RRB JE Biology Questions with Detailed Solutions

Get RRB JE Biology Questions to prepare for your upcoming exam. Solve the most expected questions and detailed solutions that can be asked in the exam.

Important RRB JE Biology Questions

Q1.

A gardener notices fallen leaves under a tree. Which strategy of plant excretion does this illustrate, and what type of waste handling is involved?

  • A.

    Excreting waste through roots only.

  • B.

    Releasing waste as oxygen only.

  • C.

    Storing waste in leaves that fall off.

    ✓ Correct
  • D.

    Converting waste into fruits.

Answer & Solution

Correct option is C

The correct answer is (C) Storing waste in leaves that fall off.

Explanation:
• Unlike animals, plants do not have specialized excretory organs. They utilize several unique strategies to dispose of metabolic waste products.
• One common strategy is to sequester (store) solid and liquid waste products inside cellular vacuoles of parts that are destined to fall off, such as old leaves, bark, and sometimes petals.
• When these leaves senesce (age) and fall to the ground (abscission), the plant effectively discards the accumulated metabolic waste along with the dead tissue.

Information Booster:
• Other Excretory Methods: Plants excrete gaseous waste (Oxygen from photosynthesis and CO2 from respiration) through stomata in leaves.
• Resins and Gums: Plants also store waste products as resins and gums, particularly in old xylem tissues (heartwood).
• Soil Excretion: Some waste substances are also actively secreted into the surrounding soil through the roots.

Additional Knowledge:
• Options A & B: These are partial truths; plants do excrete via roots and release oxygen, but the observation of "fallen leaves" points directly to the mechanism of shedding waste-filled tissues.
• Converting waste to fruits (Option D): Fruits are reproductive structures packed with stored nutrients (starch, sugars) to attract seed dispersers, not metabolic waste dumps.

Q2.
Which of the following types of connective tissue is present in the larynx of a human body?
  • A.Areolar
  • B.Adipose
  • C.Ligament
  • D.Cartilage
    ✓ Correct

Answer & Solution

Correct option is D

The correct answer is (D) Cartilage

Explanation:
• The larynx, commonly known as the voice box, is primarily composed of cartilage pieces that hold the vocal cords and the respiratory tract open.
• Cartilage is a specialized, firm, yet flexible connective tissue. It is softer than bone but harder than muscle.
• The largest cartilage of the larynx is the thyroid cartilage, which forms the "Adam's apple" prominence in the neck. Other important laryngeal cartilages include the cricoid and epiglottis.

Information Booster:
• Other locations of cartilage: Apart from the larynx, cartilage is found in the trachea (C-shaped rings), the tip of the nose, the external ear (pinna), and at the ends of long bones at the joints.
• Chondrocytes: The cells that make up cartilage are called chondrocytes, and they are embedded in a solid but pliable matrix composed of proteins and sugars.
• Blood Supply: Unlike bone, cartilage is largely avascular (lacks blood vessels), which is why cartilage injuries take a very long time to heal.

Additional Knowledge:
• Option A (Areolar): A loose connective tissue found under the skin, acting as a packing material around organs.
• Option B (Adipose): Fat-storing tissue found below the skin and around internal organs, acting as an insulator.
• Option C (Ligament): A dense connective tissue that connects bones to other bones at joints (whereas tendons connect muscles to bones).
Q3.

Match the tobacco practice with the long-term consequences of consuming it.

(a) Cigarette smoking (i) Oral cancer

(b) Chewing tobacco (ii) Emphysema

(c) Passive smoking (iii) Respiratory infections

(d) Long-term nicotine exposure (iv) Cardiovascular disorders

  • A.

    a–ii, b–i, c–iv, d–iii

  • B.

    a–iv, b–ii, c–i, d–iii

  • C.

    a–ii, b–i, c–iii, d–iv

    ✓ Correct
  • D.

    a–i, b–iii, c–ii, d–iv

Answer & Solution

Correct option is C

The correct answer is (C) a–ii, b–i, c–iii, d–iv

Explanation:
• Cigarette smoking directly damages the alveoli (air sacs) in the lungs, making it the leading cause of Emphysema.
• Chewing tobacco exposes the oral mucosa to concentrated carcinogens, directly leading to oral cancer and pre-cancerous lesions like leukoplakia.
• Passive smoking (second-hand smoke) exposes non-smokers to fine particulate matter and toxins, severely increasing the risk of respiratory infections, especially in children.
• Long-term nicotine exposure causes chronic vasoconstriction, endothelial dysfunction, and increased heart rate, culminating in cardiovascular disorders.

Information Booster:
• Nicotine Dependency: Nicotine acts on the brain's reward pathways by releasing dopamine, which makes tobacco highly addictive.
• Emphysema Characteristics: A type of COPD where the surface area for gas exchange is heavily reduced, leading to shortness of breath.
• Public Health Impact: According to the WHO, tobacco kills more than 8 million people each year, including 1.3 million non-smokers exposed to second-hand smoke.

Additional Knowledge:
• Options A, B, and D: These options incorrectly associate the delivery method of the toxin with its primary physiological impact. For example, while smoking does cause cardiovascular issues, chewing tobacco's most direct and unique localized consequence is oral cancer, making the combination in Option C the most scientifically accurate pairing.

Q4.
Which statement best explains why blood cells are NOT found in the urine of a healthy person?
  • A.They are broken down in the kidneys
  • B.They are too large to pass through glomerular pores
    ✓ Correct
  • C.They are reabsorbed in tubules
  • D.They are filtered and returned to the blood

Answer & Solution

Correct option is B

The correct answer is (B) They are too large to pass through glomerular pores

Explanation:
• The formation of urine begins with ultrafiltration in the Bowman's capsule of the nephron.
• Blood flows into the glomerulus under high pressure. The walls of the glomerular capillaries and the Bowman's capsule act as a highly selective biological sieve.
• Red blood cells, white blood cells, platelets, and large plasma proteins are physically too large to squeeze through these microscopic filtration slits (fenestrations). As a result, they remain in the bloodstream, keeping healthy urine free of blood.

Information Booster:
• Hematuria: The medical condition where blood cells do appear in urine. It indicates damage to the glomerulus, urinary tract infections, kidney stones, or trauma.
• Glomerular Filtrate: The fluid that initially passes through the filter contains water, glucose, amino acids, urea, and various salts, but lacks cells and proteins.
• Nephron: The structural and functional unit of the kidney, with each human kidney containing about 1 million nephrons.

Additional Knowledge:
• Broken down in kidneys (Option A): Incorrect. Old RBCs are primarily broken down by macrophages in the spleen and liver, not the kidneys.
• Reabsorbed in tubules (Option C): Incorrect. Because they never pass into the tubules in the first place, they do not need to be (and cannot be) reabsorbed. Reabsorption happens for smaller molecules like glucose and water.
• Filtered and returned to the blood (Option D): This phrasing is misleading. They bypass the filter entirely and continue flowing through the efferent arteriole.
Q5.
Which of the following is an example of membrane bound little structures present in a cell?
  • A.Cytoplasm
  • B.Lysosome
    ✓ Correct
  • C.Nucleoplasm
  • D.Ribosome

Answer & Solution

Correct option is B

The correct answer is (B) Lysosome

Explanation:
• Lysosomes are membrane-bound cellular organelles containing powerful hydrolytic (digestive) enzymes capable of breaking down all types of biological polymers.
• They function as the waste disposal system of the cell by digesting obsolete components, engulfed viruses or bacteria, and executing programmed cell death (apoptosis).
• Due to their distinct outer lipid bilayer membrane, they perfectly fit the description of "membrane-bound little structures."

Information Booster:
• Suicide Bags: Lysosomes are often referred to as the "suicide bags" of the cell. If a cell gets damaged, the lysosome may burst, and its enzymes digest the cell itself.
• Formation: They are formed by the budding off of vesicles from the Golgi apparatus.
• Eukaryotic Feature: Membrane-bound organelles, including lysosomes, are a defining characteristic of eukaryotic cells and are completely absent in prokaryotic cells.

Additional Knowledge:
• Cytoplasm (Option A) & Nucleoplasm (Option C): These are jelly-like fluid substances filling the cell and the nucleus, respectively; they are not "structures" or "organelles" themselves.
• Ribosome (Option D): Ribosomes are small, dense structures responsible for protein synthesis. Crucially, they are non-membrane-bound organelles and are found in both prokaryotes and eukaryotes.
Q6.
Which statement is INCORRECT regarding prokaryotic organism?
  • A.Nuclear region is defined
    ✓ Correct
  • B.Primitive form of organism
  • C.Membrane-bound organelles are absent
  • D.Single chromosome is present

Answer & Solution

Correct option is A

The correct answer is (A) Nuclear region is defined

Explanation:
• Prokaryotic cells fundamentally lack a well-defined, membrane-bound nucleus.
• Instead of a true nucleus, their genetic material is naked and concentrated in an irregular, poorly defined region of the cytoplasm known as a nucleoid.
• Because the statement "Nuclear region is defined" contradicts this core biological fact, it is the INCORRECT statement and therefore the right answer.

Information Booster:
• Etymology: The term "Prokaryote" comes from the Greek words 'pro' (meaning before) and 'karyon' (meaning nut or kernel, referring to the nucleus).
• Size and Complexity: Prokaryotes are generally much smaller (1-10 micrometers) and simpler than eukaryotic cells.
• Examples: Bacteria and Archaea (like blue-green algae or cyanobacteria) are the primary examples of prokaryotic organisms.

Additional Knowledge:
• Primitive form of organism (Option B): This is a correct statement. Prokaryotes represent the earliest forms of life on Earth, predating eukaryotes.
• Membrane-bound organelles are absent (Option C): Correct. They lack organelles like mitochondria, Golgi bodies, chloroplasts, and lysosomes.
• Single chromosome is present (Option D): Correct. Most prokaryotes possess a single, circular DNA molecule that functions as their sole chromosome.
Q7.
Chloroplast is present in which of the following parts of a cell?
  • A.Nucleoplasm
  • B.Peroxisome
  • C.Cytoplasm
    ✓ Correct
  • D.Endoplasmic reticulum

Answer & Solution

Correct option is C

The correct answer is (C) Cytoplasm

Explanation:
• The cytoplasm is the thick, jelly-like fluid that fills the inside of a cell, enclosed by the cell membrane.
• All membrane-bound organelles in a eukaryotic cell, including mitochondria, Golgi bodies, and chloroplasts, are suspended within the cytoplasm.
• Chloroplasts are specifically located in the cytoplasm of plant cells and eukaryotic algae, where they perform photosynthesis by capturing sunlight.

Information Booster:
• Chloroplast Structure: They are double-membrane organelles containing coin-like stacks called grana (composed of thylakoids) and a fluid matrix called stroma.
• Pigment: They contain the green pigment chlorophyll, which is essential for trapping solar energy to synthesize glucose from carbon dioxide and water.
• Semi-autonomous Organelle: Like mitochondria, chloroplasts have their own circular DNA and ribosomes, meaning they can replicate independently within the cell.

Additional Knowledge:
• Nucleoplasm (Option A): The fluid inside the nucleus, which contains chromatin and the nucleolus, not organelles.
• Peroxisome (Option B): A separate small organelle involved in lipid metabolism and chemical detoxification, not a location for other organelles.
• Endoplasmic Reticulum (Option D): A network of membranous tubules and sacs involved in protein and lipid synthesis. Chloroplasts exist independently of the ER in the cytoplasm.
Q8.
A low platelet count may lead to __________.
  • A.Anemia
  • B.Excessive bleeding
    ✓ Correct
  • C.Fever
  • D.Infection

Answer & Solution

Correct option is B

The correct answer is (B) Excessive bleeding

Explanation:
• Platelets (scientifically known as thrombocytes) are specialized, tiny blood cell fragments whose primary biological function is to facilitate blood clotting (coagulation).
• When a blood vessel is damaged, platelets rush to the site, stick together to form a plug, and release chemicals that convert fibrinogen into a fibrin mesh to seal the wound.
• A low platelet count (a condition termed Thrombocytopenia) impairs this clotting mechanism. Consequently, minor cuts fail to heal quickly, leading to prolonged or excessive bleeding, and bruising easily.

Information Booster:
• Dengue Fever Connection: A sharp, dangerous drop in platelet count is a classic clinical symptom of severe Dengue fever, caused by a mosquito-borne virus.
• Formation: Platelets are produced in the bone marrow from giant precursor cells called megakaryocytes.
• Normal Range: A normal, healthy human platelet count ranges from 150,000 to 450,000 platelets per microliter of blood.

Additional Knowledge:
• Anemia (Option A): This is caused by a low count of Red Blood Cells (RBCs) or insufficient hemoglobin, resulting in oxygen deprivation, not bleeding issues.
• Infection (Option D): This happens due to a low count of White Blood Cells (WBCs, specifically leukocytes), which form the body's immune defense system.
Q9.
Which combination best represents essential life processes for maintaining an individual organism?
  • A.Nutrition, respiration, transportation and excretion
    ✓ Correct
  • B.Reproduction, variation, heredity and adaptation
  • C.Locomotion, feeding, communication and defence
  • D.Growth, movement, reproduction and response

Answer & Solution

Correct option is A

The correct answer is (A) Nutrition, respiration, transportation and excretion

Explanation:
• Life processes are the basic, non-negotiable physiological functions performed by living organisms to maintain their physical existence and survive on a daily basis.
• Nutrition provides the chemical fuel. Respiration breaks down this fuel to release usable energy. Transportation (circulation) moves oxygen, nutrients, and waste throughout the body. Excretion removes toxic metabolic by-products.
• Without any single one of these four processes, an individual organism would quickly suffer system failure and die.

Information Booster:
• Metabolism: These four core processes are intimately connected to an organism's metabolism—the sum of all chemical reactions occurring inside the body.
• Reproduction Exception: While reproduction is essential for the survival and continuation of a *species*, it is not required for the survival of an *individual* organism (e.g., sterile worker bees live perfectly functional lives).
• Homeostasis: These life processes work in tandem to maintain a stable internal environment despite external changes, a concept known as homeostasis.

Additional Knowledge:
• Option B (Reproduction, variation...): These represent evolutionary and genetic processes tied to species survival and generational change, not daily individual maintenance.
• Options C and D: While locomotion, communication, and response to stimuli are important biological activities for many animals, they are not universally required for maintenance across all life forms (e.g., plants and fungi do not possess locomotion but still live).
Q10.
Which of the following is NOT correctly matched, with regard to plant and animal cells?
  • A.Plastids - Absent in animal cells
  • B.Vacuoles - Very large and present in plant cells
  • C.Plastids - Present in plant cells
  • D.Cell wall - Present in animal cells
    ✓ Correct

Answer & Solution

Correct option is D

The correct answer is (D) Cell wall - Present in animal cells

Explanation:
• Animal cells strictly lack a cell wall. Their outermost boundary is the flexible plasma membrane (cell membrane).
• The cell wall is a rigid, supportive structure found primarily in plant cells (made of cellulose), fungi (made of chitin), and bacteria (made of peptidoglycan).
• Because the statement "Cell wall - Present in animal cells" is factually incorrect, it is the right answer to the question asking for the NOT correctly matched pair.

Information Booster:
• Plastids: These are double-membrane organelles responsible for manufacturing and storing food. They are found exclusively in plant cells and some algae (e.g., chloroplasts for photosynthesis). Animal cells do not have plastids.
• Vacuoles: Plant cells typically have a single, large central vacuole that can take up to 90% of the cell volume, maintaining turgor pressure. Animal cells, if they have vacuoles at all, possess much smaller, temporary ones.
• Centrosomes: These are present in animal cells and assist in cell division but are absent in most plant cells.

Additional Knowledge:
• Option A (Plastids absent in animal cells): This is a correctly matched true statement.
• Option B (Vacuoles large in plant cells): This is a correctly matched true statement.
• Option C (Plastids present in plant cells): This is a correctly matched true statement.
Q11.
Where is perinuclear space present?
  • A.Outside the nucleus
  • B.Within the nucleolus
  • C.Inside of the nucleus
  • D.Between two layers of the nuclear envelope
    ✓ Correct

Answer & Solution

Correct option is D

The correct answer is (D) Between two layers of the nuclear envelope

Explanation:
• Eukaryotic cells possess a distinct, membrane-bound nucleus. The boundary of this nucleus is called the nuclear envelope.
• The nuclear envelope is a double-membrane structure consisting of an inner nuclear membrane and an outer nuclear membrane.
• The distinct, fluid-filled gap or region located exactly between these two parallel membranes is called the perinuclear space. It is typically about 10 to 50 nanometers wide.

Information Booster:
• Function as a Barrier: The perinuclear space acts as a physical barrier separating the nucleoplasm (inside the nucleus) from the cytoplasm (outside the nucleus), selectively regulating molecular traffic.
• ER Continuity: The outer membrane of the nuclear envelope, and thus the perinuclear space, is contiguous with the lumen of the rough endoplasmic reticulum (RER).

Additional Knowledge:
• Outside the nucleus (Option A): Refers broadly to the cytoplasm.
• Within the nucleolus (Option B) & Inside of the nucleus (Option C): The interior environment of the nucleus is filled with a matrix called the nucleoplasm, containing chromatin and the nucleolus, totally distinct from the perinuclear space.
Q12.
Which of the following is present only in plant cell?
  • A.Cell wall
    ✓ Correct
  • B.Vacuoles
  • C.Nucleus
  • D.Endoplasmic reticulum

Answer & Solution

Correct option is A

The correct answer is (A) Cell wall

Explanation:
• The fundamental difference between plant and animal cells lies in their outer boundaries.
• Plant cells possess a rigid, non-living covering outside their plasma membrane called the Cell Wall, which is primarily composed of cellulose. It provides structural support, protection, and allows the plant to stand upright.
• Animal cells completely lack a cell wall; their outermost layer is the flexible plasma membrane.

Information Booster:
• Plasmolysis: Because of the cell wall, plant cells do not burst easily when placed in a hypotonic solution. They swell until they become turgid, with the cell wall exerting an opposing pressure.
• Other Unique Plant Organelles: Aside from the cell wall, plastids (like chloroplasts containing chlorophyll) are also exclusive to plant cells.

Additional Knowledge:
• Vacuoles (Option B): Present in both, but plant cells typically have one large central vacuole (occupying 50-90% of cell volume), whereas animal cells have numerous small, temporary vacuoles.
• Nucleus & ER (Options C & D): The Nucleus and Endoplasmic Reticulum are standard eukaryotic organelles, present and highly active in both plant and animal cells.
Q13.
Why is it important to keep the level of vitamins A and K high in poultry feeds for broilers?
  • A.To increase their tolerance to cold weather
  • B.To ensure proper nutrition for healthy growth and development
    ✓ Correct
  • C.To make broilers resistant to external parasites
  • D.To reduce the size of eggs

Answer & Solution

Correct option is B

The correct answer is (B) To ensure proper nutrition for healthy growth and development

Explanation:
• Broilers are poultry birds raised primarily for meat production, requiring rapid growth and a high feed conversion ratio.
• To support this explosive growth rate, broiler feed is formulated to be highly protein-rich with adequate fat. Crucially, it must be supplemented with high levels of Vitamins A and K.
• Vitamin A ensures healthy skeletal growth, good vision, and maintains mucosal linings (immunity), while Vitamin K is essential for blood coagulation and preventing hemorrhages during rapid tissue development.

Information Booster:
• Layers vs. Broilers: While broilers are raised for meat (requiring rapid weight gain), 'layers' are raised for egg production, requiring diets particularly rich in Calcium for eggshell formation.
• Poultry Feed Types: Modern poultry diets are formulated with maize, soybean, and specialized vitamin-mineral premixes to hit precise nutritional targets.

Additional Knowledge:
• Egg size (Option D): Broilers are generally slaughtered before reaching sexual maturity; egg production parameters apply to layers, not broilers.
• Cold/Parasite resistance (Options A & C): While general health aids resilience, specific parasite resistance and thermoregulation are managed via vaccination, proper housing hygiene, and temperature controls, not just Vitamins A and K.
Q14.
A plant sheds its leaves and bark to remove stored waste products. How does this strategy differ from the way animals excrete wastes?
  • A.Plants use blood circulation for excretion, unlike animals.
  • B.Plants use digestive systems to remove waste, unlike animals.
  • C.Plants have a single organ system for waste removal, unlike animals.
  • D.Plants use parts that will be shed, while animals have specialized organs for excretion.
    ✓ Correct

Answer & Solution

Correct option is D

The correct answer is (D) Plants use parts that will be shed, while animals have specialized organs for excretion.

Explanation:
• Excretion is the biological process of eliminating toxic metabolic waste.
• Animals possess complex, specialized excretory organs and systems (such as kidneys, lungs, liver, and sweat glands) that actively filter and continuously remove wastes (like urea, uric acid, and excess salts) from their bodies.
• Plants, lacking a specialized excretory organ system, utilize passive mechanisms. They store waste products (like resins, gums, and crystals) in cellular vacuoles or in older tissues, specifically leaves, bark, or dying roots, which eventually detach and fall off, taking the waste with them.

Information Booster:
• Gaseous Waste: For plants, oxygen (a byproduct of photosynthesis) and carbon dioxide (a byproduct of respiration) are excreted directly through the stomata in leaves.
• Transpiration: Plants eliminate excess water largely through transpiration (evaporation from leaf surfaces).

Additional Knowledge:
• Options A, B & C: Plants do not possess blood circulation, a digestive system, or a single organ system for waste removal. They rely entirely on diffusion, transpiration, and shedding of dead structural parts.
Q15.
Why is potassium hydroxide used in the bell-jar experiment involving photosynthesis?
  • A.To absorb carbon dioxide
    ✓ Correct
  • B.To provide sunlight
  • C.To supply oxygen
  • D.To remove water

Answer & Solution

Correct option is A

The correct answer is (A) To absorb carbon dioxide

Explanation:
• In the classic "half-leaf" or bell-jar experiment designed to prove that carbon dioxide is essential for photosynthesis, Potassium Hydroxide (KOH) is utilized.
• KOH is a strong alkali that effectively absorbs carbon dioxide (CO2) from the surrounding air within the sealed bell jar.
• By removing CO2, the plant leaf inside the jar is deprived of this essential raw material. When tested with iodine, this leaf shows a negative result for starch, proving CO2's necessity.

Information Booster:
• Chemical Reaction: 2KOH + CO2 → K2CO3 + H2O. This reaction shows how KOH converts gaseous carbon dioxide into solid potassium carbonate.
• Photosynthesis Requirements: The four essential requirements for photosynthesis are sunlight, chlorophyll, carbon dioxide, and water.

Additional Knowledge:
• Provide sunlight (Option B) / Supply oxygen (Option C): KOH has no light-emitting properties and does not generate oxygen. Oxygen is a byproduct of photosynthesis.
• Remove water (Option D): While KOH is somewhat hygroscopic, its primary biological laboratory function in respiratory/photosynthetic setups is the targeted absorption of CO2.

More Important Questions