Kerala SSLC · Biology · Class 10
The Paths of Life Sustaining Processes: Important Questions with Answers
These are 10 important multiple-choice questions from the Kerala SSLC Biology chapter “The Paths of Life Sustaining Processes” (Kerala SCERT syllabus). Each one shows the correct answer and a short explanation of why it is right. Try answering before you read the answer. ExamSummary has 10 practice questions on this chapter in total.
Q1.During the day, what specific change occurs in the guard cells that leads to the opening of stomata?
- A)Water flows out of the guard cells causing them to become flaccid.
- B)Potassium ions accumulate in the guard cells, drawing water in and making them turgid.
- C)Carbon dioxide concentration increases inside the guard cells.
- D)The chloroplasts stop functioning due to high temperature.
Answer: B) Potassium ions accumulate in the guard cells, drawing water in and making them turgid.
The accumulation of potassium ions lowers the water potential in guard cells, causing water to enter via osmosis. This makes the guard cells turgid and curved, opening the stomatal pore for gas exchange.
Q2.In which cellular organelle does the complete oxidation of glucose occur during aerobic respiration?
- A)Ribosome
- B)Golgi Apparatus
- C)Mitochondria
- D)Endoplasmic Reticulum
Answer: C) Mitochondria
The mitochondria are known as the powerhouse of the cell because they host the Krebs cycle and electron transport chain. These processes break down pyruvate completely into carbon dioxide and water, releasing maximum ATP.
Q3.Which tissue in plants is primarily responsible for the translocation of organic nutrients like sugars from leaves to roots?
- A)Xylem
- B)Phloem
- C)Parenchyma
- D)Collenchyma
Answer: B) Phloem
Phloem tissue transports food substances synthesized in the leaves to other parts of the plant through a process called translocation. Unlike xylem, which moves water upwards, phloem transport can occur in both directions depending on the plant's needs.
Q4.What is the functional unit of the human excretory system that filters blood to form urine?
- A)Neuron
- B)Nephron
- C)Alveolus
- D)Villi
Answer: B) Nephron
The nephron is the microscopic structural and functional unit of the kidney responsible for filtering waste from the blood. It consists of a glomerulus and tubule system that regulates water and solute balance.
Q5.Although bile juice contains no digestive enzymes, how does it aid in the digestion of fats?
- A)It breaks down fats into fatty acids directly.
- B)It neutralizes stomach acid before entering the intestine.
- C)It emulsifies large fat globules into smaller droplets.
- D)It activates lipase enzymes produced by the pancreas.
Answer: C) It emulsifies large fat globules into smaller droplets.
Bile salts act as emulsifiers, breaking down large fat globules into smaller droplets to increase the surface area for enzyme action. This physical breakdown allows pancreatic lipase to digest fats more efficiently in the small intestine.
Q6.Why is the separation of oxygenated and deoxygenated blood advantageous for mammals and birds?
- A)It reduces the overall size of the heart.
- B)It allows for a highly efficient supply of oxygen to tissues.
- C)It prevents the mixing of blood with lymph fluid.
- D)It enables the heart to beat without valves.
Answer: B) It allows for a highly efficient supply of oxygen to tissues.
Separating the two types of blood ensures that oxygen-rich blood is pumped efficiently to all body parts without dilution. This high-efficiency circulatory system supports the high metabolic demands required for maintaining constant body temperature.
Q7.During intense exercise, muscle cells switch to anaerobic respiration. What is the primary end product formed in human muscles under these conditions?
- A)Ethanol
- B)Lactic Acid
- C)Acetyl CoA
- D)Citric Acid
Answer: B) Lactic Acid
When oxygen supply is insufficient, pyruvate is converted into lactic acid in the cytoplasm of muscle cells. The accumulation of lactic acid is responsible for the cramps experienced after strenuous physical activity.
Q8.Which component of blood is primarily responsible for carrying oxygen throughout the human body?
- A)Plasma
- B)White Blood Cells
- C)Red Blood Cells
- D)Platelets
Answer: C) Red Blood Cells
Red blood cells contain hemoglobin, an iron-containing protein that binds reversibly with oxygen molecules. This allows them to transport oxygen from the lungs to various tissues and organs in the body.
Q9.What is the main physiological reason for the presence of numerous alveoli in the human lungs?
- A)To increase the volume of air stored in the chest cavity.
- B)To provide a large surface area for efficient gas exchange.
- C)To filter dust particles before air reaches the blood.
- D)To produce mucus for trapping pathogens.
Answer: B) To provide a large surface area for efficient gas exchange.
Alveoli are tiny sac-like structures that vastly increase the internal surface area of the lungs. This large surface area facilitates the rapid diffusion of oxygen into the blood and carbon dioxide out of the blood.
Q10.How does the process of transpiration contribute to the survival of tall trees?
- A)It cools the leaves and helps in the upward movement of water.
- B)It absorbs nutrients directly from the atmosphere.
- C)It stores excess water in the trunk for dry seasons.
- D)It prevents the loss of carbon dioxide during the day.
Answer: A) It cools the leaves and helps in the upward movement of water.
Transpiration creates a negative pressure or suction pull that draws water and dissolved minerals up from the roots to the leaves. Additionally, the evaporation of water from leaf surfaces helps regulate the plant's temperature.