Vitamins Part 1 Quiz and Flashcards

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Questions and Answers

Which of the following is NOT a form of vitamin A?

Retinol

Cholecalciferol (correct)

Retinoic acid

Retinal

What is the primary cause of Bitot's spots?

Softening of the cornea

Impaired night vision

Perforation of the cornea

Keratinization of the conjunctiva and cornea (correct)

How does vitamin D affect calcium and phosphorus levels in the body?

Vitamin D promotes the mobilization of calcium and phosphate from the bone. (correct)

Vitamin D has no effect on calcium and phosphorus levels in the body.

Vitamin D decreases the reabsorption of calcium and phosphorus in the kidney.

Vitamin D decreases the absorption of calcium and phosphorus in the intestine.

Why is vitamin D referred to as a hormone?

Vitamin D is involved in the regulation of calcium and phosphorus metabolism. Signup and view all the answers

Which of the following is a toxic manifestation of excessive vitamin D intake?

Calcium deposition in the heart, arteries, and kidneys Signup and view all the answers

What is the primary function of vitamin D in the body?

All of the above Signup and view all the answers

Which of the following is a cause of vitamin D deficiency?

All of the above Signup and view all the answers

What is the primary cause of keratomalacia?

Softening of the cornea Signup and view all the answers

Which of the following statements about vitamins is true?

Vitamins cannot be synthesized in our bodies except for vitamin D and niacin. Signup and view all the answers

What are provitamins?

Precursors of vitamins that are converted into vitamins inside the body. Signup and view all the answers

Which of the following is an example of a vitamer?

Carotenes Signup and view all the answers

What role do vitamins play as enzyme cofactors?

Help enzymes in their work as catalysts in metabolism. Signup and view all the answers

How do vitamins differ from carbohydrates and lipids in terms of energy provision?

Vitamins do not contribute to energy metabolism. Signup and view all the answers

What distinguishes vitamins from hormones?

Vitamins are produced within the organism. Signup and view all the answers

Which characteristic describes vitamins accurately?

Essential for metabolism. Signup and view all the answers

Why do vitamins not enter tissue structures?

Due to their large molecular size. Signup and view all the answers

What is a distinguishing feature of the synthesis of the discussed vitamin compared to classical vitamins?

It is synthesized inside the body Signup and view all the answers

What is the average half-life of the discussed vitamin?

8 hours Signup and view all the answers

How does the discussed vitamin regulate its own action when not required?

It converts into an inactive metabolite Signup and view all the answers

Which type of receptor does the discussed vitamin bind to before entering the nucleus to control gene regions?

Cytosolic receptor Signup and view all the answers

Why does a person with chronic liver disease suffer from manifestations of vitamin D deficiency?

Impaired 25-α-hydroxylation Signup and view all the answers

What are the different forms of vitamin K mentioned in the text?

(K1), (K2) and (K3) Signup and view all the answers

What is the recommended daily allowance (RDA) of vitamin K according to the text?

70–140 µg Signup and view all the answers

How does a deficiency of vitamin C differ from a deficiency of vitamin K according to the text?

Increased bleeding time in vitamin C deficiency Signup and view all the answers

Study Notes

Vitamin A

Bitot's spots are caused by a primary deficiency of vitamin A
Keratomalacia is caused by a severe deficiency of vitamin A

Vitamin D

Vitamin D affects calcium and phosphorus levels in the body by regulating their absorption and utilization
Vitamin D is referred to as a hormone because it is produced in the body and has a specific biological function
A toxic manifestation of excessive vitamin D intake is hypercalcemia
The primary function of vitamin D in the body is to regulate calcium homeostasis
Causes of vitamin D deficiency include limited sun exposure, dark skin, and kidney or liver disease

Vitamins in General

Provitamins are inactive forms of vitamins that can be converted to active forms in the body
Vitamers are different forms of a vitamin that have similar biological activity
Vitamins play a role as enzyme cofactors, helping to facilitate chemical reactions in the body
Vitamins differ from carbohydrates and lipids in that they do not provide energy
Vitamins are distinguished from hormones in that they are not produced by specific glands and do not have specific targets
A characteristic that describes vitamins accurately is that they are organic compounds required in small quantities for various physiological functions
Vitamins do not enter tissue structures because they are not building blocks of tissues

Specific Vitamin (not specified which one)

A distinguishing feature of the synthesis of this vitamin is that it differs from classical vitamins
The average half-life of this vitamin is not specified
This vitamin regulates its own action when not required by degrading its receptor
This vitamin binds to a nuclear receptor before entering the nucleus to control gene regions

Vitamin K

A person with chronic liver disease suffers from manifestations of vitamin D deficiency because the liver is necessary for vitamin D activation
The different forms of vitamin K mentioned in the text are not specified
The recommended daily allowance (RDA) of vitamin K according to the text is not specified
A deficiency of vitamin C differs from a deficiency of vitamin K in that vitamin C deficiency causes scurvy, while vitamin K deficiency causes bleeding disorders

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Description

Explore the importance of vitamins as essential organic compounds required by the body for growth and health. Learn about provitamins, which are precursors converted into vitamins, and vitamers, which are different forms of a vitamin. Dive into the biochemical functions of vitamins.