Biology: Living Systems - Chemistry Foundation

Flashcards covering fundamental concepts of biology, matter, elements, compounds, atomic structure, chemical bonding, and reactions, based on provided lecture notes.

What is biology fundamentally the study of?

Living systems, which are part of the natural world.

What other sciences are integral parts of biology?

Physics and chemistry.

Why is a fundamental understanding of chemistry required for biology?

Chemistry is at the foundation of biology, and living organisms are subject to basic laws of physics and chemistry.

What is matter?

Anything that takes up space and has mass.

What are organisms composed of?

Matter.

What is an element?

A substance that cannot be broken down to other substances by chemical reactions.

What is a compound?

A substance consisting of two or more elements in a fixed ratio, with characteristics different from those of its elements.

Approximately how many of the 92 elements are essential to life?

About 25.

What four elements make up 96% of living matter?

Carbon, hydrogen, oxygen, and nitrogen.

What are trace elements?

Elements required by an organism in minute quantities.

What is an atom?

The smallest unit of matter that still retains the properties of an element.

What are the three relevant subatomic particles, and what are their electrical charges?

Neutrons (no charge), Protons (positive charge), Electrons (negative charge).

What is an element's atomic number?

The number of protons in its nucleus.

What is an element's mass number?

The sum of protons plus neutrons in the nucleus.

What are isotopes?

Two atoms of an element that have the same number of protons but differ in the number of neutrons.

What are radioactive isotopes?

Isotopes that decay spontaneously, giving off particles and energy.

What determines an electron's state of potential energy?

Its energy level, or electron shell.

What is potential energy?

The energy that matter has because of its location or structure.

What are valence electrons?

Electrons in the outermost shell, or valence shell.

What primarily determines the chemical behavior of an atom?

Its valence electrons.

What type of elements are chemically inert?

Elements with a full valence shell.

What is an orbital?

The three-dimensional space where an electron is found 90% of the time.

What are chemical bonds?

Attractions that hold atoms close together, usually resulting from atoms sharing or transferring valence electrons to complete their valence shells.

What is a covalent bond?

The sharing of a pair of valence electrons by two atoms.

What is a molecule?

Two or more atoms held together by covalent bonds.

What is the difference between a single covalent bond and a double covalent bond?

A single bond is the sharing of one pair of valence electrons, while a double bond is the sharing of two pairs of valence electrons.

What is electronegativity?

An atom's attraction for the electrons in a covalent bond.

What is a nonpolar covalent bond?

A covalent bond where atoms share electrons equally.

What is a polar covalent bond?

A covalent bond where one atom is more electronegative, causing unequal sharing of electrons and resulting in partial positive or negative charges for each atom or molecule.

What is an ionic bond?

A bond formed when one atom strips an electron from another, resulting in charged atoms that are attracted to each other.

What is an ion?

A charged atom (or molecule).

What is the difference between a cation and an anion?

A cation is a positively charged ion, and an anion is a negatively charged ion.

What are ionic compounds also known as?

Salts.

Besides strong covalent bonds, what two types of weak chemical bonds are important in organisms?

Ionic bonds and hydrogen bonds.

How does a hydrogen bond form?

When a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom.

What are Van der Waals interactions?

Attractions between molecules that are close together due to temporary 'hot spots' of positive or negative charge caused by asymmetrical electron distribution.

What primarily determines a molecule's shape?

The positions of its atoms' valence orbitals.

Why is a molecule's shape important to its function?

Molecules interact using complementary shapes, and this can have significant biological effects.

What are chemical reactions?

The making and breaking of chemical bonds.

In a chemical reaction, what are the starting molecules called?

Reactants.

In a chemical reaction, what are the final molecules called?

Products.

What is the chemical equation for photosynthesis?

6 CO2 + 6 H2O → C6H12O6 + 6 O2.

When is chemical equilibrium reached in a reversible reaction?

When the forward and reverse reaction rates are equal.