Transcript Slide 1
Part 1 Microscopes & Cells 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… I do believe that all cells must come from preexisting cells. 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? • 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 DNA (Nucleoid) Ribosomes Plasma Membrane Cytoplasm Cilia Cilium Flagella Flagellum TEM of a bacterium 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) Similarities Both have: 1. DNA 2. Cytoplasm 3. Ribosomes 4. Plasma Membrane Part 2 Eukaryotic Cells (cells with a nucleus) Comparing and Contrasting Organelles in Eukaryotic Cells The Plasma Membrane Carbohydrate side chains Proteins Hydrophilic Region Hydrophobic Region Hydrophilic Region Phospholipid TEM of a red blood cell The Plasma Membrane • 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? H2O used by cell for Respiration Plasma Membrane’s Microvilli • Fingerlike-projections from the cell’s surface that increase the surface area. Microvilli Microfilaments Intermediate Filaments Cell Wall • Surrounding the cell membrane , this feature does the following for plant cells: 1. Provides Support 2. Provides Protection Cytoplasm • The jelly-like fluid that holds all organelles within the cell Nucleus and nucleolus SEM of a freeze-fractured nuclear membrane • Ribosomes are made here: nucleolus • DNA and proteins chromatin are found in the nucleus • Openings in the nuclear membrane Nuclear pores TEM of nuclear pores Ribosomes: 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 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 ER products move here in vesicles It is the center of Warehousing, Sorting and Shipping of Proteins Vesicles Membranebound organelles that transports materials from the ER to the golgi Mitochondria Cellular Respiration takes place in this organelle. It is often called the “ powerhouse “ of the cell. Chloroplasts • An organelle that converts energy from the sun into chemical energy The process is called: Photosynthesis The Cytoskeleton • A network of fibers that extend throughout the cytoplasm • Three types: Microtubules Microfilaments Intermediate Filaments Cytoskeleton: Functions 1. Provides shape and support 2. Moves the cell and organelles Organelle 3. Regulates biochemical activities in cell Centrosome • Microtubules grow out of this structure • In animal cells, a pair of structures called centrioles (made of microtubules) help in cell division. centrosome centrioles Cilia and Flagella • Cellular projections that aide in movement • Flagella are longer & move in a snake-like motion. • Cilia are shorter, more numerous and move back & forth Lysosomes • Membrane-bound organelle that contains digestive enzymes Lysosome engulfing a peroxisome and a mitochondria Vacuoles • Large, central organelle in plants • Stores water and waste products • In animals, it stores food and is small compared plant vacuoles • Protists have a Contractile Vacuole