1.C | 2.D | 3.B | 4.D
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1. The point in the Moon's orbit when it's farthest away from the Earth is called apogee. On the contrary, the perigee is the point in the Moon's orbit when it's the nearest from the Earth. Those points are very important for tides and other natural phenomenon such as eclipse and in general for the observation of the skies.
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2. Gamma rays are a type of electromagnetic radiation cannot be focused. They diffuse from the emission points until there is an object that stops them. This is the reason why when you have to use gamma rays, you are in other rooms, in order to prevent the radiation to go through them.
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3. The corona it's the outermost layer of the Sun's atmosphere. It's also the part where most of the activity of the sun that we can see take places. It's a subject that has fascinating scientists for centuries and only recently we are studying in more details this interesting and weird place, due to the advancement of technology.
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4. Tides are a result of the gravitational attraction of the Sun and Moon. The Earth, the Sun and the Moon have masses and their own gravities. The interactions between these corps causes tides movement on Earth that are fundament to life on the planet, because they are a fundamental part in the cycle of water and air.
Answer:
miRNAs are involved in A. transcriptional silencing
Explanation:
MiRNAs are single-stranded RNAs that are involved in gene regulation. This type of RNA allows the silencing of genes through complementarity with a transcribed RNA, thus promoting their degradation and reducing their translation levels.
Answer: B) Arginine
Explanation: Having the sequence (mRNA):
5′-GUUUCCCGUAUACAUGCGUGCCGGGGGC-3, we can go through the following procedure:
1. Identifying the binding site for the initiator tRNA, which is the so-called "start codon" AUG: 5′-GUUUCCCGUAUAC<u><em>AUG</em></u>CGUGCCGGGGGC-3′
2. Look for the next codon after AUG, which is CGU:
5′-GUUUCCCGUAUACAUG<u><em>CGU</em></u>GCCGGGGGC-3
3. Look in a codon table in which amino acid corresponds to CGU. Then you will find that amino acid is Arginine.
The reason you should follow the above procedure is that during translation, ribosomes are in charge of creating a new peptide bond from mRNA using different tRNA. A tRNA is a structure with a codon attached to it and an amino acid. If a tRNA has a UAC codon attached to it, then this tRNA is going to scan the mRNA looking for the corresponding AUG (the so-called start codon). This is why the tRNA with the UAC codon attached to it is called "initiator tRNA". When initiator tRNA finds the start codon, the large subunit of the ribosome would place this tRNA plus mRNA in its so-called P site (Polypeptide site). On the right of the P site is the A site (Amino acid site) which will be waiting for the tRNA which attached codon corresponds to the next codon after the start codon AUG in the mRNA. For this case, that codon which A site is waiting for is CGU, which is attached to a tRNA containing the corresponding amino acid which is Arginine.
Answer:
False.
Explanation:
SCN9A gene may be defined as a type of transcription factor responsible for the regulation of the voltage gated sodium channels. These genes are mainly expressed in nociceptive or pain receptor.
The mutation in SCN9A may disrupt the functioning of voltage gated sodium channels and not related with voltage gated potassium channels. The person is not able to feel the pain due to mutation on SCN9A gene.
Thus, the correct answer is option (b).
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