D313 Anatomy and Physiology II - Set 3 - Part 3

Correct Answer: Vitamin A

Option a is correct because vitamin A specifically aids in maintaining a clear cornea and supports healthy vision. It is a fat-soluble vitamin found in food sources including liver, carrots, and sweet potatoes. Option b is incorrect because vitamin C is a water-soluble vitamin primarily involved in collagen synthesis and antioxidant protection. Its deficiency causes scurvy, not vision impairment or corneal deterioration issues. Option c is incorrect because vitamin B one, also known as thiamine, is a water-soluble vitamin involved in energy metabolism from carbohydrates. It is found in grains and does not specifically support vision. Option d is incorrect because vitamin D is a fat-soluble vitamin primarily involved in calcium absorption and bone health. It can be manufactured through sunlight exposure and does not specifically maintain corneal clarity.

Correct Answer: Vitamin D

Option d is correct because vitamin D is uniquely manufactured by the body through sunlight exposure on the skin. It primarily supports calcium absorption and bone health and is found in dairy products. Option a is incorrect because vitamin C cannot be manufactured by the human body and must be obtained entirely through dietary sources such as citrus fruits, tomatoes, and peppers. It supports collagen synthesis. Option b is incorrect because vitamin A cannot be manufactured by the human body through sunlight or any other internal process. It must be obtained through dietary sources including liver, carrots, and sweet potatoes. Option c is incorrect because vitamin B twelve cannot be manufactured by the body and must come from dietary animal sources like meat and dairy. It also requires intrinsic factor for absorption in the ileum.

Correct Answer: Vitamin B one (thiamine)

Option b is correct because vitamin B one, also called thiamine, is specifically involved in energy metabolism from carbohydrates. It is a water-soluble vitamin found abundantly in grain-based food sources. Option a is incorrect because vitamin D is a fat-soluble vitamin primarily supporting calcium absorption and bone health. It is obtained from dairy products and sunlight exposure, not specifically from grain food sources. Option c is incorrect because vitamin A is a fat-soluble vitamin that supports vision and corneal clarity. It is found in liver, carrots, and sweet potatoes and is not primarily involved in carbohydrate energy metabolism. Option d is incorrect because vitamin C is a water-soluble vitamin primarily involved in collagen synthesis and antioxidant protection. It is found in citrus fruits and tomatoes, not specifically in grain sources.

Correct Answer: Vitamin B twelve

Option c is correct because vitamin B twelve specifically requires intrinsic factor, a glycoprotein secreted by gastric parietal cells, for its absorption in the ileum. Its deficiency causes impaired red blood cell formation. Option a is incorrect because vitamin A is a fat-soluble vitamin that requires dietary fat for absorption but does not require intrinsic factor. Its deficiency primarily affects vision and corneal health, not red blood cells. Option b is incorrect because vitamin D is a fat-soluble vitamin absorbed with dietary fat and can also be manufactured through sunlight exposure. It does not require intrinsic factor for its absorption process. Option d is incorrect because vitamin C is a water-soluble vitamin readily absorbed in the small intestine without needing intrinsic factor. Its deficiency causes scurvy, not impaired red blood cell formation specifically.

Correct Answer: Small intestine

Option d is correct because micronutrients including both vitamins and minerals are primarily absorbed in the small intestine, where the extensive surface area of villi and microvilli facilitates efficient nutrient uptake. Option a is incorrect because the large intestine primarily absorbs water and electrolytes from remaining food residue rather than vitamins and minerals. It is not the primary absorption site for micronutrients overall. Option b is incorrect because the stomach primarily functions as a site for protein digestion and mechanical churning of food. Very limited nutrient absorption of any kind actually occurs within the stomach environment. Option c is incorrect because the oral cavity is where mechanical digestion through chewing and carbohydrate digestion through salivary amylase begin. No significant absorption of micronutrients takes place in the mouth.

Correct Answer: Glucose

Option a is correct because glucose is specifically the primary carbohydrate monosaccharide that cells throughout the body use to generate ATP energy through the sequential processes of glycolysis and cellular respiration. Option b is incorrect because while fructose is a monosaccharide found in fruits, it is not the primary carbohydrate that cells directly use for ATP production. Fructose must be converted before entering standard metabolic pathways. Option c is incorrect because sucrose is a disaccharide composed of glucose and fructose bonded together. It must be broken down into its individual monosaccharide components before cells can use it for energy. Option d is incorrect because lactose is a disaccharide found in milk composed of glucose and galactose. It must first be broken down by the enzyme lactase before its components can enter energy-producing pathways.

Correct Answer: Glycogen storage capacity is limited

Option c is correct because the liver and skeletal muscles have a definitively limited capacity for glycogen storage. Once those stores are fully saturated, excess glucose must be converted to fat through lipogenesis. Option a is incorrect because glycogen can absolutely be broken down through the catabolic process of glycogenolysis, which releases stored glucose into the bloodstream during fasting periods when energy is needed. Option b is incorrect because the body does possess the enzymes necessary for glycogen synthesis through the process of glycogenesis. The issue is storage capacity limitation, not an inability to synthesize glycogen. Option d is incorrect because glycogen does not provide more calories than fat. Fat provides nine calories per gram while carbohydrates including glycogen provide only four calories per gram of stored energy.

Correct Answer: Fat stores from adipose tissue

Option b is correct because after glycogen depletion during starvation, the body next mobilizes fat stores from adipose tissue, producing ketone bodies for energy before eventually resorting to muscle protein as last resort. Option a is incorrect because water reserves are not a fuel source that provides metabolic energy through any biochemical pathway. Water supports physiological functions but cannot be converted into ATP or glucose for energy. Option c is incorrect because minerals stored in bone tissue serve structural and electrolyte functions but are not mobilized as a fuel source during starvation. The body does not metabolize minerals to produce ATP. Option d is incorrect because vitamins stored in the liver serve as cofactors for metabolic reactions but are not themselves a fuel source. The body cannot metabolize vitamins to produce ATP or glucose for energy.

Correct Answer: Lipogenesis

Option d is correct because lipogenesis is the specific anabolic process that converts excess glucose into triglyceride fat molecules through acetyl-CoA, storing them in adipose tissue when caloric intake exceeds expenditure. Option a is incorrect because glycogenolysis is a catabolic process that breaks down stored glycogen to release glucose into the bloodstream. It releases stored energy rather than converting excess glucose into fat. Option b is incorrect because gluconeogenesis is the metabolic pathway that synthesizes new glucose molecules from non-sugar precursors during fasting. It creates glucose rather than converting excess glucose into stored fat. Option c is incorrect because beta-oxidation is the catabolic process that breaks down fatty acids into acetyl-CoA units within the mitochondria for energy production. It breaks fat down rather than building it up.

Correct Answer: Oxygen

Option a is correct because oxygen is the specific molecule required for cellular respiration to fully convert glucose into ATP energy. The process consumes oxygen and produces carbon dioxide as its metabolic waste product. Option b is incorrect because nitrogen gas makes up most of the atmosphere but is not directly used in cellular respiration for ATP production. The body does not metabolize nitrogen to generate usable cellular energy. Option c is incorrect because carbon monoxide is a toxic gas that binds to hemoglobin and interferes with oxygen transport. It is not used in cellular respiration and is harmful to the body when inhaled. Option d is incorrect because while hydrogen atoms are involved in electron transport chain reactions within mitochondria, molecular hydrogen gas is not the substance consumed from inhaled air during cellular respiration.