Nutrition

• What is photosynthesis?


  An endothermic reaction where energy from sunlight is used to make glucose from carbon dioxide and water in chloroplasts.
• What pigment absorbs sunlight in photosynthesis?


  Chlorophyll.
• Define autotrophs


  Organisms that produce their own food using simple substances like carbon dioxide and water, e.g., green plants.
• What are the main products of photosynthesis?


  • Glucose and oxygen.
• Write the word equation for photosynthesis.


  Carbon dioxide + Water → Glucose + Oxygen.
• How is glucose used by plants?


  For energy in respiration, stored as starch, used to make cellulose, lipids, and amino acids.
• Why is oxygen released during photosynthesis?


  It is a byproduct of splitting water molecules during the reaction.
• How does chlorophyll contribute to photosynthesis?


  It absorbs sunlight energy needed for the reaction.
• What is the balanced chemical equation for photosynthesis?


  6CO2​+6H2​O→C6​H12​O6​+6O2​.
• Name the three main limiting factors of photosynthesis


  Temperature, light intensity, and carbon dioxide concentration.
• Why isn’t water considered a limiting factor?


  Only small amounts are needed compared to what’s lost through transpiration.
• What happens if the temperature is too high for photosynthesis?


  Enzymes can denature, reducing the rate of photosynthesis.
• How does light intensity affect the rate of photosynthesis?


  Increased light intensity increases the rate up to a point where another factor limits it.
• What effect does carbon dioxide concentration have on photosynthesis?


  Higher CO₂ concentration increases the rate until another factor limits it.
• What is the role of the wax cuticle?


  It prevents water evaporation from the leaf surface.
• Why are palisade mesophyll cells important?


  They contain chloroplasts and are tightly packed to maximize light absorption
• What is the function of stomata in leaves?


  hey allow gas exchange—CO₂ in, O₂ out—and control water loss.
• Describe how the leaf’s structure is adapted for photosynthesis.


  Large surface area, thin structure, chlorophyll for light absorption, and a network of veins for water and carbohydrate transport.
• How can oxygen production demonstrate photosynthesis?


  Oxygen bubbles from plants like pondweed in water show photosynthesis is occurring.
• Describe the starch test for photosynthesis.


  Boil the leaf, remove chlorophyll with ethanol, apply iodine—areas with starch turn blue-black, proving photosynthesis.
• Why cover part of the leaf with foil in a light experiment?

  To show that photosynthesis (and starch production) only occurs in light-exposed areas.
• Which two mineral ions are vital for photosynthesis?

  Nitrogen and magnesium.
• What is the function of magnesium in plants?


  It is essential for chlorophyll production.
• What happens if a plant lacks nitrogen?


  Poor growth and yellow leaves due to insufficient protein synthesis.
• What is the significance of chlorophyll in photosynthesis?


  Chlorophyll absorbs sunlight, which is necessary for converting carbon dioxide and water into glucose and oxygen.
• Why is it important to decolorize the leaf before adding iodine?


  Decolorizing removes green pigment, allowing any color change with iodine to be clearly visible, indicating starch presence.
• What is the purpose of the iodine solution in the chlorophyll experiment?


  Iodine reacts with starch, turning blue-black to indicate areas where photosynthesis has occurred.
• Explain why only the green parts of the leaf turn blue-black in the experiment.

  Green parts contain chlorophyll, which is essential for photosynthesis. Without chlorophyll, starch cannot be produced.
• What are the main functions of proteins in the body?


  Proteins are essential for growth, repair of tissues, and production of enzymes and hormones.
• What is a balanced diet?


  A diet that includes all the food groups in the correct proportions.
• Name the seven key food groups.

  Carbohydrates, proteins, lipids (fats), dietary fiber, vitamins, minerals, and water.
• What is the primary function of carbohydrates?


  They provide energy.
• Which foods are primary sources of protein?


  Meat, fish, eggs, pulses, and nuts.
• What is the role of lipids in the body?


  Lipids provide insulation and energy storage.
• What is the function of Vitamin D in the body?


  Vitamin D helps in the absorption of calcium and promotes bone growth.
• Name a mineral important for red blood cell formation and where it can be found in food.

  Iron, which is found in red meat, spinach, and legumes.
• What role does fiber play in maintaining a healthy digestive system?


  Fiber adds bulk to stool, aiding in digestion and preventing constipation by keeping food moving through the intestines.
• Describe the role of the esophagus in digestion.


  The esophagus transports food from the mouth to the stomach via rhythmic muscular contractions called peristalsis.
• What is the main function of the small intestine in digestion?


  The small intestine completes digestion and is the primary site for nutrient absorption into the bloodstream.
• Why does the stomach have a thick lining of mucus?


  The mucus protects the stomach lining from being damaged by its own acidic digestive juices