Enzymes and Macromolecules: Organic Chemistry in Biology

Metabolism

All of the chemical reactions within each cell of an organism.

Chemical reactions

The breaking and forming of bonds.

Endothermic

Net absorption of energy (in the form of heat or light).

Exothermic

Net release of energy (in the form of heat or light).

Catabolic

Breaking down complex molecules into simpler ones.

Anabolic

Building simpler molecules into more complex ones.

Energy absorption

Breaking a bond requires energy to be absorbed.

Energy release

Forming a bond allows energy to be released.

Reactant (substrate)

Substance that is changed during a chemical reaction

Products

Substance that is made by a chemical reaction

Reactant energy

The amount of energy in the reactants

Product energy

The amount of energy in the products

Activation energy

The amount of energy required to be added to the system to lead to the reactants becoming the products

Enzymes

Proteins that speed up chemical reactions

Active site

The part of the enzyme that binds to the substrate

Lock-and-Key model

Enzymes are specific to certain substrates

Ball-and-Glove model

When the substrate binds to the active site, the enzyme-substrate complex changes shape (induced fit)

Enzymes: Action

Enzymes can break bonds to form two products or make bonds between substrates to form one product

Coenzyme

A middle-man that binds to the enzyme's active site, allowing substrates to bind

Inhibition

A way to slow down enzyme activity

Competitive inhibitor

Has a shape similar to the substrate, binds to the enzyme's active site without producing the product, preventing the reaction from taking place

Noncompetitive inhibitor

Does not bind to the active site of the enzyme, but binds to another part of the enzyme known as the allosteric site, changing the shape of the enzyme

Denature

Modifying the structure of a protein, generally making it nonfunctioning

Effects of denaturation

If the enzyme is denatured, the active site will be deformed and not be able to bind to the substrate

Environmental changes affecting enzymes

Can be caused by extreme changes in pH, temperature, ion strength, and solubility

Allosteric site

The alternative site on the enzyme where a noncompetitive inhibitor binds.

Rate of Chemical Reaction

Affected by environmental factors such as temperature and pH.

Temperature effect on reaction rate

Generally accepted that increasing temperature increases the rate of reaction due to faster molecular movement.

Optimal pH

Most enzymes have an optimal pH, and modifying it will impact the rate of reaction.

Denaturation temperature range

Enzymes can denature around 40-45°C.

Macromolecule

Large organic molecules (contain carbon) that make up all living things.

Organic molecule

Contains carbon.

Carbohydrates

One of the four main classes of macromolecules.

Lipids

One of the four main classes of macromolecules.

Proteins

One of the four main classes of macromolecules.

Nucleic acids

One of the four main classes of macromolecules.

Polymer

Larger, complex structure made of monomers.

Monomer

Small, basic sub-unit.

Dehydration synthesis

Process by which monomers undergo to form polymers.

Condensation

Another term for dehydration synthesis.

Polymer Decomposition

To break a polymer down into monomers, the opposite reaction is performed.

Hydrolysis

Water is added to break down the polymer.

Carbohydrate

Main function: short-term energy storage; Found in: sugars and starches; Elements: C, H, O; Properties: polar and hydrophilic.

Carbohydrate Structure

Monomer: monosaccharides; Polymer: polysaccharides.

Glucose

Main fuel for animal cells.

Galactose

Sugar in milk.

Fructose

Sugar in fruit.

Glycogen

Composed of glucose, how animals store energy.

Cellulose

Structural support in plant cell walls.

Starch

How plants store sugar.

Energy storage in carbohydrates

4 calories/gram.

Lipids Structure

Monomer: fatty acids; Polymer: triglycerides.

Energy storage in lipids

9 calories/gram.

Compact structure of lipids

Better than carbs for storage because they hold more energy.

Body's energy source order

The body can break carbohydrates down easily—typically the first thing the body will break down when it needs energy.

Lipids as energy source

When the body needs energy and runs out of easy-to-access carbs, it will break down lipids next.

Saturated fatty acid

All single bonds in the chain allows it to compact—tend to be solid at room temperature.

Unsaturated fatty acid

Double or triple bonds in the chain prevents it from compacting—tend to be liquid at room temperature.

Saturated Fats

Unhealthy because they easily solidify and clog body's pathways.

Phospholipid

Type of lipid used in cell membranes.

Phospholipid Structure

2 fatty acids (2 lipid monomers) and 1 phosphate.

Hydrophilic head

Phosphate group.

Hydrophobic tail

Fatty acids.

Phospholipid bilayer

2 layers make up the plasma membrane of our cells.

Energy storage in Proteins

4 calories/gram.

Proteins as energy source

Used by the body for energy as a last resort when it enters starvation.

Elements in Proteins

C, H, O, N.

Monomer of Proteins

Amino acids.

Polymer of Proteins

Polypeptide.

Peptide bond

Amino acids are linked together by a peptide bond.

Protein Properties

Some are polar, some are nonpolar (some are hydrophilic, some are hydrophobic).

Functions of Proteins

Many important functions including enzymes, hormones, antibodies, receptors, and energy source.

Hormones

Regulate cell processes.

Antibodies

Help immune system fight diseases.

Receptors

Aid in cell signaling.

Beta-pleated sheet

A type of secondary structure in proteins.

Alpha-helix

A type of secondary structure in proteins.

Protein Folding Levels

4 levels: Primary, Secondary, Tertiary, Quaternary.

Primary structure

Straight chain of amino acids.

Secondary structure

First-level of folding, either into alpha-helices or beta-pleated sheets; hydrogen bonding exists between different segments.

Tertiary structure

Final shape, further folding from 2O structure.

Quaternary structure

Only some proteins form this stage; multiple proteins are held together by H bonding.

Nucleic Acids Found in

DNA and RNA.

Energy storage in Nucleic Acids

Not used for energy.

Elements in Nucleic Acids

C, H, O, N, P.

Monomer of Nucleic Acids

Nucleotides.

Polymer of Nucleic Acids

Nucleic acid.

Properties of Nucleic Acids

Polar and hydrophilic.