Question

Golden rice was created by transforming rice with two beta-carotene biosynthesis genes, namely:
A) Psy and cry I genes
B) LCY-E
C) CHY-1
D) CHY-2

Answer 1

Hint: Golden rice is a variety of Oryza sativa produced from genetic engineering to biosynthesize beta-carotene, a precursor of vitamin-A, in the edible parts of rice. Malnutrition in children of developing countries leads to symptoms of vitamin A deficiency such as night blindness, anaemia, deterioration of eye tissue, and cardiovascular diseases. Due to illness, they have reduced immunity and increased morbidity and mortality rates in children.

Complete step-by-step answer:
Golden rice is also an example of bio-fortification- the creation of plants that make or accumulate micronutrients. The Rice genome lacks genes for enzymes that complete the beta-carotene pathway. These are: 1) phytoene synthase(Psy) -derived from daffodils. 2) Lycopene cyclase(crt1) – derived from soil bacteria Erwinia uredovora . Psy and crt 1 genes are transformed into rice nuclear genome and placed under the control of an endosperm specific promoter, so they are only expressed in the endosperm.
Hence the correct answer is option d.

Additional information IPP converts into Geranyl geranyl diphosphate and it converts into phytoene by the enzyme phytoene synthase. Now phytoene uses phytoene desaturase and carotene desaturase to convert into lycopene. And lycopene converts into beta carotene (vitamin A) precursor by use of the enzyme lycopene beta cyclase. Then vitamin A goes into golden rice.

Note: Advantages of golden rice: It gives more quantity of vitamin A, easy distribution, rice is a staple food in many countries, and it is a sustainable option. Disadvantages of golden rice are: it may cause allergies, genetic contamination can be there of global staple food, loss of biodiversity as it may become a weed and endanger the existence of natural rice varieties.