Lithium has an atomic number of 3 and a mass number of 7.
Which of the following is the number of protons in a lithium atom?
7.
3.
12.
4.
The Correct Answer is B
The atomic number of an element represents the number of protons in the nucleus of an atom of that element.
Since lithium has an atomic number of 3, it has 3 protons in its nucleus.
Choice A is not correct because 7 is the mass number of lithium, not the number of protons.
Choice C is not correct because 12 is not the atomic number or mass number of lithium.
Choice D is not correct because 4 is not the atomic number or mass number of lithium.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Proteins are made up of amino acids which are organic molecules that contain both an amine functional group (–NH2) and a carboxylic acid functional group (– COOH)1.
Choice A, Lipids, is not the correct answer because lipids are a group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins, monoglycerides, diglycerides, triglycerides, phospholipids, and others.
They do not contain both an amine and carboxyl group.
Choice B, Chitin, is not the correct answer because chitin is a long-chain polymer of N-acetylglucosamine, a derivative of glucose.
It does not contain both an amine and carboxyl group.
Choice C, Cellulose, is not the correct answer because cellulose is an organic compound with the formula (C6H10O5)n, a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units.
It does not contain both an amine and carboxyl group.
Correct Answer is D
Explanation
Genes are segments of DNA that encode the information for making proteins.
The sequence of nucleotides (As, Ts, Cs, and Gs) in a gene determines the amino acid sequence of the protein. DNA sequencing is the process of determining the sequence of nucleotides in a piece of DNA.
Choice A is incorrect because enzymes are proteins that catalyze chemical reactions, not DNA sequences. Choice B is incorrect because blood types are determined by the presence or absence of certain antigens on the surface of red blood cells, not by DNA sequences. Choice C is incorrect because hormones are chemical messengers that regulate various body functions, not DNA sequences.
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