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Greetings. Welcome to this 16th lecture
in this Principles of Biochemistry lecture series.
My name is Jerry Feigenson.
I'm a professor in
the Department of Molecular Biology and Genetics at Cornell University in the USA.
In the previous lecture, number 15,
you learned that chemical reactions of metabolism are highly interconnected.
And you saw why cells used stored glucose as their energy source.
And that cells use glycolysis,
not just for energy,
but also to produce chemicals needed by the cell.
And study of glycolysis introduces
some important principles of metabolism that we will see throughout the course.
In this lesson, you will learn about hormonal control
and local control within each cell of glycogen breakdown.
And you will see that the steps of hormone amplification can result in
as much as a million-fold increase in signal response.
We will look at three exquisitely controlled enzymes of glycolysis: hexokinase,
phosphofructokinase-1, and pyruvate kinase.
And we'll see some very general principles of enzyme regulation.
One is that cells keep ATP concentration nearly constant,
and so use AMP concentration of the signal of the energy state of cells.
A second principle is that,
different tissues have different hormone sensitivity.
And at the end of this lecture,
you'll see that the body can switch among different kinds of
metabolism depending upon the rate of need for ATP.