macromolecules

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Transcript macromolecules

MACRO – BIG
MICRO - SMALL
A MACROMOLECULE IS A VERY LARGE
MOLECULE COMMONLY CREATED BY
POLYMERIZATION OF SMALLER SUBUNITS.
YOU DEAL WITH POLYMERS EVERYDAY –
POLYETHYLENE, POLYPROPYLENE,
POLYSTYRENE, ETC.
WE CALL THEM PLASTICS.
POLYETHYLENE
BIOPOLYMERS INCLUDE:
1) PROTEINS
2) NUCLEIC ACIDS
3) CARBOHYDRATES
OTHER BIOLOGICAL MACROMOLECULES ARE
-
LIPIDS AND FATS
MACROCYCLES – HEMOGLOBIN AND
CHLOROPHYL
THE TWO MAJOR CARBOHYDRTE
BIOPOLYMERS ARE STARCH AND
CELLULOSE.
THEY ARE BOTH POLYMERS OF GLUCOSE.
Glucose molecule
STARCH
CELLULOSE
Glucose molecule
THE ONLY DIFFERENCE BETWEEN GLUCOSE AND CELLULOSE
IS THE WAY THE GLUCOSE MOLECULES ARE BONDED
TOGETHER.
OUR BODIES DON’T MAKE THE ENZYME THAT WILL BREAK
THE CELLULOSE BONDS.
PROTEINS
A POLYPEPTIDE IS A LONG CHAIN OF
POLYMERIZED AMINO ACIDS.
A PROTEIN CONSISTS OF ONE OR
MORE POLYPEPTIDES.
PROTEINS ARE FOLDED INTO 3
DIMENSIONAL SHAPES THAT DEPEND
ON THEIR FUNCTION.
PROTEINS CAN ACT AS ENZYMES
(CATALYSTS TO HELP IN CERTAIN
REACTIONS), CELL SIGNALING,
STRUCTURAL FUNCTIONS, ETC.
THERE ARE 20 DIFFERENT AMINO ACIDS
THAT MAKE UP PROTEINS.
PROTEINS ARE ASSEMBLED IN THE
CELLS.
THE LIFETIMES OF PROTEINS VARIES
FROM MINUTES TO YEARS – TYPICALLY 1
TO 2 DAYS.
THE BODY RECYCLES THEM – BREAKING
DOWN THE OLD ONES INTO AMINO
ACIDS AND BUILDING NEW ONES FROM
THE AMINO ACIDS.
THE SEQUENCE OF AMINO ACIDS
DETERMINES THE FUNCTION OF THE
PROTEIN.
PROTEINS ARE FORMED WHEN THE AMINE
GROUP OF ONE AMINO ACID REACTS WITH
THE ACID GROUP OF ANOTHER TO FORM AN
AMIDE LINK.
A GOOD EXAMPLE OF THE COMPLEXITY OF
A PROTEIN IS THE VOLTAGE GATED
SODIUM CHANNEL THAT IS RESPONSIBLE
FOR NERVE CONDUCTION. IT IS A VERY
LONG CHAIN PROTEIN THAT CONSISTS
OF 24 LITTLE CYLINDERS THAT THREAD
THROUGH THE LIPID MEMBRANE IN THE
NERVE CELL WALL.
AN ASIDE: HOW FAST DO NERVE SIGNALS
TRAVEL?
MUSCLE POSITION SIGNALS TRAVEL AT ABOUT
390 ft/sec.
TOUCH SIGNALS TRAVEL AT ABOUT 240 ft/sec.
PAIN SIGNALS TRAVEL AT ABOUT 2 ft/sec.
DNA – DEOXYRIBONUCLEIC ACID.
"ADN animation" by brian0918™ -
THE DOUBLE HELIX OF DNA CONSISTS OF
TWO BIOPOLYMER STRANDS WOUND
AROUND EACH OTHER.
EACH STRAND IS A POLYNUCLEOTIDE.
A NUCLEOTIDE CONSISTS OF A 5 CARBON
SUGAR, A PHOSPHATE GROUP, AND A
NITROGEN BASE. THE NITROGEN BASES
ARE:
1) A – ADENINE
2) G – GUANINE
3) C – CYTOSINE
4) T - THYMINE
THE
POLYNUCLEOTIDE
CHAIN CONSISTS
OF ALTERNATING
SUGARS AND
PHOSPHATE
GROUPS. THE
NITROGEN BASES
POINT IN FROM
THE SUGARS AND
HYDROGEN BOND
TO HOLD THE
TWO STRANDS
TOGETHER.
A PAIRS WITH T
C PAIRS WITH G
THE HYDROGEN
BONDS CAN BE
BROKEN TO
UNZIP THE
CHAINS FOR
COPYING
INFORMATION.
RNA IS A SINGLE STRANDED
POLYNUCLEOTIDE THAT USES RIBOSE AS THE
SUGAR INSTEAD OF DEOXYRIBOSE.
URACIL REPLACES THYMINE IN THE
NITROGEN BASES.
THERE ARE THREE KINDS OF RNA:
1) MESSENGER RNA - CARRIES COPIES OF
INTRUCTIONS FOR THE ASSEMBLY OF
AMINO ACIDS INTO PROTEINS FROM DNA
TO THE REST OF THE CELL
2) RIBOSOMAL RNA – MAKES UP MAJOR PART
OF RIBOSOME
3) TRANSFER RNA – TRANSFERS AMINO ACIDS
TO RIBOSOMES DURING PROTEIN
SYNTHESIS
A SEQUENCE OF 3 NUCLEOTIDES CODES FOR A
GIVEN AMINO ACID (CODON) ON DNA OR
RNA.
PHOSPHOLIPIDS MAKE UP CELL MEMBRANES. THEY
CONSIST OF TWO LONG CHAIN FATTY ACIDS
ATTACHED TO A GLYCEROL AND A PHOSPHATE
GROUP. THIS RESULTS IN A MOLECULE WITH A
POLAR END THAT LIKES WATER AND A NONPOLAR
END THAT IS NOT WATER SOLUBLE.
IF YOU PUT PHOSPHOLIPIDS IN WATER, THEY WILL
ARRANGE THEMSELVES INTO A LIPID BILAYER –
SIMILAR TO THE STRUCTURE OF A CELL MEMBRANE.
CHOLESTEROL IS ALSO FOUND IN CELL
MEMBRANES. IT MAKES THE CELL
MEMBRANE STRONGER, LESS FLUID, AND
LESS PERMEABLE TO WATER SOLUBLE
SUBSTANCES.
FATS ARE SIMILAR TO PHOSPHOLIPIDS. IN
FATS, THE PHOSPHATE HAS BEEN REPLACED BY
ANOTHER FATTY ACID GROUP.