The diagram shows a bacterial cell. Which cell structure is useful in genetic modification?
▶️ Answer/Explanation
Ans: D
The plasmid (D) is the key structure used in genetic modification of bacteria. Plasmids are small, circular DNA molecules separate from chromosomal DNA that can be easily extracted and modified to carry foreign genes.
Other structures shown have different functions: the cell wall (A) provides support, the flagellum (B) enables movement, and chromosomal DNA (C) contains essential genes. Only plasmids are routinely used as vectors in genetic engineering.
In genetic modification, scientists insert desired genes into plasmids, which are then introduced into bacterial cells for replication and protein production.
Lignin is used to make a sustainable resource known as bioplastic. Why is bioplastic a sustainable resource?
A) Lignin can be produced as rapidly as it is removed from the environment.
B) Lignin is found in xylem tissue.
C) Lignin is strong.
D) Lignin is waterproof.
▶️ Answer/Explanation
Ans: A
Bioplastics are considered sustainable when their raw materials are renewable. Lignin meets this criterion because it is a plant-derived polymer that can be replenished at the rate it is used (A), unlike petroleum-based plastics.
While lignin’s presence in xylem (B), strength (C), and waterproofing (D) are properties, they do not address sustainability. The key factor is its renewability, making A the correct answer.