291. Which of the following is the primary function of the circulatory system?
A) Digestion of food
B) Transport of nutrients and oxygen
C) Production of hormones
D) Regulation of body temperature
Correct Answer: B) Transport of nutrients and oxygen
Explanation:
The circulatory system, consisting of the heart, blood vessels, and blood, is primarily responsible for transporting oxygen, nutrients, hormones, and waste products throughout the body. Oxygen from the lungs and nutrients from the digestive system are delivered to cells, while carbon dioxide and metabolic wastes are removed for excretion. This system ensures that all tissues receive the materials they need for metabolism and function.
292. Which structure in the eye is responsible for focusing light onto the retina?
A) Cornea
B) Lens
C) Iris
D) Pupil
Correct Answer: B) Lens
Explanation:
The lens of the eye is a transparent, flexible structure that changes shape to focus light onto the retina, enabling clear vision at different distances. The cornea also helps focus light, but the lens fine-tunes the focus through the process of accommodation. The iris controls the size of the pupil, regulating the amount of light entering the eye.
293. What is the main function of the lymphatic system?
A) Transport of oxygen
B) Immune defense and fluid balance
C) Digestion
D) Excretion
Correct Answer: B) Immune defense and fluid balance
Explanation:
The lymphatic system consists of lymph nodes, lymphatic vessels, and lymphoid organs. It helps maintain fluid balance by returning excess tissue fluid to the bloodstream. It also plays a crucial role in the immune system by filtering pathogens and producing lymphocytes that defend against infections.
294. Which of the following is a function of the epidermis in plants?
A) Photosynthesis
B) Protection and prevention of water loss
C) Transport of water
D) Storage of nutrients
Correct Answer: B) Protection and prevention of water loss
Explanation:
The epidermis is the outermost layer of plant cells, providing a protective barrier against physical damage, pathogens, and excessive water loss. It often secretes a waxy cuticle that further reduces water evaporation from the plant surface.
295. What is the main function of the root system in plants?
A) Photosynthesis
B) Anchorage and absorption
C) Reproduction
D) Transpiration
Correct Answer: B) Anchorage and absorption
Explanation:
The root system anchors the plant securely in the soil and absorbs water and mineral nutrients from the ground. Roots also store food in some plants and help in vegetative propagation.
296. Which of the following is a function of the shoot system in plants?
A) Absorption of water
B) Support and transport
C) Storage of water
D) Anchorage
Correct Answer: B) Support and transport
Explanation:
The shoot system, which includes stems, leaves, flowers, and fruits, supports the plant and transports water, nutrients, and food between roots and leaves. It also facilitates reproduction and photosynthesis.
297. What is the main function of the xylem in plants?
A) Transport of food
B) Transport of water and minerals
C) Storage of nutrients
D) Photosynthesis
Correct Answer: B) Transport of water and minerals
Explanation:
Xylem is a vascular tissue responsible for transporting water and dissolved minerals from the roots to the rest of the plant. It also provides structural support to the plant.
298. What is the main function of the phloem in plants?
A) Transport of water
B) Transport of food
C) Storage of water
D) Photosynthesis
Correct Answer: B) Transport of food
Explanation:
Phloem is a vascular tissue that transports sugars and other organic nutrients (food) produced during photosynthesis from the leaves to other parts of the plant.
299. Which of the following is a function of the stomata in plants?
A) Absorption of water
B) Gas exchange and transpiration
C) Transport of nutrients
D) Storage of food
Correct Answer: B) Gas exchange and transpiration
Explanation:
Stomata are tiny pores on the surface of leaves that regulate gas exchange (carbon dioxide in, oxygen out) and allow water vapor to escape during transpiration.
300. What is the main function of the chloroplast in plant cells?
A) Cellular respiration
B) Photosynthesis
C) Protein synthesis
D) Lipid synthesis
Correct Answer: B) Photosynthesis
Explanation:
Chloroplasts contain chlorophyll and are the sites of photosynthesis, where light energy is converted into chemical energy (glucose), providing food for the plant and oxygen for the atmosphere.
301. Which of the following is a function of the mitochondria?
A) Photosynthesis
B) Cellular respiration and ATP production
C) Protein synthesis
D) Lipid synthesis
Correct Answer: B) Cellular respiration and ATP production
Explanation:
Mitochondria are the powerhouses of the cell, where cellular respiration occurs. They convert nutrients into ATP, the energy currency of the cell, through aerobic respiration.
302. What is the main function of the nucleus?
A) Energy production
B) Genetic control and cell regulation
C) Protein synthesis
D) Waste removal
Correct Answer: B) Genetic control and cell regulation
Explanation:
The nucleus contains the cell’s genetic material (DNA) and controls all cellular activities by regulating gene expression and directing protein synthesis.
303. Which of the following is a function of the ribosome?
A) Energy production
B) Protein synthesis
C) Lipid synthesis
D) DNA replication
Correct Answer: B) Protein synthesis
Explanation:
Ribosomes are the sites where proteins are synthesized according to the instructions carried by messenger RNA (mRNA).
304. What is the main function of the lysosome?
A) Energy production
B) Digestion of cellular waste
C) Protein synthesis
D) Lipid synthesis
Correct Answer: B) Digestion of cellular waste
Explanation:
Lysosomes are organelles that contain digestive enzymes, which break down cellular waste, damaged organelles, and foreign materials, helping to maintain cellular health.
305. Which of the following is a function of the Golgi apparatus?
A) Synthesizes proteins
B) Modifies, sorts, and packages proteins
C) Produces ATP
D) Breaks down cellular waste
Correct Answer: B) Modifies, sorts, and packages proteins
Explanation:
The Golgi apparatus receives proteins from the endoplasmic reticulum, modifies them, sorts them, and packages them into vesicles for transport to their final destinations.
306. What is the main function of the endoplasmic reticulum?
A) Energy production
B) Synthesis and transport of proteins and lipids
C) Digestion
D) Storage of nutrients
Correct Answer: B) Synthesis and transport of proteins and lipids
Explanation:
The endoplasmic reticulum (ER) is a network of membranes involved in the synthesis and transport of proteins (rough ER) and lipids (smooth ER), as well as detoxification.
307. Which of the following is a function of the vacuole in plant cells?
A) Protein synthesis
B) Storage and maintaining turgidity
C) Energy production
D) Waste removal
Correct Answer: B) Storage and maintaining turgidity
Explanation:
Vacuoles in plant cells store nutrients, waste products, and help maintain cell turgidity, which is essential for plant structure and support.
308. What is the main function of the plasma membrane?
A) Energy production
B) Regulates entry and exit of substances
C) Protein synthesis
D) Waste removal
Correct Answer: B) Regulates entry and exit of substances
Explanation:
The plasma membrane is a selectively permeable barrier that controls the movement of substances into and out of the cell, maintaining homeostasis.
309. Which of the following is a function of the cytoskeleton?
A) Cell movement
B) Structural support
C) Intracellular transport
D) All of the above
Correct Answer: D) All of the above
Explanation:
The cytoskeleton is a network of protein filaments that provides structural support, enables cell movement, and facilitates the transport of organelles and vesicles within the cell.
310. What is the main function of the nucleolus?
A) DNA replication
B) Ribosome synthesis
C) ATP production
D) Lipid synthesis
Correct Answer: B) Ribosome synthesis
Explanation:
The nucleolus is a region within the nucleus where ribosomal RNA (rRNA) is synthesized and assembled with proteins to form ribosomes.
311. Which of the following is a function of the peroxisome?
A) Energy production
B) Digestion of cellular waste
C) Breakdown of hydrogen peroxide
D) Protein synthesis
Correct Answer: C) Breakdown of hydrogen peroxide
Explanation:
Peroxisomes contain enzymes, such as catalase, that break down hydrogen peroxide, a harmful byproduct of metabolism, into water and oxygen.
312. What is the main function of the centriole in animal cells?
A) Protein synthesis
B) Cell division (forms spindle fibers)
C) Energy production
D) Waste removal
Correct Answer: B) Cell division (forms spindle fibers)
Explanation:
Centrioles are involved in organizing spindle fibers during cell division, ensuring accurate chromosome separation in animal cells.
313. Which of the following is a function of the adrenal gland?
A) Production of insulin
B) Production of adrenaline
C) Production of bile
D) Production of growth hormone
Correct Answer: B) Production of adrenaline
Explanation:
The adrenal glands produce adrenaline (epinephrine), which prepares the body for “fight or flight” responses by increasing heart rate, dilating airways, and mobilizing energy stores.
314. What is the main function of the thyroid gland?
A) Regulation of calcium levels
B) Regulation of metabolism
C) Production of insulin
D) Production of adrenaline
Correct Answer: B) Regulation of metabolism
Explanation:
The thyroid gland produces hormones (thyroxine and triiodothyronine) that regulate the body’s metabolic rate, growth, and development.
315. Which of the following is a function of the pancreas?
A) Production of bile
B) Production of insulin and digestive enzymes
C) Filtration of blood
D) Storage of glycogen
Correct Answer: B) Production of insulin and digestive enzymes
Explanation:
The pancreas has both endocrine (insulin and glucagon) and exocrine (digestive enzymes) functions, playing a key role in blood sugar regulation and digestion.
316. What is the main function of the liver?
A) Production of bile
B) Detoxification
C) Storage of glycogen
D) All of the above
Correct Answer: D) All of the above
Explanation:
The liver is a multifunctional organ that produces bile, detoxifies harmful substances, stores glycogen, metabolizes drugs, and synthesizes proteins such as clotting factors.
317. Which of the following is a function of the gallbladder?
A) Production of bile
B) Storage and concentration of bile
C) Digestion of fats
D) None of the above
Correct Answer: B) Storage and concentration of bile
Explanation:
The gallbladder stores and concentrates bile produced by the liver, releasing it into the small intestine to aid in fat digestion.
318. What is the main function of the spleen?
A) Production of insulin
B) Storage of blood
C) Digestion of fats
D) Production of bile
Correct Answer: B) Storage of blood
Explanation:
The spleen acts as a blood reservoir, filters blood, removes old or damaged red blood cells, and plays a role in immune defense.
319. Which of the following is a function of the kidney?
A) Filtration of blood
B) Production of urine
C) Both A and B
D) None of the above
Correct Answer: C) Both A and B
Explanation:
The kidneys filter blood to remove waste products and excess substances, forming urine that is excreted from the body.
320. What is the main function of the ureter?
A) Filtration of blood
B) Transport of urine from the kidney to the bladder
C) Storage of urine
D) Production of urine
Correct Answer: B) Transport of urine from the kidney to the bladder
Explanation:
The ureter is a muscular tube that carries urine from the kidneys to the urinary bladder for temporary storage.
321. Which of the following is a function of the urinary bladder?
A) Filtration of blood
B) Storage of urine
C) Production of urine
D) Absorption of nutrients
Correct Answer: B) Storage of urine
Explanation:
The urinary bladder stores urine until it is excreted from the body.
322. What is the main function of the urethra?
A) Transport of urine from the kidney to the bladder
B) Transport of urine from the bladder to the outside
C) Filtration of blood
D) Storage of urine
Correct Answer: B) Transport of urine from the bladder to the outside
Explanation:
The urethra is a tube that carries urine from the bladder to the exterior of the body.
323. Which of the following is a function of the stomach?
A) Absorption of nutrients
B) Digestion of proteins
C) Production of bile
D) Storage of glycogen
Correct Answer: B) Digestion of proteins
Explanation:
The stomach secretes gastric juice containing hydrochloric acid and pepsin, which break down proteins into smaller peptides.
324. What is the main function of the small intestine?
A) Absorption of nutrients
B) Storage of food
C) Production of bile
D) Filtration of blood
Correct Answer: A) Absorption of nutrients
Explanation:
The small intestine is the primary site for the absorption of nutrients from digested food, thanks to its large surface area provided by villi and microvilli.
325. Which of the following is a function of the large intestine?
A) Absorption of nutrients
B) Absorption of water
C) Digestion of proteins
D) Production of bile
Correct Answer: B) Absorption of water
Explanation:
The large intestine absorbs water and electrolytes from indigestible food matter, forming solid feces.
326. What is the main function of the esophagus?
A) Digestion of food
B) Absorption of nutrients
C) Transport of food from the mouth to the stomach
D) Storage of food
Correct Answer: C) Transport of food from the mouth to the stomach
Explanation:
The esophagus is a muscular tube that propels food from the mouth to the stomach using peristalsis.
327. Which of the following is a function of the pharynx?
A) Digestion of food
B) Absorption of nutrients
C) Passageway for air and food
D) Production of sound
Correct Answer: C) Passageway for air and food
Explanation:
The pharynx serves as a common passageway for both air (to the trachea) and food (to the esophagus).
328. What is the main function of the trachea?
A) Digestion of food
B) Absorption of nutrients
C) Transport of air to the lungs
D) Production of sound
Correct Answer: C) Transport of air to the lungs
Explanation:
The trachea, or windpipe, carries air from the larynx to the bronchi and lungs.
329. Which of the following is a function of the bronchi?
A) Digestion of food
B) Absorption of nutrients
C) Transport of air to the lungs
D) Production of sound
Correct Answer: C) Transport of air to the lungs
Explanation:
The bronchi are the main branches of the trachea that deliver air to each lung.
330. What is the main function of the larynx?
A) Digestion of food
B) Absorption of nutrients
C) Production of sound
D) Transport of air to the lungs
Correct Answer: C) Production of sound
Explanation:
The larynx, or voice box, contains the vocal cords and is responsible for sound production.
331. Which of the following is a function of the diaphragm?
A) Digestion of food
B) Absorption of nutrients
C) Breathing
D) Production of sound
Correct Answer: C) Breathing
Explanation:
The diaphragm is a dome-shaped muscle that contracts and relaxes to facilitate inhalation and exhalation.
332. What is the main function of the alveoli in the lungs?
A) Production of mucus
B) Exchange of gases
C) Filtration of blood
D) Production of sound
Correct Answer: B) Exchange of gases
Explanation:
Alveoli are tiny air sacs where oxygen from inhaled air diffuses into the blood and carbon dioxide from the blood diffuses into the air to be exhaled.
333. Which of the following is a function of the thymus?
A) Production of T-cells
B) Production of red blood cells
C) Digestion
D) Storage of calcium
Correct Answer: A) Production of T-cells
Explanation:
The thymus is where T-lymphocytes (T-cells) mature, playing a key role in the development of the immune system.
334. What is the main function of the prostate gland in males?
A) Production of sperm
B) Production of seminal fluid
C) Production of testosterone
D) None of the above
Correct Answer: B) Production of seminal fluid
Explanation:
The prostate gland secretes a milky, alkaline fluid that forms part of semen, nourishing and protecting sperm.
335. Which of the following is a function of the seminal vesicles?
A) Production of sperm
B) Production of seminal fluid
C) Production of testosterone
D) None of the above
Correct Answer: B) Production of seminal fluid
Explanation:
The seminal vesicles produce a significant portion of the seminal fluid, which contains fructose and other substances that enhance sperm viability.
336. What is the main function of the epididymis?
A) Production of sperm
B) Storage and maturation of sperm
C) Production of testosterone
D) None of the above
Correct Answer: B) Storage and maturation of sperm
Explanation:
The epididymis is where sperm are stored and mature, gaining the ability to swim and fertilize an egg.
337. Which of the following is a function of the fallopian tube in females?
A) Production of eggs
B) Transport of eggs from the ovary to the uterus
C) Production of hormones
D) Storage of sperm
Correct Answer: B) Transport of eggs from the ovary to the uterus
Explanation:
The fallopian tube transports eggs from the ovary to the uterus and is the usual site of fertilization.
338. What is the main function of the uterus?
A) Production of eggs
B) Implantation and development of the embryo
C) Production of hormones
D) Storage of sperm
Correct Answer: B) Implantation and development of the embryo
Explanation:
The uterus provides a site for the implantation of the fertilized egg and supports the development of the embryo and fetus during pregnancy.
339. Which of the following is a function of the vagina?
A) Production of eggs
B) Passageway for sperm and childbirth
C) Production of hormones
D) Storage of sperm
Correct Answer: B) Passageway for sperm and childbirth
Explanation:
The vagina serves as the passageway for sperm during intercourse and as the birth canal during childbirth.
340. What is the main function of the ovary in females?
A) Production of eggs
B) Production of hormones
C) Both A and B
D) None of the above
Correct Answer: C) Both A and B
Explanation:
The ovaries produce eggs (ova) and secrete hormones such as estrogen and progesterone, which regulate the menstrual cycle and support pregnancy.
341. Which of the following is a function of the testis in males?
A) Production of sperm
B) Production of testosterone
C) Both A and B
D) None of the above
Correct Answer: C) Both A and B
Explanation:
The testes produce sperm and secrete testosterone, which is responsible for male secondary sexual characteristics.
342. What is the main function of the placenta during pregnancy?
A) Production of sperm
B) Exchange of nutrients and gases between mother and fetus
C) Production of bile
D) Storage of urine
Correct Answer: B) Exchange of nutrients and gases between mother and fetus
Explanation:
The placenta allows the exchange of oxygen, nutrients, and waste products between the mother’s and fetus’s blood, while preventing their blood from mixing.
343. Which of the following is a function of the umbilical cord?
A) Transport of blood between mother and fetus
B) Digestion of food
C) Production of hormones
D) Storage of nutrients
Correct Answer: A) Transport of blood between mother and fetus
Explanation:
The umbilical cord contains blood vessels that transport oxygen and nutrients from the placenta to the fetus and carry waste products away.
344. What is the main function of the amniotic sac?
A) Protection and cushioning of the fetus
B) Digestion of food
C) Production of hormones
D) Storage of nutrients
Correct Answer: A) Protection and cushioning of the fetus
Explanation:
The amniotic sac is a fluid-filled membrane that surrounds and protects the developing fetus, providing cushioning against physical shocks and maintaining a stable environment.
345. Which of the following is a function of the skeletal system?
A) Support
B) Protection
C) Movement
D) All of the above
Correct Answer: D) All of the above
Explanation:
The skeletal system supports the body, protects internal organs, enables movement through attachment to muscles, and stores minerals such as calcium.
346. What is the main function of the muscular system?
A) Support
B) Movement
C) Heat production
D) All of the above
Correct Answer: D) All of the above
Explanation:
The muscular system enables movement, supports the body, and generates heat through muscle contractions.
347. Which of the following is a function of the integumentary system?
A) Protection
B) Sensation
C) Temperature regulation
D) All of the above
Correct Answer: D) All of the above
Explanation:
The integumentary system (skin) protects the body from injury and infection, senses environmental stimuli, and helps regulate body temperature.
348. What is the main function of the nervous system?
A) Rapid response to stimuli
B) Coordination and control
C) Both A and B
D) None of the above
Correct Answer: C) Both A and B
Explanation:
The nervous system detects and responds to stimuli, coordinates body activities, and controls voluntary and involuntary functions.
349. Which of the following is a function of the endocrine system?
A) Rapid response to stimuli
B) Slow, long-term regulation via hormones
C) Digestion
D) Excretion
Correct Answer: B) Slow, long-term regulation via hormones
Explanation:
The endocrine system regulates growth, metabolism, reproduction, and other long-term processes through the secretion of hormones.
350. What is the main function of the immune system?
A) Transport of oxygen
B) Defense against pathogens
C) Digestion
D) Excretion
Correct Answer: B) Defense against pathogens
Explanation:
The immune system protects the body from infections and diseases by recognizing and destroying pathogens such as bacteria, viruses, and fungi.