Podcast
Questions and Answers
Match the following vitamins with their coenzyme forms:
Match the following vitamins with their coenzyme forms:
Riboflavin = FAD and FMN Niacin = NAD and NADP Thiamin = TPP Vitamin B12 = Deoxyadenosylcobalamin
Match the following vitamins with their essential functions:
Match the following vitamins with their essential functions:
Riboflavin = Important for many enzyme systems Niacin = Normal functioning of skin, intestinal tract and nervous system Thiamin = Carbohydrate metabolism Vitamin B6 = Amino acid metabolism
Match the following vitamin deficiencies with their effects:
Match the following vitamin deficiencies with their effects:
Riboflavin = Cracks at the corners of the mouth, red and swollen tongue Niacin = Pellagra, disease of the three Ds Thiamin = Beriberi Vitamin B12 = Pernicious anemia
Match the following food sources with the corresponding vitamins:
Match the following food sources with the corresponding vitamins:
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Match the following terms with their descriptions:
Match the following terms with their descriptions:
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Match the following vitamin deficiencies with their symptoms:
Match the following vitamin deficiencies with their symptoms:
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Match the following vitamins with their importance in enzyme reactions:
Match the following vitamins with their importance in enzyme reactions:
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Match the following vitamins with their food sources:
Match the following vitamins with their food sources:
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Match the following vitamin deficiencies with their effects on the skin:
Match the following vitamin deficiencies with their effects on the skin:
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Match the following vitamins with their effects on the nervous system:
Match the following vitamins with their effects on the nervous system:
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Study Notes
Thiamine (Vitamin B1)
- Functions as a co-enzyme for carboxylase enzymes, facilitating several key reactions in metabolism.
- Involved in the decarboxylation of pyruvic acid and other keto acids.
- Catalyzes the oxidative decarboxylation of α-ketoglutarate to succinate and the oxidation of pyruvate to acetyl CoA.
- Operates in its active form as thiamine pyrophosphate (TPP).
- Essential for the enzyme transketolase in red blood cells, helping transfer two-carbon units from 2-keto sugars to aldoses.
Thiamine Deficiency
- Leads to the condition known as beriberi, which has two forms: Wet and Dry beriberi.
- Early symptoms include anorexia, dyspepsia, leg heaviness and weakness, calf muscle tenderness, and numbness or pins and needles in the legs.
- In infants, thiamine deficiency can cause infantile beriberi.
Thiamine Sources and Requirements
- Main dietary sources include whole grains.
- Daily requirement is 0.5 mg of thiamine per 1000 kcal of caloric intake.
- Additional requirements during pregnancy include an extra 0.2 mg/day; during lactation, 0.5 mg/day is needed.
Riboflavin (Vitamin B2)
- Vital for maintaining skin and eye health.
- Plays an essential role in normal metabolic processes.
Vitamins Overview
- Vitamins are organic compounds needed in small amounts for proper growth and functioning in humans and some animals.
- The term “vitamin” originated from thiamine, initially termed "vital amine" to prevent beriberi, associated with diets reliant on white rice.
- Unlike macronutrients, vitamins do not provide energy directly but assist enzymes in the energy release from carbohydrates, fats, and proteins.
Bioavailability of Vitamins
- The effectiveness of vitamins from food depends on their quantity and how well they are absorbed and utilized by the body.
- Factors influencing bioavailability include efficiency of digestion, prior nutrient intake, concurrent food intake, food preparation methods (raw or cooked), and whether the nutrient is natural or synthetic.
Precursors of Vitamins
- Some vitamins are ingested in inactive forms called precursors or provitamins, which are converted into their active forms within the body.
Fat-Soluble Vitamins
- Includes vitamins A, D, E, and K, which are found in fats and oils.
- These vitamins are absorbed similarly to lipids and are stored in the liver and fatty tissues until needed, not readily excreted.
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Description
Test your knowledge on the functions of thiamine as a coenzyme in various reactions, including decarboxylation and oxidation, and the effects of its deficiency. Learn about its role in enzymes such as transketolase and carboxylase.
