ZOOMING DOWN THE TREE OF LIFE TO LIFE'S BUILDING BLOCKS

Student Worksheet

All key components of every living cell are made of macromolecules. These are very large molecules that determine the structural and functional properties of living cells. There are four different kinds of macromolecules -- carbohydrates, nucleic acids, proteins and lipids. They are called "macro" molecules for their very large size relative to other organic molecules.

Explore the macromolecules in the Tree of Life by clicking on the squares with pictures, noticing the basic features of the macromolecules you find. Most macromolecules are polymers -long chains of similar subunits called monomers. What monomers can you find for the different kinds of macromolecules?

  CARBOHYDRATES

From maple syrup to sucrose

 *

From tree trunk to cellulose

 From leaf to starch
 PROTEINS

From a monkey to the protein hemoglobin

From the coccoon of a silk worm to the protein fibroin

 From human hair to the protein keratin

 

From a bee to the protein mellitin

 

NUCLEIC ACIDS  From parrot to its chromosomal DNA From soil bacteria to bacterial DNA  
 LIPIDS 

 From an iguana to phospholipids

   



Compare the similarities and differences between the chemistry of the biomolecules.

You have found carbohydrates in maple syrup, in the tree trunk, and in green leaves. What do they all have in common? What makes them similar and what makes them different from the other groups of macromolecules in a living cell?

 


How are lipids different from the other three kinds of macromolecules?

 

 

In how many places in a cell are those molecules distributed? Take a look at the cell picture. and answer the following questions:

If you needed to collect the nucleic acids of DNA from a cell, where would you go?
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Where is the most starch found in the plant cell?

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Where do lipids appear primarily in a cell ? What do those places have in common?

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Because they are the machines of the cell, proteins are found almost everywhere in the cell. Where are they probably NOT found?
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