Showing posts with label electron microscope. Show all posts
Showing posts with label electron microscope. Show all posts

November 19 - Happy Birthday George Emil Palade

Posted on November 19, 2018

Today's famous birthday (born on this date in 1912) has been called "the most influential cell biologist ever" - and I've never even heard of him!

Romanian scientist George Emil Palade won a Nobel prize in Physiology and Medicine (along with two others). The achievement that earned him this prize is strides taken with electron microscopes, discovering ribosomes, and procedures used to study different parts of the cell and to discover how they function.

Okay, so what's an electron microscope? What different parts are in a cell? What are ribosomes? 

An ordinary microscope lights up a specimen (with, you know, light) and uses lenses to greatly enlarge the specimen. You can magnify things 4 to 2,000 times with this sort of microscope.


An electron microscope uses a beam of electrons instead of light, to "light up" the specimen, and uses electron lens systems to magnify up to about 10,000,000 times! 

With so much magnification power, we can see the super teeny tiny parts that make up our really tiny cells. These parts are called organelles (just like the parts of the body are called organs).

Notice that, in these two comparisons (above and below), the electron
microscope has way better resolution even when it is at the same
magnification as the light microscope!


 
Some examples of cell organelles include:

The nucleus - This is sort of like the cell's brain. It stores and maintains DNA and makes copies of bits of the genetic code as commands or instructions that other organelles then carry out. 


Vacuoles - These are storage compartments that usually hold water or enzymes in a watery solution. Sometimes vacuoles hold solids.

Endoplasmic Reticulum - This organelle moves molecules to and from the nucleus.

Mitochondria - These produce energy by burning sugars.

Ribosomes - These organelles build proteins.

Golgi Apparatus - This organelle changes newly-made proteins and fats, getting them ready to be stored or to be sent out to other cells.

Cell Membrane - This is like a thin "skin" that protects the cell and keeps some sorts of molecules out while allowing other sorts in.

Cytoplasm - This substance fills in the spaces between organelles and helps hold them in place.


Did you notice that ribosomes build proteins? That's a super-power you really want your cells to have! Proteins are really large molecules made of long chains of amino acids. They are the building blocks of everything from muscles to hair to skin to cell membranes. Proteins also are crucial for lots of bodily processes like digesting food.

And ribosomes are the construction crew that put together these long chains of amino acids, following instructions from the nucleus. 


Here is an animation that helps us understand how ribosomes work. This is another short video on ribosomes and protein creation - this one for younger viewers.

And here are some fun cell organelle projects. Be sure to scroll down to the "More ideas" part!
 



Make a yummy cell cake!


April 20, 2012 - Electron Microscope Demo


The surface
of a kidney stone.
(THAT'S gotta hurt!)

– 1940















What's 10 feet high and weighs half a ton – but was used with the most delicate, tiny organisms ever?

The first American electron microscope!

Dr. Vladimir Zworykin, the Russian-American inventor who gets much of the credit for inventing television, built America's first electron microscope, and he demonstrated it for the first time on this date in 1940. The huge microscope produced magnification of 100,000 times.


The electron microscope was first conceived of—and patented—by Hungarian physicist Leo Szilard, and the first to be built was created by two Germans, Max Knoll and Ernst Ruska, in 1931. (You may know that 1931 was not a good year to be German—the worldwide stock market crash had hit Germany particularly hard, and Adolph Hitler and the Nazi party were seizing control of the country at that time!)

Snowflake
Ordinary microscopes use visible light and glass lenses to create magnified images of things, whereas an electron microscope uses a beam of electrons and electrostatic or electromagnetic “lenses” instead. We can get much more magnification and image resolution because electrons have wavelengths that are about 100,000 times shorter than the wavelengths of visible light. These days a good electron microscope can show magnifications up to 10,000,000x—and an ordinary microscope only reaches magnifications of 2,000x.

Wow! What a difference!

Enjoy Electron Microscopic Images!

Check out the up-close (way up-close!) images of scorpions, spiders and sharks on Wired Science

The eye of a fly
Pollen
Here are some images as varied as a wounded blood vessel, salt and pepper, and eyelash hairs. 

There are more and more beautiful and horrifying and interesting electron microscopic images here and here and here and hereThere's some repetition within these links—but every website has some unique images, too—and they are all pretty amazing!
A mite--
yikes!

If you haven't already, check out the Virtual Electron Microscope




Also on this date:






July 30, 2011 - Happy Birthday, Vladimir Zworykin


He is sometimes called the Father of Television!

Vladimir Zworykin was born in Russia in 1889. He studied science and engineering and worked on early television at St. Petersburg Institute of Technology. He came to the U.S. in 1918, during the Russian Civil War, by joining a scientific expedition in Siberia and continuing on to Alaska. Once in the U.S., Zworykin worked at the Westinghouse laboratories in Pittsburgh, Pennsylvania. He continued to work on improvements for television and earned his PhD from the University of Pittsburgh (the university that features that wonderful Cathedral of Learning I mentioned in yesterday's post!).

Zworykin helped develop cathode ray tubes, infrared image tubes, and the electron microscope.



Learn about the evolution of the television here. 

Have you tried out the Virtual Electron Microscope

Here is a gallery of images captured with a Scanning Electron Microscope.