SSC JE Biology Questions with Detailed Solutions

Correct Answer: (B) Acids produced by bacteria

Explanation:

• The enamel of the teeth is primarily made of calcium and phosphate minerals.
• Acids produced by bacteria in the mouth (mainly from plaque bacteria metabolizing sugars) demineralize the enamel, leading to tooth decay or dental caries.
• This process is known as acidic demineralization and is the primary cause of cavities.

Information Booster:

• Bacteria involved: Streptococcus mutans and Lactobacillus species.
• Preventive Measures:
• Brushing teeth with fluoride toothpaste strengthens enamel.
• Reducing sugar intake lowers acid production.
• Regular dental check-ups prevent advanced decay.
• Role of other options:
• A (Soft toothbrush) – Does not demineralize; helps remove plaque gently.
• C (Saliva) – Protects teeth by neutralizing acids and aiding remineralization.
• D (Toothpaste) – Cleans and protects enamel, often containing fluoride to remineralize teeth.

The correct answer is: (B) Lactobacillus acidophilus

Explanation:

• Lactobacillus acidophilus is a probiotic bacterium commonly used in fermented dairy products such as yogurt, curd, and kefir.
• It helps convert lactose into lactic acid, giving fermented dairy its sour taste and aiding in digestion.
• It also promotes a healthy gut microbiome and improves nutrient absorption.

Information Booster:

• L. acidophilus is part of the lactic acid bacteria (LAB) group, essential in dairy fermentation.
• It is Gram-positive, rod-shaped, and anaerobic, thriving in the human gut and dairy products.
• It contributes to immune modulation, cholesterol reduction, and improving lactose intolerance.
• Other LABs used in dairy include Streptococcus thermophilus and Lactobacillus bulgaricus.
• Fermented dairy products containing these bacteria are classified as functional foods due to their health benefits.

Additional Knowledge:

• Option A: Streptomyces rhizobium – Incorrect. Streptomyces is used in antibiotic production, and Rhizobium is a nitrogen-fixing bacterium in legumes.
• Option C: Staphylococcus aureus – Incorrect. A pathogenic bacterium that causes food poisoning and infections.
• Option D: Campylobacter jejuni – Incorrect. A foodborne pathogen causing gastroenteritis, not beneficial.

The correct answer is (B) Sting cells.

Explanation:

• In the phylum Nematoda (roundworms), specialized nerve cells called sting cells or stinging cells are used to capture and paralyze prey like water fleas and plankton.
• These cells can inject toxins into prey to paralyze or kill them, making it easier for the roundworms to capture and feed.

Information Booster:

• Nematodes are a diverse group of roundworms that include species living in marine, freshwater, and terrestrial environments.
• Some predatory nematodes are equipped with specialized structures that allow them to inject toxins into their prey using the sting cells.
• This ability helps them to paralyze prey, making it easier to feed on smaller organisms.

Why other options are incorrect:

• A) Collar cells: Found in sponges, these cells help in the circulation of water but are not present in nematodes.
• C) Nematocyst cells: Found in cnidarians (like jellyfish, corals), these cells contain toxins to capture prey, but they are not present in nematodes.
• D) Primary cells: This is a general term and not specific to the type of cells used by nematodes.

Correct Answer: (A) Earthworm

Explanation:

• Phylum Chordata includes animals that have, at some stage of development:
1. Notochord – A flexible rod-like structure
2. Dorsal hollow nerve cord
3. Pharyngeal slits
4. Post-anal tail
• Examples of Chordates include:

• Snake – Reptile
• Frog – Amphibian
• Rabbit – Mammal

• Earthworm belongs to Phylum Annelida, which consists of segmented worms. It lacks a notochord and dorsal nerve cord, so it is not a chordate.

Information Booster:

• Phylum Chordata:
• Divided into Subphyla: Vertebrata (animals with backbone) and others like Urochordata, Cephalochordata
• Vertebrates include fishes, amphibians, reptiles, birds, and mammals
• Phylum Annelida:
• Segmented worms like earthworm, leech, and nereis
• Have coelom, segmented body, and closed circulatory system

Other Options:

·       Snakes are reptiles, frogs are amphibians, and rabbits are mammals, all of which are groups of animals with backbones.

Answer: D. Euplectella 

Explanation:

• Glass sponges are a group of sponges known for their skeletons made of silica (silicon dioxide) spicules, which give them a glass-like appearance.
• Euplectella, commonly called the Venus’ Flower Basket, is a well-known species of glass sponge found in deep oceans.
• Other options:
• Calcarea – sponges with calcium carbonate spicules.
• Spongilla – freshwater sponges with spongin-based skeletons.
• Planaria – flatworms, not sponges.

Information Booster:

• Euplectella has a delicate lattice-like skeleton and is often used as a symbol of delicate marine architecture.
• Glass sponges are mostly found in deep-sea environments.
• Silica spicules help support the sponge’s structure and provide protection from predators.
• These sponges also have symbiotic relationships with small shrimp, which live inside the sponge for life.

The correct answer is (B) Diabetes.

Explanation:

• Diabetes is a condition characterized by the body's inability to properly regulate blood sugar (glucose) levels. This occurs due to either a lack of insulin production (Type 1 diabetes) or the body’s inability to use insulin effectively (Type 2 diabetes).
• Insulin is a hormone that helps cells absorb glucose from the bloodstream for energy. When the body either does not produce enough insulin or cannot use it properly, it results in high blood sugar levels, leading to diabetes.

Information Booster:

• Type 1 Diabetes: This is an autoimmune condition where the body's immune system attacks and destroys insulin-producing cells in the pancreas.
• Type 2 Diabetes: This is more common and typically develops over time, often due to lifestyle factors like poor diet, lack of physical activity, and obesity.
• Symptoms of Diabetes include frequent urination, excessive thirst, extreme fatigue, and blurred vision.
• Management: Diabetes can be managed through diet, exercise, medications, and in some cases, insulin therapy.

Why other options are incorrect:

• (A) Arthritis: This is a condition that involves inflammation of the joints, not related to blood sugar regulation.
• (C) Hypertension: Also known as high blood pressure, this is a cardiovascular condition and does not directly involve blood sugar regulation.
• (D) Asthma: This is a chronic respiratory condition that affects the airways, leading to difficulty in breathing, but it is not related to blood sugar control.

Correct Answer: (A) Lipase

Explanation:

• Lipase is the enzyme responsible for the digestion of fats. It breaks down fats (lipids) into fatty acids and glycerol, which can then be absorbed by the body.
• Lipase is primarily produced by the pancreas and secreted into the small intestine, where it acts on dietary fats.

Information Booster:

• Zymase is an enzyme complex found in yeast that is involved in the fermentation of sugars, converting glucose to ethanol and carbon dioxide.
• Trypsin is an enzyme produced by the pancreas that helps break down proteins into smaller peptides and amino acids, not fats.
• Invertase is an enzyme that breaks down sucrose (table sugar) into glucose and fructose.

Correct Answer: (D) To provide energy

Explanation:

• Carbohydrates are the primary source of energy for the body.
• When consumed, carbohydrates are broken down into glucose, which is used by cells to produce ATP (adenosine triphosphate), the energy currency of the body.
• They are essential for proper functioning of the brain, muscles, and other organs.

Information Booster:

• Types of Carbohydrates:
• Simple carbohydrates: Sugars like glucose, fructose, and sucrose, which provide quick energy.
• Complex carbohydrates: Starches and fibers found in grains, legumes, and vegetables, providing sustained energy.
• Storage: Excess glucose can be stored as glycogen in the liver and muscles for later use.
• Importance: Adequate carbohydrate intake prevents fatigue and protein breakdown, ensuring that proteins are used primarily for growth and repair, not energy.

So, the primary function of carbohydrates is to provide energy.

The correct answer is (D) It easily destroys Vitamin D.

Explanation:

• Cooking food generally makes it easier to digest, kills harmful microorganisms, and can improve taste and texture.
• It also results in the loss of some nutrients, particularly water-soluble vitamins like Vitamin C.
• Vitamin C is heat-sensitive, so cooking can easily destroy it.
• Vitamin D, however, is a fat-soluble vitamin and is stable under normal cooking temperatures, so it is not easily destroyed by cooking.

Information Booster:

• Water-soluble vitamins (Vitamin C, B-complex) are more sensitive to heat, light, and water.
• Fat-soluble vitamins (Vitamins A, D, E, K) are generally stable during cooking.
• Proper cooking methods like steaming, microwaving, or sautéing help retain most nutrients in food.

Why other options are incorrect:

• A. It makes digestion easier: True, as cooking softens food and breaks down fibers.
• B. It results in the loss of some nutrients: True, especially heat-sensitive vitamins.
• C. It easily destroys Vitamin C: True, because Vitamin C is very heat-sensitive.

The correct answer is (C) Camillo Golgi.

Explanation:

• The ‘Black Reaction’ (also called Golgi staining) was discovered by Camillo Golgi, an Italian physician and scientist, in 1873.
• This staining technique uses silver nitrate to selectively stain individual neurons, allowing them to be visualized in their entirety, including dendrites and axons.
• Golgi’s method was revolutionary in neuroanatomy, as it enabled scientists to study the structure of the nervous system in unprecedented detail.

Information Booster:

• The Golgi stain was critical in the development of the Neuron Doctrine, which states that neurons are the fundamental structural and functional units of the nervous system.
• Santiago Ramón y Cajal, a Spanish neuroscientist, later used Golgi’s method to map the neuronal circuitry of the brain, earning him the Nobel Prize alongside Golgi in 1906.
• The technique is still foundational in neuroscience research for studying neuron morphology and connectivity.

Why other options are incorrect:

• A. Robert Remak: Known for discovering unmyelinated nerve fibers, not the Black Reaction.
• B. Albert Kölliker: Made contributions to muscle and nerve histology, but did not develop the staining technique.
• D. Jacques Loeb: Worked in physiology and bioengineering, not neuron staining.

The correct answer is (D) Protein.

Explanation:

• Protein is one of the most essential nutrients for growth and development. It plays a crucial role in the formation of muscles, tissues, enzymes, and hormones.
• Amino acids, the building blocks of protein, are required for biological processes such as muscle growth, immune function, and the repair of damaged cells and tissues.
• Protein-rich foods include meat, fish, eggs, dairy products, legumes, tofu, and nuts. It is crucial for the growth of children, maintenance of health in adults, and tissue repair during recovery.

Information Booster:

• Protein helps in maintaining and repairing the body’s tissues.
• It supports muscle development and is required for immune system functioning.
• Essential amino acids from proteins are critical for growth and development.

Why other options are incorrect:

• A) Salt: While salt (sodium) is necessary for fluid balance, nerve function, and muscle contractions, it is not directly related to growth and development.
• B) Spices: Spices provide flavor and may offer some antioxidant benefits, but they are not essential for growth and development.
• C) High sugar: High sugar intake is not essential for growth and can lead to health issues such as diabetes and weight gain.

The correct answer is (B) Mesophyll.

Explanation:

• Photosynthesis primarily occurs in the mesophyll tissue of plant leaves. The mesophyll is the inner tissue of the leaf, and it contains chloroplasts, which are the sites where photosynthesis takes place.
• The upper and lower mesophyll layers include the palisade mesophyll (which is tightly packed with chloroplasts) and the spongy mesophyll (which has more air spaces for gas exchange).
• The process of photosynthesis involves the absorption of light energy by chlorophyll in the chloroplasts to convert carbon dioxide and water into glucose and oxygen.

Information Booster:

• Phloem and xylem are responsible for transporting nutrients and water, but not for photosynthesis.
• The epidermis is the outermost layer of cells that acts as a protective barrier, but it does not play a role in photosynthesis.

Why other options are incorrect:

• A) Phloem: Transports food produced by photosynthesis, not involved in the process.
• C) Xylem: Transports water and minerals, not involved in photosynthesis.
• D) Epidermis: Serves as a protective outer layer, not where photosynthesis occurs.

The correct answer is (A) Mitochondria.

Explanation:

• The mitochondria are often referred to as the "energy factories" of the cell. They are responsible for generating ATP (adenosine triphosphate) through the process of cellular respiration, which provides energy for various cellular activities.
• Mitochondria have their own DNA and are involved in a variety of important processes, such as metabolism, intracellular signaling, and cellular differentiation. They also play a role in cell death (apoptosis).

Information Booster:

• Mitochondria have a double membrane structure: the outer membrane and the inner membrane, which is highly folded to form cristae. These folds increase the surface area for ATP production.
• The inner membrane houses the electron transport chain (ETC) and ATP synthase, which are crucial for energy production in the cell.
• Mitochondria are involved in calcium signaling, and heat production (especially in brown fat cells), and help regulate the redox balance in the cell.

Why other options are incorrect:

• B) Golgi apparatus: The Golgi apparatus is involved in sorting, modifying, and packaging proteins and lipids for transport within or outside the cell, but it is not the cell's energy producer.
• C) Peroxisome: Peroxisomes contain enzymes that break down fatty acids and detoxify harmful substances, but they are not directly involved in energy production.
• D) Lysosome: Lysosomes contain digestive enzymes that break down waste materials and cellular debris, but they do not function as the cell’s energy factory.

The correct answer is (D) Soybean.

Explanation:

• Soy milk is made from soybeans, not from animals like cow, goat, or buffalo. It is a plant-based beverage and is made by soaking, grinding, and boiling soybeans. The resulting liquid is soy milk.
• Soy milk is a popular alternative to dairy milk, especially for those who are lactose intolerant or follow a vegan diet.

Information Booster:

• Soy milk is a rich source of protein, vitamins, and minerals. It is often used in cooking, baking, and as a milk substitute for cereal, coffee, or tea.
• It is also dairy-free and cholesterol-free, making it a heart-healthy alternative to regular milk.

The correct answer is (C) Phosphorus.

Explanation:

• Phosphorus is a vital mineral that plays a key role in the formation and maintenance of healthy bones and teeth.
• About 85% of the phosphorus in the human body is found in bones and teeth, where it combines with calcium to form calcium phosphate, giving bones and teeth their strength and structure.
• Phosphorus also plays an important role in energy metabolism, as it is a component of ATP (adenosine triphosphate), the energy currency of the body.

Information Booster:

• Calcium and Phosphorus balance is crucial; an imbalance can lead to weak bones or osteoporosis.
• Phosphorus-rich foods include dairy products, meat, fish, poultry, nuts, and whole grains.
• Besides bones and teeth, phosphorus is also essential for cell repair, DNA and RNA synthesis, and proper kidney function.

Why other options are incorrect:

• A. Fluoride: Important for preventing dental cavities but not directly essential for bone structure.
• B. Sodium: Essential for fluid balance and nerve function, not for bones or teeth.
• D. Potassium: Helps in muscle function and maintaining blood pressure, but not directly for bone and teeth health.