Ribosomes Questions in English

(C) Ribosomes are the smallest organelles found in the cell.
They are non-membrane-bound organelles composed of $RNA$ and proteins.
Because they lack a membrane,they are found in both prokaryotic and eukaryotic cells.
They are primarily responsible for protein synthesis.

(D) Self-duplication refers to the ability of an organelle to replicate itself independently of the cell cycle.
$1$. Mitochondria and Chloroplasts are semi-autonomous organelles that contain their own $DNA$ and ribosomes,allowing them to undergo self-duplication.
$2$. Centrioles are involved in the formation of the spindle apparatus and also undergo self-duplication during the cell cycle.
$3$. Ribosomes are non-membrane-bound organelles composed of $rRNA$ and proteins. They are synthesized in the nucleolus and do not possess the machinery or genetic material required for self-duplication.
Therefore,the correct answer is $D$.

(B) Mitochondria are semi-autonomous organelles that contain their own genetic material $(DNA)$ and protein-synthesizing machinery.
In most eukaryotes,mitochondrial ribosomes are of the $70S$ type,similar to prokaryotic ribosomes.
However,in mammals,the mitochondrial ribosomes are specifically $55S$,consisting of a large subunit $(39S)$ and a small subunit $(28S)$.

(C) $r-RNA$ stands for Ribosomal Ribonucleic Acid.
It is a type of non-coding $RNA$ which is the primary component of ribosomes, essential for all living cells.
Ribosomes are the cellular machinery for protein synthesis, and $r-RNA$ provides the structural and catalytic framework for this process.

(C) Ribosomes are small,dense,granular structures composed of $RNA$ and proteins.
They are the sites where amino acids are assembled into polypeptide chains,a process known as protein synthesis.
Therefore,ribosomes are often referred to as the protein factories of the cell.

(B) Ribosomes are non-membrane-bound organelles found in all living cells.
They are primarily composed of Ribosomal $RNA$ $(rRNA)$ and proteins.
Unlike other organelles,they do not contain $DNA$ as a structural component.
Therefore,the correct composition is $RNA$ and proteins.

(D) Ribosomes are cellular organelles composed of $RNA$ and proteins.
They are essentially ribonucleoprotein complexes.
In terms of mass,$RNA$ (specifically $rRNA$) constitutes the majority of the ribosome's structure,typically accounting for about $60\%$ to $65\%$ of its total mass,while proteins make up the remaining $35\%$ to $40\%$.
Therefore,$RNA$ is the component present in the highest amount in a ribosome.

(B) The statements describe the characteristics of $Ribosomes$:
$1$. $Ribosomes$ are granular structures observed under an electron microscope as dense particles.
$2$. They were first observed by $George\, Palade$ in $1953$.
$3$. They are composed of $Ribonucleic\ Acid$ $(RNA)$ and proteins.
$4$. They are non-membrane-bound organelles found in both prokaryotic and eukaryotic cells.

(B) Enzymes are proteins in nature. The process of protein synthesis occurs on the ribosomes,which are the sites of protein translation in the cell. Therefore,enzymes are synthesized on the ribosomes.

(A) In the term $70S$ for prokaryotic ribosomes,'$S$' stands for the Svedberg unit (also known as the sedimentation coefficient).
It is a measure of the rate at which a particle sediments in a centrifuge,which depends on the size,density,and shape of the particle.
Therefore,the correct option is $A$.

(A) Ribosomes are cellular organelles composed of $RNA$ and proteins. They are responsible for protein synthesis in the cell. Unlike mitochondria,chloroplasts,and the nucleus,ribosomes do not contain $DNA$.

(B) Ribosomes are the most abundant organelles in a cell. They are found in large numbers in both prokaryotic and eukaryotic cells,as they are essential for protein synthesis. While $DNA$ is present,it is usually restricted to the nucleus or specific organelles. Plastids are found only in plant cells,and Golgi apparatus are present in limited numbers per cell.

(B) Ribosomes are the granular structures first observed under the electron microscope as dense particles by George Palade in $1953$. They are composed of ribonucleic acids $(RNA)$ and proteins and are not surrounded by any membrane.
Eukaryotic ribosomes are $80S$ (where '$S$' stands for the sedimentation coefficient,Svedberg's unit),while prokaryotic ribosomes are $70S$.
In eukaryotic cells,$70S$ ribosomes are also found within organelles such as chloroplasts and mitochondria,which supports the endosymbiotic theory of their origin.
Therefore,$70S$ ribosomes are present in prokaryotic cells,as well as in the chloroplasts and mitochondria of eukaryotic cells.

(A) Ribosomes are the cellular organelles responsible for protein synthesis. They are composed of ribosomal $RNA$ $(rRNA)$ and proteins. They translate messenger $RNA$ $(mRNA)$ into polypeptide chains,which is why they are known as the protein factories of the cell.

(B) true cell organelle is defined as a membrane-bound structure found within the cytoplasm of a cell.
$A$,$C$,and $D$ (Lysosome,Chloroplast,and Mitochondrion) are all membrane-bound organelles.
$B$ (Ribosome) is a non-membrane-bound organelle found in both prokaryotic and eukaryotic cells.
Therefore,it is not considered a 'true' membrane-bound organelle.

(B) The $RER$ (Rough Endoplasmic Reticulum) is named 'rough' because of the presence of $80S$ ribosomes attached to its outer surface.
These ribosomes are the sites of protein synthesis,which is why the $RER$ is primarily involved in the synthesis and transport of proteins within the cell.

(B) Prokaryotic cells lack membrane-bound organelles such as mitochondria,Golgi apparatus,and endoplasmic reticulum. However,they contain ribosomes,which are non-membrane-bound organelles responsible for protein synthesis. In prokaryotes,these are of the $70S$ type.

(C) In eukaryotic cells,ribosomes are primarily of the $80S$ type,which are found in the cytoplasm and attached to the rough endoplasmic reticulum.
However,eukaryotic cells also contain $70S$ ribosomes within their organelles,specifically in the mitochondria and chloroplasts.
Therefore,eukaryotic cells possess both $70S$ and $80S$ types of ribosomes.

(B) Ribosomes are complex cellular structures composed of ribosomal $RNA$ $(rRNA)$ and proteins.
They serve as the primary site for protein synthesis in all living cells.
During translation,ribosomes read the messenger $RNA$ $(mRNA)$ sequence and link amino acids together in the correct order to form polypeptide chains.

(C) Prokaryotic cells contain $70S$ type ribosomes.
These ribosomes are composed of two subunits: a larger subunit of $50S$ and a smaller subunit of $30S$.
The '$S$' stands for Svedberg's unit (sedimentation coefficient),which is a measure of density and size.
In contrast,eukaryotic cells contain $80S$ ribosomes,which are composed of $60S$ and $40S$ subunits.

(C) Ribosomes are complex cellular structures composed of ribosomal $RNA$ $(rRNA)$ and proteins. Because they are primarily made up of these two components,they are frequently referred to as $Ribonucleoprotein$ particles.
$Microsomes$ are vesicles formed from the endoplasmic reticulum during cell fractionation.
$Dictyosomes$ are the stacks of flattened sacs that make up the Golgi apparatus in plant cells.
$Oxysomes$ (or $F_0-F_1$ particles) are found on the inner mitochondrial membrane and are involved in $ATP$ synthesis.

(C) Ribosomes are non-membrane-bound organelles found in both prokaryotic and eukaryotic cells.
They are composed of ribosomal $RNA$ $(rRNA)$ and proteins.
Unlike lysosomes,lomasomes,and sphaerosomes,which are membrane-bound structures,ribosomes lack a lipid-protein membrane.

(A) Protein synthesis occurs on ribosomes.
Ribosomes are small,dense,granular structures composed of $RNA$ and proteins.
They are the sites where amino acids are assembled into polypeptide chains based on the genetic code provided by mRNA.
$SER$ (Smooth Endoplasmic Reticulum) is involved in lipid synthesis,while the Golgi apparatus is involved in packaging and modification of proteins,and lysosomes are involved in intracellular digestion.

(B) The electron microscope has a much higher resolution and magnification power compared to a light microscope.
Ribosomes are very small,dense,granular structures composed of $RNA$ and proteins,typically measuring about $15-20 \ nm$ in diameter.
Due to their extremely small size,they cannot be resolved by a light microscope and are visible only under an electron microscope.
Chloroplasts,leucoplasts,and the nucleus are relatively larger organelles that can be observed using a standard light microscope.

(A) Eukaryotic ribosomes are of the $80S$ type. They consist of two subunits: a larger subunit of $60S$ and a smaller subunit of $40S$. Prokaryotic ribosomes are of the $70S$ type,consisting of a larger subunit of $50S$ and a smaller subunit of $30S$. Therefore,the larger subunit of a eukaryotic ribosome is $60S$.

(A) Ribosomes are non-membrane-bound organelles found in both prokaryotic and eukaryotic cells.
In prokaryotes,they are of the $70S$ type,while in eukaryotes,they are of the $80S$ type (in the cytoplasm) and $70S$ type (in organelles like mitochondria and chloroplasts).
Other options like mitochondria,$ER$ (Endoplasmic Reticulum),and the nucleus are membrane-bound organelles that are exclusively found in eukaryotic cells.

(D) Prokaryotic cells are characterized by the absence of membrane-bound organelles such as the Golgi apparatus,mitochondria,and endoplasmic reticulum.
Ribosomes are non-membrane-bound organelles found in both prokaryotic and eukaryotic cells.
In prokaryotic cells,the ribosomes are of the $70S$ type,whereas in eukaryotic cells,they are of the $80S$ type (in the cytoplasm).
Therefore,the correct answer is $D$.

(C) Ribosomes are non-membrane-bound organelles found in both prokaryotic and eukaryotic cells.
In prokaryotes,they are of the $70S$ type,while in eukaryotes,they are of the $80S$ type (in the cytoplasm) and $70S$ type (in mitochondria and chloroplasts).
Mesosomes are specific to prokaryotes,and the nucleolus is a membrane-less structure found only within the nucleus of eukaryotic cells.

(B) Cell organelles can be classified based on the presence or absence of a membrane.
$1$. Endoplasmic reticulum,Lysosomes,and Golgi complex are single-membrane bound organelles.
$2$. Ribosomes are non-membrane bound organelles found in both prokaryotic and eukaryotic cells.
Therefore,the correct option is $B$.

(A) Ribosomes are non-membrane-bound organelles found in both prokaryotic and eukaryotic cells.
In prokaryotes,they are $70S$ type,while in eukaryotes,they are $80S$ type in the cytoplasm and $70S$ type in organelles like mitochondria and chloroplasts.
Centrioles,mitochondria,and Golgi bodies are membrane-bound or complex structures found only in eukaryotic cells.

(D) Ribosomes are non-membrane-bound organelles found in all living cells.
In eukaryotic cells,ribosomes are found in two primary locations:
$1$. They are present as free-floating particles in the cytoplasm.
$2$. They are attached to the surface of the rough endoplasmic reticulum $(RER)$.
Therefore,both options $(A)$ and $(C)$ are correct.

(B) Ribosomes are non-membrane-bound organelles found in all living cells.
They are present in the cytoplasm,attached to the rough endoplasmic reticulum $(RER)$,and also within semi-autonomous organelles like mitochondria and chloroplasts.
In mitochondria and chloroplasts,they are of the $70S$ type,similar to those found in prokaryotes.

(A) Ribosomes are the granular structures first observed under the electron microscope as dense particles by George Palade in $1953$.
They are composed of ribonucleic acids $(RNA)$ and proteins and are not surrounded by any membrane.
Eukaryotic ribosomes are $80S$ (where '$S$' stands for the sedimentation coefficient,Svedberg's unit),while prokaryotic ribosomes are $70S$.
Each ribosome consists of two subunits.
The $70S$ ribosome is composed of two subunits: a larger subunit of $50S$ and a smaller subunit of $30S$.

(C) In bacteria,which are prokaryotic organisms,the site of protein synthesis is the $70S$ ribosomes.
These ribosomes are found free in the cytoplasm or attached to the plasma membrane.
Unlike eukaryotic cells,bacteria lack a membrane-bound nucleus and other organelles like the endoplasmic reticulum,so protein synthesis occurs exclusively on these ribosomes.

(A) Prokaryotic ribosomes are of the $70S$ type.
These ribosomes are composed of two subunits: a larger $50S$ subunit and a smaller $30S$ subunit.
The diameter of these ribosomes is approximately $15-20 \, nm$.
Among the given options,$20 \, nm$ is the most accurate representation of their size.

(A) Ribosomes are non-membrane-bound organelles found in both prokaryotic and eukaryotic cells.
They are composed of ribonucleic acids $(RNA)$ and proteins.
According to the $NCERT$ textbook,the diameter of ribosome particles is approximately $15-20 \ nm$.

(C) polysome (or polyribosome) is a complex structure consisting of several ribosomes attached to a single $m-RNA$ molecule.
These ribosomes translate the $m-RNA$ into proteins simultaneously,which increases the efficiency of protein synthesis within the cell.
Therefore,the correct definition is that multiple ribosomes are associated with a single $m-RNA$ strand.

(A) Ribosomes are the cellular organelles responsible for protein synthesis.
Prokaryotic cells contain $70S$ ribosomes,which are composed of two subunits: a larger subunit of $50S$ and a smaller subunit of $30S$.
The '$S$' stands for Svedberg unit,which is a measure of the rate of sedimentation in a centrifuge.
Therefore,the correct combination is $50S$ and $30S$.

(C) Ribosomes are the sites of protein synthesis in cells.
In prokaryotic cells,ribosomes are of the $70S$ type.
These $70S$ ribosomes consist of two subunits: a larger $50S$ subunit and a smaller $30S$ subunit.
In contrast,eukaryotic cells contain $80S$ ribosomes in their cytoplasm,which consist of $60S$ and $40S$ subunits.

(C) In prokaryotic cells,the ribosomes are of the $70S$ type.
These ribosomes consist of two subunits: a larger subunit of $50S$ and a smaller subunit of $30S$.
The $S$ stands for Svedberg's unit (sedimentation coefficient),which is a measure of density and size.
Therefore,the correct combination is $50S + 30S$.

(A) Ribosomes are complex cellular structures composed of ribosomal $RNA$ $(rRNA)$ and various proteins.
They serve as the site for protein synthesis in the cell.
$rRNA$ constitutes the structural and catalytic component of the ribosomes,which is essential for the translation of $mRNA$ into polypeptide chains.

(A) Ribosomes are the granular structures first observed under the electron microscope as dense particles by George Palade in $1953$. They are composed of ribonucleic acids $(RNA)$ and proteins and are not surrounded by any membrane. The eukaryotic ribosomes are $80S$ (where '$S$' stands for the sedimentation coefficient,also known as Svedberg's unit),while the prokaryotic ribosomes are $70S$. The $80S$ eukaryotic ribosome consists of two subunits: a larger subunit $(60S)$ and a smaller subunit $(40S)$.

(A) Ribosomes are the cellular organelles primarily composed of $r-RNA$ (ribosomal $RNA$) and structural proteins.
In a polysome (or polyribosome) complex,multiple ribosomes are attached to a single strand of $m-RNA$ (messenger $RNA$) to translate it into multiple copies of a polypeptide chain simultaneously.
Therefore,the correct composition is $r-RNA$ and proteins for ribosomes,and $m-RNA$ for the polysome complex.

(D) Ribosomes are the cellular organelles responsible for protein synthesis. They are composed of $RNA$ and proteins and are found either free in the cytoplasm or attached to the rough endoplasmic reticulum $(RER)$. During translation,ribosomes read the $mRNA$ sequence and assemble amino acids into polypeptide chains.

(D) The endoplasmic reticulum $(ER)$ is a network of membranous tubules and sacs.
In cells that are actively involved in protein synthesis,the outer surface of the rough endoplasmic reticulum $(RER)$ is studded with ribosomes.
These ribosomes are the sites of protein synthesis,which is why the $RER$ appears 'rough' under an electron microscope.
Therefore,the correct answer is $D$ (Ribosomes).

(C) Ribosomes are granular structures first observed under the electron microscope as dense particles by George Palade in $1953$.
They are composed of ribonucleic acids $(RNA)$ and proteins and are not surrounded by any membrane.
In eukaryotic cells,ribosomes are found either free in the cytoplasm or attached to the outer surface of the rough endoplasmic reticulum $(RER)$.

(D) Ribosomes are non-membrane-bound organelles found in both prokaryotic and eukaryotic cells. They are composed of ribosomal $RNA$ $(rRNA)$ and various proteins. They are the sites of protein synthesis within the cell.

(D) Ribosomes are the smallest organelles found in cells. They are non-membrane-bound structures composed of $RNA$ and proteins. They are responsible for protein synthesis and are found in both prokaryotic and eukaryotic cells.

(C) Ribosomes are non-membrane-bound organelles found in all living cells.
In prokaryotic cells,they are found in the cytoplasm.
In eukaryotic cells,they are found in the cytoplasm,as well as within organelles like mitochondria and chloroplasts,and attached to the rough endoplasmic reticulum.
Among the given options,the cytoplasm is the primary location where ribosomes are found.

(A) In eukaryotic cells,ribosomes are of the $80S$ type.
These ribosomes consist of two subunits: a larger subunit of $60S$ and a smaller subunit of $40S$.
The '$S$' stands for Svedberg's unit,which is a measure of sedimentation coefficient.
In contrast,prokaryotic cells contain $70S$ ribosomes,which are composed of $50S$ and $30S$ subunits.