Free BACE Chemistry and Biochemistry Questions and Answers — Questions and Answers
Question 1: What type of bond is formed when two atoms share electrons?
- Hydrogen bond
- Covalent bond (Correct answer)
- Metallic bond
Correct answer: Covalent bond
A covalent bond is characterized by the sharing of electrons between two atoms. This sharing allows both atoms to achieve a more stable electron configuration, typically by filling their outermost electron shells. Covalent bonds are strong and are the fundamental type of bond found in organic molecules and biological macromolecules.
Question 2: Which macromolecule serves as the primary source of energy for most organisms?
- Proteins
- Lipids
- Nucleic acids
- Carbohydrates (Correct answer)
Correct answer: Carbohydrates
Carbohydrates are the primary and most readily available source of energy for most organisms. They are broken down through cellular respiration to produce ATP, the main energy currency of the cell. Glucose, a simple carbohydrate, is a key molecule in this energy-generating pathway.
Question 3: What is the pH of a neutral solution?
- 0
- 7 (Correct answer)
- 14
- -7
Correct answer: 7
The pH scale measures the acidity or alkalinity of a solution, ranging from 0 to 14. A pH of 7 indicates a neutral solution, meaning it has an equal concentration of hydrogen ions (H+) and hydroxide ions (OH-). Pure water at 25°C is a classic example of a neutral solution with a pH of 7.
Question 4: What are the monomers of proteins?
- Fatty acids
- Nucleotides
- Amino acids (Correct answer)
- Monosaccharides
Correct answer: Amino acids
Proteins are large, complex macromolecules essential for virtually every cellular process. Their fundamental building blocks, or monomers, are amino acids. These amino acids link together via peptide bonds to form long polypeptide chains, which then fold into specific three-dimensional structures to become functional proteins.
Question 5: Which element is the backbone of organic molecules?
- Oxygen
- Nitrogen
- Carbon (Correct answer)
- Phosphorus
Correct answer: Carbon
Carbon is the backbone of all organic molecules due to its unique ability to form four stable covalent bonds with other atoms, including other carbon atoms. This tetravalency allows carbon to create diverse and complex molecular structures, such as long chains, branched structures, and rings. These intricate carbon frameworks are essential for the vast array of biological molecules that make up living organisms.
Free BACE Chemistry and Biochemistry Questions and Answers
What type of bond is formed when two atoms share electrons?