#1
Which element is the primary building block of organic molecules?
Carbon
ExplanationCarbon serves as the backbone for organic compounds due to its ability to form diverse covalent bonds.
#2
Which type of macromolecule is primarily responsible for energy storage in living organisms?
Carbohydrates
ExplanationCarbohydrates store energy in the form of glucose, readily available for cellular processes.
#3
Which of the following macromolecules is a polymer of nucleotides?
Nucleic acid
ExplanationNucleic acids, such as DNA and RNA, are composed of nucleotide monomers, forming long polymer chains.
#4
Which of the following is not a function of lipids in living organisms?
Cellular structure
ExplanationWhile lipids contribute to cell membranes, their primary functions include energy storage, insulation, and signaling.
#5
Which of the following is a characteristic feature of saturated fatty acids?
They have a straight chain structure.
ExplanationSaturated fatty acids lack double bonds between carbon atoms, resulting in a straight molecular structure at room temperature.
#6
Which of the following is a function of RNA?
Transferring genetic information from DNA to ribosomes
ExplanationRNA molecules, particularly messenger RNA (mRNA), carry genetic instructions from DNA to ribosomes for protein synthesis.
#7
What is the main function of enzymes in biological systems?
Speeding up chemical reactions
ExplanationEnzymes catalyze reactions by lowering the activation energy required for reactions to occur.
#8
Which of the following is not a type of carbohydrate?
Cholesterol
ExplanationCholesterol is a lipid, not a carbohydrate, and serves as a structural component of cell membranes.
#9
What is the monomer unit of proteins?
Amino acid
ExplanationAmino acids are the building blocks of proteins, joining together via peptide bonds to form polypeptide chains.
#10
Which of the following is a polysaccharide?
Starch
ExplanationStarch, a polymer of glucose, serves as a storage polysaccharide in plants.
#11
Which of the following is a structural carbohydrate found in the cell walls of plants?
Cellulose
ExplanationCellulose provides structural support to plant cells, forming the main component of cell walls.
#12
What is the primary function of ATP (adenosine triphosphate) in cells?
Energy storage
ExplanationATP serves as the primary energy currency of cells, storing and transferring energy for various cellular processes.
#13
What is the primary structure of proteins determined by?
The sequence of amino acids
ExplanationThe sequence of amino acids dictates the primary structure of proteins, influencing their overall function.
#14
What is the primary function of DNA in cells?
Storing genetic information
ExplanationDNA acts as the hereditary material, storing genetic information essential for cellular processes and inheritance.
#15
Which of the following is not a type of protein structure?
Quaternary
ExplanationQuaternary structure refers to the arrangement of multiple protein subunits, not a distinct protein structure itself.
#16
Which of the following is not a component of a nucleotide?
Amino group
ExplanationAmino groups are not part of nucleotides; instead, nucleotides consist of a phosphate group, a sugar molecule, and a nitrogenous base.
#17
Which of the following is a function of nucleic acids in living organisms?
Storing and transmitting genetic information
ExplanationNucleic acids, such as DNA and RNA, play crucial roles in storing genetic information and facilitating its transmission during cellular processes like replication and transcription.