Biochemistry Test Practice

Eukaryotic Cells

• Simple cells without a nucleus (e.g., bacteria)

• Complex cells with a nucleus and organelles (e.g., animal and plant cells)

• Cells that only exist in multicellular organisms

• Cells that lack membrane-bound organelles

Phospholipid Bilayer

• The single-layered structure of cell membranes, composed of hydrophilic heads and hydrophobic tails.

• The double-layered structure of cell membranes, composed of hydrophilic heads and hydrophobic tails.

• A rigid structure that provides support to the cell, made of proteins and carbohydrates.

• A fluid mosaic model that describes the arrangement of proteins in the cell wall.

Water Flow in Cells

• Movement from areas of high solute concentration to areas of low solute concentration.

• Movement from areas of low solute concentration to areas of high solute concentration.

• Movement from areas of equal solute concentration to areas of low solute concentration.

• Movement from areas of high solute concentration to areas of equal solute concentration.

Hydrophobic Molecules

• Molecules that dissolve easily in water

• Molecules that repel water and do not dissolve in it, usually nonpolar (e.g., fats, oils)

• Molecules that are attracted to water and dissolve in it

• Molecules that are polar and mix well with water

Nonpolar Bonds

• Covalent bonds where electrons are shared equally (e.g., C-C, C-H).

• Ionic bonds where electrons are transferred from one atom to another.

• Polar covalent bonds with unequal sharing of electrons.

• Metallic bonds where electrons are pooled among many atoms.

R-Groups in Membrane Proteins

• Side chains in proteins that help them embed in or interact with the membrane.

• A type of lipid that forms the bilayer of membranes.

• Proteins that are only found on the surface of membranes.

• Carbohydrates that are attached to membrane proteins.

Passive Transport

• Movement of substances against their concentration gradient with energy input.

• Movement of substances down their concentration gradient without energy input.

• Movement of substances in and out of the cell using vesicles.

• Movement of substances that requires active energy expenditure.

Hydrophobic Interactions

• The tendency of nonpolar molecules to clump together in water.

• The attraction between polar molecules in a solution.

• The repulsion of water by ionic compounds.

• The mixing of oil and water to form a stable solution.

Methyl Group (-CH₃)

• A functional group that makes molecules more hydrophobic.

• A functional group that increases solubility in water.

• A functional group that is always polar.

• A functional group that decreases molecular weight.

Carboxyl Group (-COOH)

• A functional group that can donate a hydrogen ion (H⁺), making a molecule acidic.

• A functional group that accepts a hydrogen ion (H⁺), making a molecule basic.

• A functional group that is non-polar and does not interact with water.

• A functional group that contains only carbon and hydrogen atoms.