Cell : The Unit of Life - PYQs and MCQs

Q9161. When the centromere is situated in the middle of two equal arms of chromosomes, the chromosome is referred as

acrocentric telocentric metacentric sub-metacentric

Year: NEET 2021

✅ Correct Answer: metacentric

🧠 Solution:

Metacentric chromosomes have the centromere at the center, producing two equal arms, e.g. human chromosomes 1 and 3.

Q9160. The organelles that are included in the endomembrane system are

Golgi complex, endoplasmic reticulum, mitochondria and lysosomes Golgi complex, mitochondria, ribosomes and lysosomes endoplasmic reticulum, Golgi complex, lysosomes and vacuoles endoplasmic reticulum, mitochondria, ribosomes and lysosomes

Year: NEET 2021

✅ Correct Answer: endoplasmic reticulum, Golgi complex, lysosomes and vacuoles

🧠 Solution:

The endomembrane system includes nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles and plasma membrane. It functions in modification, packaging and transport of proteins and lipids.

Q9159. Which of the following is an incorrect statement?

The perinuclear space forms a barrier between the materials present inside the nucleus and that of the cytoplasm Microbodies are present both in plant and animal cells Mature sieve tube elements possess a conspicuous nucleus and usual cytoplasmic organelles Nuclear pores act as passages for proteins and RNA molecules in both directions between nucleus and cytoplasm

Year: NEET 2021

✅ Correct Answer: Mature sieve tube elements possess a conspicuous nucleus and usual cytoplasmic organelles

🧠 Solution:

Mature sieve tube elements contain P-proteins, mitochondria, ER and plastids but do not possess a conspicuous nucleus.

Q9158. Match the List-I with List-II. List-I A. Cristae B. Thylakoids C. Centromere D. Cisternae List-II 1. Primary constriction in chromosome 2. Disc-shaped sacs in Golgi apparatus 3. Infoldings in mitochondria 4. Flattened membranous sacs in stroma of plastids

3 4 1 2 2 3 4 1 4 3 2 1 1 4 3 2

Year: NEET 2021

✅ Correct Answer: 3 4 1 2

🧠 Solution:

(A)-(3), (B)-(4), (C)-(1), (D)-(2). The inner membrane of mitochondria forms infoldings called cristae which increase surface area for enzymes of respiration. Thylakoids are flattened membranous sacs in chloroplasts. Primary constriction forms the centromere. Cisternae are flattened membrane saccules of Golgi apparatus.

Q9176. Many ribosomes may associate with a single mRNA to form multiple copies of a polypeptide simultaneously. Such strings of ribosomes are termed as

nucleosome polyhedral bodies polysome plastidome

Year: NEET 2018

✅ Correct Answer: polysome

🧠 Solution:

Polysomes are strings of ribosomes attached to a single mRNA molecule producing multiple copies of a polypeptide.

Q9175. Which one of the following events does not occur in rough endoplasmic reticulum?

Cleavage of signal peptide Phospholipid synthesis Protein folding Protein glycosylation

Year: NEET 2018

✅ Correct Answer: Phospholipid synthesis

🧠 Solution:

Phospholipid synthesis occurs in smooth endoplasmic reticulum, not in rough endoplasmic reticulum.

Q9174. Nissl bodies are mainly composed of

nucleic acids and SER DNA and RNA proteins and lipids free ribosomes and RER

Year: NEET 2018

✅ Correct Answer: free ribosomes and RER

🧠 Solution:

Nissl granules are composed of rough endoplasmic reticulum bearing ribosomes and are sites of protein synthesis in neurons.

Q9173. Which of the following is true for nucleolus?

It takes part in spindle formation It is a membrane-bound structure It is a site for active ribosomal RNA synthesis Larger nucleoli are present in dividing cells

Year: NEET 2018

✅ Correct Answer: It is a site for active ribosomal RNA synthesis

🧠 Solution:

Nucleolus is a naked structure lacking membrane and is the site of active ribosomal RNA (rRNA) synthesis.

Q9172. The Golgi complex participates in

respiration in bacteria formation of secretory vesicles fatty acid breakdown activation of amino acid

Year: NEET 2018

✅ Correct Answer: formation of secretory vesicles

🧠 Solution:

Golgi complex participates in the formation of secretory vesicles. Vesicles from endoplasmic reticulum pass through cisternae and are budded off as secretory vesicles from the maturing face.

Q9121. Which among the following is not a prokaryote?

Oscillatoria Mycobacterium Nostoc Saccharomyces

Year: NEET 2018

✅ Correct Answer: Saccharomyces

🧠 Solution:

Saccharomyces is a fungus, i.e. it is a eukaryote. They possess a well defined nucleus and other cell organelles.

Q9120. Which one of the following elements is responsible for maintaining turgor in cells?

Sodium Calcium Magnesium Potassium

Year: NEET 2018

✅ Correct Answer: Potassium

🧠 Solution:

Among the given elements, potassium (K⁺) is responsible for maintaining turgor pressure in cell because it regulates the proton pumps involved in opening and closing of stomata.

Q9177. Which of the following cell organelles is responsible for extracting energy from carbohydrates to form ATP?

Mitochondrion Ribosome Chloroplast Lysosome

Year: NEET 2017

✅ Correct Answer: Mitochondrion

🧠 Solution:

Mitochondria are the powerhouses of the cell and contain enzymes for aerobic respiration that produce ATP.

Q9122. Which of the following components provides sticky character to the bacterial cell?

Plasma membrane Cell wall Nuclear membrane Glycocalyx

Year: NEET 2017

✅ Correct Answer: Glycocalyx

🧠 Solution:

Glycocalyx is the outer most mucilage layer of the cell envelope. It gives sticky character to the bacterial cell.

Q9123. Select the wrong statement.

Bacterial cell wall is made up of peptidoglycan Pili and fimbriae are mainly involved in motility of bacterial cells Cyanobacteria lack flagellated cells Mycoplasma is a wall-less microorganism

Year: NEET 2016, Phase II

✅ Correct Answer: Pili and fimbriae are mainly involved in motility of bacterial cells

🧠 Solution:

Fimbriae or pili are used for attachment rather than motility. These are formed of protein called pilin.

Q9183. Select the mismatch.

Gas vacuoles — Green bacteria cells Large central vacuoles — Animal cells Protists — Eukaryotes Methanogens — Prokaryotes

Year: NEET 2016 Phase II

✅ Correct Answer: Large central vacuoles — Animal cells

🧠 Solution:

Large central vacuoles are characteristic of plant cells, not animal cells.

Q9182. A cell organelle containing hydrolytic enzyme is

lysosome ribosome mesosome microsome

Year: NEET 2016 Phase II

✅ Correct Answer: lysosome

🧠 Solution:

Lysosomes contain hydrolytic enzymes involved in intracellular digestion and are called suicidal bags.

Q9181. Microtubules are the constituents of

centrosome, nucleosome and centrioles spindle fibres, centrioles and cilia centrioles, spindle fibres and chromatin cilia, flagella and peroxisomes

Year: NEET 2016 Phase I

✅ Correct Answer: spindle fibres, centrioles and cilia

🧠 Solution:

Microtubules form spindle fibres, centrioles, cilia and flagella and are components of cytoskeleton.

Q9180. Mitochondria and chloroplast are semi-autonomous organelles. They are formed by division of pre-existing organelles and contain DNA but lack protein synthesising machinery. Which option is correct?

Both I and II are false II is true, but I is false I is true, but II is false Both I and II are true

Year: NEET 2016 Phase I

✅ Correct Answer: I is true, but II is false

🧠 Solution:

Mitochondria and chloroplasts contain DNA and ribosomes (70S) and can synthesise some of their own proteins.

Q9179. Which one of the following cell organelles is enclosed by a single membrane?

Mitochondria Chloroplasts Nuclei Lysosomes

Year: NEET 2016 Phase I

✅ Correct Answer: Lysosomes

🧠 Solution:

Lysosomes are single membrane bound organelles. Nucleus, mitochondria and chloroplast are double membrane bound.

Q9178. Water soluble pigments found in plant cell vacuoles are

chlorophylls xanthophylls anthocyanins carotenoids

Year: NEET 2016 Phase I

✅ Correct Answer: anthocyanins

🧠 Solution:

Anthocyanins are water soluble pigments present in vacuoles and appear red, purple or blue depending on pH.

Q9192. The Golgi complex plays a major role

in post translational modification of proteins and glycosidation of lipids in trapping the light and transforming it into chemical energy as energy transferring organelles in digesting proteins and carbohydrates

Year: NEET 2013

✅ Correct Answer: in post translational modification of proteins and glycosidation of lipids

🧠 Solution:

Golgi complex plays a major role in post translational modification of proteins and glycosidation of lipids. Chloroplasts contain chlorophyll which traps light and transforms it into chemical energy. Lysosomes are involved in digesting proteins, fats and carbohydrates. Mitochondria are energy transferring organelles.

Q9191. A major site for synthesis of lipids is

RER SER symplast nucleoplasm

Year: NEET 2013

✅ Correct Answer: SER

🧠 Solution:

The Smooth Endoplasmic Reticulum (SER) is the major site for synthesis of lipids. RER is actively involved in protein synthesis and secretion. Nucleoplasm is the site for active ribosomal RNA synthesis. Symplast is the system of interconnected protoplasts through which water movement occurs.

Q9190. Which one of the following organelles in the figure correctly matches with its function? Nucleus, Rough endoplasmic reticulum, Golgi apparatus

Rough endoplasmic reticulum, formation of glycoproteins Rough endoplasmic reticulum, protein synthesis Golgi apparatus, formation of glycolipids Golgi apparatus, protein synthesis

Year: NEET 2013

✅ Correct Answer: Rough endoplasmic reticulum, protein synthesis

🧠 Solution:

Rough Endoplasmic Reticulum (RER) – Protein synthesis. Smooth Endoplasmic Reticulum (SER) – Lipid synthesis. Golgi apparatus – Important site of formation of glycoproteins and glycolipids.

Q9166. Which is the important site of formation of glycoproteins and glycolipids in eukaryotic cells?

Golgi bodies Peroxisomes Polysomes Endoplasmic reticulum

Year: NEET (Sep.) 2020

✅ Correct Answer: Golgi bodies

🧠 Solution:

Golgi apparatus forms glycoproteins and glycolipids. N-linked sugars form in ER, O-linked sugars in Golgi.

Q9168. Non-membranous nucleoplasmic structures in nucleus are the site for active synthesis of

tRNA rRNA mRNA protein synthesis

Year: NEET (Odisha) 2019

✅ Correct Answer: rRNA

🧠 Solution:

Nucleolus is the non-membranous nucleoplasmic structure responsible for rRNA synthesis.

Q9167. Which of the following cell organelles is present in the highest number in secretory cells?

Mitochondria Lysosomes Golgi complex Endoplasmic reticulum

Year: NEET (Odisha) 2019

✅ Correct Answer: Golgi complex

🧠 Solution:

Golgi complex is highly developed in secretory cells for modification, packaging and secretion.

Q9118. Which of the following organic compounds is the main constituent of lecithin?

Cholesterol Arachidonic acid Phospholipid Phosphoprotein

Year: NEET (Odisha) 2019

✅ Correct Answer: Phospholipid

🧠 Solution:

Phospholipids are main constituents of lecithin. These molecules are composed of choline and inositole. It is found in all living cells as a major component of cell membrane.

Q9117. What will be the direction of flow of water when a plant cell is placed in a hypotonic solution?

Water will flow into the cell Water will flow in both directions Water will flow out of the cell No flow of water in any direction

Year: NEET (Odisha) 2019

✅ Correct Answer: Water will flow into the cell

🧠 Solution:

The behaviour of the plant cells with regard to water movement depends on the surrounding solution. When a plant cell is placed in hypotonic solution then the water will flow into the cell and the cell will swell.

Q9165. Which of the following elements helps in maintaining the structure of ribosomes?

Copper Magnesium Zinc Molybdenum

Year: NEET (Oct.) 2020

✅ Correct Answer: Magnesium

🧠 Solution:

Mg²⁺ ions bind ribosomal subunits. Below 0.0001 M Mg²⁺, ribosomal subunits dissociate.

Q9164. Match the following columns. Column I A. Smooth Endoplasmic Reticulum B. Rough Endoplasmic Reticulum C. Golgi complex D. Centriole Column II 1. Protein synthesis 2. Lipid synthesis 3. Glycosylation 4. Spindle formation

4 2 1 3 3 1 2 4 1 2 3 4 2 1 3 4

Year: NEET (Oct.) 2020

✅ Correct Answer: 2 1 3 4

🧠 Solution:

Smooth ER synthesises lipids. Rough ER synthesises proteins. Golgi complex performs glycosylation. Centrioles help in spindle formation.

Q9163. The biosynthesis of ribosomal RNA occurs in

ribosomes Golgi apparatus nucleolus microbodies

Year: NEET (Oct.) 2020

✅ Correct Answer: nucleolus

🧠 Solution:

Ribosomal RNA is synthesised in the nucleolus. mRNA and tRNA are also synthesised in the nucleus.

Q9162. Inclusion bodies of blue-green, purple and green photosynthetic bacteria are

contractile vacuoles microtubules gas vacuoles centrioles

Year: NEET (Oct.) 2020

✅ Correct Answer: gas vacuoles

🧠 Solution:

Gas vacuoles are membrane-bound inclusion bodies in aquatic prokaryotes. They are permeable to gases and help in buoyancy regulation.

Q9171. Which of the following statements regarding mitochondria is incorrect?

Inner membrane is convoluted with infoldings Enzymes of electron transport are embedded in outer membrane Mitochondrial matrix contains single circular DNA molecule and ribosomes Outer membrane is permeable to monomers of carbohydrates, fats and proteins

Year: NEET (National) 2019

✅ Correct Answer: Enzymes of electron transport are embedded in outer membrane

🧠 Solution:

The enzymes of electron transport are embedded in the inner membrane of mitochondria. The electron transport chain consists of coenzymes and cytochromes that participate in electron transfer. All other statements are correct.

Q9170. The shorter and longer arms of a submetacentric chromosome are referred to as

m-arm and n-arm, respectively p-arm and q-arm, respectively q-arm and p-arm, respectively s-arm and l-arm, respectively

Year: NEET (National) 2019

✅ Correct Answer: p-arm and q-arm, respectively

🧠 Solution:

In a submetacentric chromosome, the centromere is near the center, producing unequal arms designated as p (short) and q (long).

Q9169. Which of the following statements is not correct?

Lysosomes have numerous hydrolytic enzymes Lysosomes are formed by the process of packaging in the endoplasmic reticulum The hydrolytic enzymes of lysosomes are active under acidic pH Lysosomes are membrane bound structures

Year: NEET (National) 2019

✅ Correct Answer: Lysosomes are formed by the process of packaging in the endoplasmic reticulum

🧠 Solution:

Lysosomes are formed by budding from the trans-face of Golgi apparatus. Enzymes are synthesised in rough ER.

Q9119. The concept of ‘Omnis cellula-e-cellula’ regarding cell division was first proposed by

Rudolf Virchow Aristotle Schleiden Theodor Schwann

Year: NEET (National) 2019

✅ Correct Answer: Rudolf Virchow

🧠 Solution:

Rudolf Virchow proposed the concept of “omnis cellula-e-cellula”, i.e. all cells are derived from the pre-existing cells.

Q9186. Cellular organelles with membranes are

chromosomes, ribosomes and endoplasmic reticulum nuclei, ribosomes and mitochondria endoplasmic reticulum, ribosomes and nuclei lysosomes, Golgi apparatus and mitochondria

Year: CBSE AIPMT 2015

✅ Correct Answer: lysosomes, Golgi apparatus and mitochondria

🧠 Solution:

Membrane bound organelles include lysosomes, Golgi apparatus, mitochondria, ER, nucleus and vacuoles.

Q9185. Which of the following are not membrane bound?

Mesosomes Ribosomes Vacuoles Lysosomes

Year: CBSE AIPMT 2015

✅ Correct Answer: Ribosomes

🧠 Solution:

Ribosomes are non-membranous structures composed of rRNA and proteins.

Q9184. Balbiani rings are sites of

polysaccharide synthesis nucleotide synthesis RNA and protein synthesis lipid synthesis

Year: CBSE AIPMT 2015

✅ Correct Answer: RNA and protein synthesis

🧠 Solution:

Balbiani rings are puffs in polytene chromosomes where active transcription of RNA and protein synthesis occurs.

Q9126. A protoplast is a cell

Without plasma membrane Without cell wall Undergoing division Without nucleus

Year: CBSE AIPMT 2015

✅ Correct Answer: Without cell wall

🧠 Solution:

A protoplast is a cell without cell wall. It may be plant, bacterial or fungal cell whose wall is removed mechanically or enzymatically.

Q9125. Which of the following structure is not found in a prokaryotic cell?

Mesosome Nuclear envelope Plasma membrane Ribosome

Year: CBSE AIPMT 2015

✅ Correct Answer: Nuclear envelope

🧠 Solution:

In a prokaryotic cell, nuclear envelope is not found. Genetic material lies in direct contact with the cytoplasm.

Q9124. The structures that help some bacteria to attach to rocks and/or host tissues are

Fimbriae Mesosomes Holdfast Rhizoids

Year: CBSE AIPMT 2015

✅ Correct Answer: Fimbriae

🧠 Solution:

Fimbriae are small bristle like fibres sprouting out of the cell. In some bacteria, they help in attachment to rocks and host tissues.

Q9189. Match the following and select the correct answer. Column I: A. Centriole, B. Chlorophyll, C. Cristae, D. Ribozymes Column II: 1. Infoldings in mitochondria, 2. Thylakoids, 3. Nucleic acids, 4. Basal body of cilia or flagella

A B C D = 1 2 4 3 A B C D = 1 3 2 4 A B C D = 4 2 1 3 A B C D = 4 3 1 2

Year: CBSE AIPMT 2014

✅ Correct Answer: A B C D = 4 2 1 3

🧠 Solution:

(a) Centriole: In organisms with flagella and cilia, the position of these organelles is determined by the mother centriole which becomes the basal body. (b) Chlorophyll: Chlorophyll molecules are specially arranged in and around photosystem that are embedded in the thylakoid membrane of chloroplast. (c) Cristae: These are folds in the inner membrane of mitochondria which provide a large amount of surface area for chemical reactions. (d) Ribozymes (Ribonucleic acid enzyme): is an RNA molecule that is capable of catalysing specific reactions of nucleic acids.

Q9188. The osmotic expansion of a cell kept in water is chiefly regulated by

vacuoles mitochondria plastids ribosomes

Year: CBSE AIPMT 2014

✅ Correct Answer: vacuoles

🧠 Solution:

The osmotic expansion of a cell kept in water is chiefly regulated by vacuole. It is the single and large organelle which constitutes about 20% of plant cells and is small and multiple in animal cells. Vacuole stores water and macromolecules including ions, sugar, amino acids, protein and carbohydrates. The membrane that surrounds the vacuole is called tonoplast. The vacuole contains cell sap in it. The cell sap has high osmotic pressure which regulates turgor pressure in plant cells.

Q9187. The solid linear cytoskeletal elements having a diameter of 6 nm and made up of a single type of monomer are known as

intermediate filaments lamins microfilaments microtubules

Year: CBSE AIPMT 2014

✅ Correct Answer: microfilaments

🧠 Solution:

Microfilaments (actin filament) are the thinnest filaments of the cytoskeleton. They are found in the cytoplasm of the eukaryotic cells. They constitute the cytoskeleton through which the cells acquire shape; their diameter is approximately 6nm (avg.). These are the polymer of actin sub-units.

Q9194. What is true about ribosomes?

These are found only in eukaryotic cells These are self-splicing introns of some RNAs The prokaryotic ribosomes are 80S, where S stands for sedimentation coefficient These are composed of ribonucleic acid and proteins

Year: CBSE AIPMT 2012

✅ Correct Answer: These are composed of ribonucleic acid and proteins

🧠 Solution:

Ribosomes are large, non-membranous, RNA-protein complexes which are necessary for protein synthesis. In prokaryotes, 70S type of ribosomes are found while 80S type of ribosomes are found in eukaryotes.

Q9193. Ribosomal RNA is actively synthesised in

nucleoplasm nucleolus lysosomes ribosomes

Year: CBSE AIPMT 2012

✅ Correct Answer: nucleolus

🧠 Solution:

In eukaryotes, the site of synthesis of most of the ribosomal RNA (rRNA) is nucleolus. The nucleolar organiser contains many copies of ribosomal DNA (repetitive DNA). The RNA cistron of nucleolar DNA forms 45S precursor with the help of RNA polymerase. This 45S RNA undergoes cleavage with the help of nucleases to give 18S, 28S and 5.8S rRNA units. Out of different rRNAs, the 5S rRNA is not synthesised in nucleolus; it is synthesised outside it.

Q9127. Select the correct statement regarding cell membrane.

Na⁺ and K⁺ ions move across cell membrane by passive transport Lipids are arranged in a bilayer with polar heads towards inner part Proteins make up 60–70% of the cell membrane Fluid mosaic model of cell membrane was proposed by Singer and Nicolson

Year: CBSE AIPMT 2012

✅ Correct Answer: Fluid mosaic model of cell membrane was proposed by Singer and Nicolson

🧠 Solution:

In 1972, Singer and Nicolson proposed the fluid mosaic model of plasma membrane.

Q9129. Which one of the following also acts as a catalyst in a bacterial cell?

sn RNA 5S rRNA 23S rRNA hn RNA

Year: CBSE AIPMT 2011

✅ Correct Answer: 23S rRNA

🧠 Solution:

23S rRNA acts as a ribozyme and catalyses peptide bond formation in bacterial ribosomes.

Q9128. Which one of the following organisms is not an example of eukaryotic cells?

Escherichia coli Amoeba proteus Paramecium caudatum Euglena viridis

Year: CBSE AIPMT 2011

✅ Correct Answer: Escherichia coli

🧠 Solution:

The bacterium Escherichia coli is a prokaryote and lacks a true nucleus.

Q9131. The plasma membrane consists mainly of

Proteins embedded in a carbohydrate bilayer Phospholipids embedded in a protein bilayer Proteins embedded in a polymer of glucose molecules Proteins embedded in a phospholipid bilayer

Year: CBSE AIPMT 2010

✅ Correct Answer: Proteins embedded in a phospholipid bilayer

🧠 Solution:

According to Singer and Nicolson (1972), plasma membrane consists of a continuous bilayer of phospholipid molecules with embedded globular proteins.

Q9130. Which one of the following structures between two adjacent cells is an effective transport pathway?

Plastoquinones Plasmalemma Plasmodesmata Endoplasmic reticulum

Year: CBSE AIPMT 2010

✅ Correct Answer: Plasmodesmata

🧠 Solution:

Plasmodesmata are cytoplasmic bridges that permit translocation of solutes between adjacent plant cells.

Q9195. Cytoskeleton is made up of

calcium carbonate granules proteinaceous filaments callose deposits cellulosic microfibrils

Year: CBSE AIPMT 2009

✅ Correct Answer: proteinaceous filaments

🧠 Solution:

The cytoplasm of all eukaryotic cells is criss-crossed by a network of protein fibres that support the shape of the cell and anchor organelles at fixed locations. It is a dynamic system which includes three types of proteinaceous filaments—actin filaments, microtubule and intermediate filament.

Q9133. Plasmodesmata are

locomotory structures membranes connecting the nucleus with plasmalemma connections between adjacent cells lignified cemented layers between cells

Year: CBSE AIPMT 2009

✅ Correct Answer: connections between adjacent cells

🧠 Solution:

The primary cell wall contains many small openings or pores situated in primary pit fields. The cytoplasm of adjacent cells communicates through these pores by means of cytoplasmic bridges called plasmodesmata. They permit circulation of fluid and passage of solutes between cells.

Q9132. Middle lamella is mainly composed of

hemicellulose muramic acid calcium pectate phosphoglycerides

Year: CBSE AIPMT 2009

✅ Correct Answer: calcium pectate

🧠 Solution:

The middle lamella is a cementing layer between the cells. It is made up of Ca and Mg pectates. The basic chemical unit of pectin is galacturonic acid which has the capability of salt formation with calcium and magnesium (an acid–base reaction).

Q9198. In germinating seeds, fatty acids are degraded exclusively in the

proplastids mitochondria peroxisomes glyoxysomes

Year: CBSE AIPMT 2008

✅ Correct Answer: glyoxysomes

🧠 Solution:

Glyoxysomes are found in the cells of yeast, Neurospora and oil-rich seeds of many higher plants. During germination of oily seeds, the stored lipid molecules of glyoxysomes are hydrolysed by the enzyme lipase to glycerol and fatty acids. The long chain fatty acids are then broken down by successive removal of two carbon fragments in the process of β-oxidation. Peroxisomes are present in all photosynthetic cells of higher plants in etiolated leaf tissue. It is the site of hydrogen peroxide metabolism and glycolate cycle. Mitochondria is the site of aerobic respiration in eukaryotic cell. It is called power house of the cell.

Q9197. Vacuole in a plant cell

lacks membrane and contains water and excretory substances is membrane-bound and contains water and excretory substances lacks membrane and contains air is membrane-bound and contains storage proteins and lipids

Year: CBSE AIPMT 2008

✅ Correct Answer: is membrane-bound and contains water and excretory substances

🧠 Solution:

The vacuoles of plant cells are bounded by a single semipermeable membrane known as tonoplast. These vacuoles contain water, phenol, flavonols, anthocyanins, alkaloids and storage products such as sugars and proteins. The vacuoles of animal cells are bounded by a lipoproteinaceous membrane and their function is storage, transmission of materials and maintenance of internal pressure of cell.

Q9196. The two subunits of ribosome remain united at a critical ion level of

magnesium manganese copper calcium

Year: CBSE AIPMT 2008

✅ Correct Answer: magnesium

🧠 Solution:

Magnesium is constituent of chlorophyll, middle lamella, and connected with phosphate transfer in respiration. It is concerned with binding of ribosomes, DNA and RNA synthesis. Manganese activates enzymes of respiration, photosynthesis and nitrogen metabolism performing oxidation, reduction, decarboxylation, photolysis of water, etc. Copper is activator of plastocyanin, cytochrome oxidase, RuBP carboxylase and many other enzymes. It functions in electron transfer, maintenance of carbohydrate/nitrogen balance, chlorophyll synthesis, etc. Calcium is constituent of middle lamella, activator of enzymes connected with chromosome formation and many aspects of metabolism.

Q9134. Keeping in view the fluid mosaic model for the structure of cell membrane, which statement is correct with respect to the movement of lipids and proteins from one lipid monolayer to the other (flip-flop movement)?

Neither lipids nor proteins can flip-flop While proteins can flip-flop, lipids cannot Both lipids and proteins can flip-flop While lipids can rarely flip-flop, proteins cannot

Year: CBSE AIPMT 2008

✅ Correct Answer: While lipids can rarely flip-flop, proteins cannot

🧠 Solution:

Lipid molecules very rarely migrate from one lipid monolayer to the other. Such movement is called flip-flop or transbilayer movement. Proteins do not perform flip-flop movement.

Q9199. Select the wrong statement from the following

Both chloroplasts and mitochondria contain an inner and an outer membrane Both chloroplasts and mitochondria have an internal compartment, the thylakoid space bounded by the thylakoid membrane Both chloroplasts and mitochondria contain DNA The chloroplasts are generally much larger than mitochondria

Year: CBSE AIPMT 2007

✅ Correct Answer: Both chloroplasts and mitochondria have an internal compartment, the thylakoid space bounded by the thylakoid membrane

🧠 Solution:

Thylakoid space which is known as lumen is present only in chloroplasts. The inner membrane of mitochondria is folded to form cristae.

Q9200. Which of the following statements regarding mitochondrial membrane is not correct?

The outer membrane resembles a sieve The outer membrane is permeable to all kinds of molecules The inner membrane is highly convoluted forming a series of infoldings The enzymes of the electron transfer chain are embedded in the outer membrane

Year: CBSE AIPMT 2006

✅ Correct Answer: The enzymes of the electron transfer chain are embedded in the outer membrane

🧠 Solution:

In mitochondria, the enzymes of electron transport chain are found in the inner membrane while outer membrane contains enzymes involved in mitochondrial lipid synthesis and those enzymes that convert lipid substrates into other forms that are subsequently metabolised in the matrix.

Q9135. A major breakthrough in the studies of cells came with the development of electron microscope because

electron beam can pass through thick materials the resolution power of electron microscope is much higher than that of light microscope electron microscope uses electrons having longer wavelength than photons the resolving power of electron microscope is 200–350 nm as compared to 0.1–0.2 nm for light microscope

Year: CBSE AIPMT 2006

✅ Correct Answer: the resolution power of electron microscope is much higher than that of light microscope

🧠 Solution:

The resolving power of light microscope is about 0.25 µm–0.3 µm while that of electron microscope is 2–10 Å (theoretically 0.25 Å). Hence, electron microscope provides much higher resolution.

Q9207. Extranuclear inheritance is a consequence of presence of genes in

endoplasmic reticulum and mitochondria lysosomes and ribosomes ribosomes and chloroplast mitochondria and chloroplasts

Year: CBSE AIPMT 2005

✅ Correct Answer: mitochondria and chloroplasts

🧠 Solution:

Extra nuclear or extra chromosomal or cytoplasmic or organellar inheritance is a consequence of presence of genes in mitochondria and chloroplast. Extra chromosomal units function either independently or in collaboration with nuclear genetic system.

Q9206. Chlorophyll in chloroplast is located in

grana Both (a) and (c) stroma pyrenoid

Year: CBSE AIPMT 2005

✅ Correct Answer: grana

🧠 Solution:

Chlorophyll is a specialised light absorbing pigment which is found in the inner wall of granum. Each granum is a flat, sac-like structure in which light reaction of photosynthesis takes place.

Q9205. Proteins synthesis in an animal cell occurs

on ribosomes present in the nucleolus as well as in cytoplasm on ribosomes present in cytoplasm as well as in mitochondria only on the ribosomes present in cytosol only on ribosomes attached to the nuclear envelope and endoplasmic reticulum

Year: CBSE AIPMT 2005

✅ Correct Answer: on ribosomes present in cytoplasm as well as in mitochondria

🧠 Solution:

Protein synthesis takes place in ribosomes attached on wall of ER. In an eukaryotic cell ribosomes are present in cytoplasm, mitochondria and chloroplasts. So, in these places protein synthesis also takes place.

Q9202. Flagella of prokaryotic and eukaryotic cells differ in

location in cell and mode of functioning microtubular organisation and function type of movement and placement in cell microtubular organisation and type of movement

Year: CBSE AIPMT 2005

✅ Correct Answer: microtubular organisation and type of movement

🧠 Solution:

Flagella of prokaryotic and eukaryotic species differ in microtubular organisation and type of movement. In eukaryotes the arrangement is 9+2 and specialised while in prokaryotes arrangement is 9 0+ and simple.

Q9201. The main organelle involved in modification and routing of newly synthesised proteins to their destinations is

mitochondria lysosome chloroplast endoplasmic reticulum

Year: CBSE AIPMT 2005

✅ Correct Answer: endoplasmic reticulum

🧠 Solution:

Porter coined the name Endoplasmic Reticulum (ER). It is a network of tubules, vesicles and cisternae within an eukaryotic cell (absent in prokaryotic cells). Two types of ER are recognised: Smooth ER, which does not have ribosomes and helps in synthesis of lipid and glycogen, and Rough ER, whose wall contains ribosomes and is involved in protein synthesis and transfer.

Q9137. The main difference in Gram (+) and Gram (–) bacteria resides in their

cell wall cell membrane cytoplasm flagella

Year: CBSE AIPMT 2005

✅ Correct Answer: cell wall

🧠 Solution:

Gram staining differentiates bacteria based on the thickness and lipid content of the cell wall. Gram (+) bacteria have thick peptidoglycan walls, while Gram (–) bacteria have thin walls rich in lipids.

Q9136. A student wishes to study the cell structure under a light microscope having 10X eyepiece and 45X objective. Which colour of light should be used for best resolution?

Blue Red Green Yellow

Year: CBSE AIPMT 2005

✅ Correct Answer: Blue

🧠 Solution:

Resolving power = Wavelength of light / (2 × NA). Blue light (≈500 nm) has the shortest wavelength among visible light and hence provides the best resolution.

Q9204. Flagella of prokaryotic and eukaryotic cells differ in

type of movement and placement in cell microtubular organisation and type of movement microtubular organisation and function location in cell and mode of functioning

Year: CBSE AIPMT 2004

✅ Correct Answer: microtubular organisation and function

🧠 Solution:

The outer membrane resembles a sieve that is permeable to all molecules of 10,000 daltons mole weight or less, including small proteins. The inner membrane is impermeable and highly convoluted, forming a series of infoldings, known as cristae, in the matrix space.

Q9203. In chloroplasts, chlorophyll is present in

inner membrane outer membrane stroma thylakoids

Year: CBSE AIPMT 2004

✅ Correct Answer: thylakoids

🧠 Solution:

The thylakoids of chloroplast are flattened vesicles arranged as a membranous network within the stroma. 50% of chloroplast proteins and various components involved (namely chlorophyll, carotenoids and plastoquinone) are present in thylakoid membranes that are involved in photosynthesis.

Q9208. Ribosomes are produced in

Golgi body nucleolus mitochondria cytoplasm

Year: CBSE AIPMT 2002

✅ Correct Answer: nucleolus

🧠 Solution:

The proteins required for the formation of ribosome are synthesised within the cytoplasm through the process of translation. These proteins are later shifted to nucleus and then to nucleolus where the RNA and proteins are assembled into ribosomal sub-units. In prokaryotes (bacteria) ribosomes are synthesised in cytoplasm. In eukaryotes, the process takes place both in the cell cytoplasm and in the nucleolus which is a region within the cell nucleus.

Q9138. In fluid mosaic model of plasma membrane

upper layer is non-polar and hydrophilic upper layer is polar and hydrophobic phospholipids form a bimolecular layer in middle part proteins form a middle layer

Year: CBSE AIPMT 2002

✅ Correct Answer: phospholipids form a bimolecular layer in middle part

🧠 Solution:

According to the fluid mosaic model, phospholipids form a bimolecular layer with proteins embedded in it, not arranged as continuous layers.

Q9209. Microtubules are absent in

centriole spindle fibres mitochondria flagella

Year: CBSE AIPMT 2001

✅ Correct Answer: mitochondria

🧠 Solution:

Microtubules are present only in eukaryotes; and are component of cilia and flagella as well as spindle (during cell division). They are straight, hollow rods measuring about 25nm in diameter and 200nm to 25µm in length. Microtubules give shape and support to the cell.

Q9157. In plants, inulin and pectin are

insect-attracting material excretory material reserve materials wastes

Year: CBSE AIPMT 2001

✅ Correct Answer: reserve materials

🧠 Solution:

Inulin is a polymer of fructose used as stored food in roots and tubers. Pectin is a mucopolysaccharide present in plant cell walls.

Q9156. Element necessary for the middle lamella

Cu K Ca Zn

Year: CBSE AIPMT 2001

✅ Correct Answer: Ca

🧠 Solution:

Middle lamella functions as cementing layer between plant cells and is mainly composed of calcium and magnesium pectate.

Q9211. The cell organelle involved in glycosylation of protein is

ribosome mitochondria peroxisome endoplasmic reticulum

Year: CBSE AIPMT 2000

✅ Correct Answer: endoplasmic reticulum

🧠 Solution:

The proteins synthesised by the ribosomes bound to ER are passed into the lumen of ER where an oligosaccharide is added to them (i.e. these are glycosylated).

Q9210. Lysosomes are reservoirs of

RNA and protein fats hydrolytic enzymes secretory glycoproteins

Year: CBSE AIPMT 2000

✅ Correct Answer: hydrolytic enzymes

🧠 Solution:

Lysosomes were discovered by Christian de Duve (1955) from rat liver. Matile (1964) discovered lysosomes in plants. Generally, lysosomes are 0.2–0.8 µm in size, irregular membranous vesicles filled with hydrolytic enzymes. They are polymorphic. About 40 enzymes (all hydrolytic) are present in lysosomes. These include proteases, nucleases, glycosidases, lipases, phospholipases, phosphatases and sulphatases.

Q9214. Which of the following organ has single membrane?

Mitochondria Cell wall Nucleus Spherosomes

Year: CBSE AIPMT 1999

✅ Correct Answer: Spherosomes

🧠 Solution:

Cell wall does not have a membrane. The mitochondria and nucleus are surrounded by double membraned envelope.

Q9213. The proteins are synthesised at

centrosomes ribosomes mitochondria Golgi bodies

Year: CBSE AIPMT 1999

✅ Correct Answer: ribosomes

🧠 Solution:

During protein synthesis, smaller sub-units of ribosomes attach to mRNA. The ribosomes provide space as well as enzyme for the synthesis of proteins. Therefore, these are known as protein factories or workbenches of protein.

Q9212. Some of the enzymes which are associated in converting fats into carbohydrates, are present in

glyoxysomes Golgi bodies liposomes microsomes

Year: CBSE AIPMT 1999

✅ Correct Answer: glyoxysomes

🧠 Solution:

Besides catalase, the glyoxysomes contain enzymes for the glyoxylate cycle through which fats are converted into carbohydrates.

Q9140. The eukaryotic genome differs from the prokaryotic genome because

genes are organised into operons in eukaryotes DNA is circular and single stranded in prokaryotes DNA is complexed with histones in prokaryotes repetitive sequences are present in eukaryotes

Year: CBSE AIPMT 1999

✅ Correct Answer: repetitive sequences are present in eukaryotes

🧠 Solution:

A large portion (20–50%) of eukaryotic genome consists of repetitive DNA, which does not code for proteins.

Q9139. DNA is mainly found in

cytoplasm nucleolus nucleus both nucleus and cytoplasm

Year: CBSE AIPMT 1999

✅ Correct Answer: nucleus

🧠 Solution:

Most DNA is found in the nucleus, though small amounts are also present in mitochondria and chloroplasts.

Q9216. Microtubule is involved in the

membrane architecture cell division DNA recognition muscle contraction

Year: CBSE AIPMT 1998

✅ Correct Answer: cell division

🧠 Solution:

Microtubules are one of the essential protein filaments of the cytoskeletons of probably all eukaryotic cells and their cilia, flagella, basal bodies, centrioles and mitosis and meiosis spindles. Each microtubule is made up of a hollow cylinder of 13 protofilaments of the tubulin protein. The diameter of each microfibril is 25 nm. The function of microtubule is to guide organelle and chromosome movement in the cell, cause cell elongation and help in movements of cilia/flagella.

Q9218. Genes located on mitochondrial DNA

generally show maternal inheritance are not inherited show biparental inheritance like the nuclear genes are always inherited from the male parent

Year: CBSE AIPMT 1997

✅ Correct Answer: generally show maternal inheritance

🧠 Solution:

Mitochondria are found only in eukaryotic cells, they contain a single circular double stranded DNA molecule (mtDNA). Available evidences show that mitochondria of female parent are transferred to progeny during fertilisation. Recent studies have shown that factors responsible for cytoplasmic male sterility are located in mitochondrial DNA.

Q9217. Protein synthesis in an animal cell takes place

only in cytoplasm in the cytoplasm as well as in mitochondria in the nucleolus as well as in the cytoplasm only on ribosomes attached to nucleus

Year: CBSE AIPMT 1997

✅ Correct Answer: in the cytoplasm as well as in mitochondria

🧠 Solution:

Protein synthesis is a complex process; it essentially involves DNA for the synthesis of mRNA (transcription) which contains information for the synthesis of proteins (translation). The process of translation takes place on ribosomes which are found in cytoplasm (in attached form on ER) and in mitochondria (in the free form).

Q9215. Telomeres are part of

mitochondria endoplasmic reticulum ribosomes chromosome

Year: CBSE AIPMT 1997

✅ Correct Answer: chromosome

🧠 Solution:

In every chromosome, there is a small region called primary constriction in which there is a centromere where two sister chromatids are held together and spindle fibres get attached during cell division.

Q9219. Lysosomes have a high content of

DNA ligases lipoproteins hydrolytic enzymes polyribosomes

Year: CBSE AIPMT 1996

✅ Correct Answer: hydrolytic enzymes

🧠 Solution:

Lysosomes or suicidal bags are filled with about 40 types of acid hydrolases (digestive enzymes) like acid proteases, acid nucleases, acid phosphatases, acid sulphatases, acid lipases, acid glycosidases working at an optimum pH ≤ 5 for controlling intracellular digestion of macromolecules.

Q9222. The desmosomes are concerned with

cytolysis cellular excretion cell division cell adherence

Year: CBSE AIPMT 1995

✅ Correct Answer: cell adherence

🧠 Solution:

Desmosomes (macula adherens) consist of intercellular thickening materials, disc-shaped intracellular thickening adjacent to each membrane with tonofibrils. These act as intercellular cementing material, adhere cells together at places like spot welding.

Q9221. The prokaryotic flagella possess

helically arranged protein molecule protein membrane enclosed fibre ‘9+2’ membrane enclosed structure unit membrane enclosed fibre

Year: CBSE AIPMT 1995

✅ Correct Answer: helically arranged protein molecule

🧠 Solution:

Prokaryotic (bacterial) flagellum is made up of flagellin protein arranged helically. It does not show 9+2 organisation and ATPase activity. These flagella do not beat but rotate like a propeller that brings about backward pushing of water. Gram+ve bacteria have two rings in the basal body. Gram−ve bacteria have four rings: the L, P, M and S rings.

Q9220. The function of rough endoplasmic reticulum is

lipid synthesis protein synthesis steroid synthesis fat synthesis

Year: CBSE AIPMT 1995

✅ Correct Answer: protein synthesis

🧠 Solution:

Rough Endoplasmic Reticulum (RER) provides surface for ribosomes for synthesis of secretory (serum proteins), lysosomal and membrane proteins, glycoproteins and helps in packaging of polypeptide chains into enzymes/proteins. It also provides membrane to Golgi bodies for forming vesicles and lysosomes.

Q9227. Organelle/organoid involved in genetic engineering is

mitochondrion lomasome plasmid Golgi apparatus

Year: CBSE AIPMT 1994

✅ Correct Answer: plasmid

🧠 Solution:

Plasmids are small, self-replicating extra chromosomal, non-essential genetic/DNA elements. Plasmid consists of a ring of circular, supercoiled double stranded naked DNA carrying genes for replication and for one or more cellular non-essential functions. They are ideal vectors for genetic engineering, gene cloning since they are self-replicating, carry non-essential genes and have a restriction site for one or more restriction endonucleases.

Q9226. Cell organelles having hydrolases/digestive enzymes are

peroxisomes mesosomes ribosomes lysosomes

Year: CBSE AIPMT 1994

✅ Correct Answer: lysosomes

🧠 Solution:

Lysosomes (or suicidal bags or cellular house keepers or scavenger of cell) are single membrane bound, spherical microbodies, filled with different types of acid hydrolases (digestive enzymes) working at pH ≤ 5 and can digest almost every type of organic matter except cellulose. Primary lysosome (storage granules) unites with food vacuole (phagosome) forming secondary lysosomes (heterophagosomes or digestive vacuoles) which cause intracellular digestion (heterophagy).

Q9225. Organelle having flattened membrane bound cisternae and lying near the nucleus is

Golgi apparatus mitochondrion nucleolus centriole

Year: CBSE AIPMT 1994

✅ Correct Answer: Golgi apparatus

🧠 Solution:

Golgi body or dictyosome has a stack of single membrane bound cisternae with swollen ends, network of tubules and vesicles. Cisternae are parallel membrane-lined narrow sacs which are interconnected. Golgi body has two faces: concave or distal or maturing (M) face or trans face towards cell membrane and cis or convex or proximal or forming (F) face towards rough ER and nuclear membrane. New cisternae are formed from SER and added from F-face.

Q9224. Mitochondrial cristae are sites of

phosphorylation of flavoproteins oxidation-reduction reactions breakdown of macromolecules protein synthesis

Year: CBSE AIPMT 1994

✅ Correct Answer: oxidation-reduction reactions

🧠 Solution:

Mitochondrial cristae bear the functional unit, i.e., oxysomes, Fernandes and Moran (F F0 1−) particles or electron transport particle. Since inner membrane is impermeable to ATP, ATP is synthesised on oxysomes having ATPase in F1 (stalk) and proton channels on F0 (base). ATPase helps in oxidative phosphorylation, synthesising ATP through electron transport system by undergoing oxidation-reduction reactions.

Q9223. Inner membrane convolutions of a mitochondrion are known as

lamellae thylakoids grana cristae

Year: CBSE AIPMT 1994

✅ Correct Answer: cristae

🧠 Solution:

Mitochondrial inner membrane is convoluted several times to form cristae.

Q9230. Golgi apparatus is absent in

bacteria and blue-green algae yeast None of the above higher plants

Year: CBSE AIPMT 1993

✅ Correct Answer: bacteria and blue-green algae

🧠 Solution:

Golgi bodies are absent in prokaryotic cells (i.e., bacteria, cyanobacteria, mycoplasma), in mature RBC, mature sperms, mature eggs, sperms of bryophytes, pteridophytes and mature sieve tubes. In contrast, active eukaryotic cells are rich in Golgi bodies. Maximum number (25,000) of Golgi bodies are found in rhizoidal cells of Chara.

Q9229. Membranous bag with hydrolytic enzymes which is used for controlling intracellular digestion of macromolecules is

nucleosome lysosome endoplasmic reticulum phagosome

Year: CBSE AIPMT 1993

✅ Correct Answer: lysosome

🧠 Solution:

The intracellular digestion, i.e., the breakdown of substances within the cytoplasm of a cell is controlled by lysosomes. Intracellular digestion occurs in animals that lack a digestive tract, e.g., in Pycnogonida, Mollusca, Cnidaria and Porifera.

Q9228. In plant cells, peroxisomes are associated with

photoperiodism phototropism photorespiration photosynthesis

Year: CBSE AIPMT 1993

✅ Correct Answer: photorespiration

🧠 Solution:

Peroxisomes are microbodies arising from ER and containing enzymes for peroxide formation. In plants, they occur in green mesophyll cells of leaves of C3 plants and are involved in photorespiration through interacting with chloroplast and mitochondria. In animals, they are involved in lipid synthesis, purine catabolism, gluconeogenesis, etc.

Q9146. Angstrom (Å) is equal to

10⁻¹⁰ m 0.0001 µm 10⁻⁸ cm all of the above

Year: CBSE AIPMT 1993

✅ Correct Answer: all of the above

🧠 Solution:

1 Å = 10⁻¹⁰ m = 10⁻⁸ cm = 10⁻⁴ µm.

Q9145. Balbiani rings (puffs) are sites of

lipid synthesis polysaccharide synthesis RNA and protein synthesis DNA replication

Year: CBSE AIPMT 1993

✅ Correct Answer: RNA and protein synthesis

🧠 Solution:

Balbiani rings are regions of polytene chromosomes where DNA is actively transcribed for RNA and protein synthesis.

Q9144. Genophore or bacterial genome is made of

a single stranded DNA histones and non-histones RNA and histones a single double stranded DNA

Year: CBSE AIPMT 1993

✅ Correct Answer: a single double stranded DNA

🧠 Solution:

The bacterial genome (genophore) consists of a single circular, double stranded DNA molecule.

Q9143. Cell recognition and adhesion occur due to biochemicals of cell membrane named

lipids proteins and lipids glycoproteins and glycolipids proteins

Year: CBSE AIPMT 1993

✅ Correct Answer: glycoproteins and glycolipids

🧠 Solution:

Glycoproteins and glycolipids form the glycocalyx which functions in cell recognition, adhesion and antigen specificity.

Q9142. Names of Schleiden and Schwann are associated with

protoplasm as physical basis of life theory of cell lineage cell theory nucleus as control centre

Year: CBSE AIPMT 1993

✅ Correct Answer: cell theory

🧠 Solution:

Matthias Schleiden and Theodor Schwann jointly proposed the cell theory.

Q9141. Which is correct about cell theory in view of current knowledge?

Modified cell theory states that all cells reproduce It needs modification due to discovery of subcellular structures Cell theory does not hold good for viruses All living objects consist of cells capable of reproduction

Year: CBSE AIPMT 1993

✅ Correct Answer: Cell theory does not hold good for viruses

🧠 Solution:

Viruses are acellular and do not follow cellular organisation, hence are exceptions to cell theory.

Q9235. Experiments on Acetabularia by Hammerling proved the role of

chromosomes in heredity nucleus in heredity cytoplasm in controlling differentiation nucleocytoplasmic ratio

Year: CBSE AIPMT 1992

✅ Correct Answer: nucleus in heredity

🧠 Solution:

J. Hammerling (1953) carried the grafting experiments involving exchange of nucleus (located at the base) in Acetabularia. He proved the role of nucleus in heredity, growth, etc.

Q9234. Which one is apparato reticolare interno?

Microtubules Microfilaments Golgi apparatus Endoplasmic reticulum

Year: CBSE AIPMT 1992

✅ Correct Answer: Golgi apparatus

🧠 Solution:

Golgi body (dictyosomes, lipochondria) is a stack of flattened membrane bound sac-like body. They form internal reticulare apparatus (apparato reticolare interno).

Q9233. An outer covering membrane is absent over

nucleolus plastids lysosome mitochondrion

Year: CBSE AIPMT 1992

✅ Correct Answer: mitochondrion

🧠 Solution:

Ribosomes are smallest, membraneless sub-microscopic organelles, called as protein factories. They act as a template, bringing together different components involved in the protein synthesis.

Q9232. Oxysomes or F F0 1− particles occur on

chloroplast surface inner mitochondrial membrane thylakoids mitochondrial surface

Year: CBSE AIPMT 1992

✅ Correct Answer: inner mitochondrial membrane

🧠 Solution:

Oxysomes are the elementary particles or F0 1− or Fernandes-Moran particle present on the inner membrane of mitochondria. They are about 10^4−10^10 number and have a base of F0 sub-unit toward C-face (11 × 1.5 nm), a stalk (0.5–3.5 nm) and a head or F1 sub-unit (8.5–10 nm diameter) towards matrix or M-face.

Q9231. All plastids have similar structure because they can

store starch, lipids and proteins be present together perform same function get transformed from one type to another

Year: CBSE AIPMT 1992

✅ Correct Answer: get transformed from one type to another

🧠 Solution:

All plastids are similar in structure because these are interconvertible and get transformed from one type to another. Leucoplasts are formed from proplastids and leucoplasts; chloroplasts can arise from pre-existing chloroplasts, proplastids and leucoplasts and chromoplasts can develop from proplastids, leucoplasts and chloroplasts.

Q9236. Ribosomes were discovered by

Porter de Robertis Palade Golgi

Year: CBSE AIPMT 1991

✅ Correct Answer: Palade

🧠 Solution:

Ribosomes were first observed by Claude (1941), he called them as microsomes. Robinson and Brown (1950) noticed them in plant cells of bean roots and Palade (1955) detected them in animal cells and called these structures as ribosomes.

Q9150. Fluid mosaic model of cell membrane was put forward by

Danielli and Davson Singer and Nicolson Watson and Crick Garner and Allard

Year: CBSE AIPMT 1991

✅ Correct Answer: Singer and Nicolson

🧠 Solution:

Fluid mosaic model of plasma membrane was proposed by S. J. Singer and G. L. Nicolson in 1972.

Q9149. Cell wall shows

complete permeability differential permeability impermeability semi-permeability

Year: CBSE AIPMT 1991

✅ Correct Answer: complete permeability

🧠 Solution:

Cell wall is non-living, porous, permeable, inert, hydrophilic, rigid and semi-transparent protective covering around the plasmalemma.

Q9148. Resolution power is the ability to

magnify image distinguish two trees distinguish two close objects distinguish amongst organelles

Year: CBSE AIPMT 1991

✅ Correct Answer: distinguish two close objects

🧠 Solution:

Resolution power is the ability of a microscope to distinguish between two points that are closely situated. Higher resolution produces a clearer image.

Q9147. Addition of new cell wall particles amongst the existing ones is

apposition intussusception aggregation deposition

Year: CBSE AIPMT 1991

✅ Correct Answer: apposition

🧠 Solution:

Apposition or accretion is defined as the addition of new cell wall particles amongst the existing one, such as deposition of secondary walls in layers from outside over the existing primary wall. Intussusception is internal growth of the primary wall occurring during cell growth. Deposition refers to molecules settling out of solution. Aggregation refers to direct mutual attraction between particles.

Q9152. Electron microscope has a high resolution power. This is due to

high numerical aperture of glass lenses used low wavelength of light source used very low wavelength of electron beam electromagnetic lenses

Year: CBSE AIPMT 1990, 1992

✅ Correct Answer: very low wavelength of electron beam

🧠 Solution:

Resolving power depends on wavelength of radiation. In electron microscope, very low wavelength of electrons provides higher resolution.

Q9154. Nucleoproteins are synthesised in

nucleolus nucleoplasm nuclear envelope cytoplasm

Year: CBSE AIPMT 1990

✅ Correct Answer: cytoplasm

🧠 Solution:

Nucleoproteins include ribonucleoproteins present in ribosomes and deoxyribonucleoproteins found in chromosomes.

Q9151. Magnification of compound microscope is not connected with

numerical aperture focal length of objective focal length of eye piece tube length

Year: CBSE AIPMT 1990

✅ Correct Answer: numerical aperture

🧠 Solution:

Magnification depends on focal length of objective and eyepiece and length of body tube. It does not depend on numerical aperture.

Q9238. Organelles can be separated from cell homogenate through

differential centrifugation X-rays diffraction chromatography auto-radiography

Year: CBSE AIPMT 1989

✅ Correct Answer: differential centrifugation

🧠 Solution:

Differential centrifugation is the mechanical separation of individual sub-cellular components from homogenate in centrifuge at low speed. Depending upon the size, specific gravity, mass, density, different organelles are separated and settled at the bottom of the centrifuge tube at different centrifugal speeds. Ultracentrifuges have 50,000–1,00,000 rpm and are used for the separation of minute cell organelles and constituents on the basis of different densities.

Q9237. Polyribosomes are aggregates of

only rRNA several ribosomes held together by string of mRNA peroxisomes ribosomes and rRNA

Year: CBSE AIPMT 1989

✅ Correct Answer: several ribosomes held together by string of mRNA

🧠 Solution:

Polyribosomes or ergasomes are formed by the combination of 6-8 ribosomes attached on a single strand of mRNA. mRNA brings about polymerisation of a specific protein molecule, with the help of ribosomes, from amino acid molecules found in the cytosol.

Q9153. Plasma membrane is made up of

proteins, some nucleic acid and lipids proteins and lipids proteins and carbohydrates proteins, lipids and carbohydrates

Year: CBSE AIPMT 1989

✅ Correct Answer: proteins, lipids and carbohydrates

🧠 Solution:

Plasma membrane is a living, quasi-fluid, trilaminar membrane consisting of proteins, lipids, water and carbohydrates.

Q9155. According to fluid mosaic model, plasma membrane is composed of

phospholipids and hemicellulose phospholipids, extrinsic proteins and intrinsic proteins phospholipids and oligosaccharides phospholipids and integral proteins

Year: CBSE AIPMT 1988

✅ Correct Answer: phospholipids, extrinsic proteins and intrinsic proteins

🧠 Solution:

In fluid mosaic model, phospholipids form a bilayer with proteins embedded irregularly. Integral proteins are embedded, while extrinsic proteins are superficially attached.

NEET / Biology / Cell : The Unit of Life