Monday, September 1, 2008

Summary of 5.4

CONCEPT 5.4: Proteins perform most functions in cells.


Key Terms:

protein -- a polymer constructed from a set of just 20 kinds of monomers called amino acids
amino acid -- monomer that makes up proteins; contains carboxy and amino functional groups
polypeptide -- cell create proteins by linking amino acids together into a chain
denaturation -- loss of normal shape of a protein due to heat or other factor


Notes:

The Functions of Proteins
* proteins are responsible for almost all of the day-to-day functioning of organisms
* proteins with less-visible functions defend the body from harmful small molecules, and other that act as signals, conveying messages from one cell to another


Amino Acids
* three of the central carbon's partners are the same in all amino acids
* the side group is responsible for each amino acid
- ex. side group of the amino acid - leucine = hydrocarbon

Building a Protein
* need a lot of amino acids to build up a protein


Protein Shape
* An unfavorable change in temperature, pH, or some other quality of the environment can cause a protein to unravel and lose its normal shape (denaturation)



Concept Check 5.4

1. Give at least two examples of proteins you can "see" in the world around you. What are their functions?
animals, and plants; proteins are responsible during everyday functioning organisms.

2. Relate amino acids, polypeptides, and proteins.
They are all made out of a lot of molecules, and they all support the living things tfor do their works.


3. Explain how heat can destroy a protein.



4. Which part of an anmino acid's structure are the same in all amino acids? Which part is uniques?

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