Macromolecules

Condensation/ Dehydration synthesis:

  • Also known as dehydration synthesis, it is a chemical reaction that combines two molecules by removing a water molecule.

  • Occurs when a hydroxyl group (-OH) from one molecule combines with a hydrogen atom (-H) from another molecule, forming a covalent bond.

  • Results in the formation of a larger molecule and the release of a water molecule.

  • Commonly involved in the formation of complex carbohydrates, proteins, and lipids.

  • Anabolic process that requires energy.

Hydrolysis Reactions:

  • Hydrolysis is the reverse process of condensation/dehydration synthesis.

  • Involves the breakdown of a larger molecule into smaller molecules by the addition of a water molecule.

  • Occurs when a covalent bond is broken by adding a hydroxyl group (-OH) to one molecule and a hydrogen atom (-H) to another molecule.

  • Releases energy and is a catabolic process.

  • Commonly involved in the digestion of complex carbohydrates, proteins, and lipids into simpler forms for absorption and use by cells.

Macromolecules

Monomers and Polymers

  • Carbohydrates:

    • Monomer: Monosaccharides (e.g., glucose)

    • Polymer: Polysaccharides (e.g., starch, cellulose)

  • Proteins:

    • Monomer: Amino acid

    • Polymer: Polypeptides (formed by peptide bonds between amino acids)

  • Lipids:

    • Monomer: Fatty acids and glycerol

    • No true polymers

  • Nucleic acids:

    • Monomer: Nucleotides

    • Polymer: DNA and RNA (formed by phosphodiester bonds between nucleotides)

Types of Bonds

  • Carbohydrates:

    • Glycosidic bonds between monosaccharides

  • Proteins:

    • Peptide bonds between amino acids

  • Lipids:

    • Ester bonds between fatty acids and glycerol

  • Nucleic acids:

    • Phosphodiester bonds between nucleotides

Structure, Function, Location, Sources, Properties, Examples

Carbohydrates:

  • Structure: Composed of carbon, hydrogen, and oxygen atoms

  • Function: Provide energy and structural support

  • Location: Found in plants and animals

  • Sources: Fruits, vegetables, grains

Protein:

  • Structure: Composed of amino acids linked together by peptide bonds.

  • Function: Essential for growth, repair, and maintenance of body tissues. Enzymes, antibodies, and hormones are examples of proteins.

  • Location: Found in all cells of the body.

  • Sources: Meat, poultry, fish, dairy products, legumes, nuts, and seeds.

  • Properties: Proteins are diverse in structure and function, with different amino acid sequences determining their unique properties.

  • Examples: Hemoglobin, collagen, insulin, antibodies.

Lipids:

  • Structure: Composed of fatty acids and glycerol.

  • Function: Energy storage, insulation, protection of organs, and cell membrane structure.

  • Location: Found in adipose tissue, cell membranes, and certain organs.

  • Sources: Oils, butter, fatty meats, avocados, nuts, and seeds.

  • Properties: Lipids are hydrophobic and insoluble in water.

  • Examples: Triglycerides, phospholipids, cholesterol.

Nucleic Acid:

  • Structure: Composed of nucleotides (sugar, phosphate, and nitrogenous base).

  • Function: Store and transmit genetic information (DNA) and participate in protein synthesis (RNA).

  • Location: DNA is found in the nucleus of cells, while RNA is found in the nucleus and cytoplasm.

  • Sources: DNA is found in all living organisms, while RNA is synthesized from DNA.

  • Properties: Nucleic acids have a double-stranded (DNA) or single-stranded (RNA) helical

Functional Groups Found in Each Macromolecule

Carbohydrates:

  • Hydroxyl group (-OH): Found in all carbohydrates, attached to carbon atoms.

  • Aldehyde group (-CHO): Found in aldose sugars, at the end of the carbon chain.

  • Ketone group (-C=O): Found in ketose sugars, within the carbon chain.

Lipids:

  • Carboxyl group (-COOH): Found in fatty acids, acts as an acid by releasing H+ ions.

  • Hydroxyl group (-OH): Found in glycerol, attached to carbon atoms.

  • Ester group (-COO-): Found in triglycerides, formed by the reaction between a carboxyl group and a hydroxyl group.

Proteins:

  • Amino group (-NH2): Found in amino acids, acts as a base by accepting H+ ions.

  • Carboxyl group (-COOH): Found in amino acids, acts as an acid by releasing H+ ions.

  • R-group: Found in amino acids, varies and determines the specific properties of each amino acid.

Nucleic Acids:

  • Phosphate group (-PO4): Found in nucleotides, provides a negative charge and is involved in the formation of phosphodiester bonds.

  • Pentose sugar: Found in nucleotides, either ribose (RNA) or deoxyribose (DNA).

  • Nitrogenous base: Found in nucleotides, can be adenine (A), thymine (T), cytosine (C), guanine (G) (DNA), or uracil (U) (RNA).

Food Tests for Macromolecules

Carbohydrate Tests

Monosaccharides

a) Benedict's Test: Used to detect monosaccharides like glucose and fructose.

  • Positive result: Formation of a brick-red precipitate.

  • Negative result: Form Blue color

b) Glucose Test Stripes:

  • Positive result: Green

  • Negative result: Yellow

Polysaccharides

b) Iodine Test: Identifies the presence of starch.

  • Positive result: Formation of a blue-black color.

  • Negative result: Yellowish brown

Protein Tests

Biuret Test: Used to detect the presence of proteins.

  • Positive result: Formation of a violet color.

  • Negative result: Blue color

  • Detects peptide bond

Lipid Tests

Paper:

  • Positive result: translucent paper

Intro to Enzymes

  • Kinetic energy: energy of movement (the type of energy that does work) that makes things change​

  • Potential energy: energy of state or position, or stored energy

  • Chemical energy: energy, including atoms and molecules, contained in the bonds of chemical compounds

  • Thermodynamics: study of energy

    • First Law: Energy is neither created nor destroyed.​

    • Second Law: When energy is converted from one form to another, some of that energy becomes unavailable for doing work.​

  • Metabolism: the sum total of all chemical reactions occurring in a biological system at a given time​

    • Exergonic reactions release the energy bound up in the reactants and yield simpler, low energy products.​

      • ex: Photosynthesis

    • Endergonic reactions require energy input to take simple, low energy reactants and build complex, high energy products. 

      • ex: Cellular respiration

  • Anabolic : require energy inputs; energy is captured in the chemical bonds that form.​

    • Endergonic

  • Catabolic: release energy; break down complex molecules into simpler ones.​ Energy stored in the chemical bonds is released.​

    • Exergonic

  • Spontaneous reaction: product favored

  • Catalysts(enzymes; proteins) speeds up reaction

    • Input of activation energy aka energy barrier(amount of energy needed to overcome bonds and form new ones) puts reactants into transition state(almost product state)

  • Enzyme lowers activation energy

    • enzymes end in -ase

    • sugars ends in -ose

Enzymes

  • Reactants are substrates

  • Lock and Key model:

    • Enzyme substrate complex: E(nzyme) + S(ubstrate)= ES = E + P(roduct)

  • Induced fit model: Enzymes’ active site change shape to make substrate bind fit

  • Saturated: all enzyme molecules are bounded to substrate molcules

    • If reaction rate and substrate concentration graph levels off, it is due to the solution being too saturated

  • Lower rate of reaction by changing conditions that affects enzyme(pH, temperature, conc of other molecules)

  • To catalyze a reaction:

    • Induces strain on substrate

    • substrate orientation

    • adding chemical group (R group)

  • Enzyme pathways: product of one reaction is a substrate for the next.

    • Feedback inhibition: final product acts as a noncompetitive inhibitor of the first enzyme, which shuts down the pathway.

  • Cell regulates metabolism by controlling amount of enzymes

  • Irreversible inhibition: inhibitor is covalently binds to a side chain in the active site. The enzyme is permanently inactivated.

  • Reversible inhibition:

    • A competitive inhibitor: competes with natural substrate for active site.

      A noncompetitive inhibitor: binds at a site distinct from the active site-this causes change in enzyme shape and function.

  • Determine if inhibitor is competitive or noncompetitive:

  1. Determine the saturation curve of an enzyme catalyzed reaction WITHOUT the presence of the inhibitor.

  2. Run the same reaction in the presence of the inhibitor and see how it changes the saturation curve.

  3. Competitive inhibition can be overcome by increasing the substrate concentration.

    Noncompetitive inhibition cannot be overcome by

    increasing substrate concentration.

  • Allosteric activation:

    • allosteric macromolecule binds the allosteric site, opening up the active site for the substrate.

    • A functional group can be added to the enzyme, changing the shape of the enzyme, opening up the active site.

  • Allosteric regulation--non-substrate molecule binds a site other than the active site (the allosteric site)

    • Enzyme changes shape and the active site changes