Consider statements about the nucleus: 1. It is bounded by a single membrane. 2. It contains the nucleolus. 3. Nuclear pores allow RNA export. Which are correct? MCQ with Answer and Explanation
Consider statements about the nucleus: 1. It is bounded by a single membrane. 2. It contains the nucleolus. 3. Nuclear pores allow RNA export. Which are correct?
A. 1, 2 and 3
B. 2 and 3 only
C. 1 and 3 only
D. 1 and 2 only
Answer: Option B
Solution (By JKSSB Mock Tests)
The nucleus is bounded by a double membrane called the nuclear envelope, not a single membrane. It houses the nucleolus, which is the site of ribosomal RNA synthesis. The nuclear envelope is perforated by nuclear pores that regulate the bidirectional transport of molecules, including the export of mRNA to the cytoplasm. Thus, statements 2 and 3 are correct.
Explanation:
Acetobacter aceti oxidizes ethanol to acetic acid under aerobic conditions, used in vinegar production. Lactobacillus produces lactic acid, Streptomyces produces antibiotics, E. coli is used in genetic engineering but not vinegar.
Explanation:
Riboflavin is vitamin B₂, a component of coenzymes FAD and FMN involved in redox reactions. Thiamine is B₁, niacin is B₃, pyridoxine is B₆. Riboflavin deficiency causes angular stomatitis.
Explanation:
The jejunum, with its long villi and microvilli, is the primary site for absorption of digested nutrients. The ileum also absorbs vitamin B₁₂ and bile salts.
No comments yet. Be the first to start the discussion!