Question 1

Which of the following is the primary function of hemoglobin in the human body?

Accepted Answer

Hemoglobin is an iron-containing protein in red blood cells that binds to oxygen in the lungs and transports it to tissues throughout the body. It also carries carbon dioxide back to the lungs for exhalation.

Question 2

The human skeleton is composed of approximately how many bones in an adult?

Accepted Answer

An adult human skeleton typically contains 206 bones. This number decreases from birth because infants are born with approximately 270 bones, many of which are made of cartilage. As the child grows, many of these bones fuse together, resulting in the lower number in adults.

Question 3

Which of the following is the primary function of haemoglobin in the human body?

Accepted Answer

Haemoglobin is an iron-containing protein in red blood cells that binds to oxygen in the lungs and transports it to tissues throughout the body. It also carries carbon dioxide back to the lungs for exhalation.

Question 4

Which gland in the human body is responsible for the production and secretion of insulin?

Accepted Answer

The pancreas is an endocrine gland that produces insulin, a hormone that regulates blood glucose levels. Specifically, insulin is produced by beta (β) cells located in the islets of Langerhans within the pancreas.

Question 5

Which of the following vitamins is fat-soluble and plays a crucial role in vision and immune function?

Accepted Answer

Vitamin A is a fat-soluble vitamin essential for vision (it forms retinal, a component of rhodopsin in the retina), immune function, and skin health. It is stored in the liver and fatty tissues. Deficiency causes night blindness and can lead to corneal scarring.

Question 6

Vitamin D is primarily synthesized in the human body when skin is exposed to which type of radiation?

Accepted Answer

Vitamin D is synthesized in the skin when exposed to ultraviolet B (UVB) radiation from sunlight. This is why it is often called the 'sunshine vitamin.' The synthesis involves conversion of 7-dehydrocholesterol to previtamin D3.

Question 7

Which of the following hormones is produced by the pancreas and regulates blood glucose levels?

Accepted Answer

Insulin is a hormone produced by beta cells in the islets of Langerhans within the pancreas. It lowers blood glucose by promoting glucose uptake into cells and glycogen synthesis. Glucagon, also from the pancreas (alpha cells), raises blood glucose.

Question 8

The human skeleton serves multiple functions. Which of the following is NOT a primary function of the skeletal system?

Accepted Answer

The primary functions of the skeletal system are: (1) support and structure, (2) protection of organs, (3) movement (with muscles), (4) mineral storage (calcium and phosphorus), and (5) blood cell production (in bone marrow). Digestion is a function of the digestive system, not the skeleton.

Question 9

Which of the following vitamins is fat-soluble and is essential for vision, immune function, and skin health?

Accepted Answer

Vitamin A is a fat-soluble vitamin that is essential for vision (it forms retinal, a component of rhodopsin in the retina), immune function (maintains epithelial tissues), and skin health. It is stored in the liver and fatty tissues. Sources include carrots, sweet potatoes, and leafy greens.

Question 10

Vitamin D is primarily synthesized in the human body through exposure to which type of radiation?

Accepted Answer

Vitamin D is synthesized in the skin when exposed to ultraviolet B (UVB) radiation from sunlight. This is why it is often called the 'sunshine vitamin.' The process begins with 7-dehydrocholesterol in the skin being converted to previtamin D3.

Question 11

Which of the following is the correct sequence of blood flow through the human heart?

Accepted Answer

The correct sequence is: deoxygenated blood enters the right atrium via the superior and inferior vena cava → flows to the right ventricle → pumped to the lungs via the pulmonary artery → oxygenated blood returns via the pulmonary vein to the left atrium → flows to the left ventricle → pumped to the body via the aorta.

Question 12

The pancreas performs both endocrine and exocrine functions. Which hormone is secreted by the endocrine portion (islets of Langerhans) of the pancreas?

Accepted Answer

The islets of Langerhans in the pancreas contain beta cells that secrete insulin, which regulates blood glucose levels. Alpha cells secrete glucagon, which raises blood glucose.

Question 13

Deficiency of which mineral causes goiter, a condition characterized by enlargement of the thyroid gland?

Accepted Answer

Iodine deficiency causes goiter. Iodine is an essential component of thyroid hormones (thyroxine and triiodothyronine). Without adequate iodine, the thyroid gland enlarges as it attempts to produce sufficient thyroid hormones, resulting in goiter.

Question 14

Vitamin B12 (Cobalamin) is essential for which of the following processes in the human body?

Accepted Answer

Vitamin B12 is crucial for DNA synthesis, red blood cell formation, and myelin sheath maintenance in nerve cells. Deficiency leads to pernicious anemia and neurological damage.

Question 15

The hormone responsible for regulating blood glucose levels is secreted by which gland?

Accepted Answer

Insulin, the hormone that regulates blood glucose levels by promoting glucose uptake into cells and storage as glycogen, is secreted by the pancreas, specifically by beta cells in the islets of Langerhans.

Question 16

Which of the following statements about the human kidney is correct?

Accepted Answer

The kidney filters blood to produce urine through three main processes: glomerular filtration in Bowman's capsule, selective reabsorption in the proximal convoluted tubule, and secretion in the distal convoluted tubule.

Question 17

The functional unit of the kidney responsible for filtering blood and forming urine is called:

Accepted Answer

The nephron is the functional unit of the kidney. Each kidney contains approximately 1 million nephrons. Each nephron consists of a renal corpuscle (glomerulus and Bowman's capsule) and a renal tubule (proximal convoluted tubule, loop of Henle, and distal convoluted tubule), where filtration, reabsorption, and secretion occur.

Question 18

Which of the following vitamins is synthesized by the human body when the skin is exposed to sunlight?

Accepted Answer

Vitamin D is synthesized in the skin when exposed to ultraviolet B (UVB) radiation from sunlight. This is why it is often called the 'sunshine vitamin'. Vitamins A, B12, and C cannot be synthesized by the human body and must be obtained through diet.

Question 19

Which of the following vitamins is synthesized by the human body and does NOT require dietary intake under normal circumstances?

Accepted Answer

Vitamin D is synthesized in the skin when exposed to ultraviolet-B (UVB) radiation from sunlight. The precursor 7-dehydrocholesterol is converted to cholecalciferol (vitamin D₃), which is then hydroxylated in the liver and kidneys to form the active hormone calcitriol. Adequate sun exposure can meet most vitamin D requirements without dietary sources.

Question 20

The enzyme responsible for breaking down hydrogen peroxide (H₂O₂) into water and oxygen in human cells is:

Accepted Answer

Catalase is a metalloenzyme containing heme iron that catalyzes the decomposition of hydrogen peroxide (a toxic byproduct of cellular metabolism) into water and oxygen: 2H₂O₂ → 2H₂O + O₂. It is found in peroxisomes and is crucial for protecting cells from oxidative damage.

SSC CHSL Biology — Human Body

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