1.
what two forms are vitamin A found in
Correct Answer
D. A & B
Explanation
Vitamin A is found in two forms: preformed vitamin A and provitamin A. Preformed vitamin A is also known as retinol and is found in animal sources such as liver, eggs, and dairy products. Provitamin A, on the other hand, is found in plant-based sources such as fruits and vegetables. Provitamin A compounds, like beta-carotene, can be converted into retinol by the body. Therefore, both preformed vitamin A and provitamin A contribute to the overall vitamin A intake.
2.
Provitamin A is found in
Correct Answer
B. Plant foods
Explanation
Provitamin A is found in plant foods. Provitamin A refers to compounds that can be converted into vitamin A by the body. Plant foods such as carrots, sweet potatoes, spinach, and kale are rich sources of provitamin A. Animal origin foods, on the other hand, do not contain provitamin A. Hence, the correct answer is plant foods.
3.
What are the three forms of vitamin A found in the body, mark all that apply
Correct Answer(s)
A. Retinal
B. Retinol
D. Retinoic acid
Explanation
Retinal, Retinol, and Retinoic acid are the three forms of vitamin A found in the body. Retinal is involved in the visual cycle and is necessary for vision. Retinol is the storage form of vitamin A and is converted to retinal in the body. Retinoic acid is involved in gene expression and cell differentiation. Retone and Retane are not forms of vitamin A found in the body.
4.
Which of these forms is involved in regulating growth and embryonic development
Correct Answer
A. Retinoic acid
Explanation
Retinoic acid is involved in regulating growth and embryonic development. It is a biologically active form of vitamin A that acts as a signaling molecule in various biological processes, including cell differentiation, proliferation, and morphogenesis. Retinoic acid binds to specific receptors in the nucleus of target cells, regulating the expression of genes involved in growth and development. Retinol and retinal are other forms of vitamin A, but they are not directly involved in the regulation of growth and embryonic development like retinoic acid.
5.
Which form is important for vision,
Correct Answer
B. Retinal
Explanation
Retinal is the correct answer because it is a form of vitamin A that is essential for vision. It is converted from retinol in the retina of the eye and plays a crucial role in the process of light detection and signal transmission to the brain. Retinal combines with proteins in the retina to form visual pigments, which are responsible for absorbing light and initiating the visual process. Without sufficient retinal, the visual system would not function properly, leading to vision problems.
6.
Which form is the major storage and transport form of vitamin A
Correct Answer
B. Retinol
Explanation
Retinol is the major storage and transport form of vitamin A. It is a preformed, active form of vitamin A that is found in animal-based foods. Retinol is converted to retinal and retinoic acid in the body, which are important for vision, growth, and development. Retinol is stored in the liver and released into the bloodstream when needed, making it the primary form of vitamin A used for storage and transportation in the body.
7.
What is needed to convert retinol to retinoic acid
Correct Answer
B. Rentinal is the intermediate in the conversion
Explanation
Retinol needs to be converted to retinoic acid in order to be utilized by the body. This conversion occurs in multiple steps, and one of the intermediates in this process is rentinal. Rentinal acts as a crucial molecule in the conversion of retinol to retinoic acid. However, the exact mechanism of this conversion requires the presence of an enzyme, which is not mentioned in the given options but is necessary for the conversion to take place.
8.
Is the conversion of retinol to retinal a reversible reaction
Correct Answer
A. Yes
Explanation
The conversion of retinol to retinal is a reversible reaction because it can occur in both directions. Retinol can be converted to retinal, and retinal can be converted back to retinol. This means that the reaction can proceed in either direction depending on the conditions and the availability of the necessary enzymes and cofactors.
9.
Where is most of vitamin A stored in the body
Correct Answer
A. The liver
Explanation
Vitamin A is mainly stored in the liver. The liver plays a crucial role in the metabolism of vitamin A, as it is responsible for storing and releasing it as needed by the body. This organ acts as a reservoir for vitamin A, ensuring a steady supply for various physiological functions. The liver's ability to store vitamin A allows the body to maintain adequate levels of this essential nutrient, which is important for vision, immune function, and cell growth and differentiation.
10.
80-90% of CQ10 in the liver is stored in which cells
Correct Answer
B. Stellate cells
11.
There is enough supply of vitamin A in the liver to last for
Correct Answer
C. Several months
Explanation
The liver is known to store vitamin A, which can be utilized by the body as needed. Since the question states that there is enough supply of vitamin A in the liver, it suggests that the liver has a significant storage capacity for this vitamin. Therefore, it can be inferred that the supply of vitamin A in the liver can last for several months before it is depleted.
12.
What is needed to hydrolyse retinyl esters in the small intesting to release retinol
Correct Answer
B. Pancreatic lipase
Explanation
Pancreatic lipase is needed to hydrolyze retinyl esters in the small intestine to release retinol. Lipases are enzymes that break down lipids, and pancreatic lipase specifically acts on triglycerides, which include retinyl esters. Therefore, pancreatic lipase is responsible for breaking down retinyl esters into retinol, allowing for its absorption and utilization in the body. HCI and salivary lipase are not directly involved in the hydrolysis of retinyl esters.
13.
How does rentinol travel to the liver
Correct Answer
B. In chylomicrons
Explanation
Retinol, a form of vitamin A, travels to the liver via lymph in chylomicrons. Chylomicrons are large lipoprotein particles that are formed in the small intestine after the absorption of dietary fats. These chylomicrons carry retinol along with other lipids and fat-soluble vitamins through the lymphatic system, eventually reaching the liver where they are metabolized and utilized.
14.
Thyroxine increases Vitamin A absorption
Correct Answer
A. True
Explanation
Thyroxine is a hormone produced by the thyroid gland that plays a crucial role in regulating metabolism. It has been found that thyroxine increases the absorption of Vitamin A in the body. Vitamin A is an essential nutrient that is important for maintaining healthy vision, immune function, and cell growth. Therefore, it is true that thyroxine increases Vitamin A absorption.
15.
For retinol to be transported from the liver to other tissues it needs Rentinol binding proteins
Correct Answer
A. True
Explanation
Retinol is a form of vitamin A that is stored in the liver. In order for retinol to be transported from the liver to other tissues in the body, it needs to bind to specific proteins called Retinol binding proteins (RBP). These proteins act as carriers, allowing retinol to be transported through the bloodstream to where it is needed. Therefore, the statement that retinol requires Retinol binding proteins for transportation is true.
16.
What helps to absorb preformed Vitamin A, mark all that apply
Correct Answer(s)
A. Bile
B. Fat
C. Pancreatic secretions
Explanation
Bile, fat, and pancreatic secretions all help to absorb preformed Vitamin A. Bile is produced by the liver and stored in the gallbladder, and it aids in the digestion and absorption of fats, including fat-soluble vitamins like Vitamin A. Fat is necessary for the absorption of fat-soluble vitamins, as they require the presence of dietary fat to be absorbed into the bloodstream. Pancreatic secretions, which include enzymes like lipase, also play a role in breaking down and absorbing fats. HCI, or hydrochloric acid, is not involved in the absorption of preformed Vitamin A.
17.
Retinol binding protein is dependant upon which mineral for its production
Correct Answer
C. Zinc
Explanation
Retinol binding protein is dependent on zinc for its production. Zinc is an essential mineral that plays a crucial role in various biological processes, including protein synthesis. In this case, zinc is required for the synthesis of retinol binding protein, which is responsible for transporting vitamin A in the blood. Without sufficient zinc, the production of retinol binding protein may be impaired, leading to potential deficiencies in vitamin A transport and metabolism.
18.
Vitamin A is excreted in which ways, mark all that apply
Correct Answer
D. All of the above
Explanation
Vitamin A is a fat-soluble vitamin that is stored in the body's tissues. It can be excreted through various ways, including as carbon dioxide when it is metabolized, in urine as a waste product, and in feces through the body's digestive system. Therefore, all of the given options are correct as they represent different routes through which vitamin A can be excreted from the body.
19.
50% of Vitamin A is kept in the body as stored primarily in ___
Correct Answer
B. The liver
Explanation
Vitamin A is primarily stored in the liver. The liver plays a crucial role in the metabolism and storage of various nutrients, including fat-soluble vitamins like Vitamin A. It acts as a reservoir for Vitamin A, storing it until the body needs it. The liver also helps in the conversion of Vitamin A into its active forms, which are essential for various physiological functions. Therefore, the liver is the main site of storage for Vitamin A in the body.
20.
Protein is important to carotenoids being converted to vitamin A
Correct Answer
A. True
Explanation
Protein is important for the conversion of carotenoids into vitamin A. This is because carotenoids, which are plant pigments, need to be broken down and metabolized in order to be converted into vitamin A. Protein plays a crucial role in this process by providing the necessary enzymes and co-factors needed for the conversion to occur. Without sufficient protein, the conversion of carotenoids to vitamin A may be impaired, leading to a deficiency in this essential nutrient. Therefore, it is true that protein is important for carotenoids to be converted to vitamin A.
21.
Vitamin A is required for the absorption, storage and metabolism of which mineral
Correct Answer
B. Iron
Explanation
Vitamin A is required for the absorption, storage, and metabolism of iron. Iron is an essential mineral that plays a crucial role in various bodily functions, including oxygen transport, energy production, and immune system function. Vitamin A helps in the absorption of iron from the diet and its storage in the body. It also aids in the metabolism of iron, ensuring that it is utilized effectively by the body. Therefore, the correct answer is Iron.
22.
What other vitamin protects vitamin A from oxidation in the gut, at storages sites and during transport
Correct Answer
A. Vitamin E
Explanation
Vitamin E is the correct answer because it acts as an antioxidant and protects vitamin A from oxidation. Oxidation can occur in the gut, storage sites, and during transport. Vitamin E helps prevent the breakdown of vitamin A by neutralizing free radicals, which can cause damage to the vitamin. Therefore, vitamin E plays a crucial role in preserving the integrity and effectiveness of vitamin A in the body.
23.
Ingestion of mineral oils does what to Vitamin A
Correct Answer
B. Decreases absorption
Explanation
Ingestion of mineral oils decreases the absorption of Vitamin A. This is because mineral oils can interfere with the normal digestion and absorption processes in the body, leading to a decrease in the uptake of nutrients, including Vitamin A.
24.
An vitamin A deficiency also causes a reduction in Iron status
Correct Answer
A. True
Explanation
Vitamin A deficiency can indeed lead to a reduction in iron status. This is because vitamin A plays a crucial role in the absorption and utilization of iron in the body. Without sufficient vitamin A, iron absorption may be impaired, leading to decreased iron levels and potentially resulting in iron deficiency anemia. Therefore, it is true that a deficiency in vitamin A can cause a reduction in iron status.
25.
Vitamin A is required for the correct metabolism of which mineral
Correct Answer
C. Calcium
Explanation
Vitamin A is required for the correct metabolism of calcium. Vitamin A plays a crucial role in maintaining healthy bones and teeth, and it helps in the absorption and utilization of calcium in the body. Without sufficient vitamin A, the body may struggle to properly metabolize and utilize calcium, leading to potential deficiencies and health issues related to calcium metabolism.
26.
The pigments in the rods of the eyes, known as purple vision are called
Correct Answer
A. Rhodopsin
Explanation
Rhodopsin is the correct answer because it is the pigment found in the rods of the eyes that is responsible for purple vision. When light enters the eye, it is absorbed by rhodopsin, triggering a chemical reaction that sends signals to the brain, allowing us to see in low light conditions. Rodspin and retinal are not the correct terms for the pigments in the rods of the eyes.
27.
The Iodopsin in the cones are responsible for
Correct Answer
B. Vision in bright light
Explanation
The Iodopsin in the cones is responsible for vision in bright light. Cones are photoreceptor cells in the retina that are responsible for color vision and visual acuity. Iodopsin is the light-sensitive pigment found in cones, and it is most effective in well-lit conditions. Therefore, it enables us to see clearly and distinguish colors in bright light situations.
28.
Both pigments in the cones and rods consist of a protein called opsin and one molecule of
Correct Answer
A. Retinal
Explanation
The correct answer is Retinal because both pigments in the cones and rods consist of a protein called opsin and one molecule of retinal. Retinal is a form of vitamin A that is essential for vision. It is responsible for absorbing light and triggering a series of chemical reactions that ultimately result in the transmission of visual information to the brain. Without retinal, the cones and rods would not be able to function properly, leading to impaired vision.
29.
When light hits the pigment in the retina it causes the retina portion to change shape
Correct Answer
B. Fron cis retinal to trans retinal
Explanation
When light hits the pigment in the retina, it causes a chemical reaction in the retinal molecule. This reaction converts cis retinal to trans retinal. This change in shape of the retinal molecule triggers a series of events that ultimately leads to the generation of electrical signals, which are then transmitted to the brain for visual perception. Therefore, the correct answer is "from cis retinal to trans retinal".
30.
The light hitting the pigment in the retina also causes the pigment to lose its colour and is called
Correct Answer
B. Bleaching of the pHotopigment
Explanation
When light hits the pigment in the retina, it causes the pigment to lose its color. This process is known as bleaching of the photopigment. The term "bleaching" refers to the light-induced chemical change that occurs in the pigment molecules, causing them to become colorless. This phenomenon is an essential step in the visual process, as it allows the photoreceptor cells to respond to light stimuli and transmit visual information to the brain. Therefore, the correct answer is "bleaching of the photopigment."
31.
Can retinoic acid be converted back to retinal
Correct Answer
B. No
Explanation
Retinoic acid cannot be converted back to retinal. Retinal is the oxidized form of retinol, while retinoic acid is the oxidized form of retinal. Once retinal is oxidized to retinoic acid, it cannot be reversed or converted back to retinal. Therefore, the answer is no.
32.
If the eyes experience a flash of light, vision will not be restored until what is reformed
Correct Answer
B. Rhodopsin
Explanation
Rhodopsin is a light-sensitive protein found in the rods of the retina. When light enters the eye, it is absorbed by rhodopsin, which then undergoes a chemical reaction, triggering a signal that is sent to the brain for visual processing. This process allows us to see in low light conditions. Therefore, if the eyes experience a flash of light, vision will not be restored until rhodopsin is reformed, indicating that the chemical reaction needs to occur again for normal vision to return.
33.
If amounts of retinol in the blood are not adequate to replace the retinal lost during the visual cycle then the eyes will recover from flashes of light
Correct Answer
B. Slowly
Explanation
If the amounts of retinol in the blood are not sufficient to replace the retinal lost during the visual cycle, it means that the necessary components for vision regeneration are lacking. As a result, the eyes will take a longer time to recover from flashes of light, indicating a slow recovery process.
34.
Nyctalopia is
Correct Answer
B. Night blindness
Explanation
Nyctalopia refers to night blindness, which is the inability to see clearly in low light conditions. This condition causes difficulty in seeing in the dark or in poorly lit environments. People with night blindness may experience reduced vision, poor depth perception, and difficulty adjusting to changes in light. It is important to note that nyctalopia does not cause total blindness or trouble seeing in bright light, but specifically affects vision in low light situations.
35.
Vitamin A is necessary for the differentiation and maintenance of which cells
Correct Answer
A. Goblet & epithelial cells
Explanation
Vitamin A is necessary for the differentiation and maintenance of goblet and epithelial cells. Goblet cells are responsible for producing mucus, which helps to protect and lubricate the surfaces of various organs, such as the respiratory and digestive systems. Epithelial cells form the lining of various organs and tissues throughout the body, providing a protective barrier and facilitating absorption and secretion. Vitamin A plays a crucial role in the development and function of these cells, ensuring their proper differentiation and maintenance.
36.
In a vitamin A deficiency the mucous secreting cells are replaced by ___________ producing cells in many body tissues.
Correct Answer
B. Keratin producing cells
Explanation
In a vitamin A deficiency, the mucous secreting cells are replaced by keratin producing cells in many body tissues. This is because vitamin A is essential for the maintenance and differentiation of epithelial cells, including the mucous secreting cells. Without sufficient vitamin A, these cells cannot function properly and are replaced by keratin producing cells, which are a type of epithelial cell that produces keratin, a protein that forms the protective outer layer of the skin and other tissues.
37.
Vitamin A is important the normal growth and remodelling of
Correct Answer
B. Bone
Explanation
Vitamin A is important for the normal growth and remodelling of bone. It plays a crucial role in bone formation, maintenance, and repair. It helps in the production of osteoblasts, which are cells responsible for bone formation. Additionally, vitamin A aids in the absorption and utilization of calcium, a mineral essential for strong and healthy bones. Without sufficient vitamin A, bone growth and development can be impaired, leading to weakened bones and an increased risk of fractures.
38.
Due to its role with iron metabolism and cell differentition vitamin A is involved in the production of haemoglobin and red blood cells
Correct Answer
A. True
Explanation
Vitamin A plays a crucial role in iron metabolism, which is necessary for the production of hemoglobin and red blood cells. Hemoglobin is the protein in red blood cells that carries oxygen throughout the body. Without sufficient levels of vitamin A, iron cannot be properly utilized, leading to anemia and impaired red blood cell production. Therefore, it is true that vitamin A is involved in the production of hemoglobin and red blood cells.
39.
How long will it take a vitamin A defeiciency to show
Correct Answer
D. One to two years
Explanation
This is due to liver stores
40.
The first detectable symptom of a vitamin A deficiency is
Correct Answer
B. Night blindness
Explanation
Night blindness is the correct answer because it is a well-known symptom of vitamin A deficiency. Vitamin A is essential for the production of rhodopsin, a pigment in the retina that helps with vision in low light conditions. When there is a deficiency of vitamin A, the production of rhodopsin is impaired, leading to difficulty seeing in dim light or at night. This symptom is often one of the earliest signs of vitamin A deficiency and can progress to more severe vision problems if left untreated.
41.
Xeropthalmis is
Correct Answer
B. Abnormalities in the conjunctiva and cornea that cause progressive blindness
Explanation
Xeropthalmis refers to abnormalities in the conjunctiva and cornea that cause progressive blindness. This condition occurs when the cornea becomes dry and hard, leading to vision impairment. It is characterized by spots on the eyes and can result in the gradual loss of eyesight over time.
42.
What is hyperkeratosis
Correct Answer
B. Lumps of keratin obstruct hair follicles
Explanation
Hyperkeratosis is a condition characterized by the buildup of keratin, a protein found in the outer layer of the skin. This excess keratin can form lumps or plugs that block the hair follicles, leading to various skin issues such as rough and dry skin. Flushing of the skin is not directly associated with hyperkeratosis, making it an incorrect option.
43.
What are the three types of toxicity that exist with vitamin A
Correct Answer(s)
A. Acute
B. Chronic
D. Teratogenic
Explanation
The three types of toxicity that exist with vitamin A are acute, chronic, and teratogenic. Acute toxicity occurs when there is a sudden and severe overdose of vitamin A, leading to symptoms such as nausea, dizziness, and blurred vision. Chronic toxicity happens when there is a long-term excessive intake of vitamin A, leading to symptoms like bone pain, hair loss, and liver damage. Teratogenic toxicity refers to the harmful effects of excess vitamin A on fetal development, causing birth defects.