Life Processes PDF

**1. List two functions of finger-like projections in the small intestine.** - **Increase surface area** for better absorption of nutrients. - **Help in absorbing digested food** into the blood. **2. State the role of the enzyme trypsin and lipase. Who secretes them?** - **Trypsin:** Helps...

**1. List two functions of finger-like projections in the small intestine.** - **Increase surface area** for better absorption of nutrients. - **Help in absorbing digested food** into the blood. **2. State the role of the enzyme trypsin and lipase. Who secretes them?** - **Trypsin:** Helps in **protein digestion** by breaking them into amino acids. - **Lipase:** Helps in **fat digestion** by breaking them into fatty acids and glycerol. - **Secreted by:** **Pancreas** **3. Difference between heterotrophs and autotrophs?** **Heterotrophs** **Autotrophs** ---------------------------- --------------------------------- Cannot make their own food Can make their own food Depend on plants/animals Use sunlight for photosynthesis Example: Humans, animals Example: Plants, algae *(Note: \"Hetrotrophs\" is a spelling mistake; the correct term is **heterotrophs**.)* **4. Three differences between arteries and veins?** **Arteries** **Veins** ---------------------------------- -------------------------------------- Carry **oxygen-rich blood** Carry **carbon dioxide- rich blood** Blood flows **at high pressure** Blood flows **at low pressure** Thick, elastic walls It contain Valves **5. Two ways in which glucose is oxidized to provide energy in the human body?** - **Aerobic respiration:** Glucose breaks down with **oxygen**, producing **energy, CO₂, and water**. - **Anaerobic respiration:** Glucose breaks down **without oxygen**, producing **less energy and lactic acid**. **6. Name four types of metabolic waste produced by humans.** - **Carbon dioxide (CO₂)** - **Urea** - **Excess water** - **Salts** **7. Name two human excretory organs other than kidneys.** - **Lungs** (Remove CO₂) - **Skin** (Removes sweat) **8. What is peristaltic movement?** - **Peristalsis** is the **wave-like movement of muscles** in the food pipe and intestines. - It **pushes food forward** in the digestive system. **9. Why do stomata remain closed during the daytime in desert plants?** - **Desert plants close stomata during the day** to **prevent water loss** due to heat. - They **open at night** for gas exchange and do **CAM photosynthesis** to **store CO₂** for daytime use. **Q-Significance of Photosynthesis** 1. **Produces Oxygen** -- Essential for respiration in living beings. 2. **Prepares Food** -- Converts sunlight into glucose, the primary source of energy. 3. **Maintains CO₂-O₂ Balance** -- Absorbs CO₂ and releases O₂, keeping air clean. REACTION ### **Why is Blood Circulation in Humans Called Double Circulation?** Blood circulation in humans is called **double circulation** because the blood **passes through the heart twice** in one complete cycle. It ensures **efficient oxygenation** and **distribution of nutrients**. **Brief Description of Urine Formation** Urine is produced in the **kidneys** through three main steps: 1. **Filtration** -- Blood is filtered in the **glomerulus**, removing waste, water, and small molecules while keeping proteins and blood cells. 2. **Reabsorption** -- Useful substances (**glucose, water, salts**) are reabsorbed into the blood from kidney tubules. 3. **Secretion** -- Excess **wastes, toxins, and ions** are added to the urine to maintain balance. **Final Step:** - The urine, now containing **urea, salts, water, and other wastes**, passes into the **urinary bladder** through the **ureters**. - It is **stored** in the bladder until it is excreted through the **urethra**.