In the process of photosynthesis, the splitting of water molecules is associated with:
A. Photosystem II
B. NADP reductase
C. Photosystem I
D. Cytochrome b6f complex
Answer: Option A
Solution (By JKSSB Mock Tests)
Photolysis of water occurs at the manganese cluster of photosystem II, releasing electrons, protons, and oxygen. The electrons replace those lost by P680. Photosystem I reduces NADP⁺. Cytochrome b6f transports electrons between the two photosystems. Thus, water splitting is a hallmark of PSII.
Explanation:
Mycoplasma is a genus of bacteria that naturally lack a cell wall; they are the smallest known free-living organisms. Their membrane contains sterols providing some rigidity. Other bacteria typically have peptidoglycan cell walls. Fungi have chitinous walls, plant cells have cellulose walls. The absence of cell wall makes Mycoplasma pleomorphic and resistant to antibiotics targeting cell wall synthesis like penicillin.
Explanation:
Lymphatic vessels collect interstitial fluid (lymph) and return it to the venous circulation (subclavian veins). This maintains fluid balance. Along the way, lymph nodes filter pathogens. The heart pumps blood, kidneys filter blood, lungs exchange gases. The lymphatic system is unidirectional.
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