Ch 4: The Nucleotide Structure of DNA & RNA

About This Chapter

Watch DNA and RNA video lessons and learn about nucleotides, DNA, RNA, chemical structure and more. Each lesson is accompanied by a short multiple-choice quiz you can use to check your understanding of these science topics.

Nucleic Acids: DNA and RNA

DNA and RNA - you may hear those terms thrown around in everyday life, perhaps on your favorite criminal investigation show, but what do these terms really mean? To unravel the intricacies of nucleic acids, you'll need to learn the language of nucleotides. From the beginning, we'll show you how sugars, phosphate groups and nitrogenous bases use phosphodiester bonds to form polynucleotides. This arrangement allows the cell to use the nucleotide language to create an impressive array of proteins necessary for life. The alphabet that comprises this language is short but achieves miraculous results.

Each nucleotide is identical except for its nitrogenous base. Adenine, cytosine, guanine and thymine form DNA's four-letter alphabet. We'll give you an easy way to remember which ones are purines and which ones are pyrimidines. You've probably heard of parallel lines before, but what does it mean to be antiparallel? Our lesson on complementary base pairing will explain this and more.

Next, we'll climb the double helix ladder as we make sense of the Watson-Crick model of DNA. You'll explore the series of discoveries and experiments that made this breakthrough possible. We'll also examine DNA as a hereditary molecule. One of the implications is that, unless you have an identical twin, you and your DNA are truly unique.

Our last lesson will cover the differences between RNA and DNA when it comes to sugars, nitrogenous bases and structures. With the central dogma of molecular biology, you'll learn how DNA and RNA work together to create proteins. We'll go into greater detail with three major types of RNA and their functions. Finally, you'll learn why DNA is used much more often than RNA as evidence in criminal investigations. Even better, we cover this vast wealth of information in four short lessons.

Chapter Practice Exam
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Practice Final Exam
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