DNA and RNA are composed of long chains of monomers known as nucleotides. On the guanine molecule shown below, which arrow best indicates the 5' end of the subunit?
Answer(s): D
This question is testing your familiarity of nucleotide structures found in DNA and RNA. Nucleotides are monomers, or subunits, that are the building blocks of DNA and RNA molecules. Each nucleotide consists of a phosphate group, a pentose ring, and a nitrogenous base. In the case of the guanine nucleotide shown, the 5' end corresponds to the phosphate group attached to the fifth carbon on the pentose ring, indicated by the arrow labeled IV. This phosphodiester bond represents the 5' of a nucleotide making choice D the best answer. The arrow labeled III corresponds to the third carbon in the pentose ring. The hydroxyl group attached to the third carbon represents the 3' end of a nucleotide. The arrow labeled II represents the first labeled carbon. Lastly, arrow I points to the nitrogenous base of guanine.
The body compensates for increased environmental temperature by:
The body compensates for increased environmental temperature by sweating and losing water through the skin. Respiration and heart rate increase during exercise in response to internal demand for more oxygen. Salt retention has little to do with environmental temperature.
Which of the following phases are common to cells undergoing meiosis and mitosis?I). G0 phaseII). G2 phaseIII). S phase
Answer(s): C
This question asks the examinee to determine a phase within the cell life cycle that is common to both mitotic- dividing cells and meiotic-dividing cells. The cell cycle is composed of interphase and M phase. In mitotic- dividing cells, interphase includes G1 phase, S phase, G2 phase, and in highly specialized cells, such as neurons, a G0 phase. Similarly, meiotic-dividing cells include interphase and M phase, but germ cells do not exist in growth arrest phase (G0). Thus, II and III are correct making answer choice C the best answer.
Which structure shows two amino acids linked by 1 peptide bond?
Amino acids are joined by a peptide bond: 1) the leading amino acid has a primary amine group to the left, 2) the peptide bond has a carbonyl group immediately following the first amino acid side chain, 3) bonded to a secondary amine leading the second amino acid side chain, and 4) the second amino acid finishes with a carboxylic acid group. Choice D is correct.
A segment of DNA from a lab mouse is determined to be 5 GGATCCTCATG 3.Which of the following DNA segments would be the result of this original DNA sequence experiencing both a point mutation and a deletion?
A point mutation is one in which a single DNA base has be replaced by another and a deletion in one in which a single DNA base has been deleted. The question asks us to look for an answer choice that has had both a point mutation and a deletion. Only choice (C) matches these requirements.A, D: Neither (A) nor (D) has had any deletions at all the length of the DNA chain is unchanged. B: Two deletions have occurred as well as a point mutation. Both the 7th and 10th nucleotide are missing (both T).
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