BIOL 111 Molecules of Life - Lecture 1: Energy, Elements, Atoms, and Bonding

These vocabulary flashcards cover the fundamental concepts of energy, atomic structure, isotopes, and chemical bonding as presented in the BIOL 111 lecture.

Kinetic Energy

Energy associated with movement or heat.

Potential Energy

Energy possessed because of position or chemical energy.

Element

A substance that cannot be broken down to other substances by chemical reactions, with 92 occurring naturally.

Essential Elements of Life

The four elements—carbon ($C$), oxygen ($O$), hydrogen ($H$), and nitrogen ($N$)—that make up $96\%$ of living matter.

Trace Elements

Elements required by an organism in minute quantities, such as iron ($Fe$) and iodine ($I$).

Goitre

A medical condition caused by a deficiency in the trace element iodine.

Atom

The smallest unit of matter which still retains the properties of an element, consisting of protons, neutrons, and electrons.

Dalton

The unit for relative mass; protons and neutrons have a relative mass of 1, while electrons have a relative mass of approximately $\frac{1}{1840}$.

$$1.66 \times 10^{-24}\,g$$

The actual mass of a single proton or neutron.

Atomic Number

The number of protons in an atom's nucleus, which determines the identity of the element.

Atomic Mass

The sum of the masses of all components in an atom (electrons, protons, and neutrons), measured in Daltons.

Isotopes

Atoms of the same element that have the same atomic number but different mass numbers due to a different number of neutrons.

Radioactive Isotopes of Carbon

$^{14}C$ (half-life $t_{1/2} = 5730\,yr$) and $^{11}C$ (half-life $t_{1/2} = 20.3\,min$).

Atomic Orbitals

Regions around the nucleus (e.g., $1S$, $2S$, $2P$) that contain no more than 2 electrons each; filled orbitals are more stable than unfilled ones.

Valence Electrons

Unpaired electrons in the outermost shell that are able to interact with other unpaired electrons to form chemical bonds.

Compound

A substance consisting of two or more elements in a fixed ratio, such as table salt ($NaCl$).

Covalent Bond

A strong bond ($400\,kJ/mole$) formed by the sharing of electrons between two atoms.

Non-polar Covalent Bond

A type of covalent bond characterized by the equal sharing of electrons, such as in $H_2$ ($H-H$).

Polar Covalent Bond

A type of covalent bond characterized by the unequal sharing of electrons, such as the $O-H$ bond in $H_2O$.

Hydrogen Bond

A weak interaction ($10-20\,kJ/mole$) between molecules with polar bonds, such as those holding the structure of DNA together.

Ionic Bond

A very strong bond ($700\,kJ/mole$) formed when two atoms with very different attractions for valence electrons transfer an electron, resulting in a crystal.

Van der Waal’s Forces

Very weak ($0.5\,kJ/mole$), short-range interactions between electron clouds that are collectively strong.

Protein Folding

The process by which several interactions (bonds) hold proteins like pepsin, haemoglobin, and keratin in the correct shape for function.