12 public questions tagged with this topic.
Ribosomes are not membrane-bound organelles; they are freely floating in the cytoplasm or attached to the rough ER.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Human Genome Project and DNA Fingerprinting
Ribosomes are made of ribosomal RNA (rRNA) and proteins, and they facilitate protein synthesis.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Human Genome Project and DNA Fingerprinting
Translation initiation **requires the ribosome, mRNA, and tRNA** to start protein synthesis.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Genetic Code and Translation
Ribosomes **are not membrane-bound organelles**; they are found freely in the cytoplasm or attached to the rough ER in eukaryotes.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance DNA Structure Double Helix and Packaging - Nucleosome
The cytoplasm is the semi-fluid matrix and principal arena of cellular reactions. Ribosomes are non-membrane-bound RNA–protein particles occurring freely in the cytoplasm, on rough ER, and within mitochondria and chloroplasts.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Mitochondria Plastids Ribosomes and Other Organelles
George Palade first observed ribosomes as dense particles under the electron microscope in 1953. Ribosomes consist of RNA and proteins and are not surrounded by a membrane.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Mitochondria Plastids Ribosomes and Other Organelles
Ribosomes are non-membrane-bound structures composed of RNA and proteins. They serve as the sites of protein synthesis in both prokaryotic and eukaryotic cells.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Endomembrane System - ER Golgi Lysosome Vacuole
Prokaryotic ribosomes are approximately 15 nm by 20 nm, are associated with the plasma membrane and contain 50S and 30S subunits, forming a 70S ribosome. Several ribosomes on one mRNA constitute a polysome.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
Several ribosomes may attach to a single mRNA to form a polyribosome or polysome. The ribosomes of the polysome translate the mRNA into protein.
Ref: NCERT Class 11 Biology Chapter 8: Cell: The Unit of Life Prokaryotic Cell - Structure and Components
Mitochondrial protein synthesis translating thirteen highly hydrophobic inner membrane subunits of oxidative phosphorylation complexes relies on 55S mitochondrial ribosome in mammals. This ribosome composed of 28S small and 39S large subunits is tethered to inner membrane near OXA1L translocase enabling co-translational insertion of nascent chains. Translation uses nucleus-encoded mitochondrial initiation factors mtIF2, mtIF3, elongation factors mtEFTu, mtEFG1, termination factor mtRF1a, distinct from cytosolic 80S machinery, sensitive to antibiotics, and regulated by mitochondrial tRNA modifications and membrane potential coupling. This refined regulation supports accurate ribosomal assembly, quality control and translational fidelity under diverse physiological conditions and growth states.
Ref: Watson Molecular Biology of the Gene, 7th ed., Chapter 14, Mitochondrial 55S ribosome in OXPHOS protein synthesis
mRNA, tRNA, rRNA is the accurate answer because it correctly identifies the biological function or role described in this question. In Acid, Base, pH, understanding the specific functions of molecules, enzymes, or structures is fundamental. mRNA, tRNA, rRNA fulfills this particular biological role through its specific structural properties, biochemical activity, or physiological mechanism. The other options (DNA, RNA, protein, DNA, rRNA, tRNA, and mRNA, snRNA, miRNA) serve different biological functions or are associated with other processes, pathways, or structural roles within the cell or organism.
Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 2
Cytosol is the scientifically accurate answer to this question. Within the study of Acid, Base, pH, this concept is well-established through extensive research and is documented in standard scientific literature. The specific properties, mechanisms, or characteristics of Cytosol directly address what is being asked. Among the other options, Nucleus, Mitochondria only, and Golgi do not correctly answer this question because they either refer to different concepts, describe properties of other molecules or processes, or represent common misconceptions about this topic.
Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 2
