Biochemistry Unit Assessment: Atoms, Water, and Carbon-Based Molecules

Comprehensive practice flashcards covering atoms, subatomic particles, chemical bonding, properties of water, acids and bases, carbon chemistry, macromolecules, reaction mechanisms, and indicator tests.

What are the three primary subatomic particles and their electrical charges?

Protons have a positive electrical charge, electrons have a negative electrical charge, and neutrons have no electrical charge.

How is the nucleus of an atom defined?

The dense center of an atom, containing protons and neutrons.

What is the difference between an element and a compound?

An element is made up of only one particular type of atom, whereas a compound is a substance made of atoms of different elements bonded together in a certain ratio (such as $H_2O$ and $CO_2$).

How does an atom become an ion?

An atom becomes an ion when it gains or loses electrons, which typically results in a full outermost energy level.

What is an ionic bond and how do electrons behave during its formation?

An ionic bond is formed by the electrical force between two ions of opposite charge, occurring when electrons are transferred from one atom to another based on valence electrons.

What is a covalent bond?

A strong chemical bond formed when two atoms share one or more pairs of electrons to fill their outermost energy levels.

What is the definition of a molecule?

Two or more atoms held together by covalent bonds.

What does it mean that water is a polar molecule?

Water has slightly charged regions due to unequal electron sharing, giving oxygen a slight negative charge and hydrogen slight positive charges.

How do hydrogen bonds form between water molecules?

They form between the oppositely charged regions of polar water molecules (between a slightly positive hydrogen atom and a slightly negative atom).

Which property of water allows it to resist changes in temperature?

High specific heat.

How do cohesion and adhesion differ in water?

Cohesion is the attraction among water molecules that causes water to form beads, while adhesion is the attraction between water molecules and other substances, which assists in capillary action and transporting water in plants.

How is a solution distinguished from a solute and a solvent?

A solution is a homogeneous mixture where substances are evenly distributed; the solvent is the substance that dissolves another substance (such as blood plasma or water), and the solute is the substance that dissolves.

Why don't oil and water mix based on molecular polarity?

Oil is a nonpolar molecule and cannot easily dissolve in a polar solvent like water because polar and nonpolar substances do not readily interact ('like dissolves like').

How are acidic, basic, and neutral solutions evaluated on the pH scale?

Acidic solutions have a pH from $0$ to less than $7$ with a higher concentration of $H^+$ ions; neutral solutions have a pH of $7$; basic solutions have a pH greater than $7$ up to $14$ with a higher concentration of $OH^-$ ions.

What is the biological role of a buffer?

A buffer locks or releases $H^+$ ions to help maintain a stable pH in an organism, preventing sudden changes in acidity or basicity.

Why is carbon considered the building block of life?

Carbon's outer energy level is not full, allowing each carbon atom to form covalent bonds with up to four other atoms, resulting in structures such as straight chains, branched chains, and rings.

What is the relationship between a monomer and a polymer?

A monomer is a single molecular subunit (building block), whereas a polymer is a large macromolecule made of many linked monomers.

What are the structural classifications of carbohydrates based on sugar units?

Monosaccharides (single sugar monomers), disaccharides (two sugar units bonded together), and polysaccharides (complex polymers made of many bonded sugars).

How do saturated and unsaturated fatty acids differ in structure?

Saturated fatty acids contain only single bonds between carbon atoms, holding the maximum number of hydrogens, whereas unsaturated fatty acids contain one or more carbon-carbon double bonds.

What is the difference between dehydration synthesis and hydrolysis reactions?

Dehydration synthesis links monomers together to form a polymer by removing water molecules, while hydrolysis breaks polymers apart into monomers by adding water molecules.

What specific type of bond links amino acids together in a protein?

A peptide bond.

Which indicator tests are used to detect simple sugars, starch, proteins, and lipids?

Benedict's test identifies simple sugars (monosaccharides), iodine tests for starch (polysaccharides), biuret tests for proteins, and the brown paper bag test detects lipids.