Chemistry of Life Flashcards

Flashcards covering key terms and definitions from Chapter 2: Chemistry of Life.

Atomic Mass and Mass Number Notation

Standard notation for representing atoms where the superscript denotes the mass number ($A$) and the subscript denotes the atomic number ($Z$), as demonstrated in isotopes such as $C_6^{12}$ and $C_6^{14}$.

Hydrophilic vs. Hydrophobic

Hydrophilic molecules contain positive or negative charges (ions) and dissolve readily in water, whereas hydrophobic molecules are uncharged, do not dissolve in water, and form few or no hydrogen bonds.

Protons

Positively charged subatomic particles located in the nucleus of an atom.

Electrons

Negatively charged subatomic particles that orbit the nucleus and have significantly less mass and then protons.

Neutrons

Subatomic particles with no electrical charge located in the nucleus of an atom.

Atomic Number

The number of protons in an atom, denoted by $Z$.

Atomic Mass

The total combined mass of the protons and neutrons in an atom.

Isotopes

Atoms of the same element that have the same atomic number ($Z$) but different mass numbers ($A$) due to varying numbers of neutrons.

Ions

Atoms or molecules that carry a positive or negative electrical charge due to the loss or gain of electrons.

Valence Electrons

Electrons located in the outermost energy shell of an atom that can participate in chemical bonding.

When electrons are transferred from one atom to another.

Covalent Bonds

When two atoms share electrons.

Polar Covalent Bond

When electrons are shared unequally between atoms, such as in a water molecule.

Non-Polar Covalent Bond

When electrons are shared equally between atoms.

Single Bond

A covalent bond formed by sharing $2$ electrons.

Double Bond

A covalent bond formed by sharing $4$ electrons.

Triple Bond

A covalent bond formed by sharing $6$ electrons.

Hydrogen Bond

Hydrogen bonds are weak individually and when it bonds to water it leads to its high surface tension, cohesive and adhesive properties.

Cohesion

The property of water molecules sticking to each other.

Adhesion

The property of water molecules sticking to other types of molecules or surfaces.

pH Scale

A scale ranging from $0$ to $14$ that measures the balance of hydrogen ($H^+$) and hydroxide ($OH^-$) ions in a solution.

Monomers

Subunits that link together to form larger polymer molecules.

Polymers are composed of subunits called _________

a. __________ link together to form _________ __________

b. _________ breaks polymers

c. A chemical reaction is a:

Polymers are composed of subunits called monomers.

• a. Monomers link together to form a polymer.

• b. Hydrolysis breaks polymers.

• c. Process that breaks or forms chemical bonds to change reactants into products.

Monosaccharides

The monomer subunits of carbohydrates that serve as chemical fuel for cells.

Polysaccharides

Large carbohydrate polymers formed from the monosaccharides building block.

Triglycerides

The structural form of fat molecules consisting of glycerol and fatty acids.

Phospholipids

Lipids that constitute a major component of cell membranes.

What are five properties that organisms must have to be “alive”? Define each.

1. Cellular Organization: All living organisms are composed of one or more cells, which are the basic units of life. 2. Metabolism: Living organisms undergo chemical reactions to transform energy and matter for growth and maintenance. 3. Homeostasis: Organisms maintain stable internal conditions despite external environmental changes. 4. Growth and Development: Living organisms undergo regulated growth and development throughout their life cycles. 5. Reproduction: Organisms have the ability to reproduce and pass genetic information to the next generation.

What are the three Domains of Life? Which Domain do Humans fall into?

The three Domains of Life are Bacteria, Archaea, and Eukarya. Humans belong to the Domain Eukarya.

Examples of Eukaryotes and Prokaryotes

Eukaryotes include organisms like plants, animals, and fungi, while prokaryotes consist of bacteria and archaea. Eukaryotic cells have a nucleus and membrane, whereas prokaryotic cells do not.

What is matter made of and What is the smallest unit of an element?

What is at its core?

1-2. Atoms 3. Nucleus

When do atoms feel the most stable?

When they have a full outer shell of electrons

What’s so special about He (atomic #2), Neon (atomic #10) and Argon (atomic #18)?

They are noble gases with full outer electron shells, making them very stable and non-reactive.

Why do atoms form bonds?

To achieve stability by having full outer electron shells.

What is a molecule and how is it different than an atom?

A molecule is a group of two or more atoms bonded together, which can consist of the same or different elements. Unlike an atom a molecule represents the chemical combination of atoms.

Electrons are _________ from one atom to another

What is an example of atoms that form ionic bonds?

Ionic Bond/Sodium and chlorine atoms form a classic ionic bond to create sodium chloride

What are the 6 most common elements in the body?

Carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.

Why is carbon important?

Carbon is essential for life as it is the primary building block of organic molecules, forming the backbone of proteins, nucleic acids, carbohydrates, and lipids.

What is the difference between organic vs. inorganic molecules?

Organic molecules contain carbon and are typically associated with living organisms, while inorganic molecules usually do not contain carbon and are found in non-living matter.

List the complex macromolecules that make up living things.

Carbohydrates

• Subunit: Monosaccharides (simple sugars like glucose)

• Purpose: Provide fast energy for cells and structural support in plants (like cell walls).

• Examples: Glucose, starch, glycogen, and cellulose.

Proteins

• Subunit: Amino acids (20 different types)

• Purpose: Build muscle, speed up chemical reactions as enzymes, and support the immune system.

• Examples: Enzymes (like amylase), antibodies, and keratin.

Lipids

• Subunit: Fatty acids and glycerol (though they do not form true polymers)

• Purpose: Store long-term energy, provide insulation, and form cell membranes.

• Examples: Fats, oils, phospholipids, and steroids (like cholesterol).

Nucleic Acids

• Subunit: Nucleotides (made of a sugar, a phosphate group, and a nitrogenous base)

• Purpose: Store, transmit, and express genetic information.

• Examples: DNA and RNA

Chemical fuel: __________ _________ comes from monosaccharides

Adenosine triphosphate (ATP)

What is the storage form of carbohydrates in animals? How about in Plants?

In animals, carbohydrates are stored as glycogen, while in plants, they are stored as starch.

Structural Carbohydrates in Plants and Insects

Plants use cellulose in their cell walls for structure, while insects use chitin to form their exoskeletons.

Digestible vs. Indigestible Carbohydrates in Humans

Humans can digest starch and glycogen for energy, but cannot digest cellulose (fiber) because humans lack the specific enzymes required to break its chemical bonds.

Building Blocks of Proteins

Amino acids

Variable Structure of Amino Acids

The side chain attached to the central carbon, which gives each amino acid its unique chemical properties.

Primary vs. Tertiary Protein Structure Relationship

Yes, the primary sequence of amino acids determines the tertiary structure because interactions among the specific R groups dictate how the protein folds into its final three-dimensional shape.

Structure of Triglycerides

A fat molecule consisting of one glycerol molecule bonded to three fatty acid chains.

Saturated vs. Unsaturated Fats

Saturated fats contain single bonds between carbon atoms, unsaturated fats contain one or more double bonds.

Examples of Sterols

Cholesterol and steroid hormones.

Phospholipid Structure and Role in Cells

Lipids composed of a hydrophilic head and two hydrophobic tails that assemble to form the structure of cell membranes.

Differences Between DNA and RNA

DNA is double-stranded, contains deoxyribose sugar and thymine ($T$), and stores genetic information; RNA is single-stranded, contains ribose sugar and uracil ($U$), and functions in protein synthesis.