Summary 5.4

=Protenins perform most functions=

*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 carboxyl and amino functional groups.
polypeptide: a chain of proteins linked by amino acids together.
denaturation: loss of normal shape of a protein due to heat or other factor.

*The Functions of Proteins

protein: a polymer by set of just 20 kinds of nomonmers(amino acids).
-functioning of organisms in daily life
ex) hair and fur, amke muscles, and provide nutrient storage
-less visible functions ex) circulate in the blood
fend the body from harmful microorganisms
hers that act as signals
-structure of proteins is the key to understanding their elaborate and diverse functions.

*Amino Acids
amino acid: consists central carbon atom bonded to four partners
- 3 parts are all the same

- one part=>hydrogen atom

- two others are a carboxyl group and amino group

+ 'side group' or 'R-group', the fourth bond of the central carbon, cause the difference about amino acids.

ex) leucine, and serine

*Building Protein

polypeptide: cells create proteins by linking amino acids together into a chain.

- the link is created by a dehydration between amino group of amino acid and the carboxyl group of amino acid in the cahin.

- body createds variety of proteins by arranging different amino acids in different orders.

- most polypeptide chains are at least 100 amino acids in length due to the 20 choices for each amino acid.

- each protein has unique sequence of amino acids.

*Protein Shape

- functional protein has one or more polypeptides precisely twisted, folded, and coiled.

- protein's shpe is also influenced by environment, usually aqueous

-> water attracts hydrophilic side groups and rejects hydrophobic

denaturation: changes in shape of protein due to temperatur, pH,or some other qualities

-ex) egg's white liquid part turning into solid while heating up.

*Concept Check 5.4

1. Give at least two examples of proteins you can "see" in the world around you. What are their functions?

- Hair protects our head to be warm.
- Egg's white part is very nutrient

2. Relate amino acids, polypeptides, and proteins.

- Protein is made out of lots of amino acids and polypeptide is a chain that cells created by linking amino aicds. Therefore, amino acid is just a building blocks of these.

3. Explain how heat can destroy a protein.

- Heating up a protein is a change in temperature and that causes protein to unravel and change its shapes

4. Which parts of an amino acid's structure are the same in all amino aicds? Which part is unique?

- All amino acid has centeral carbon and side groups is the unique part where determines the property of proteins.