* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Structure
Survey
Document related concepts
Cell growth wikipedia , lookup
Extracellular matrix wikipedia , lookup
Tissue engineering wikipedia , lookup
Signal transduction wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell culture wikipedia , lookup
Cell nucleus wikipedia , lookup
Cell encapsulation wikipedia , lookup
Cytokinesis wikipedia , lookup
Cell membrane wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Transcript
The Cell Theory Some Random Cell Facts • The average human being is composed of around 100 Trillion individual cells!!! • It would take as many as 50 cells to cover the area of a dot on the letter “i” Discovery of Cells • 1665- English Scientist, Robert Hooke, discovered cells while looking at a thin slice of cork. • He described the cells as tiny boxes or a honeycomb • He thought that cells only existed in plants and fungi Anton van Leuwenhoek • 1673- Used a handmade microscope to observe pond scum & discovered single-celled organisms • He called them “animalcules” • He also observed blood cells from fish, birds, frogs, dogs, and humans • Therefore, it was known that cells are found in animals as well as plants • 1838- German Botanist, Matthias Schleiden, concluded that all plant parts are made of cells • 1839- German physiologist, Theodor Schwann, who was a close friend of Schleiden, stated that all animal tissues are composed of cells. Development of Cell Theory • 1858- Rudolf Virchow, German physician, after extensive study, concluded that cells must arise from preexisting cells. The Cell Theory Complete • The 3 Basic Components of the Cell Theory were now complete: • 1. All organisms are composed of one or more cells. • 2. The cell is the basic unit of life in all living things. • 3. All cells are produced by the division of preexisting cells. 2 Basic Types of Cells 1) Prokaryotic examples ??? 2) Eukaroytic examples???? Plasma membrane • Structure – Main component is phospholipids that are arranged in a double layer (bilayer) – Has scattered proteins within the phospholipids Function of the Plasma Membrane • Regulate what gets into or leaves the cell • Structure Nucleus – Surrounded by a double membrane – This “nuclear membrane” has pores • Function – Holds the chromosomes (DNA) and the nucleolus Nuclear envelope • Double layer of membrane • Has pores • Surrounds the nucleus • Regulates what goes into and out of the nucleus Chromosomes • Structure – String-like structures in the nucleus made of DNA and protein • Function – Contain your genes Nucleolus • Structure – Small dark structure in the nucleus • Function – Produce ribosomes Ribosomes • Small structures (NOT made of membrane) • Make proteins Central Vacuole • Structure – LARGE sac made of membrane – Found in center of plant cells • Function – Stores chemicals and water Smooth Endoplasmic Reticulum • Structure – Canals and tubes made of membrane • Function – Makes lipids (oils, phospholipids, steroids) – Detoxifies poisons Rough Endoplasmic Reticulum • Structure – Canals and tubes made of membrane – Have ribosomes attached to the outside • Function – Transport materials in the cell – Make proteins (those exported from the cell, those found on the plasma membrane, those found in lysosomes) Golgi Apparatus • Structure • Function – Stacks of membrane – Chemically modifies sacs substances – has a receiving end (from – Packages material for ER) and a shipping end transport out of the cell or to other locations within the cell Vesicles • Structure – Small membrane “bubbles” that bud off the ER or Golgi • Functions – Transport materials to new locations Lysosomes • Structure – Sacs of membrane that contain hydrolytic enzymes – -found mostly in animal cells • Function – Use enzymes to break down old organelles – In white blood cells are used to destroy bacteria Mitochondria • Structure – Surrounded by a double membrane • Folds found on the inside • Function – Cellular Respiration • Converts energy in sugars into the energy of ATP molecule Chloroplasts • Structure – Surrounded by a double layer of membrane • Disks found inside • Function – Convert solar energy into chemical energy (food) – Site of photosynthesis Perioxisome • Structure – Small membranous sac • Function – Some reactions occurring here produce H2O2 (toxic) • So, it also contains an enzyme (catalase) that converts this to water and oxygen gas • Structure Cell Wall – Found outside the plasma membrane – Plant made of cellulose • Function – Give support to certain cells (plant) – Does NOT determine what can get into/out of the cell Cytoskeleton • Structure • Made of protein fibers – Microtubules • Hollow tube – Microfilaments • Small rods – Intermediate filaments • Function – Give the cell shape – Help to move organelles around the cell Fig. 4-17 Nucleus Nucleus Actin subunit Fibrous subunits 7 nm Microfilament Tubulin subunit 10 nm 25 nm Intermediate filament Microtubule Centrioles • Structure – Made of rings of microtubules – Found in pairs that lie at right angles • Look similar to a pair of barrels • Function – Found in animal cells – Help organize the tubulin required for cell division Cilia • Structure – Microtubules that extend from the cell (still covered by the plasma membrane) – Short and many of them • Function – In single-celled organisms, they can move the organism from place to place – If anchored in place, can set up a current, moving fluid across the surface of a cell Fig. 4-1c Fig. 4-18a Cilia http://www.youtube.com/watch?v=YHb2Ja ujIPo&feature=related&safety_mode=true& persist_safety_mode=1 Flagella Structure • Same as cilia, but are longer and there are just a few of them • Prokaryotes also have them – Not made of microtubules Function • Move the cell within its environment How large can cells get? -depends on how efficiently they can get nutrients in and wastes out 10 µm 30 µm 30 µm Surface area of one large cube = 5,400 µm2 10 µm Total surface area of 27 small cubes = 16,200 µm2 Fig. 4-20 Glycoprotein complex with long polysaccharide EXTRACELLULAR FLUID Collagen fiber Connecting glycoprotein Integrin Plasma membrane Microfilaments CYTOPLASM Fig. 4-21 Tight junctions Anchoring junction Gap junctions Plasma membranes of adjacent cells Extracellular matrix Fig. 4-22 Walls of two adjacent plant cells Vacuole Plasmodesmata cell wall Cytoplasm Plasma membrane B C D A CD (CONTAINING DIGESTIVE ENZYMES) E BE AB BD AC BC AE AD BE A BD BC B AE C AD AC D AB E D B C A