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biology

Gac

Gac is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Gac rather than just read about it. In short: Gac, from the Vietnamese gấc (pronounced [ɣək˦˥]), scientific name Momordica cochinchinensis, is a species of plant in the melon and cucumber family Cucurbitaceae native to countries throughout Southeast Asia and to Queensland, Australia. It is notable for its vivid orange-reddish color resulting from a mix of beta-carotene and lycopene.

Gac — main illustration
Gac — illustration

Key takeaways

  • Gac belongs to biology; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Gac to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Gac from memory before moving on to harder problems.

Reference excerpt

Gac, from the Vietnamese gấc (pronounced [ɣək˦˥]), scientific name Momordica cochinchinensis, is a species of plant in the melon and cucumber family Cucurbitaceae native to countries throughout Southeast Asia and to Queensland, Australia. It is notable for its vivid orange-reddish color resulting from a mix of beta-carotene and lycopene.

Description Momordica cochinchinensis is a perennial tendril climber that may reach up to 15 metres (50 feet) long and a stem diameter up to four centimetres (1+1⁄2 inches). The palmate leaves have 3 to 5 lobes and are carried on a petiole (leaf stem) measuring 6–10 cm (2+1⁄2–4 in) long. They are arranged alternately on the stems and measure up to 20 cm (8 in) wide and long. This species is dioecious, meaning that male and female flowers are borne on separate plants. The inflorescence on a male plant consists of either a solitary flower or a raceme up to 10 cm (4 in) long, while female flowers are solitary. All flower buds are fully enclosed by bracts, which split open as the flower matures. The mature flowers have five yellowish petals and a black centre. The fruit are ovoid to broadly ellipsoid, about 15 cm (6 in) long by 10 cm (4 in) diameter, and are covered with numerous small spines on the skin. They are initially green but turn a deep orange/red at maturity, and they contain numerous irregularly-shaped brown or grey seeds, which are enclosed in a bright red aril.

Phenology In the northern hemisphere this species flowers from June to August and fruit appear around August to October. In Australia, flowering occurs from December to January and fruit appear from February to April.

Phytochemistry The fruit, seeds, and seed oil contain substantial amounts of beta-carotene and lycopene, which collectively impart the characteristic red-orange color to the fruit's tissues. Both aril and seeds are rich in monounsaturated and polyunsaturated fatty acids, with oil containing 69% unsaturated fats, including 35% as polyunsaturated fats. Gac has a high concentration of linoleic acid (omega-6) and omega-3 fatty acids.

Taxonomy This species was first described in 1790 by the Portuguese botanist João de Loureiro, who published it in his book Flora cochinchinensis. Loureiro gave this plant the combination Muricia cochinchinensis and noted that it was found in "Cochinchinâ, & Chinâ." In 1826 the German botanist Kurt Polycarp Joachim Sprengel transferred the species to the genus Momordica.

Etymology The genus name Momordica is derived from the Latin word mordeo meaning to bite, a reference to the seeds' appearance as though chewed. The species epithet cochinchinensis means "from Cochinchina", the region in the southern part of Vietnam where the plant was first observed by Loureiro.

Common names As this plant is native to many countries throughout the Asia-Pacific region, it has a diverse number of common names including: bhat kerala (Assamese), mu bie gua, mu bie zi and teng tong (Chinese), balsam pear, Chinese cucumber, and giant spiny gourd (English), kakur, kantola and kakrol (Hindi), tepurang (Indonesian), mokube tsushi (Japanese), makkao (Khmer), khaawz (Laotian), pupia, teruah and torobuk (Malay), jhuse karelaa (Nepalese), pakurebu (Sulawesi), buyok buyok (Tagalog), phak khao (Thai), and gac (Vietnamese).

Cultivation As gac plant is dioecious, both male and female plants are needed; hence, farmers must have at least one corresponding male plant growing in or around the gardens for the fruit-bearing female plants to be pollinated. When grown from seed, the ratio of male to female plants is unpredictable. Pollination may be facilitated by insects, but hand pollination allows for better fruit yield. An alternative method is to graft female material onto the main shoot of a male plant. For maximum insect-aided pollination, the recommended ratio is about 1 male for every 10 female plants. If propagating from vines, farmers make diagonal cut (around 15–20 cm or 6–8 in long and 3–6 mm or 1⁄8–1⁄4 in wide), then root the tubers in water or well-aerated, moist potting media before planting. Apart from Southeast Asian countries where the fruits are native, gac can be grown in sub-tropical climate regions. Cool temperatures inhibit growth.

Uses Gac has been commonly used in its native countries, mainly as food and traditional medicine. Its use as a folk medicine dates back over centuries in China and Vietnam. Gac seeds, known as mù biē zǐ (meaning 'wooden turtle seed'), are used for a variety of internal and topical purposes in traditional medicine. The aril surrounding gac seeds when the fruits are ripe is cooked with sticky rice to make xôi gac, a traditional Vietnamese dish with a striking red color that is served during Tết (Lunar New Year), as well as other special occasions. In Sri Lanka, gac is used in curry, and in Thailand, it is served with ice cream. Additionally, the unripe green fruit is eaten in some parts of India and the Philippines. The spiny skin is removed and the fruits are sliced and cooked sometimes with potato or bottle gourd. In the Philippines, it is particularly common in the far northern province of Ilocos Norte, where it is called by several names: sugod-sugod, parog-parog, and libas. There, the unripe fruits are commonly added as a vegetable in dinengdeng, pinakbet, and, alongside its young shoots blanched, ginisa. Due to the high contents of beta-carotene and lycopene, extracts from the fruit's arils are used to manufacture dietary supplements or are sometimes mixed into food and drink as a food dye.

Gallery

References

External links Media related to Momordica cochinchinensis at Wikimedia Commons

Illustrations

Gac illustration
Gac illustration
Gac illustration
Gac illustration
Gac illustration

Worked examples

Example 1 — a first encounter with Gac

Start with the simplest possible case. Write down what Gac claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Gac before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Gac ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Gac

In research
Gac appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Gac in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Gac is common in secondary-school and first-year university syllabi. It links to neighbouring topics Dietary supplements, Dioecious plants, Edible fruits, so understanding it makes those chapters shorter.
In everyday life
Look for Gac outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Gac in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Gac means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Gac out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Gac in simple terms?

Gac, from the Vietnamese gấc (pronounced [ɣək˦˥]), scientific name Momordica cochinchinensis, is a species of plant in the melon and cucumber family Cucurbitaceae native to countries throughout Southeast Asia and to Queensland, Australia. It is notable for its vivid orange-reddish color resulting f…

Why does Gac matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Gac?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Gac.

Tags

  • Dietary supplements
  • Dioecious plants
  • Edible fruits
  • Flora of China
  • Flora of Queensland
  • Flora of tropical Asia
  • Medicinal plants of Asia
  • Medicinal plants of Oceania
  • Momordica
  • Plants described in 1790
  • Plants used in traditional Chinese medicine
  • Taxa named by João de Loureiro

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