Chemistry of Life Flashcards

Flashcards on Chemistry of Life

Main Elements in Living Things

Four main elements in living things: Carbon, Hydrogen, Oxygen, and Nitrogen

Trace Elements

Elements required in small quantities, examples include Iron and Iodine

Isotopes

Different forms of an element with varying numbers of neutrons

Radioactive Isotopes

Isotopes with an unstable nucleus that decays over time

Intramolecular Bonds

Bonds within a molecule or compound, such as covalent and ionic bonds

Intermolecular Bonds

Bonds between molecules, such as hydrogen bonds and Van der Waals forces

Covalent Bond

Bond formed when two atoms share electrons

Nonpolar Covalent Bond

Covalent bond where electrons are shared equally

Polar Covalent Bond

Covalent bond where electrons are shared unequally

Ionic Bond

Bond formed when electrons are transferred from one atom to another

Hydrogen Bond

Bond formed when a partial positive hydrogen of a molecule is attracted to a partial negative atom of a second molecule

Van der Waals Forces

Instantaneous dipole-dipole attraction between temporarily partial positive and partial negative atoms of nonpolar molecules

pH

Measure of the hydrogen ion concentration ranging from 0-14

Buffers

Substances that minimize changes in the concentrations of H+ and OH- in a solution

Adhesion

The attraction between different kinds of molecules.

Cohesion

The binding together of like molecules, often by hydrogen bonds.

Solution

A homogeneous mixture of two or more substances.

Solvent

The dissolving agent of a solution.

Solute

The substance dissolved in a solution.

Aqueous Solution

A solution where water is the solvent.

Hydrophilic

Substance that is attracted to water and dissolves in water.

Hydrophobic

Substance repelled by water.

Organic Molecules

Molecules containing carbon and hydrogen bonds

Inorganic Molecules

Molecules that do not contain carbon-hydrogen bonds.

Isomers

Molecules with the same molecular formula but different structures and properties.

Structural Isomers

Isomers differing in the covalent arrangement of their atoms.

Geometric Isomers

Isomers that have the same covalent partnerships but differ in spatial arrangements.

Enantiomers (Optical Isomers)

Mirror images of each other

Macromolecule

Large molecule formed by joining small molecules

Monomer

Small molecular unit that is the building block of a larger molecule

Polymer

Long chain of small molecular units (monomers) connected together.

Dehydration Synthesis

Process used to build polymers by removing a water molecule.

Hydrolysis

Process used to breakdown a polymer by adding water

Functional Groups

Chemically reactive groups of atoms within an organic molecule

Carbohydrates

Source of energy, C:H:O ratio = 1:2:1

Monosaccharide

One sugar unit

Disaccharide

2 sugar units bonded together via dehydration synthesis

Glycosidic Linkage

Covalent bond between 2 sugars

Polysaccharide

Few hundred to a few thousand monomer sugar units connected in a chain by glycosidic linkages formed via dehydration synthesis

Starch

Energy storage in plants consists of amylose (unbranched) amylopectin (branched)

Glycogen

Short-term energy storage in animals, stored in skeletal muscle & liver

Cellulose

Structural component of plants cell walls

Chitin

Structural component of exoskeletons and fungal cell walls

Lipids

Biological macromolecules that have a major hydrocarbon component and are mostly nonpolar and therefore hydrophobic.

Steroids

Core structure consisted of four fused carbon rings. Ex: Cholesterol.

Fat (Triglyceride)

Glycerol linked to three fatty acids

Saturated Fats

No double bonds in hydrocarbon chain, saturated with hydrogens and are very linear (e.g. animal fats - solid)

Unsaturated Fats

Double bond and have ‘bends’ in hydrocarbon chain (e.g. plant oils - liquid)

Trans Fats

Increase shelf life of food & Raises LDL and lowers HDL cholesterol

Phospholipids

Consist of a 3-carbon glycerol linked to a negatively charged phosphate group, and two fatty acids

Nucleic Acids

Encodes genetic material called genes that contain instructions for building proteins

Nucleotide

Monomer of nucleic acids

Polynucleotide

Polymer of nucleic acids

DNA

Double helix, two strands connected in a helical fashion

RNA

Single Stranded, contains Uracil instead of Thymine

Amino Acid

Protein monomer

Polypeptide

Protein polymer

Peptide Bonds

Covalent bond that connects two amino acids together

Primary structure

Sequence of amino acids in a polypeptide chain determined by the DNA. Involves peptide bonds connecting the amino acids together in a chain

Secondary structure

Stabilized by hydrogen bonds between non-R-group atoms of non-adjacent amino acids. Alpha helix and Beta pleated sheet

Tertiary structure

How the whole polypeptide chain is folded in and around itself; held together by bonds between the R-groups within the polypeptide chain

Quaternary structure

Overall protein structure involving the interactions between two or more polypeptide chains (subunits)

Chaperonins

Proteins that assist in the proper folding of other proteins

Denaturation

The native shape of the protein changes which affects its function by High temperatures or pH levels outside the optimum range

Enzymes

Biological catalysts that reduce the amount of energy required to start a reaction

Substrates

Reactant(s) which binds to enzyme

Enzyme-substrate complex

Temporary association between the substrate and the active site of the enzyme

Product

End result of reaction

Activation energy (EA)

Initial energy investment needed to start a reaction

Induced Fit Model

3-D structure of enzyme fits substrate binding to active site due to H-bonds and/or ionic bonding causing enzyme to change shape leading to a tighter fit

Enzyme Inhibitors

molecules that reduce enzyme activity

Competitive Inhibition

Inhibitor & substrate “compete” for active site

Non-Competitive Inhibitor

Inhibitor binds to an allosteric site (a site other than the active site), causing enzyme to change shape

Cofactor

Non-protein molecule or ion that is required for the proper functioning of an enzyme

Coenzymes

Type of cofactor (organic cofactor)

Allosteric Regulation

Describes any case in which a protein’s function at one site is affected by the binding of a regulatory molecule at another site

Feedback Inhibition

A metabolic pathway is switched off by the inhibitory binding of its end product, which acts as an allosteric inhibitor of an earlier enzyme in the pathway