Mendel and the Properties of Cells

Reading Assignment

Read about Brother Gregory and what he knew about the newly discovered "cells".

Read the fictionalized story and discover what science and scientists were just learning about cellular life. Later re-read this material and follow the hyperlinks in the text that lead to the modern principles of cell biology.

2) The e- textbook The World of Cells and Eukaryotic Cell Structure.

These chapters deal with the structure of cells, the two major types of cells, the problems of size (cross reference this to Brother Gregory!), the movement of materials in and out of cells, and eukaryotic cell structure.

First "Assignment Questions":

1. What did Gregor Mendel know about eukaryotic cell structure?
   (write about three paragraphs for this answer).

2. What was the 'cell size problem', and why was it a problem?
   

3. How does material get into and out of cells? In your answer, compare the difference between liquids and solids.

4. What are the differences between plant and animal cells?

5. Why should Brother Gregory have a been interested in the cell nucleus?

   (You should create a word processor document of your answers to the assigned questions. Then (a) post the resulting document on the appropriate page of the newsgroup (if required), and (b) keep it safe for possible inclusion in your portfolio.)

2) Here is your third set of research assignments from Brother Gregory.

1) The Size of Cells.

One day he went out to two village ponds near Brno and collected samples of free living, free swiming, single celled organims called Paramoecium. He brought these samples back to the monastery and looked at them under his microscope.

When he compared the two samples, he thought he could detect a slight difference in the size of the cells from the pond at Adamov to the size of the cells collected from the pond at Buchlov, but he was not sure.

He wants you, his researcher, to scientifically determin wether or not the length of the cells from the Adamov pond are larger, smaller, or no different from the cells from the Buchlov pond.

You should put into your portfolio:

1. A series of measurements of cell sizes from both samples.
2. A set of graphs showing the number of cells from each pond that have those sizes.
3. Calculations and rationale for your answer to the question.

2) How Many Carbon Atoms?

Every sample he has tested so far contains carbon, which scientists are begining to think is an important element in all biological molecules.

Brother Gregory wants you to find out how many carbon atoms there are in each of his pure biological materials. To do this he has arranged for you to travel to the laboratory of Herr Doktor Justus von Liebig in Munich.

In Doktor Liebig's laboratory you will burn a carefully measured amount of each sample in air and collect the carbon dioxide given off. You will then weigh the carbon dioxide produced and draw graphs of how much carbon dioxide gas is generated by a given amount of sample.

From these graphs, and the molecular weight of the biological molecules you will determin how many carbon atoms there are in each molecule.

You should put into your portfolio:

1. A set of graphs showing the relationship between the number of grams of the biological substance and the number of grams of carbon dioxide produced.
2. Calculations and rationale for your answers to the question of how many carbon atoms are in these molecules.

Second "Assignment Questions":

1. Describe the molecular nature of the cell membrane. What special properties does it have?

2. Compare the properties of lipids and polysaccharides. Give some examples of the use of these two molecules inside cells.

3. What properties does the element carbon have that make it ideal for use in living things and as a consitiuent of biological molecules?

4. What are some of the roles proteins play in cells?

5. What is the role of DNA and RNA? Why would Brother Gregory liked to have known about these molecules?

   (You should create a word processor document of your answers to the assigned questions. Then (a) post the resulting document on the appropriate page of the newsgroup (if required), and (b) keep it safe for possible inclusion in your portfolio.)