Albert L. Lehninger Quotes

Cells of all kinds share certain structural features.

Organisms possess extraordinary attributes, properties that distinguish them from other collections of matter. What are these distinguishing features of living organisms?

The first living organisms on Earth doubtless arose in an aqueous environment, and the course of evolution has been shaped by the proper­ ties of the aqueous medium in which life began.

The distinguishing characteristics of eukary­otes are the nucleus and a variety of membrane-enclosed organelles with specific functions.

In thermodynamic terms, formation of the solution occurs with a fa vorable free-energy change: ΔG = ΔH - TΔS, where ΔH has a small positive value and TΔS a large positive value; thus ΔG is negative.

The remarkable similarity of metabolic pathways and gene sequences across the phyla argues strongly that all modern organisms are derived from a common evolutionary progenitor by a series of small changes (mutations), each of which conferred a selective advantage to some organism in some ecological niche.

The unity and diversity of organisms become apparent even at the cellular level.

Perhaps the most remarkable property of living cells and organisms is their ability to reproduce themselves for countless generations with nearly perfect fidelity. This continuity of inherited traits implies constancy, over millions of years, in the structure of the molecules that contain the genetic information.

All living organisms fall into one of three large groups (domains) [Bacteria, Archeara, Eukarya] that define three branches of evolution from a common progenitor.

Despite these common properties, and the fundamental unity of life they reveal, it is difficult to make generalizations about living organisms.

We can consider cellular energy conversions—like all other energy conversions—in the context of the laws of thermodynamics.

The chemistry of living organisms is organized around carbon, which accounts for more than half the dry weight of cells.

Biochemistry asks how the remarkable properties of living organisms arise from the thousands of different biomolecules.

Virtually every chemical reaction in a cell occurs at a significant rate only because of the presence of enzymes.

The current understanding that all organisms share a common evolutionary origin is based in part on this observed universality of chemical intermediates and transformations, often termed "biochemical unity."