Download Polymer: Macromolecule

I. Polymers & Macromolecules
Figure 1: Polymers
● Polymer:
● Macromolecule:
Figure 2: Polymerization via Dehydration Synthesis
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● Dehydration
Synthesis:
Figure 3: Depolymerization via Hydrolysis
● Hydrolysis:
II. Organic Macromolecules
Class I Macromolecules: Carbohydrates
Figure 4: General Structure
● General
characteristics of carbohydrates include the following:
a) Ring structure composed of C,H,& O in a ratio of nearly 1:2:1 (ratio deviates in more complex carbs)
b) Names of carbohydrates generally end in the suffix -OSE
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Carbohydrates: Monosaccharides
Figure 4.1: Monosaccharrides
● Monosaccharides:
a) Monosaccharides are sweet tasting sugars (interact with “sweet” taste buds).
b) Glucose is the most abundant monosaccharide & is thus the major nutrient (energy source) for cells.
Chemical Testing for Monosaccharides
Figure 4.2: Benedicts Solution
Blue
Green
Yellow
Orange
Red
● Benedict’s
Solution is blue in color can be used to test for the presence of some monosaccharides. A positive test for
the presence of monosaccharides is a brick red by product when a mixture thought to contain simple sugars is heated.
Carbohydrates: Disaccharides
Figure 5: Disaccharides (Sucrose)
Glucose
Fructose
Sucrose
*As a result of the dehydration synthesis reaction between monosaccharides (glucose & fructose) a covalent bond
called a Glycosidic Bond is formed to produce the dissacharide (sucrose).
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● Disaccharides:
a) Like monosaccharides, disaccharides are sweet-tasting sugars.
Carbohydrates: Polysaccharides
Figure 6: Polysaccharides
● Polysaccharides:
a) Polysaccharides are NOT sweet-tasting sugars (not compatible with “sweet” taste buds)
Figure 6.1: Storage Polysaccharides (Starch)
● Starches
are moderately branched molecules used by plants to store excess glucose produced by photosynthesis. Can
be quickly broken down (hydrolyzed) back into glucose for cellular energy when needed.
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Chemical Testing for Starch
Figure 6.2: Lugol’s Iodine Test
●Lugol’s
Iodine (I) Solution is amber (yellow-brown) in color & is used to test for the presence of starch. In the
presence of iodine, starch will produce a blue-black color. If not present, the iodine solution will remain amber in
color.
Figure 6.3: Storage Polysaccharides (Glycogen)
● Glycogen
is a heavily branched molecule synthesized in liver cells from excess glucose following digestion. Stored in
both liver & muscle cells until needed.
● Storage
Polysaccharide:
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Figure 6.4: Structural Polysaccharides (Cellulose)
● Cellulose
is an unbranched molecule & a component of plant cell walls consisting of glucose subunits. Form fibers
that strengthen cell walls. Not easily digested most organisms because of a lack of enzymes that hydrolyze the bonds
between the glucose subunits.
Figure 6.5: Structural Polysaccharides (Chitin)
● Found
in arthropods (insect & crustacean) exoskeletons & fungi cell walls. Chitin forms tough structures because, like
cellulose, its molecules it can be arranged into fibers.
● Structural
Polysaccharide:
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Class II Macromolecules: Lipids
Figure 7: Lipids Classes
● Consist of a diverse array of molecules including fats, phospholipids, steroids, & waxes.
● Are not considered polymers because they are not composed of similar subunits.
● Despite the differences among types of lipids, they all share the property of being nonpolar
& insoluble in water.
● Lipid:
Lipids: Fats/Triglycerides
Figure 8: Fat Structure
● Consist
of 1 GLYCEROL MOLECULE & 3 FATTY ACIDS. At one end of each fatty acid is a “head” consisting of a
carboxyl group (acidic) followed by a long carbon “tail”. The nonpolar C-H bonds in the fatty acid tails make fat
molecules HYDROPHOBIC.
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● Fats
form via dehydration synthesis whereby the –OH groups of glycerol react COVALENTLY with the carboxyl groups
of the fatty acids; each reaction forms an Ester Bond & results in the release one water molecule (3 total).
● Fats/Triglycerides:
Figure 8.1: Saturated Fats
Figure 8.2: Unsaturated Fats
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Lipids: Phospholipids
Figure 9: Phospholipid
● Have
both hydrophobic (fatty acid tails) & hydrophilic (phosphate head) regions. Thus in water, phospholipids form
droplets where the hydrophilic heads contact the water & the hydrophobic tails are restricted to the water-free
interior. Due to this behavior, phospholipids are a major component of biological membranes.
● Phospholipids:
Lipids: Steroids
Figure 10: Steroids (Cholesterol)
● Steroids:
a) Cholesterol is the simplest of all steroids & is the building block of more complex steroid molecules.
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Figure 10.1: Steroids (Testosterone & Estrogen)
● Testosterone
is a steroid that promotes the development of secondary sex characteristics in males during puberty,
while Estrogen has a similar effect in females. Both steroids are produced from the modification of cholesterol.
● Waxes
are lipids that form between alcohols & fatty acids & are highly variable in structure. Both animals & plants
produce waxes; in the case of plants, these waxes prevent water loss from body tissue that may result in the plant
drying out & dying.
Chemical Testing for Lipids
● Lipids do not dissolve in water, but DO dissolve in ethanol. Shake some of the test sample with ethanol. Pour the
liquid into a test tube of water, leaving any undissolved substances behind. If there are lipids dissolved in the ethanol,
they will come out of solution in water, forming a cloudy white film.
Class III Macromolecules: Proteins
Figure 11: Amino Acids (Monomers of Proteins)
● Proteins
are the most complex of all organic macromolecules & contain carbon, hydrogen, oxygen, & nitrogen.
● The
building blocks of proteins are Amino Acids. All 20 amino acids consist of an amino group (-NH2), carboxyl group
(-COOH), & side chain attached to a central carbon. It is the functional unit of the side chain (R) that makes all amino
acids unique.
● Names
of most proteins end in the suffix –IN or –ASE (if the protein is an enzyme)
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● Proteins:
Figure 11.1: Peptide Synthesis (Dipeptide)
● When
the –COOH group of one amino acid is adjacent to the NH2 group of another, an enzyme will join them via
dehydration synthesis to form a Peptide Bond. The resulting molecule is known as a Dipeptide. As many more amino
acids are added, a long Polypeptide chain is formed.
● All
polypeptide chains have a –COOH (carboxyl group) at one end & an –NH2 (amino group) at the other:
● Once
formed, a polypeptide chain begins to fold in a specific way dictated by its unique sequence of amino acids to
form a Protein.
● Proteins
are 3-D polypeptides that can perform a specific function within the cell. Three to four levels of folding are
often observed within protein molecules …
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Figure 11.2: Levels of Protein Structure
●Primary
Structure: represents the unique amino acid sequence of a polypeptide –involves peptide bonds only.
●Secondary
Structure: represents coiled or folded segments of the polypeptide chain established by H-bonds between
amino & carboxyl groups.
●Tertiary
Structure: is the folding of the polypeptide through the interaction of adjacent R-Groups. This bonding can
result in the polypeptide taking on a 3-D shape, enabling it to become fully functional.
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●Quaternary
Structure: represents the most complex protein structure that forms when two or more polypeptide chains
of tertiary structure join to form a functional protein. NOT ALL PROTEINS REACH THIS LEVEL! The same types of
interactions that produce tertiary structure also contribute to quaternary structure.
Figure 11.3: Specificity of Proteins
● Protein
Specificity:
a) Protein Binding Sites arise due to the specific manner in which polypeptides fold to achieve either tertiary or
quaternary structure.
b) The shape of the binding site is very specific & allows proteins to only recognize & bind to a particular class of
molecule or Substrate.
Chemical Test for Proteins
● The presence of protein in solution can be indicated by the use of Biuret Solution. In the presence of protein, biuret
turns from blue to pink in color.
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Figure 11.4: Protein Denaturation
● Denaturation:
a) The denaturation of a protein can be initiated by extreme heat (NOT cold!!), pH, physical stress, & salt
concentrations.
Class IV Macromolecules: Nucleic Acids
Figure 12: Nucleotide (Building Block of DNA, RNA)
● The
units that comprise nucleic acids are called Nucleotides, which consist of a 5-sided sugar, a phosphate group, &
a nitrogenous base. Bases can be classified as Purines or Pyrimidines based on their structures:
a) Purine Nitrogenous Bases: consist of a 5-sided + 6-sided ring & include Adenine (A) & Guanine (G)
b) Pyrimidine Nitrogenous Bases: consist of a 6-sided ring & include Thymine (T), Cytosine (C), & Uracil (U)
● DNA
nucleotides lack an OH on the 2’-carbon of the sugar (deoxyribose). In addition, DNA nucleotides may bear the
bases A, C, G, or T on the 1’-carbon whereas RNA nucleotides may bear A, C, G, or U.
● DNA
is also double stranded & contains information for the production of proteins. RNA is single stranded & is
involved in relaying genetic information from DNA to regions of the cell responsible for protein production.
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Figure 12.1: DNA vs RNA Structure
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