Biochemistry and Molecular Biology: How Life Works

Biochemistry and Molecular Biology- How Life Works

One of the triumphs of modern science has been our ever-improving understanding of how life works—how chemical reactions at the cellular level account for respiration, digestion, reproduction, locomotion, and a host of other living processes. This exciting subject is biochemistry—and its allied field of molecular biology. In the past century, progress in these complementary disciplines has been astonishing, and a week rarely passes without major advances in medicine, physiology, genetics, nutrition, agriculture, or other areas, where biochemistry and molecular biology are shedding new light on life.

Anybody pursuing a career in a biology-based field—whether as a physician, pharmacist, or forester—must take biochemistry and molecular biology in college, usually after extensive preparation in biology and organic chemistry. But what about the rest of us? How do curious non-scientists get an accessible introduction to these fascinating ideas?

Biochemistry and Molecular Biology: How Life Works is that much-needed introduction, in 36 information-packed half-hour lectures tailored to viewers with no more science background than high school chemistry. Using the innovative methods that have earned him a multitude of teaching awards, Professor Kevin Ahern of Oregon State University covers the essential topics of a first-semester college course in biochemistry and molecular biology. You plunge into the thick of amino acids, proteins, enzymes, genes, and much more, learning the intricate workings of living cells, while discovering thought-provoking connections between the microworld and your own life.

Not only do these sciences tell us what’s happening at the most basic levels of living systems, but they also shed light on things such as:

  • Fad diets: Nutrients such as vitamin B12 are so beneficial that it’s tempting to ingest them in excess. But the body’s metabolic pathways are so finely tuned that these fad diets are either pointless or harmful. Similarly, artificial sweeteners can disrupt the gut bacteria and end up worse in some ways than sugar.
  • Wonder drugs: Medicines such as aspirin and penicillin were used long before anyone knew how they worked. But we now understand they contain compounds that inhibit specific cellular enzymes. By deciphering the biochemistry of disease agents, scientists can design drugs specifically to target their vulnerabilities.
  • DNA storage: With its paired bases, the double helix molecule of DNA is a remarkably efficient digital-storage medium. Advances in molecular biology now make it possible to create a sequence of bases of any length to encode information, meaning that all of the world’s data could be stored in a couple of pounds of DNA.

Drawing on years of classroom experience and his three popular textbooks, Professor Ahern conducts a graphics-intensive tour in which you always know where you are, even as you navigate the complex pathways of glycolysis and the Krebs citric acid cycle—two of the major stages leading from food to energy. Each step in a biological process is highlighted with detailed graphics so that you never lose your way. It’s quite a trip!

Designed for anyone curious about how life works, this course will especially appeal to:

  • Self-learners eager to tackle the fundamental science of life;
  • Those wanting a deeper grasp of diet and disease;
  • News enthusiasts keen to follow the biotechnology revolution;
  • Students enrolled in biochemistry or molecular biology;
  • Health care professionals who want an up-to-date review; and
  • Science teachers wishing to see a true master at work.

Enlightening and Also Entertaining

Among Professor Ahern’s teaching strategies are his “metabolic melodies”—clever poems and songs that he composed to aid students in memorizing material. An example, featured in Lecture 26, covers the replication of DNA:

  • Bases, sugars, phosphate bonds
  • Double helix, on and on
  • Need to jumpstart DNAs?
  • Get the enzyme called primase
  • When it comes to leading strands
  • Polymerase III is in command…

…and so on, through the enumeration of enzymes that play a role in unwinding the double helix of DNA and synthesizing new strands. Dr. Ahern’s verses (some to the tune of well-known songs, such as When Johnny Comes Marching Home) embody the enthusiastic, whimsical style that makes Biochemistry and Molecular Biology both enlightening and entertaining. Yet this delightful course is surprisingly deep and each viewing can teach you something new.

Start Simple; Build from There

Noting that biochemistry deals chiefly with just six bonding elements (out of the more than 100 in the periodic table of elements), Professor Ahern starts the course by stressing the subject’s underlying simplicity. Water is also a simplifying feature, since its unique properties—and ubiquity—make life possible. The cellular structure of life is another organizing principle of great elegance. Expanding on these themes and the nature of chemical bonds, you see how only twenty amino acids form the building blocks of proteins, which are the basis of all living tissues. And the instructions for building proteins are in the genes that comprise DNA and its related molecule, RNA.

As you proceed through the course, complexity mounts in intriguing ways, but there are always surprising links to an astonishing array of questions such as:

  • How does caffeine wake us up? Caffeine blocks the binding of sleep-inducing adenosine to its receptors on neurons. Caffeine also triggers an increase in blood glucose, particularly first thing in the morning, providing the same lift as from a piece of candy. That’s why, except for taste, sugar is not needed in a cup of coffee or tea.
  • Why do people obsessively check their phones? Interacting with other people, in person or via the phone, is a social activity favored by evolution because of its survival advantage. Our brains encourage us in this pursuit by a jolt of the “feel-good” chemical dopamine. The same neural pathway is hijacked by drug addiction.
  • Why don’t elephants get cancer? Cancer in humans is promoted by inactivation of a protein called p53, which plays a role in repairing DNA damage. While humans have just one pair of p53 genes, elephants have a whopping 20 pairs, making it much less likely that their tumor-suppressing system will be knocked out.

Biochemistry and Molecular Biology is thoroughly up to date, reflecting the subject as it is taught in the classroom today. For example, the relationship between an enzyme and its substrate (the substance on which it acts) was long portrayed as like a key fitting into a lock; the two had to match precisely, like puzzle pieces. In fact, Dr. Ahern points out, the fit is more like a foot slipping into a shoe that is not quite broken in. The footwear stretches before a comfortable fit is achieved. Something comparable happens between an enzyme and it substrate; their shapes alter slightly before they tightly bind, which is the point at which the catalyzed reaction begins. Similarly, proteins were once conventionally thought to have relatively fixed 3-D structures. But numerous proteins have at least one region that is intrinsically disordered— a trait that allows them to bind to a wider variety of partners.

Discover the “Science of Us”

Biochemistry is a much younger science than astronomy, physics, chemistry, and biology, which date back to ancient times. Only with the accidental synthesis of urea (the principal component of urine) in 1828 did scientists begin to accept that ordinary chemistry might be behind living processes. Thus the humble urea molecule was the first inkling that a science of bio-chemistry was even possible. The field of molecular biology is even younger, getting its most-celebrated boost with the discovery of the double helix structure of DNA in 1953—a breakthrough that was the key to the long-sought mechanism for transmission of genetic information. Together, biochemistry and molecular biology have sparked a scientific revolution every bit as momentous as Einstein’s relativity or Hubble’s discovery of the expanding universe. In this case, the dramatic change in thinking is directed inward—to the qualities that make us who we are. This remarkable field of study, says Professor Ahern in Biochemistry and Molecular Biology,is truly “the science of us.”

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