Microscopes & Cells

Microscopes and Cells: History In 1663, __________ coined the term “cells” 10 years later, _________________ observed bacteria and protozoa In 1833, __________ observed and coined the term “nucleus” Robert Hooke Anton van Leeuwenhoek Robert Browne Don’t copy down this slide – just listen

Cell Theory: History In 1838 (and 1839) German scientists, ________________ & ________________ independently came up with the “Cell Theory” Matthias Schleiden Theodore Schwann Guten Tag, Dr. Shwann Guten Tag, Dr. Schleiden 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 _______ & _______ cells. Most eukaryotic cells are between __ and ___  m. What is the limit of the light microscope? Why? What is used to see smaller objects? __________________ plantanimal Electron Microscopes 0.2  m It is limited to the visible light spectrum

Electron Microscopy ___________ Electron Microscopes (TEM) emit light through a thin piece of heavy metal ion stained tissue ________ Electron Microscopes (SEM) reflect light off of a piece of heavy metal ion stained tissue Transmission Scanning

Prokaryotic Cells (cells without a nucleus) for ex. bacteria DNA (Nucleoid) Ribosomes Plasma Membrane FlagellumFlagella Cytoplasm TEM of a bacterium CiliumCilia Label this diagram in your handout

Eukaryotic Cells (cells with a nucleus) Eukaryotic cells include both plants and animal cells Plant cell Animal cell

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) TEM of a red blood cell Hydrophilic Region Hydrophobic Region Phospholipid Proteins Carbohydrate side chains Don’t copy down this slide – this is just review

The Plasma Membrane (in all cells) It is a semi-permeable barrier that allows for the passage of certain things based upon ______, _______, and _____________. What are the forms of transport across a cell membrane? size charges solubility in fat Active and Passive Transport Start taking notes in your table given to you in class

Microvilli are fingerlike- projections from the cell’s membrane that increase the surface area. Plasma Membrane’s Microvilli Add this to the info on plasma membrane

Cell Wall (in plant cells and prokaryotic cells) Surrounding the, this feature does the following for plant cells and prokaryotes: 1.Provides Support 2.Provides Protection cell membrane

Cytoplasm (in all cells) The jelly-like fluid that holds all organelles within the cell

Nucleus and nucleolus (in eukaryotic cells) Ribosomes are made here: DNA and proteins form found in the nucleus Openings in the nuclear membrane SEM of a freeze-fractured nuclear membrane TEM of nuclear pores nucleolus chromatin, Nuclear pores

Ribosomes: (in all cells) Function in TEM of ribosomes Free ribosomes Attached ribosomes (on ER) protein synthesis (formation) Ribosome unit free ribosomes 1.Proteins made by free ribosomes stay in the cell attached ribosomes 2.Proteins made by attached ribosomes are shipped out of the cell or sent to the membrane

Endoplasmic Reticulum (in eukaryotic cells) There are two types: 1. ER has ribosomes attached. Modifies & transports proteins 2. ER does not have ribosomes on it. Synthesizes Breaks down carbohydrates Detoxifies drugs & poisons Rough Smooth lipids

Golgi Apparatus (in eukaryotic cells) ER products move here in It is the center of Warehousing, Sorting and Shipping of Proteins vesicles

Vesicles (in eukaryotic cells) Organelles that transport materials from the ER to the golgi and eventually to the plasma membrane

Mitochondria (in eukaryotic cells) takes place in this organelle. It is often called the “ “ of the cell because it creates energy for the cell Cellular Respiration powerhouse

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 (made of microtubules) help in cell division. centrioles centrosome

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. Cilia and Flagella (in all cells)

Lysosomes (in animal cells) Membrane-bound organelle in animal cells that contains ___________enzymes that help clean-up the cell digestive Lysosome engulfing a worn-out organelle

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