Polymers (long chains) of AMINO ACIDS –arranged in specific sequence –linked by PEPTIDE BONDS –range in length from a few to 1000+
Post on 27-Dec-2015
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• Polymers (long chains) of AMINO ACIDS
– arranged in specific sequence
– linked by PEPTIDE BONDS
– range in length from a
few to 1000+
AMINO ACIDSAMINO ACIDS • building blocks of proteins • there are 20 common amino acids• structure of an amino acid: • elements included in a
protein:-carbon-hydrogen-oxygen-nitrogen-sulfur (usually)
PROTEIN STRUCTURE
• a protein’s function depends on its specific 3-D shape
Protein Shape:Protein Shape:
• determined by environmental
conditions
• DENATURATION: protein loses its natural shape, and therefore loses its function! This can be caused by:– extreme heat– pH changes
Functions of ProteinsFunctions of Proteins
• structural support (e.g. hair, nails)
• signaling (e.g. hormones)
Functions of ProteinsFunctions of Proteins • movement (contraction
of muscles)
• transporting oxygen in the
blood
Functions of ProteinsFunctions of Proteins
• defense (antibodies of immune system)
• catalysis of reactions (ENZYMES)
PROTEINS WORKING AS ENZYMESPROTEINS WORKING AS ENZYMES
ENZYMES:
• are proteins
• control the speed of reactions (often they increase the speed of reactions)
• each enzyme is specific to a SUBSTRATE
• SUBSTRATE = the substance the enzyme acts on
Substrate ==> enzyme-sub.==> product
+ complex +
enzyme enzyme
• ACTIVE SITE = region of an enzyme which binds to the substrate
– is usually a pocket or groove on surface
– compatible “fit” between shape of enzyme’s active site and shape of substrate
Factors Affecting Enzyme Activity
1. Temperature:
– as temp increases, reaction rate increases
– BUT, if temp gets too high, enzyme
denatures and loses its shape and function
– optimal range for human enzymes: 35-40°C
2. pH:
-optimal range for most enzymes: pH 6-8
*some enzymes operate best at extremes of pH (e.g. digestive enzyme pepsin, found in the acidic environment of the stomach, works best at pH 2)
Structure of Nucleic AcidsStructure of Nucleic Acids
• polymers made up of monomers called NUCLEOTIDES
• Elements present:
-carbon
-hydrogen
-oxygen
-nitrogen
-phosphorus
• each nucleotide consists
of:1. a simple sugar
-deoxyribose in DNA-ribose in RNA
2. phosphate group 3. a base (e.g. in DNA, the bases are A, G,
C, and T)
• nucleotides are joined together in DEHYDRATION SYNTHESIS
• results in a “backbone” with a repeating pattern of sugar-phosphate-sugar-phosphate...
1. DNA = Deoxyribonucleic acid
• forms the genetic code - the instructions for the proteins (amino acid sequences) of an organisms’ proteins
• is copied and passed
from one generation
of cells to another
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