Which of the following describes a vector quantity?

Correct Answer: D

Rationale: Velocity is a vector quantity as it encompasses both magnitude (speed) and direction. When describing the motion of an object, it is crucial to consider both aspects. Speed (option A) is a scalar quantity, representing only the magnitude of motion without indicating direction. Distance (option B) is also a scalar quantity, indicating the extent of an object's motion without considering direction. Mass (option C) is a scalar quantity, measuring the amount of matter in an object and not involving direction.

Correct Answer: D

Rationale: Amino acids are linked together by covalent bonds to form proteins. Specifically, the bond that links amino acids together is called a peptide bond, which is a type of covalent bond. The peptide bond forms between the amino group of one amino acid and the carboxyl group of another amino acid, resulting in the formation of a peptide chain. While hydrogen bonds, ionic bonds, and disulfide bonds are important for protein structure and stability, the primary bond responsible for linking amino acids in a protein chain is the covalent peptide bond. Hydrogen bonds are involved in maintaining the secondary structure of proteins, such as alpha helices and beta sheets. Ionic bonds and disulfide bonds contribute to tertiary and quaternary structures of proteins by stabilizing interactions between different parts of the protein or between different protein subunits, respectively.

Correct Answer: B

Rationale: Rationale: - Proteins are made up of long chains of amino acids. - Amino acids are the building blocks of proteins and are considered monomers. - Monomers are the individual units that can be linked together to form larger molecules called polymers. - In the context of proteins, amino acids are the monomers that are linked together through peptide bonds to form polypeptide chains, which then fold into functional proteins. - Residues refer to the specific amino acids within a protein after certain modifications or cleavages have occurred, so it is not the correct term for the building blocks of proteins. - Macromolecules are large molecules made up of smaller subunits, such as proteins, nucleic acids, and carbohydrates, but they are not the specific building blocks of proteins. - Peptides are short chains of amino acids linked by peptide bonds, but they are not the fundamental building blocks of proteins.

Correct Answer: B

Rationale: The unit of measurement for energy is the Joule (J). Energy is defined as the capacity to do work or produce heat, and the Joule is the standard unit used to measure energy in the International System of Units (SI). A Watt (A) is a unit of power, measured in joules per second, Newton (C) is a unit of force, and Kilogram (D) is a unit of mass. The Joule (J) is the appropriate unit for quantifying energy, making it the correct answer in this context.

Correct Answer: A

Rationale: A joule is the SI unit of energy and work, defined as the work done by a force of one newton acting over a distance of one meter. Therefore, a joule is equivalent to a newton-meter (N·m), which represents the product of force (newton) and distance (meter). This unit reflects the energy transferred when a force of one newton moves an object one meter. Choice B, Watt (W), is the unit of power and is not equivalent to a joule. Choice C, Kilogram (kg), is a unit of mass. Choice D, Ampere (A), is the unit of electric current.