Ribosomes Questions in English

(D) Peptide synthesis,also known as protein synthesis or translation,is the process by which cells build proteins.
Ribosomes are the cellular organelles responsible for protein synthesis.
They translate the genetic information encoded in $mRNA$ into a polypeptide chain (a sequence of amino acids linked by peptide bonds).
Therefore,the correct site for peptide synthesis is the ribosomes.

(D) In eukaryotic cells,ribosomes are found in multiple locations.
$1$. They are attached to the surface of the Rough Endoplasmic Reticulum $(RER)$.
$2$. They are present in the cytoplasm as free ribosomes.
$3$. They are also found within semi-autonomous organelles like mitochondria and chloroplasts (as $70S$ ribosomes).
Therefore,all the given options are correct locations for ribosomes in a eukaryotic cell.

(A) $1$. Ribosomes are the granular structures first observed under the electron microscope as dense particles by George Palade in $1953$.
$2$. They are composed of ribonucleic acids $(RNA)$ and proteins and are not surrounded by any membrane.
$3$. Eukaryotic ribosomes are $80S$ (where '$S$' stands for the sedimentation coefficient,Svedberg's unit),while the prokaryotic ribosomes are $70S$.
$4$. Chloroplasts and mitochondria,which are semi-autonomous organelles in eukaryotic cells,contain $70S$ ribosomes,similar to prokaryotic cells.
$5$. The rough endoplasmic reticulum $(RER)$ has $80S$ ribosomes attached to its surface,which are involved in protein synthesis.
$6$. Therefore,chloroplasts contain $70S$ ribosomes,and the endoplasmic reticulum surface contains $80S$ ribosomes.

(C) Ribosomes are the cellular organelles primarily composed of ribosomal $RNA$ $(rRNA)$ and proteins. They are the sites of protein synthesis in the cell. While $rRNA$ is synthesized in the nucleolus,it functions as a structural and catalytic component within the ribosomes.

(B) Protein synthesis is the fundamental biological process occurring in all living cells. Ribosomes are the cellular organelles responsible for the translation of $mRNA$ into polypeptide chains,which are the primary structures of proteins. Therefore,ribosomes are known as the 'protein factories' of the cell.

(A) Ribosomes are cellular organelles primarily composed of ribosomal $RNA$ $(r-RNA)$ and proteins.
$r-RNA$ acts as a structural and catalytic component of the ribosome,facilitating the process of protein synthesis (translation).
Therefore,the correct answer is $r-RNA$.

(C) The $Ribosome$ is the primary site for protein synthesis in the cell. It consists of $rRNA$ and proteins. While the $Nucleus$ contains the genetic information $(DNA)$ required to code for proteins, and the $Endoplasmic \text{ } reticulum$ is involved in the folding and transport of proteins, the $Ribosome$ itself is the machinery that contains the necessary components and catalytic activity (specifically the $23S \text{ } rRNA$ in prokaryotes or $28S \text{ } rRNA$ in eukaryotes) to link amino acids together to form polypeptide chains. Therefore, the $Ribosome$ is the correct answer.

(C) Protein synthesis is the process by which cells make proteins.
In eukaryotic cells,the primary site for protein synthesis is the cytoplasm,specifically on the ribosomes.
Ribosomes can be found free-floating in the cytoplasm or attached to the rough endoplasmic reticulum.
Therefore,the cytoplasm is the correct location among the given options.

(C) During the process of protein synthesis (translation),the $t-RNA$ (transfer $RNA$) acts as an adapter molecule.
It picks up specific amino acids from the cytoplasm and transports them to the ribosome.
The ribosome serves as the site for protein synthesis,where $m-RNA$ is read and the amino acids brought by $t-RNA$ are linked together to form a polypeptide chain.

(C) Ribosomes are complex molecular machines found within all living cells that serve as the site of biological protein synthesis.
They link amino acids together in the order specified by the messenger $RNA$ $(mRNA)$ molecules.
Therefore,ribosomes are often referred to as the 'protein factories' of the cell.

(D) The correct answer is $D$.
$1$. Membrane-bound organelles include the endoplasmic reticulum,nucleus,lysosomes,Golgi apparatus,vacuoles,and mitochondria.
$2$. Ribosomes are non-membrane-bound organelles composed of ribonucleoproteins,found in both prokaryotic and eukaryotic cells.
$3$. Mesosomes are infoldings of the plasma membrane in prokaryotes,which are membrane-bound structures.

(D) : Ribosomes are small,spherical,non-membrane-bound organelles found in living cells that serve as the site for protein synthesis.
Ribosomes are composed of two subunits,one large and one small,which consist of ribosomal $RNA$ $(rRNA)$ and proteins.
Unlike the nucleus,mitochondria,and chloroplasts,which contain their own genetic material,ribosomes do not contain any $DNA$.

(B) : Ribosomes are small,spherical,non-membrane-bound organelles found in both prokaryotic and eukaryotic cells. They are the sites of protein synthesis. Ribosomes consist of two subunits,one large and one small,each of which is composed of ribosomal $RNA$ $(rRNA)$ and proteins. They do not contain any $DNA$.

(A) : Ribosomes are found in all living cells except mammalian erythrocytes or red blood corpuscles.
Depending upon their location,ribosomes are of two types: cytoplasmic ribosomes and organelle ribosomes.
Cytoplasmic ribosomes (cytoribosomes) may remain free in the cytoplasmic matrix or attached to the cytosolic surface of the endoplasmic reticulum with the help of special ribophorin or $SRP$ proteins.
Organelle ribosomes are found within other organelles,specifically in plastids (plastiribosomes) and mitochondria (mitoribosomes).
Cytoplasmic ribosomes are of the $80S$ type in eukaryotic cells,whereas organelle ribosomes are of the $70S$ type.

(D) : Peptide synthesis inside a cell takes place in ribosomes.
Ribosomes are the cellular organelles responsible for protein synthesis (translation).
They are found in all living cells,either floating freely in the cytoplasm or attached to the endoplasmic reticulum.
The major constituents of ribosomes are $RNA$ and proteins,which are present in approximately equal amounts.

(A) The correct answer is $A$. Ribosomes are small organelles with a diameter of $150 \ \mathring{A} - 250 \ \mathring{A}$.
Each ribosome consists of two subunits: a smaller subunit and a larger subunit.
These two subunits are held together by $Mg^{2+}$ ions at a critical concentration of approximately $0.001 \ M$.
If the concentration of $Mg^{2+}$ ions in the cytoplasm decreases,the two subunits dissociate.
Conversely,when the $Mg^{2+}$ ion concentration increases,the two subunits associate to form a functional ribosome or a dimer.

(C) : Ribosomes may occur in rosettes or helical groups called polyribosomes or polysomes (Greek: $Poly$ - many,$soma$ - body).
The different ribosomes of a polyribosome are connected with a $10 - 20 \ \mathring{A}$ thick strand of messenger $RNA$ or $mRNA$,and its maintenance requires energy.
Polyribosomes are formed during periods of active protein synthesis when a number of copies of the same polypeptide are required.

(A) The ribosome is known as the cellular factory because it is the site of protein synthesis in the cell. It translates the genetic information from $mRNA$ into polypeptide chains,which are essential for cellular structure and function.

(C) Ribosomes are composed of ribosomal $RNA$ $(rRNA)$ and proteins.
$rRNA$ is a nucleic acid,and the backbone of all nucleic acids ($DNA$ and $RNA$) consists of a sugar-phosphate backbone.
Therefore,phosphorus $(P)$ is an essential component of the structure of ribosomes.

(C) Ribosomes are non-membrane-bound organelles found in all living cells. They are present in the cytoplasm and are also found attached to the rough endoplasmic reticulum $(RER)$. Furthermore,ribosomes are present within semi-autonomous organelles like mitochondria and chloroplasts. Therefore,they are often referred to as 'organelles within an organelle'.

(C) polysome (or polyribosome) is a structure formed when several ribosomes attach to a single $mRNA$ molecule.
This allows for the simultaneous translation of a single $mRNA$ strand into multiple polypeptide chains,which significantly increases the efficiency of protein synthesis in the cell.

(A) In the context of 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.
This unit is named after the Swedish chemist Theodor Svedberg,who invented the ultracentrifuge.
Therefore,$70S$ indicates the sedimentation rate of the prokaryotic ribosome as a whole.

(A) Ribosomes are small,granular structures composed of $RNA$ and proteins.
They are the sites of protein synthesis in the cell.
Therefore,ribosomes are often referred to as the 'protein factories' of the cell.
Lipids are synthesized in the Smooth Endoplasmic Reticulum $(SER)$,while carbohydrates and vitamins are not synthesized by ribosomes.

(C) Cells that are actively involved in protein synthesis and secretion require a high number of ribosomes. Ribosomes are the sites of protein synthesis. While the Rough Endoplasmic Reticulum $(RER)$ is studded with ribosomes and is responsible for the synthesis and transport of proteins,the ribosomes themselves are the fundamental organelles responsible for the translation of $mRNA$ into polypeptide chains. Therefore,cells specialized for protein secretion,such as pancreatic acinar cells or plasma cells,contain an abundance of ribosomes.

(D) 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).
Peroxisomes,mitochondria,and mesosomes are not present in all prokaryotic and eukaryotic cells. Mesosomes are specific to prokaryotes,while mitochondria and peroxisomes are membrane-bound organelles found only in eukaryotes.

(D) Ribosomes are non-membrane-bound organelles found in both prokaryotic and eukaryotic cells.
They are composed of ribonucleic acids $(RNA)$ and proteins.
The size of ribosomes in eukaryotic cells $(80S)$ is approximately $15 \,\text{nm}$ to $20 \,\text{nm}$ in diameter.
Therefore,option $D$ is the correct statement regarding the size of ribosomes.

(B) In $Eubacteria$ (prokaryotes),the cellular machinery for protein synthesis is represented by $70S$ ribosomes. While eukaryotic cells contain $80S$ ribosomes in the cytoplasm,they also possess $70S$ ribosomes within their organelles like mitochondria and chloroplasts. Therefore,the presence of ribosomes is a common feature shared between prokaryotic and eukaryotic cells,as they are essential for protein synthesis in both.

(D) polyribosome (or polysome) is a structure consisting of multiple ribosomes attached to a single $m-RNA$ molecule.
These ribosomes translate the $m-RNA$ simultaneously,which allows for the rapid synthesis of multiple copies of the same polypeptide chain.
This process is highly efficient for protein synthesis in both prokaryotic and eukaryotic cells.

(D) Ribosomes were first observed by George $E$. Palade in $1955$ using an electron microscope.
He described them as dense particles in the cytoplasm.
Therefore,the discovery of ribosomes is attributed to George $E$. Palade.

(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.

(A) Protein synthesis is the process by which cells make proteins.
In all living cells,the primary site for protein synthesis is the $Ribosome$.
Ribosomes are small,dense,granular structures composed of $RNA$ and proteins,which act as the machinery for translating $mRNA$ into polypeptide chains.

(A) Ribosomes are the protein synthesis machinery of the cell. They are synthesized in the $Nucleolus$,which is a dense,spherical structure present inside the nucleus. The nucleolus is the site of active ribosomal $RNA$ $(rRNA)$ synthesis and assembly of ribosomal subunits.

(D) Protein synthesis in eukaryotic animal cells occurs on ribosomes.
Ribosomes are found in the cytoplasm (as free ribosomes) and also within certain organelles like mitochondria (mitochondrial ribosomes).
While the rough endoplasmic reticulum and nuclear envelope are major sites for protein synthesis,ribosomes are also functional in the cytoplasm and the mitochondrial matrix.
Therefore,the most comprehensive answer is that protein synthesis occurs on ribosomes present in the cytoplasm and in mitochondria.

(C) Ribosomes are composed of two subunits: a larger subunit and a smaller subunit.
These two subunits remain separate in the cytoplasm when the concentration of $Mg^{2+}$ ions is low.
When the concentration of $Mg^{2+}$ ions increases to a critical level,the two subunits associate to form a functional $80S$ (in eukaryotes) or $70S$ (in prokaryotes) ribosome.
Therefore,$Mg^{2+}$ ions are essential for the structural integrity and assembly of ribosomal subunits.

(C) The synthesis of peptides,or protein synthesis,is the process by which cells build proteins.
This process occurs on the $Ribosomes$,which are small,dense,granular structures found either free in the cytoplasm or attached to the rough endoplasmic reticulum.
$Ribosomes$ are known as the 'protein factories' of the cell because they translate messenger $RNA$ $(mRNA)$ into polypeptide chains.

(B) Ribosomes are non-membrane-bound organelles found in both prokaryotic and eukaryotic cells.
They are composed of ribosomal $RNA$ $(rRNA)$ and proteins.
Prokaryotic ribosomes are $70S$ (composed of $50S$ and $30S$ subunits),while eukaryotic ribosomes are $80S$ (composed of $60S$ and $40S$ subunits).
The $S$ stands for Svedberg's unit,which represents the sedimentation coefficient.
Therefore,option $B$ is the correct statement.

(C) Ribosomes are non-membrane bound organelles found in both prokaryotic and eukaryotic cells.
Mesosomes are infoldings of the plasma membrane in prokaryotes.
Vacuoles are membrane-bound organelles found in plant and animal cells.
Lysosomes are membrane-bound organelles containing digestive enzymes.
Therefore,the correct answer is $C$.

(A) polysome (or polyribosome) is a structure formed when multiple ribosomes attach to a single $m-RNA$ strand during the process of translation. This allows for the simultaneous synthesis of multiple polypeptide chains from the same $m-RNA$ molecule,significantly increasing the efficiency of protein synthesis in the cell.

(D) When multiple ribosomes are attached to a single $mRNA$ strand,the structure is known as a $polysome$ or $polyribosome$.
This structure allows for the simultaneous translation of a single $mRNA$ molecule into multiple copies of the same polypeptide chain,thereby increasing the efficiency of protein synthesis.

(B) In protein synthesis,a single $mRNA$ molecule can be translated by multiple ribosomes simultaneously.
This structure,where several ribosomes are attached to a single $mRNA$ strand,is known as a $Polysome$ or $Polyribosome$.
This mechanism allows the cell to produce multiple copies of the same polypeptide chain efficiently from a single $mRNA$ template.

(N/A) $\Rightarrow$ Ribosomes of prokaryotes are associated with the plasma membrane of the cell.
$\Rightarrow$ They are about $15 \ nm$ by $20 \ nm$ in size and are made up of two subunits,$50 \ S$ and $30 \ S$,which when present together form $70 \ S$ prokaryotic ribosomes.
$\Rightarrow$ Several ribosomes may attach to a single $mRNA$ molecule and form a chain called polyribosomes or polysomes.
$\Rightarrow$ Ribosomes are the site of protein synthesis.

(N/A) $\Rightarrow$ Ribosomes are granular structures first observed under the electron microscope as dense particles by George Palade in $1953$.
$\Rightarrow$ Ribosomes are composed of ribonucleic acid $(RNA)$ and proteins and are not surrounded by any membrane.
$\Rightarrow$ Eukaryotic ribosomes are $80S$,while prokaryotic ribosomes are $70S$. Here,'$S$' stands for the sedimentation coefficient,which is an indirect measure of density and size.
$\Rightarrow$ Both $70S$ and $80S$ ribosomes are composed of two subunits.

(A) Eukaryotic ribosomes are of the $80S$ type,where '$S$' stands for Svedberg's unit (sedimentation coefficient).
Prokaryotic ribosomes are of the $70S$ type.
Therefore,the correct answer is $70S$.

(C) Ribosomes are complex cellular structures composed of ribosomal $RNA$ $(rRNA)$ and various proteins.
In a typical eukaryotic ribosome,there are approximately $80$ different types of proteins that associate with the $rRNA$ molecules to form the functional subunits ($60S$ and $40S$).
Therefore,the correct number of protein types involved in the structure is $80$.

(C) Organelles can be classified based on the presence or absence of a membrane.
$Mitochondria$ and $Chloroplast$ are double-membrane bound organelles.
$Vacuole$ is surrounded by a single membrane called the $tonoplast$.
$Ribosome$ is a non-membrane bound organelle found in both prokaryotic and eukaryotic cells.
Therefore, the correct answer is $Ribosome$.

(B) Ribosomes are sub-spherical granular structures found in both prokaryotic and eukaryotic cells. They are composed of $RNA$ and proteins and are not surrounded by any membrane.

(C) Several ribosomes may attach to a single $mRNA$ molecule and form a chain called a polysome or polyribosome.
The ribosomes of a polysome translate the $mRNA$ into proteins.
This structure allows for the simultaneous synthesis of multiple polypeptide chains from a single $mRNA$ strand.

(A) In an animal cell,protein synthesis occurs on ribosomes. Ribosomes are found in the cytoplasm (either free or attached to the rough endoplasmic reticulum) and also within certain organelles like mitochondria. Mitochondria possess their own $70S$ ribosomes,which are responsible for synthesizing proteins encoded by the mitochondrial genome. Therefore,protein synthesis occurs both in the cytoplasm and within the mitochondria.

(A) Prokaryotes possess $70\; S$ ribosomes,which are composed of a small $(30\; S)$ subunit and a large $(50\; S)$ subunit.
Option $A$ is incorrect because $50\; S$ and $30\; S$ subunits combine to form $70\; S$ ribosomes,not $80\; S$ ribosomes (which are characteristic of eukaryotes).
Ribosomes serve as the site for protein synthesis.
Polysomes (or polyribosomes) are clusters of ribosomes attached to a single $mRNA$ molecule,facilitating the synthesis of multiple copies of identical polypeptides simultaneously.

(B) Ribosomes are cell organelles that are non-membrane bound and are found in both prokaryotes and eukaryotes.
Lysosomes,centrioles,and mitochondria are membrane-bound organelles (or structures) found in eukaryotes,but they are not present in prokaryotes.