Showing posts with label cells. Show all posts
Showing posts with label cells. Show all posts

March 27 - Plant-Cells Day!

 Posted on March 27, 2022

This is an update of my post published on March 27, 2011:



On this day in 1776, Charles-François Brisseau de Mirbel was born in France, and on this same day in 1817, Carl von Nägeli was born in Switzerland.

Above, Mirbel. Below, Nägeli


They both grew up to be scientists who study plants (who are called botanists), and they both added to our knowledge of cell biology (which is called cytology).


Mirbel is actually considered a founder of the study of plant cells. He observed that each plant cell has a continuous membrane. Von Nägeli studied cell division and pollen formation, and he may have been the first to describe chromosomes (which he referred to as “transitory cytoblasts”).

Cell division


By the way, von Nägeli was a bit of a mystic who, some science historians say, did a lot of harm by dismissing Gregor Mendel's work on genetics—even going so far as to discourage Mendel from experimenting further in the area. Not cool, von Nägeli! Not. Cool!


Learn about plant cells!

Plant cells, just like all other cells, have many parts. Check out the cell parts at the Cells Alive website: move the mouse over the interactive diagram to see the various names for cell parts, and click one of the organelles (or its label) to find out more about that part.

Do some puzzles with a cell theme. 

You can make an incredible edible cell with instructions found here. Or an edible cell-in-a-baggie; again, instructions found here.


 

Find more cell-model websites here.







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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!


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April 5 – Happy Birthday, Matthias Jakob Schleiden

Posted on April 5, 2015

Chemists had struggled to figure out what made different materials behave differently, and wondered if matter was made up of discrete particles. Finally, in the early 1800s, chemist John Dalton made some experimental discoveries that resulted in the modern theory of matter being made up of atoms.

As Dalton later said, “Chemistry began then to assume a new appearance."

Today's famous birthday did a similar service for the field of biology. Born on this date in Germany, in 1804, Matthias Schleiden studied plants. His botanical studies particularly concentrated on observing plant parts under the microscope. Schleiden wrote that all the different parts of a plant are composed of discrete cells.


Schleiden is credited as being the co-founder of the cell theory, because Theodor Schwann wrote about animals tissues being made up of cells.

Cells are now known as the building block of life, the basic structural unit of all living things.

Celebrate Schleiden by learning about cells!
Also on this date:













More Easter











Anniversary of the eruption of Tambora 














Writer, leader, and educator Booker T. Washington's birthday








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