Date post: | 27-Dec-2015 |
Category: |
Documents |
Upload: | myrtle-rich |
View: | 214 times |
Download: | 0 times |
• 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)
• nucleic acids store and transmit hereditary information
• Two types of nucleic acids:1. DNA
2. RNA
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