Crossing over occurs at the four-strand stage when two homologous chromosomes, each consisting of a pair of sister chromatids, are paired. Each crossover involves just two of the four strands and generates two recombinant strands.
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Answer:
The right option for blanks is mRNA, amino acids and polypeptide chain (protein).
Reason:
During protein synthesis first of all mRNA formation occurs from DNA template. Then mRNA come out from nucleus into cytoplasm and bind with ribosome, where tRNA come and binds to mRNA codon with the help of anticodons. and add amino acids. In this way a chain of polypeptide is formed.
Answer: b)Steroid hormone receptors are located within the cytoplasm of a cell.
Explanation: Steroid hormones are the element present in the body that provides management in inflammation, metabolism, illness resistant , improves immune function etc. They are obtained from the cholesterol. The particular receptors of the steroid hormone is located at the cytoplasm.
Other options are incorrect because steroid hormone binds the certain receptors only not neurotransmitters .It does not have domain of 20 trans-membrane and is bound to ligand for activation.Thus , the correct option is option(b).
Answer: A warm current is just the reverse. A warm current is moving away from the Equator toward the poles. The water in a warm current is warmer than the surrounding water.
Explanation: The surface water temperature varies considerably between the Equator and the poles. As the ocean water is distributed across the Earth's surface by drifts and currents (see the infrared satellite photo of the warm Gulf Stream moving north along the east coast of Florida), warm water from the lower latitudes is moved into the higher latitudes and cold water is moved Equatorward. If you will remember, we noted in the section on Latitude that this redistribution of heat by ocean water is one of the major ways excess energy is moved poleward (and cold water is moved Equatorward).
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Except: Cells need energy to survive.
That's the Answer.