Biochemistry and Molecular Interactions: Elements, Bonds, and Isotopes

What is biochemistry?

The study of how living things function on a molecular level using principles of chemistry.

What are the main elements of life and their approximate percentages?

Hydrogen (10%), Carbon (20%), Oxygen (62%), Nitrogen (3%), and Other elements (5%).

What are ions?

Charged ions or molecules, usually metals, that can be cations (positive, loss of electrons) or anions (negative, gain of electrons).

What are intramolecular forces?

Forces that occur within a molecule, including covalent and ionic bonds.

What are intermolecular forces?

Forces that occur between molecules, including van der Waals forces, London dispersion forces, dipole-dipole interactions, and hydrogen bonds.

What are London dispersion forces?

The weakest intermolecular forces, resulting from temporary dipoles that occur when electrons in adjacent atoms occupy positions that create temporary attractions.

What are dipole-dipole forces?

Intermolecular forces that occur between the positive end of one polar molecule and the negative end of another polar molecule.

What is hydrogen bonding?

A special type of dipole-dipole attraction between a hydrogen atom covalently bonded to a very electronegative atom (like N, O, or F) and another electronegative atom.

What are isotopes?

Atoms of the same element that contain a different number of neutrons, resulting in different properties; some are radioactive.

How is carbon dating used?

It measures the amount of radioactive carbon-14 in a sample to determine the time elapsed since the death of a plant or organism.

What is the half-life of carbon-14?

5730 years, the time it takes for half of the carbon-14 in a sample to decay.

What are isomers?

Compounds that have the same molecular formula but different structural formulas.

What is the significance of thalidomide?

Originally marketed as a tranquilizer for morning sickness, it caused birth defects when given to pregnant women.

When is an atom considered stable?

When its valence shell is full.

What are valence electrons?

Electrons located in the outermost shell of an atom.

How do atoms achieve stability?

By bonding to fill their outermost energy level or valence shell.

What types of bonding help atoms fill their outermost energy level?

Covalent bonding and ionic (electrovalent) bonding.

What is the role of valence electrons in chemical bonding?

They determine how atoms bond and interact with each other, influencing their reactivity.

What happens during covalent bonding?

Atoms share electrons to achieve a full valence shell.

What is the difference between covalent and ionic bonds?

Covalent bonds involve sharing electrons, while ionic bonds involve the transfer of electrons from one atom to another.

What is the effect of electronegativity in bonding?

It influences how electrons are shared in covalent bonds and can lead to polar molecules.