Which of the following is a correct statement about prokaryotic DNA?
A. It is enclosed within a nuclear membrane.
B. It is circular and located in the nucleoid region.
C. It consists of multiple linear chromosomes.
D. It is linear and associated with histones.
Answer: Option B
Solution (By JKSSB Mock Tests)
Prokaryotic DNA is typically circular, double-stranded, and found in a nucleoid region without a nuclear membrane. It is not associated with histones (though some Archaea have histone-like proteins). Plasmids are extra-chromosomal DNA. Eukaryotic DNA is linear and complexed with histones. This difference is fundamental in cell classification.
Explanation:
Oxytocin, released from the posterior pituitary, stimulates uterine smooth muscle contractions during parturition (childbirth) and milk ejection during lactation. Prolactin stimulates milk production. Estrogen and progesterone regulate reproductive cycle and maintain pregnancy. Oxytocin is also known as the 'love hormone' and functions through positive feedback during labor.
Explanation:
ATP (adenosine triphosphate) is the immediate energy currency for cellular processes. Hydrolysis of its high-energy phosphate bonds releases energy. Glucose and acetyl CoA are fuels, NADPH is an electron donor for biosynthesis. ATP is generated by substrate-level phosphorylation and oxidative phosphorylation.
Explanation:
Hydroponics involves growing plants with their roots in a mineral nutrient solution in water, without soil. This allows precise control of nutrients and is used in research and commercial production. Aquaculture is fish farming, tissue culture is in vitro plant propagation, vermiculture is earthworm composting.
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