Most cells are microscopic The surface area of a cell is important for carrying out the cell’s functions, such as acquiring adequate nutrients and oxygen – A small cell has more surface area relative to its cell volume and is more efficient Large cell has much smaller surface area relative to its volume than smaller cells Major characteristics of Prokaryotic & Eukaryotic Cells Characteristics Prokaryotic Cells Eukaryotic Cells Plasma Membrane Yes Yes Cytosol w/organelles Yes Yes Ribosomes Yes Yes Nucleus No Yes Size 1 um-10 um 10 um- 100 um Internal membranes No Yes Types of Cells Prokaryotes unicellular organisms found in all environments. largest group of organisms, mostly due to the vast array of bacteria which comprise the bulk of the prokaryote classification Pro- means “before” and karyon- means “nucleus” Prokaryotes Cont. Characteristics: No nuclear membrane (genetic material dispersed throughout cytoplasm)=no nucleus (nucleoid) No membrane-bound organelles Very small and simple internal structure Most primitive type of cell Have cell membrane and ribosomes Prokaryote Examples Staphylococcus Staphylococcus aureus Escherichia coli (E. coli) Streptococcus Streptococcus pneumoniae Escherichia coli cells E. Coli colonies Types of Cells Cont. Eukaryotes generally more advanced than prokaryotes. There are many unicellular organisms which are eukaryotic but all cells in multicellular organisms are eukaryotic Eu- means “true” and karyon- means “nucleus” Eukaryotes Cont. Characteristics: Nuclear membrane surrounding genetic material (have a nucleus) Numerous membrane-bound organelles Complex internal structure Appeared approximately one billion years ago Typically larger than prokaryotes Eukaryotic Examples Human liver cell Human breast cancer cell Centric diatom (protista) Bread Yeast (Fungus) Human Red Blood Cells, Platelets, and T-lymphocytes (from the animalia kingdom) Golden colonial alga (protista) Now it’s time to Cellebrate!!! Plasma Membrane Made up of Phospholipids, proteins, and associated carbohydrates Regulates what gets in and out of cells Important for communication Organelles An organelle is a small structure that performs a specialized function within a cell The cytoplasm contains many individual organelles Organelle means “little organ” Organelles Cont. Nucleus: structure that contains nearly all of the cell’s DNA “control center” of the cell Nucleolus: spherical body within cell. Site where ribosomes are assembled Nuclear Membrane (AKA-Nuclear envelope): membrane surrounding the nucleus Nuclear Pores: controls what may enter or leave nucleus Chromatin: complex of DNA and protein stored in nucleus, which makes up chromosomes Chromosomes: condensed chromatin Ribosomes Ribosomes: protein factories Composed of rRNA and proteins Form ribosomal subunits Free ribosomes: float in cytosol and generally produce proteins used in cell Bound ribosomes: attached to ER, make proteins for export from cell Types of Organelles Endoplasmic Reticulum (ER): network of membranes within cell that process/transport proteins & other macromolecules Smooth ER: without ribosomes Synthesis of lipids Metabolism of carbs Detoxification of drugs/poisons Rough ER: studded with ribosomes Produce proteins secreted by cell Proteins are packaged into vesicles, bud off ER & move toward Golgi Apparatus HEY!!! Wakeup!!!! Organelles Cont. Golgi Apparatus: network of membranes in a cell that, in conjunction with the ER, process/transport proteins and other macromolecules Modification, storage, and shipping Contains special enzymes that attach carbohydrates and lipids to a protein Have polarity Cis face receives vesicles, trans face ships vesicles Organelles Cont. Lysosomes- saclike membrane filled with chemicals and enzymes that can break down almost any substance within cell “Clean up crew” for the cell Vacuoles: saclike structure within cell that stores material such as proteins, fats, and carbohydrates in animal cells. In plants, vacuoles store water & dissolved salts Provides plants with support (Central vacuole) Maybe if I sleep, I can learn gooder Organelles Cont. Mitochondrion: found in the cells of most plants and animals that produces energy from chemical fuel and oxygen Plural-mitochondria “Powerhouse of the cell” Outer & inner membrane: inner highly folded (increase surface area for respiration) Inner compartment- fluid filled (mitochondrial matrix) Organelles Cont. Chloroplasts: organelle found in plants and certain types of algae; harvests the energy of sunlight Plastid that stores chlorophyll used in photosynthesis Endosymbiotic Theory: mitochondria/chloroplasts share similar origin, descended from prokaryotes and engulfed by ancestors or eukaryotic cells Both have double membrane Both have ribosomes and DNA Both reproduce independently within cell Organelles Cont. Peroxisomes: single membrane Responsible for metabolic functions that involve transfer of H from compounds to O, making hydrogen peroxide Break down fatty acids to be sent to mitochondria Detoxify alcohol by transferring H from poison to O Cytoskeleton- supporting framework of a cell Microtubules- protein tubulin, largest, shape & support cell, organelles can move along, important in cell division, cilia & flagella Microfilaments- protein actin, smaller scale support, involved w/movement (muscle cells) Intermediate filaments- more permanent in cell, maintain shape of cell and position certain organelles Centrosomes- near nucleus, microtubules grow here, contain centrioles in animal cells Centriole: small structure in animal cells that help to organize microtubules Used during cell division Flagella- long and few in #, propel unicellular organisms Cilia- shorter and more numerous, locomotion, move fluids over surface of tissue (lining of trachea) ECM (Extracellular Matrix)- just external to plasma membrane Composed of glycoproteins secreted by cell (collagen) Strengthens tissues and serves to transmit external stimuli into cell Adjacent cells communicate, interact, and adhere through specialized junctions between them Tight junctions prevent leakage of extracellular fluid across a layer of epithelial cells Desmosomes fasten cells together into sheets Gap junctions are channels that allow molecules to flow between cells Plasmodesmata- openings in plant cell wall that allow passage of materials Cell Wall- protects plant and maintain shape (cellulose) Look Out!!! Plant Cell Only Animal Cells Only Central Vacuoles Lysosomes Chloroplasts Centrioles Cell Wall of cellulose Flagella, cilia Plasmodesmata Extracellular matrix Desmosomes, tight/gap junctions