Bt cotton is a genetically modified crop that contains a gene from: MCQ with Answer and Explanation

Bt cotton is a genetically modified crop that contains a gene from:
A. Agrobacterium tumefaciens
B. Bacillus thuringiensis
C. Escherichia coli
D. Pseudomonas fluorescens
Answer: Option B
Solution (By JKSSB Mock Tests)
Bt cotton is a transgenic crop developed by inserting cry genes (e.g., cryIAc, cryIIAb) from the soil bacterium Bacillus thuringiensis (Bt). These genes code for crystal proteins (Cry proteins) that are toxic to certain insect pests, particularly the cotton bollworm. When the insect ingests the protein, it is activated in its alkaline gut, creating pores in the gut lining, leading to the insect's death.

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Practice More Biology Questions

Question #1
Consider statements about plant reproduction: 1. Pollination is the transfer of pollen to the stigma. 2. Double fertilization is unique to gymnosperms. 3. Seeds develop from ovules. Which are correct?
A. 1 and 2 only
B. 1 and 3 only
C. 1, 2 and 3
D. 2 and 3 only

Correct Answer: Option B


Explanation:
Pollination is the mechanism of transferring pollen grains from the anther to the stigma of a flower. After fertilization, the ovule develops into a seed and the ovary into a fruit. Double fertilization, involving syngamy and triple fusion, is a unique characteristic of angiosperms, not gymnosperms. Therefore, statements 1 and 3 are correct.

This question belongs to: Science Biology
Question #2
The condition caused by vitamin D deficiency in adults is:
A. Rickets
B. Scurvy
C. Kwashiorkor
D. Osteomalacia

Correct Answer: Option D


Explanation:
Osteomalacia is softening of bones in adults due to vitamin D deficiency, leading to bone pain and muscle weakness. Rickets is the childhood equivalent, affecting growth plates. Scurvy is vitamin C deficiency, kwashiorkor is protein deficiency. Vitamin D is essential for calcium absorption and bone mineralization.

This question belongs to: Science Biology
Question #3
The pigment that is the primary electron donor in photosystem I is:
A. Chlorophyll b
B. P700
C. P680
D. Carotenoid

Correct Answer: Option B


Explanation:
P700 is the reaction center chlorophyll a of photosystem I, absorbing light at 700 nm. It donates electrons to ferredoxin. P680 is the reaction center of PSII. Chlorophyll b and carotenoids are accessory pigments. The two photosystems work in series to transfer electrons from water to NADP⁺.

This question belongs to: Science Biology