Download amino acids

NOTES: 2.3 part 2
Nucleic Acids & Proteins
So far, we’ve covered…
the following MACROMOLECULES:
● CARBOHYDRATES…
● LIPIDS…
Let’s review…
CARBOHYDRATES:
● elements?
● purpose(s)?
● monomers / building blocks?
● polymers?
● examples?
CARBOHYDRATES:
● elements?
-C, H, O
● purpose(s)?
-Energy for cells; energy storage;
structure / support
● monomers / building blocks?
-monosaccharides (“single sugars”)
CARBOHYDRATES:
● polymers?
-polysaccharides
● examples?
-MONO: glucose, fructose, ribose
-DI: sucrose, maltose
-POLY: starch,
cellulose, glycogen
LIPIDS:
● elements?
● purpose(s)?
● monomers / building blocks?
● polymers?
● examples?
LIPIDS:
● elements?
-C, H, O
● purpose(s)?
-long-term energy storage; insulation;
part of cell membrane
● monomers / building blocks?
-glycerol
-fatty acids
LIPIDS:
● polymers / macromolecules?
-fats; phospholipids; steroids
● examples?
-saturated fats: butter, lard
-unsat. fats: olive oil, corn oil
-phospholipids
(in cell memb.)
-cholesterol
And now we will look at:
● NUCLEIC ACIDS &
● PROTEINS
● nucleic acids store and transmit
hereditary information
● Two types of nucleic acids:
1) DNA
2) RNA
Structure 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) a 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-phosphatesugar-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
2) RNA = Ribonucleic acid
● functions in the actual
synthesis of proteins
coded for by DNA
● Polymers (long chains) of AMINO ACIDS
– arranged in specific sequence
– linked by PEPTIDE BONDS
– range in length from a
few to 1000+
AMINO ACIDS
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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)
Amino Acid Monomers
● Cells use 20 amino acids to make
thousands of proteins
● amino acids differ from each other at their
“side” or “R” chains
● because they are so different, and can be
put together in almost infinite
combinations, proteins are
among the most diverse
macromolecules.
Glycine (Gly)
Alanine (Ala)
Valine (Val)
Leucine (Leu)
Isoleucine (Ile)
Nonpolar
Methionine (Met)
Phenylalanine (Phe)
Tryptophan (Trp)
Proline (Pro)
Polar
Serine (Ser)
Threonine (Thr)
Cysteine (Cys)
Tyrosine (Tyr)
Asparagine (Asn) Glutamine (Gln)
Acidic
Basic
Electrically
charged
Aspartic acid (Asp) Glutamic acid (Glu)
Lysine (Lys)
Arginine (Arg)
Histidine (His)
● Amino acids are linked together
through DEHYDRATION
SYNTHESIS to form PEPTIDE
BONDS
PROTEIN STRUCTURE
● a protein’s function depends on its
specific 3-D shape
Levels of Protein Shape /
Organization:
● amino acids are
assembled into
polypeptide chains
according to instructions
coded in DNA!
● there are 4 levels of
structure for proteins…
Levels of Protein Shape /
Organization:
● PRIMARY: linear sequence of
amino acids;
● SECONDARY: folding or coiling
of the chain (in small,
local areas);
Levels of Protein Shape /
Organization:
● TERTIARY: complete, 3-D arrangement of
the polypeptide chain;
● QUATERNARY: some proteins include
multiple polypeptide chains that come
together to form 1 functioning unit
Protein Shape:
● determined by genes
● stabilized by ionic & covalent
bonds, H-bonds, van der Waals
forces
Protein Shape:
● can be altered 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 Proteins
● structural support (e.g. hair, nails)
● signaling (e.g. hormones)
Functions of Proteins
● movement (contraction
of muscles)
● transporting oxygen in the
blood
Functions of Proteins
● defense (antibodies of
immune system)
● catalysis (speeding up)
of reactions (ENZYMES)
**more about enzymes in
2.4!!