Unit 1 AP Bio Practice Quiz

Water's polarity, resulting from the electronegativity difference between oxygen and hydrogen, allows it to interact with many solutes. This interaction makes water an excellent solvent in biological systems.

Carbon's tetravalency allows it to form four covalent bonds with other atoms, enabling the creation of complex and diverse organic molecules. This unique bonding capacity is fundamental to the structure of biological compounds.

Proteins are polymers made by linking amino acids together through peptide bonds. Other macromolecules, such as carbohydrates and nucleic acids, are formed through different types of polymerization.

Enzymes act as catalysts by lowering the activation energy required for a reaction, thereby increasing the reaction rate. They are not consumed in the reaction and do not permanently change the reaction pathway.

Hydrogen bonds between the backbone atoms of proteins stabilize secondary structures like alpha-helices and beta-sheets. While other bonds contribute to overall protein structure, hydrogen bonds are key for secondary structural formation.

Biological membranes are formed by a phospholipid bilayer where the hydrophilic heads face the aqueous environments and the hydrophobic tails face each other. This arrangement is crucial for membrane function and selective permeability.

The carboxyl group can donate a proton, which gives amino acids their acidic character. This functional group is essential in regulating the pH and structure of proteins.

Raising temperature increases the kinetic energy of molecules, resulting in more frequent collisions between enzymes and substrates. However, if the temperature exceeds an optimal level, enzymes may denature, reducing their activity.

Buffers resist drastic changes in hydrogen ion concentration, ensuring that the pH remains within a narrow range optimal for enzyme function. This stability is vital for maintaining proper metabolic processes in cells.

Dehydration synthesis involves the removal of water to covalently join two molecules, such as forming a peptide bond between amino acids. This process is fundamental in building macromolecules like proteins.

Glycosidic bonds connect individual sugar units (monosaccharides) together to form more complex carbohydrates like disaccharides and polysaccharides. This linkage is key to the structure and function of many biomolecules.

Saturated fatty acids contain no carbon-carbon double bonds which allows them to pack tightly and be solid at room temperature. In contrast, unsaturated fatty acids have one or more double bonds that introduce kinks, causing them to be liquid.

The induced fit model explains that enzymes undergo a conformational change when a substrate binds, which improves the alignment of catalytic residues and enhances the reaction rate. This flexible fitting mechanism is key to enzyme specificity and efficiency.

The presence of double bonds in unsaturated fatty acids creates kinks that prevent tight packing, thereby increasing membrane fluidity. This fluid characteristic is important for proper membrane function and dynamic cellular processes.

Glycolysis is the metabolic pathway that converts glucose into pyruvate, producing a net gain of ATP and NADH in the process. This pathway occurs in the cytosol and serves as a fundamental energy-producing process in the cell.

Enzymes are highly specific because their active sites have unique three-dimensional structures that complement specific substrates. This precise fit enhances catalytic efficiency by stabilizing the transition state during a reaction.

In biological systems, both pH and enzyme concentration critically affect the rate of reactions. Variations in pH can alter enzyme shape and active site charge, while enzyme concentration directly influences the number of active sites available for catalysis.

A mutation in the active site typically decreases the enzyme's affinity for its substrate, which is reflected by an increased Km value. If only the binding affinity is compromised while the catalytic turnover remains unchanged, Vmax may not vary significantly.

Energy coupling involves pairing an unfavorable, endergonic reaction with a favorable, exergonic reaction such as ATP hydrolysis. This pairing allows cells to drive processes that would not normally proceed on their own.

Denaturation disrupts the non-covalent interactions that maintain a protein's secondary and tertiary structures, commonly due to changes in pH or high temperatures. The primary structure, or amino acid sequence, remains largely intact during denaturation.