Transcript Slide 1
Microscopes & Cells Don’t copy down this slide – just listen Microscopes and Cells: History • In 1663, Robert __________ Hooke coined the term “cells” • 10 years later, Anton van Leeuwenhoek _________________ observed bacteria and protozoa Browne • In 1833, Robert __________ observed and coined the term “nucleus” Guten Tag, Dr. Shwann Cell Theory: History Guten Tag, Dr. Schleiden • In 1838 (and 1839) German scientists, Matthias Schleiden ________________ & Theodore Schwann ________________ independently came up with the “Cell Theory” It appears we have come up with a very similar theory… What shall we call this theory? Cell Theory 1. All living things are composed of one or more cells. 2. Cells are organisms' basic units of structure and function. 3. Cells form by free-cell formation, similar to the formation of crystals (spontaneous generation). • In 1855, German physician Rudolph Virchow discovered that… all cells must come from pre-existing cells. Please add the above as point #4 to the cell theory How big are cells? • Eukaryotic cells include plant animal cells. _______ & _______ • Most eukaryotic cells are between 10 __ and ___ 100 m. • What is the limit of the light microscope? 0.2 m • Why? It is limited to the visible light spectrum • What is used to see smaller objects? __________________ Electron Microscopes Electron Microscopy • ___________ Transmission Electron Microscopes (TEM) emit light through a thin piece of heavy metal ion stained tissue Scanning Electron • ________ Microscopes (SEM) reflect light off of a piece of heavy metal ion stained tissue Prokaryotic Cells (cells without a nucleus) for ex. bacteria Label this diagram in your handout DNA (Nucleoid) Ribosomes Plasma Membrane Cytoplasm Cilia Cilium Flagella Flagellum TEM of a bacterium Eukaryotic Cells (cells with a nucleus) Plant cell Animal cell Eukaryotic cells include both plants and animal cells Differences and similarities between Prokaryotes and Eukaryotes Differences Prokaryotes lack: 1.True nucleus 2.Membrane bound organelles Prokaryotes are much smaller than eukaryotes (prokaryotes are ~1 – 10 m and eukaryotes are 10 – 100 m ) Similarities Both have: 1. DNA 2. Cytoplasm 3. Ribosomes 4. Plasma Membrane The Plasma Membrane (1) Carbohydrate side chains Don’t copy down this slide – this is just review Proteins Hydrophilic Region Hydrophobic Region Hydrophilic Region Phospholipid TEM of a red blood cell The Plasma Membrane (in all cells) Start taking notes in your table given to you in class • It is a semi-permeable barrier that allows for the passage of certain things based upon charges and size ______, _______, solubility in fat _____________. • What are the forms of transport across a cell membrane? Active and Passive Transport Plasma Membrane’s Microvilli Add this to the info on plasma membrane • Microvilli are fingerlikeprojections from the cell’s membrane that increase the surface area. Cell Wall (in plant cells and prokaryotic cells) • Surrounding the cell membrane , this feature does the following for plant cells and prokaryotes: 1. Provides Support 2. Provides Protection Cytoplasm (in all cells) • The jelly-like fluid that holds all organelles within the cell Nucleus and nucleolus SEM of a freeze-fractured nuclear membrane (in eukaryotic cells) • Ribosomes are made here: nucleolus • DNA and proteins form chromatin, found in the nucleus • Openings in the nuclear membrane Nuclear pores TEM of nuclear pores Ribosomes: (in all cells) Function in protein synthesis (formation) 1. Proteins made by free ribosomes stay in the cell 2. Proteins made by attached ribosomes are shipped out of the cell or sent to the membrane Free ribosomes Attached ribosomes (on ER) TEM of ribosomes Ribosome unit Endoplasmic Reticulum (in eukaryotic cells) There are two types: 1. Rough ER has ribosomes attached. • Modifies & transports proteins 2. Smooth ER does not have ribosomes on it. • • • Synthesizes lipids Breaks down carbohydrates Detoxifies drugs & poisons Golgi Apparatus (in eukaryotic cells) ER products move here in vesicles It is the center of Warehousing, Sorting and Shipping of Proteins Vesicles (in eukaryotic cells) Organelles that transport materials from the ER to the golgi and eventually to the plasma membrane Mitochondria (in eukaryotic cells) Cellular Respiration takes place in this organelle. It is often called the “ powerhouse “ of the cell because it creates energy for the cell Chloroplasts (in plant cells) • An organelle that converts energy from the sun into chemical energy (sugar) The process is called: Photosynthesis The Cytoskeleton (in all cells) • A network of fibers that extend throughout the cytoplasm, • Three types: Microtubules Microfilaments Intermediate Filaments Cytoskeleton: Functions 1. Provides shape and support (skeletal) 2. Moves the organelles within the cell and helps move flagella/cilia Organelle Centrosome (in eukaryotic cells) and Centrioles (in animal cells only) • Centrosomes make microtubules. • In animal cells, a pair of structures called centrioles (made of microtubules) help in cell division. centrosome centrioles Cilia and Flagella (in all cells) • Hair-like projections that aide in movement • Cilia are shorter, more numerous and move back & forth • Flagella are longer & move in a snake-like motion. Lysosomes (in animal cells) • Membrane-bound engulfing a organelle in animal cells Lysosome worn-out organelle that contains digestive ___________enzymes that help clean-up the cell Vacuoles (in eukaryotic cells) • Large, central organelle in plants • Stores water and waste products • In animals, it stores food and is small in size compared to plant vacuoles