The disease caused by the variant Creutzfeldt-Jakob disease is linked to: MCQ with Answer and Explanation

Explanation:
Mitochondria are double-membrane organelles with circular DNA (like prokaryotes) and 70S ribosomes, supporting the endosymbiotic origin. They are absent in prokaryotes. They are the site of aerobic respiration. The matrix contains enzymes for Krebs cycle. The inner membrane forms cristae, housing electron transport chain and ATP synthase.

Explanation:
Photosynthesis consists of light-dependent reactions occurring in the thylakoid membranes (grana) where water is split, releasing oxygen, and light-independent reactions (Calvin cycle) occurring in the stroma where CO2 is fixed. The oxygen released during photosynthesis comes from the photolysis of water, not from carbon dioxide. Thus, statements 1 and 2 are correct.

Explanation:
pUC19 is a small, high-copy-number cloning vector. A crucial feature for selecting recombinant clones is the presence of the lacZ' gene, which codes for the alpha-peptide of beta-galactosidase. The multiple cloning site (MCS) is located within this lacZ' gene. When foreign DNA is inserted into the MCS, it disrupts the lacZ' gene (insertional inactivation). On media containing X-gal and IPTG, colonies with empty vectors turn blue, while colonies with recombinant plasmids (disrupted lacZ') remain white, allowing easy visual selection.