what are the other sources of the first vitamin?
Carrots
Vitamin A
All forms of vitamin A have a beta-ionone ring to which an isoprenoid chain is attached, called a "retinyl group". Both structural features are essential for vitamin activity. The orange pigment of carrots (beta-carotene) can be represented as two connected retinyl groups, which are used in the body to contribute to vitamin A levels. Alpha-carotene and gamma-carotene also have a single retinyl group, which give them some vitamin activity. None of the other carotenes have vitamin activity. The carotenoid beta-cryptoxanthin possesses an ionone group and has vitamin activity in humans.
what is metabolism? The set of life-sustaining chemical reactions in organisms. what are the key biochemicals? Amino acids, carbohydrates, nucleic acid and lipids how is the name of the second one formed? Carbon + hydrogen + oxygen (usually with a hydrogen–oxygen atom ratio of 2:1 as in water) can you tell me about its structure? A typical monosaccharide has the structure H–(CHOH)(C=O)–(CHOH)–H how is the aforementioned structure cyclised? The open-chain form of a monosaccharide often coexists with a closed ring form where the aldehyde/ketone carbonyl group carbon (C=O) and hydroxyl group (–OH) react forming a hemiacetal with a new C–O–C bridge. what can you tell me about the fourth biochemical mentioned above? Often called fats, they are hydrophobic biological molecules but will dissolve in organic solvents such as alcohol, benzene. what is its role in our health? To  facilitate absorption of fat-soluble vitamins A, D, E, K and carotenoids;
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Vitamin A [SEP] Introduction
In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to retinol (chemically an alcohol) in the small intestine. The retinol form functions as a storage form of the vitamin, and can be converted to and from its visually active aldehyde form, retinal. All forms of vitamin A have a beta-ionone ring to which an isoprenoid chain is attached, called a "retinyl group". Both structural features are essential for vitamin activity. The orange pigment of carrots (beta-carotene) can be represented as two connected retinyl groups, which are used in the body to contribute to vitamin A levels.