During which phase of the cell cycle does the centrosome duplicate?
A. G1 phase
B. M phase
C. S phase
D. G2 phase
Answer: Option C
Solution (By JKSSB Mock Tests)
The centrosome, which contains two centrioles, duplicates during the S phase of the cell cycle, concurrent with DNA replication. This ensures that by the time the cell enters mitosis, it has two fully formed centrosomes to organize the mitotic spindle. G1 is for growth, G2 is for preparation for M phase, and M phase is for actual division.
Explanation:
GIP (glucose-dependent insulinotropic peptide) is released from the small intestine in response to fat and glucose, inhibiting gastric secretion and motility. Gastrin stimulates acid secretion, secretin stimulates bicarbonate, CCK stimulates gallbladder contraction.
Explanation:
Innate (natural) immunity is non-specific, present at birth, and provides the first line of defense. It includes physical barriers (skin), phagocytes, and chemical defenses. Adaptive immunity is acquired and specific.
Explanation:
Ribosomes are the molecular machines where mRNA is translated into a polypeptide chain (protein). They consist of two subunits (large and small) and are found free in the cytoplasm or attached to rough ER. The nucleus stores genetic information, Golgi modifies and packages proteins, mitochondria produce ATP. Thus, protein synthesis occurs at ribosomes.
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