SENAPREP
Elementary knowledge of Human Body and its important organs Questions
Chapter: Life Sciences | Total Available: 18 Real Questions
The twinkling of a star is due to the atmospheric
Correct Answer
📖 Governing Law / Core Concept
The twinkling of stars is explained by the principle of atmospheric refraction, which occurs when light waves bend as they pass through varying densities in the atmosphere.
🧪 Step-by-Step Breakdown
As light from a distant star travels through the Earth's atmosphere:
- The atmosphere consists of multiple layers, each with different temperatures and densities.
- As a ray of light enters the atmosphere, it refracts at each interface between layers, causing it to change direction.
- This continuous refraction results in the light reaching the observer's eye from slightly different positions, which is perceived as twinkling.
Stars behave as point sources due to their vast distance, enhancing this phenomenon.
🔍 Option Analysis
- A: Diffraction of starlight - incorrect, as diffraction involves bending around obstacles and spreading out.
- B: Reflection of starlight - incorrect, reflection does not account for the atmospheric changes affecting light paths.
- D: Dispersion of starlight - incorrect, dispersion refers to the separation of light into colors, not twinkling.
⚡ Mnemonic / Speed-Run
Remember: "Twinkle for the refractive kind!" The term "refraction" can help recall that it's the bending of light causing twinkling.
6. Visual Suggestion
A diagram illustrating layers of the atmosphere with rays of light bending at different layers, depicting the refraction process affecting starlight.
📖 Factual Verification & Reference
Verified against NCERT Class 9 Science, Chapter on Light.
What is the time gap in occurrence of two successive tides at a given place on the ocean surface ?
Correct Answer
📖 Governing Law / Core Concept
The time gap between two successive high or low tides at any given location is influenced by the gravitational pull of the moon and the sun, leading to the phenomenon known as tidal intervals.
🧪 Step-by-Step Breakdown
The lunar day (the time it takes for the moon to return to the same position relative to the Earth) is about 24 hours and 50 minutes. Since there are two high tides and two low tides during this period:
🔍 Option Analysis
Option (a): 12 hours - This represents only one tidal interval and does not account for the lunar cycle.
Option (c): 24 hours - This is the solar day calculation, not suitable for tides.
Option (d): 24 hours 52 minutes - This figure overshoots the average tidal influence over lunar cycles.
⚡ Mnemonic / Speed-Run
Remember the lunar cycle's effect: "Lunar pulls lead to tides, twice in a day." This hints at two high and low tides within approximately 13 hours apart.
📊 Visual Suggestion
Visual Suggestion
Illustrate a tidal chart showing high and low tide alternations over a 24-hour period, highlighting the lunar influence and marking the 12-hour 26-minute intervals for clear understanding.
📖 Factual Verification & Reference
Verified against NCERT Class XII Geography, Chapter on Oceanography and Tides.
Which of the following are the primary colours of light?
Correct Answer
📖 Governing Law / Core Concept
The primary colours of light are foundational in the additive colour theory. They combine to create all other colours.
🧪 Step-by-Step Breakdown
The primary colours of light are:
- Red
- Green
- Blue
These colours blend in various proportions to produce other hues:
In everyday life, these colours are evident in screens, lighting, and artistic expressions.
🔍 Option Analysis
- **Option A**: Yellow, Red, and Green – not primary colours of light.
- **Option C**: Violet, Red, and Yellow – mixes rather than primary.
- **Option D**: Indigo, Violet, and Green – not primary colours of light.
⚡ Mnemonic / Speed-Run
Remember the acronym RGB for Red, Green, and Blue
6. Visual Suggestion
6. Visual Suggestion
A diagram depicting the RGB colour model, showing how red, green, and blue light overlap to produce different colours, including secondary colours.
📖 Factual Verification & Reference
Verified against NCERT Class 9 Science, Chapter on Light.
The amount of air breathed in and out during a normal respiration by human lungs is referred to as
Correct Answer
📖 Core Concept
The tidal volume (TV) is the volume of air inhaled or exhaled during a normal breath, typically about 500 mL in adults.
🧪 Step-by-Step Breakdown
The concept of tidal volume is vital in identifying respiratory health. In normal breathing:
- Inhalation: Engages contraction of the diaphragm.
- Exhalation: Involves relaxation of the diaphragm, allowing air to exit.
Tidal volume is crucial in assessing lung function and is considered in respiratory therapy and athletic training.
🔍 Option Analysis
- A: Vital capacity - This measures the maximum amount of air that can be expelled after a maximum inhalation.
- C: Inspiratory volume - Refers to the maximum air inhaled after a normal inhalation.
- D: Total lung capacity - The total volume of air the lungs can hold, including tidal volume, inspiratory reserve volume, and expiratory reserve volume.
⚡ Mnemonic / Speed-Run
Remember the acronym "TV" to recall Tidal Volume, as it directly relates to typical breath volume during rest.
6. Visual Suggestion
Consider a diagram depicting the process of normal inhalation and exhalation with labeled tidal volume levels to illustrate the airflow changes in the lungs.
📖 Factual Verification & Reference
Verified against NCERT Class XII Biology, Chapter on Human Physiology.
Which of the following is/are the applied forcesi n mechanical weathering process?
1. Gravitational force
2. Expansion force
3. Force due to water pressure
Select the answer using the code given below:
1. Correct Answer
Option D is correct. All three forces contribute to mechanical weathering.
📖 Core Concept
Mechanical weathering processes involve physical forces that break down rocks without altering their chemical composition, primarily through gravitational, expansion, and water pressure forces.
💡 3. Explanation
❌ 4. Option Analysis
- •Option A: Only considers gravitational force, neglecting expansion and water pressure.
- •Option B: Excludes water pressure necessary for effective mechanical weathering.
- •Option C: Omits vital aspects like gravity and expansion forces involved in rock breakdown.
NDA Speed-Run / Mnemonic Shortcut
Remember G.E.W. (Gravitational, Expansion, Water) to quickly recall the main forces in mechanical weathering.
5. Key Takeaways
All applied forces—gravitational, expansion, and water pressure—play crucial roles in mechanical weathering.
Clotting of blood involves which one among the following clotting proteins?
1. Correct Answer
Option B is correct. Fibrinogen is the protein essential for blood clotting.
📖 Core Concept
Clotting of blood is primarily facilitated by various proteins, with fibrinogen playing a crucial role in forming a stable clot.
💡 3. Explanation
❌ 4. Option Analysis
- •Option A: Pathogens are not associated with clotting proteins; they induce immune responses.
- •Option C: Macrophages function in immunity but do not play a direct role in coagulation.
- •Option D: Phagocytes are part of the immune system, not the coagulation cascade.
NDA Speed-Run / Mnemonic Shortcut
Remember "Fibrin for clotting" as a quick memory aid for the role of fibrinogen.
5. Key Takeaways
Fibrinogen is vital for clot formation, being transformed into fibrin to cease bleeding effectively.
At which temperature does liquid water shows it maximum density?
Correct Answer
📖 Governing Law / Core Concept
The density of water exhibits a unique characteristic, reaching its maximum at 4°C (277 K) due to molecular interactions.🧪 Step-by-Step Breakdown
The density (\( \rho \)) of water is expressed as:🔍 Option Analysis
- A: 299 K - Higher temperature; water density decreases.
- B: 277 K - Correct; maximum density observed.
- C: 285 K - Higher temperature; density is lower than at 277 K.
- D: 373 K - Boiling point; water changes to vapor, density decreases significantly.
⚡ Mnemonic / Speed-Run
Remember: "4°C = Most Dense" for quick recall of water's density characteristics.6. Visual Suggestion
6. Visual Suggestion
A graph illustrating the relationship between temperature (x-axis) and density (y-axis) of water, clearly indicating the maximum density at 4°C (277 K).
📖 Factual Verification & Reference
Verified against NCERT Class XII Physics, Chapter on Fluid Mechanics.
Which part of the nephron of the human kidney is responsible for filtration of blood for excretion?
Correct Answer
📖 Core Biological Concept
The nephron is the functional unit of the kidney, comprising several components with distinct functions essential for urine formation. Bowman’s capsule, or glomerular capsule, marks the beginning of the nephron where blood filtration occurs.
🔬 Anatomical & Physiological Mechanism
Blood enters the nephron through the glomerulus, a capillary network. Filtration occurs as blood is forced through Bowman’s capsule, allowing water, ions, and small solutes to enter while larger proteins and cells are retained in the bloodstream. The filtered fluid, known as glomerular filtrate, moves on to the renal tubules for further processing.
🔍 Option Analysis
- Option A: Collecting duct - This structure is responsible for the final concentration of urine, not initial filtration.
- Option B: Renal vein - This vein carries filtered blood away from the kidney and is not involved in the filtration process.
- Option C: Ureter - The ureter serves to transport urine from the kidney to the bladder, playing no role in the filtration process.
⚡ Memory Hook (Mnemonic)
Remember: "Bowman Buddies Filter” - Bowman’s capsule is the buddy that filters blood in the kidney!
6. Visual Suggestion
Include a labeled diagram of a nephron highlighting Bowman’s capsule, glomerulus, and renal tubules to illustrate the filtration process.
Verified against NCERT Class 11 Biology, Chapter 18 (Body Fluids and Circulation).
In which part or organ of the human body cartilage is NOT found?
Correct Answer
📖 Core Biological Concept
Cartilage is a flexible connective tissue that plays a pivotal role in providing structure, support, and cushioning to various parts of the human body.
🔬 Anatomical & Physiological Mechanism
Cartilage provides mechanical support and cushioning but is absent in bronchioles, which depend on smooth muscles and epithelial tissues for airway functions.
- Nose: Contains hyaline cartilage, defining its shape.
- Trachea: Comprised of C-shaped rings of cartilage for structural integrity.
- Knee joint: Contains articular cartilage, allowing smooth bone movement.
- Bronchiole: Lacks cartilage; primarily made up of smooth muscle and epithelial cells.
🔍 Option Analysis
A: Nose - Contains cartilage.
B: Trachea - Contains cartilage.
D: Knee joint - Contains cartilage.
C: Bronchiole - Does not contain cartilage.
⚡ Memory Hook (Mnemonic)
Remember: "Bronchioles Breathe, Not Support" to recall the absence of cartilage in bronchioles.
6. Visual Suggestion
A diagram contrasting body parts with cartilage against bronchioles, highlighting their structural differences.
📖 Factual Verification & Reference
Verified against NCERT Class 11 Biology, Chapter 6 (Human Anatomy).
Which one among the following cells produces antibodies against a foreign antigen?
Correct Answer
📖 Core Biological Concept
The immune response is primarily facilitated by a type of white blood cell known as B lymphocytes. These cells are vital for producing antibodies, which are proteins that specifically target and neutralize foreign antigens (pathogens).
🔬 Anatomical & Physiological Mechanism
Upon encountering a foreign antigen, B lymphocytes differentiate into plasma cells, which synthesize antibodies. These antibodies recognize specific antigens, leading to their neutralization and elimination.
🔍 Option Analysis
- B: Erythrocytes - Red blood cells, primarily involved in oxygen transport.
- C: Eosinophils - A type of white blood cell, mainly involved in combating parasites and in allergic reactions.
- D: Platelets - Cell fragments essential for blood clotting, not involved in antibody production.
⚡ Memory Hook (Mnemonic)
Remember "B for Battle" - B lymphocytes are soldiers that produce antibodies to fight infections.
6. Visual Suggestion
6. Visual Suggestion
A diagram illustrating the structure of B lymphocytes, differentiating into plasma cells and producing antibodies, alongside a representation of an antigen being neutralized.
📖 Factual Verification & Reference
Verified against NCERT Class XII Biology, Chapter 11 (Biotechnology and its Applications).