English Comprehension PYQs

Key Points

• RNA or ribonucleic acid is a nucleic acid that plays a crucial role in gene expression and protein synthesis.
• RNA is broadly classified as:
• mRNA - Messenger RNA acts as a template RNA that carries genetic information for protein synthesis.
• tRNA - Transfer RNA carries amino acid to the site of protein synthesis and helps in reading the genetic code.
• rRNA - Ribosomal RNA plays structural and catalytic in the cell.
• Plant cells are eukaryotic cells that consist of various membrane-bound organelles.
• RNA may be associated with a number of the such organelles or cell components.

Explanation:

Nuclei - 

• RNA is synthesized in the nucleus through the process of transcription.
• The newly synthesized RNA molecules, known as pre-mRNA, undergo further processing in the nucleus before being transported to the cytoplasm.
• Mature mRNA molecules are exported to the cytoplasm through nuclear pores for translation.

Cytoplasm - 

• The cytoplasm is the region of the cell outside the nucleus, where most of the cellular activities take place.
• In plant cells, RNA is found throughout the cytoplasm and is involved in various processes such as translation, RNA interference and RNA splicing.

Mitochondria - 

• Mitochondria are double membrane-bound organelles that produce energy for the cell through the process of cellular respiration.
• They have their own genome, and RNA is synthesized in the mitochondrial matrix.
• Mitochondrial RNA plays a critical role in mitochondrial protein synthesis.

Chloroplasts - 

• Chloroplasts are also double membrane-bound organelles found in plant cells that are responsible for photosynthesis.
• Chloroplasts also possess their own genome, and RNA is synthesized in the chloroplast stroma.
• Chloroplast RNA is involved in the translation of chloroplast-encoded proteins.

Ribosomes-

Ribosomal RNA (rRNA) is a crucial component of ribosomes, which are the sites of protein synthesis in cells.

Endoplasmic reticulum (ER) - 

• The ER is a complex network of membranes that plays a crucial role in protein synthesis, folding and transport.
• The ER associated with ribosomes are called Rough ER and they synthesize proteins.
• Here, the RNA is present in the ribosomes as rRNA.
• RNA molecules synthesized in the ER are involved in the synthesis of secreted proteins, membrane proteins, and proteins that are transported to other organelles.

Confusion Points

• Ribosomal RNA can be included as cytoplasmic RNA too.

• Plant tissues are broadly divided into 2 groups based on their capability of division - 
• Meristematic tissue - have the capability of active cell division.
• Permanent tissue - usually do not divide.
• Meristems consist of undifferentiated cells and can be further divided on the basis of their location.

1. Apical Meristem - 

• It produces the primary tissue and occurs at the tip of the root and shoot.
• They help in elongation of the root and the stem.

2. Lateral Meristem - 

• It is present at the mature parts of the root and the stem.
• It is responsible for increase in the girth and thickness of the stem.
• They appear later than primary meristems and hence, also called secondary meristem.

3. Intercalary Meristem - 

• It is the meristem which occur between the mature tissues.
• They occur at the base of leaves or nodes and may help in elongation of internodes.
• They also occur in grasses, where they regenerate the lost parts grazed off by the herbivores.

​Hence, the correct answer is option 3.

Concept:

• Plant tissues are broadly divided into 2 groups - 
• Meristematic tissue - have the capability of active cell division.
• Permanent tissue - usually do not divide.
• The permanent tissues are again of 2 types - 
• Simple - having cells of similar structure and function.
• Complex - having different types of cells.

Important Points

• Xylem is a type of complex permanent tissue in plants.
• It helps in conduction of water and minerals from the roots to the stem and leaves.
• It is composed of 4 different types of cells that are known as xylem elements:

1. Tracheid - 

• These are elongated tube-like cells with tapering ends.
• They have thick, lignified walls and lack protoplasm.
• Hence, these are dead cells.

2. Vessel - 

• It is a long cylindrical structure formed by individual vessel members.
• The vessel members have a central cavity and lignified walls.
• These are interconnected with each other via perforations present on the common cell walls.
• These cells also lack protoplasm and are dead.
• It is a unique characteristic of angiosperms.

3. Xylem Parenchyma - 

• These are the thin-walled, and the only living cells of the xylem tissue.
• They may store food in the form of starch, fat or special substances like tannins.

4. Xylem Fibre - 

• These are also dead cells with highly thickened walls.
• They contain a central lumen, which may be septate or aseptate.

Therefore, the correct answer is option 3.

Concept:

Resistance: 

Parallel circuits:

• ​A parallel circuit is a circuit in which the resistors are arranged with their heads connected together, and their tails connected together
• The current in a parallel circuit breaks up, with some flowing along each parallel branch and re-combining when the branches meet again.
• The total resistance of a set of resistors in a parallel is found by adding up the reciprocals of the resistance values and then taking the reciprocal to the total.
• Equivalent resistance of resistors in parallel: 1/Req = 1/R₁ + 1/R₂ + 1/R₃

 Circuit:

• It is the degree to which a substance prevents the flow of electricity through it.
• Series circuits:
• ​A series circuit is a circuit in which resistors are arranged in a chain.
• The current is the same through each resistor.
• The total resistance of the circuit is found by simply equivalent resistance of resistors in series R = R₁ + R₂ + R₃.

 

Calculation:

R₁ = 11 Ω , R₂ = 22 Ω  and R₃ = 33 Ω 

These are connected in parallel,

1/Req = 1/R1 + 1/R2 + 1/R3

1/Req = 1/11 + 1/22 + 1/33

1/Req = 1/6

R_eq = 6 Ω  

The correct answer is option (4)

Concept:

• The r.m.s. (root mean square) potential difference between the red live wire and the black neutral wire in the Indian domestic electric supply is 220 volts.
• In India, the standard domestic electric supply operates at a frequency of 50 Hz and a nominal voltage of 220 volts. The r.m.s. voltage is a measure of the effective voltage, taking into account the varying voltage levels in an alternating current (AC) system.
• The red wire, known as the live wire, carries the alternating current from the power source to the electrical devices in a building. It alternates between positive and negative voltage values, resulting in a sinusoidal waveform.
• The black wire, known as the neutral wire, completes the circuit by providing a return path for the current back to the power source. It is connected to the earth ground for safety purposes.

Explanation:

• The r.m.s. potential difference of 220 volts means that the effective voltage between the red live wire and the black neutral wire, considering the alternating nature of the voltage, is 220 volts.
• This voltage is the standard provided in Indian domestic electric supply to ensure safe and efficient operation of electrical appliances and equipment.

The correct answer is option (2)

Concept:

The hydrogen bomb and the uranium bomb are both based on nuclear reactions, but they differ in the specific type of nuclear reaction involved.

• The hydrogen bomb is based on nuclear fusion.
• The uranium bomb is based on nuclear fission.
• The hydrogen bomb, also known as a thermonuclear bomb, utilizes the process of nuclear fusion. It involves the fusion of isotopes of hydrogen, typically deuterium and tritium, under extremely high temperatures and pressures.
• The fusion reaction releases an immense amount of energy.
• On the other hand, the uranium bomb, also known as an atomic bomb or nuclear bomb, relies on nuclear fission.
• In this type of bomb, the nucleus of a heavy atom, such as uranium-235 or plutonium-239, is split into two smaller nuclei, releasing a significant amount of energy.

The correct answer is option (1)

Explanation:

Sound waves:

• Sound waves are longitudinal waves, meaning that the particles of the medium (in this case, air) vibrate in the same direction as the wave propagation.
• In air, sound waves travel as compressions and rarefactions, where the air particles compress and expand in the direction of the wave.

Light waves:

• On the other hand, light waves are transverse waves.
• They oscillate perpendicular to the direction of wave propagation. In the case of light waves in air, the electric and magnetic fields oscillate at right angles to the direction of the wave.

Therefore, sound waves are longitudinal waves, and light waves are transverse waves in air.

The correct answer is option (1)

Calculation:

Given,

initial velocity u = 12 m/s.

acceleration = -6 m/s²  (negative since decelerating)

t = 2 sec. 

Distance covered by the car till it stops after applying the brake, i.e., when final velocity "v" = 0.

From the equation of motion 

v² = u² + 2as

v = 0 and u = 12 m/s

a = -6 m/s² 

distance covered "s" would be calculated as 

0² = 12² - 2 × 6 × s

s = 12²/12

= 12 m

So, distance covered by the car after the application of brakes will be 12m

The correct answer is option (1)

Explanation: 

Sodium hydrogen carbonate (or baking soda) is used in fire extinguishers.

The solution of sodium hydrogen carbonate and sulphuric acid in separate containers present in Soda-acid type fire extinguishers.

When the knob of the fire extinguisher is pressed (or when the fire extinguisher is inverted), then sulphuric acid mixes with sodium hydrogen carbonate solution to produce a lot of carbon dioxide gas.

The pressure of this CO2 gas forces a stream of liquid to fall on the burning substance.

The carbon dioxide gas (coming out along with the liquid) forms a blanket around the burning substance and cuts off the supply of air to the burning substance.

Since the supply of air is cut off, the process of burning substance.

Since the supply of air is cut off, the process of burning stops and fire gets extinguished.

The stream of liquid falling on the burning substance also helps in putting off the fire by cooling the burning substance to below its ignition temperature.

Conclusion: 

Therefore, the chemical composition of a soda-acid type fire extinguisher is Solution of sodium hydrogen carbonate and sulfuric acid  

Thus, the correct answer is option (1)

Explanation:

When diluting a concentrated nitric acid solution, the concentration of [H₃O⁺] ions per volume decreases, not increases. This is because dilution involves adding solvent (usually water) to a solution, which increases the total volume while the amount of solute (here, the H₃O⁺ ions) remains the same. So, the concentration, which is the ratio of solute to solvent, decreases. Therefore, statement 1 is incorrect.

When a concentrated acid is added to water for preparing a dilute acid, then the heat is evolved gradually and easily absorbed by the large amount of water (to which the acid is being added). Therefore, statement 3 is correct.

However if water is added to concentrated acid, then large amount of heat is evolved at once. This heat changes some of the water to steam explosively which can splash the acid on our face or clothes and cause acid burns. Even the glass container may break due to the excessive heating. Therefore, statement 2 is incorrect.

Thus, the correct answer is option (3)

Explanation:

pH is a measure of the acidity or basicity of a solution, and ranges from 0 to 14.

Solutions with a pH below 7 are acidic, while solutions with a pH above 7 are basic (also called alkaline). A pH of 7 is neutral, meaning it is neither acidic nor basic.

Let's look at each substance and its pH value:

Coffee: Coffee is slightly acidic, with a pH of around 5.

Lemon juice: Lemon juice is more acidic than coffee, with a pH of around 2-3.

Milk of magnesia: Milk of magnesia is a basic solution used to treat indigestion and constipation. It has a pH of around 10.5-11.

Blood: The pH of blood is tightly regulated by the body and is usually between 7.35 and 7.45, making it slightly basic.

Now we can order the substances based on their pH values, from lowest to highest:

Lemon juice (pH 2-3) < Coffee (pH 5) < Blood (pH 7.35-7.45) < Milk of magnesia (pH 10.5-11)

Therefore, the correct order is option (4) -

Lemon juice < Coffee < Blood < Milk of magnesia.

Explanation:

The statement that is not true for the anodizing process is:

Clean aluminium article is the anode and oxygen gas is evolved at the cathode.

• Anodizing is an electrochemical process that forms a protective layer of aluminum oxide on the surface of aluminum and its alloys. The process involves immersing the aluminum article in an electrolyte solution and passing an electric current through it, with the aluminum article serving as the anode.
• During anodizing, oxygen gas is not evolved at the cathode. Instead, the cathode is typically made of an inert material such as lead or stainless steel, and hydrogen gas is evolved at the cathode. This is because the hydrogen ions in the electrolyte solution are reduced to hydrogen gas at the cathode.

The other statements are true:

• Anodizing makes aluminum corrosion resistant by creating a hard, durable, and porous layer of aluminum oxide on the surface of the aluminum.
• Metals like aluminum, titanium, and magnesium can be anodized because they are reactive metals that readily form a protective oxide layer.
• Anodizing is used in the aircraft industry because it provides a lightweight and durable surface that can withstand harsh environmental conditions.

Thus, the correct option is (3)

The correct answer is Option 2.

Key Points

• Saturated hydrocarbons will generally give a clean flame, while unsaturated carbon compounds will give a yellow, sooty flame with lots of black smoke.
• Naphthalene is an unsaturated compound. In unsaturated hydrocarbons, the proportion of carbon is larger than that of saturated hydrocarbons. i.e., the carbon-to-hydrogen ratio is high.
• As a result, some unburnt carbon particles are also formed during the combustion of unsaturated compounds.
• In the flame, these unburned hot carbon particles emit yellow light, so the flame appears yellow. Hence, naphthalene burns with a yellow flame.
• However, limiting the supply of air results in incomplete combustion of even saturated hydrocarbons, giving a sooty flame.
• Hence, the most appropriate reason for a yellow sooty flame is incomplete combustion.

The correct answer is option 2

Explanation:

Reducing agent: The element/compound that removes oxygen or donates hydrogen and itself gets oxidized. 

Oxidizing agent: The element/compound that donates oxygen or removes hydrogen and itself gets reduced. 

Fe2O3(s) + 2Al(s) → Al2O3 (s)+ 2Fe(l)

The above reaction is called as thermite reaction and aluminium reduces iron oxide produce iron metal with the evolution of lot of heat and the heat evolved is used for welding purpose. Due to this excess heat, iron metal is produced in the molten state not Al metal.

In the above chemical reaction;

• Fe2O3 is getting reduced to Fe.
• Al is oxidized to Al2O3.
• Al is the reducing agent.
• Fe2O3 (iron oxide) is the oxidizing agent.

The correct answer is option (1)

The correct answer is New Zealand.

Key Points

• Vicky visited New Zealand.
• Stewart Island, Bay of Plenty, and Hawke Bay are all locations in New Zealand.

Additional Information

• Stewart Island: Stewart Island is the third-largest island in New Zealand and is located at the southern tip of the country.
• Bay of Plenty: The Bay of Plenty is a large bay on the northeastern coast of the North Island of New Zealand. It's known for its beautiful beaches and harbors.
• Hawke Bay: Hawke Bay is located on the eastern coast of the North Island of New Zealand, and it's renowned for its vineyards, agriculture, and scenic landscapes.

The correct answer is Red Fort, Qutab Minar, Humayun Tomb.

Key Points

• World Heritage Sites are cultural and natural sites considered to be of outstanding value to humanity.
• Delhi has a rich historical and cultural background due to the many invasions that have taken place in the region.
• If Manav plans to visit all the UNESCO World Heritage Sites in Delhi, he will visit Red Fort, Qutub Minar and Humayun's Tomb.

Additional Information

• The Red Fort was built by Shah Jahan in the mid-17^th century and remains a major tourist attraction.
• The fort was designated a UNESCO World Heritage Site in 2007.
• Qutub Minar was added to the list of World Heritage Sites by UNESCO in 1993.
• Humayun's Tomb, built in 1570, is the first garden-tomb in the Indian subcontinent and was declared a UNESCO World Heritage Site in 1993.
• Neither India Gate nor Jama Masjid has been designated as a World Heritage Site by UNESCO (United Nations Educational, Scientific and Cultural Organization).

The correct answer is Kanpur, Prayagraj, Patna, Bhagalpur.

Key Points

• If one moves from west to east then the correct order of cities along the banks of river Ganga is Kanpur, Prayagraj, Patna, Bhagalpur.

Additional Information

• The River Ganges:
• It is a transboundary river of Asia that flows through India and Bangladesh.
• It originates in the state of Uttarakhand and flows south and east through the Gangetic plain of India and Bangladesh, ultimately emptying into the Bay of Bengal.
• Major left-bank tributaries include the Gomti River, Ghaghra River, Gandaki River and Kosi River.
• Major right-bank tributaries include the Yamuna River, Son River, Punpun and Damodar.
• Yamuna River is the largest tributary of the Ganga River.
• Kanpur, Allahabad, Haridwar, Mirzapur, Bhagalpur, Varanasi, Kannauj, Patna are some of the cities situated on the banks of the river Ganga.
• Sabi and Banganga are famous rivers, which flow in Jaipur city.

The correct answer is Chhattisgarh.

Key Points

• Chhattisgarh has the longest extension in the north-south direction.
• The northern and southern parts of the state are hilly, while the central part is a fertile plain.
• The highest point in the state is the Gaurlata near Samri, Balrampur - Ramanujganj district.
• Chhattisgarh is the tenth largest state of India with an area of 135,194 square kilometers.
• The native language of the people of Chhattisgarh is Chhattisgarhi.
• Present Chhattisgarh came into existence on 1^st November 2000 by separating from Madhya Pradesh state.

Key Points

• World Wetlands Day - 
• It is celebrated on 2 February every year.
• It aims at raising awareness about the ecological significance of wetlands.
• This date also commemorates the date of adoption of the Ramsar Convention on Wetlands, 1971.
• International Tiger Day - 
• It is observed on 29 July and aims to create awareness regarding the need for tiger conservation.
• It was started in 2010 at the Tiger Summit, held at St. Petersburg in Russia.
• World Water Day - 
• It is held on 22 march every year, starting from 1993.
• It deals with the water and sanitation crisis in the world.
• It aims to raise awareness regarding the global scarcity of fresh drinking water.
• International Mother Earth Day - 
• It is observed on 22 April every year.
• It was designated by the UN General Assembly in 2009.
• It is aimed at the protection and restoration of the ecosystems on Earth.

Corrected Table:

Hence, the correct answer is option 2.

The correct answer is NCT of Delhi.

Key Points

• Six states and one Union Territory have achieved the best rating of Level 2 (L2) in the Union Education Ministry's Performance Grading Index (PGI) 2020-21.
• These are Andhra Pradesh, Kerala, Maharashtra, Punjab, Chandigarh, Rajasthan and Gujarat.
• So far no state has been able to achieve the highest level of L1.

Additional Information

• Performance Grading Index (PGI) is a relatively new index that measures the performance of States/UTs on a uniform scale to catalyze transformational change in the school education sector.
• One of the objectives of the PGI is to provide information on the status of school education in states and union territories, including key levels and critical areas of performance that drive their performance.
• It points out the shortcomings and helps States/UTs to prioritize areas of intervention to ensure that the school education system is strengthened at every level.