Assertion (A): Mitochondria are called semi-autonomous organelles. Reason (R): They possess their own DNA and ribosomes and can synthesize some proteins. MCQ with Answer and Explanation
Assertion (A): Mitochondria are called semi-autonomous organelles. Reason (R): They possess their own DNA and ribosomes and can synthesize some proteins.
A. Both A and R are true, but R is not the correct explanation.
B. A false, R true.
C. Both A and R are true, and R is the correct explanation.
D. A true, R false.
Answer: Option C
Solution (By JKSSB Mock Tests)
Mitochondria have circular DNA and 70S ribosomes, enabling them to transcribe and translate some proteins independently, hence semi-autonomous. They still depend on nuclear genes for most proteins. The reason correctly explains the assertion.
Consider the following statements about the liver:
1. It stores glycogen.
2. It secretes bile.
3. It produces insulin.
Which of the above is/are correct?
Explanation:
The lymphatic system drains excess tissue fluid (lymph) back to the venous blood. Blood circulation is the cardiovascular system; lymph nodes filter lymph; thymus is a primary lymphoid organ.
Explanation:
The BBB restricts entry of pathogens and large molecules, maintaining brain homeostasis. Tight junctions between capillary endothelial cells are the structural basis. R explains A.
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