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Chapter

Cover Biochemistry

Enzymes  

This chapter looks at the fact that biochemists have investigated enzymes for more than 140 years, long before they had any realistic understanding of the physical basis of the living state. Using the technologies devised by biochemists, life scientists gradually determined the properties of biological systems. The chapter recounts how work on enzymes eventually demonstrated that almost every event in living organisms occurs because of enzyme-catalysed reactions. The chapter emphasizes how most of the thousands of biochemical reactions that sustain living processes occur at imperceptible rates without enzymes. Enzymes are, in fact, the means by which living organisms channel the flow of energy and matter.

Chapter

Cover Biological Science

Body Plans  

This chapter tackles the growth and forms of living organisms which depend on physical and mathematical imperatives and are shaped by the pressures of evolution. It notes that the diversity of organisms is due to differences in habitats, sizes, and shapes. Multicellular organisms develop by the replication and differentiation of cells. Furthermore, cells vary in their capacity for differentiation between organisms and at different stages of life. While plant structures emerge at fixed points, complex animals have originated from a bilaterian ancestor evolved in two distinct branches according to whether the blastopore forms the mouth or anus. The chapter illustrates that organisms representing virtually all forms of eukaryotic life develop hard body materials.

Chapter

Cover Biochemistry

Living Cells  

This chapter talks about cells, which are the structural units of all living organisms. The human body represents a remarkable illustration of the diversity of cells as it contains about 200 types. This great variation reflects the variety of functions that cells can perform. However, no matter what their shape, size, or species, cells are also amazingly similar. The chapter shows how cells are surrounded by a membrane that separates them from their environment. It explains that they are composed of the same types of molecules. The chapter reviews the structural hierarchy of life on earth and argues that it extends from the biosphere to biomolecules. Cells are considered the basic unit of life, since they are the smallest entities that are actually alive.

Chapter

Cover Biochemistry

Energy  

This chapter considers energy as essential to life, but what is it and why is it so vital to living organisms? It is because energy is the basic constituent of the universe. The relationship between matter and its energy equivalent is defined by Albert Einstein’s famous equation E = mc2 . This equation emphasizes that energy and matter are interconvertible as matter is condensed energy. The chapter defines energy as the capacity to do work, explaining that work is organized molecular motion that causes the displacement or movement of an object by the application of force and results in a specific physical change. Energy comes in many interconvertible forms: gravitational, nuclear, radiant, chemical, mechanical, electrical, and thermal.

Chapter

Cover The Evolution of Life

The Evidence for Evolution  

This chapter provides an overview of the science of evolution, which explains how the vast diversity of living things is governed by a few simple natural principles. The outward diversity of animals and plants is based on a very restricted range of materials, body plans, power sources, and instructions, relative to those we use in everyday life. Evolution is modification through descent. All organisms are similar, not because they have been perfectly engineered, but rather because they all descend from the same common ancestor. The chapter is concerned mainly with descent—how we know that the diversity of living forms springs from a single root. The chapter then introduces the concepts of extinction, adaptation, development, sex, and diversity.

Chapter

Cover Biological Science

The Structure of Living Organisms  

This chapter focuses on the structure of living organisms. The basic units of life, particularly when it comes to cells and the organelles inside them, are enclosed structures bounded by membranes. Biochemistry helps in unveiling and investigating the structure and function of cells, which are identified to be self-contained units of life. The chapter then details differentiation as the process of cell specialization. This happens even though all cells in an organism have similar genetic composition. It explores the link between the tissues of multicellular animals and multicellular plants while explaining that both require mechanisms for the internal coordination of cellular activity based on chemical signals and electrochemical transmissions conducted by nerve tissues.

Chapter

Cover Biological Science

Interaction with the External Environment  

This chapter considers the environmental variables that influence the survival and reproduction of organisms. Living organisms, their structures, and their life processes evolved from ancestral organisms through a combination of variation and selection. The forces of selection act on the phenotype of individuals, so genes are not particularly under selection pressure directly. The chapter explains how light, geography, gravity, and the electromagnetic spectrum affect most biological processes. It then argues that plants and animals must adapt to the imperatives of the gaseous environment and the physical imperatives of heat transfer to and from the environment to survive and reproduce.

Chapter

Cover Biological Science

The Emergence of Life on Earth  

This chapter explains how life emerged and looks at the subsequent development of understanding life. All modern living organisms are cellular, and looking at the characteristics of cells provides some ideas about the locations where and when life may have originated, and when this might have occurred. Geochemistry shows how some of Earth's dominant global features are the result of its formation history and accretionary environment. The chapter discusses the notion that life is based on aqueous organic chemistry. The chemistry of carbon is a known example of functioning biology. It also covers the correlation between DNA, RNA and functional proteins.

Chapter

Cover Photosynthetic Life Origin, Evolution, and Future

Endosymbiosis: How eukaryotes acquired photosynthesis  

This chapter looks at how an oxygenic cyanobacterial cell is taken up by a scavenging heterotrophic eukaryotic cell. It reviews evidence that a very rare and unique event led to the combination of a cyanobacterial cell with a much larger heterotrophic eukaryotic cell to form the first eukaryotes capable of oxygenic photosynthesis. It also discusses how primary endosymbiosis started the beginning of the evolution of photosynthetic algae and plants, both terrestrial and aquatic. The chapter investigates the reduction of cyanobacterial endosymbiont from a free-living organism to an organelle. It details how plastids evolved in algae and plants, sometimes acquiring new non-photosynthetic functions related to storage, reproduction, or defence.

Chapter

Cover Foundations of Chemical Biology

Lipids: cells as compartments  

This chapter examines the molecular components of the membranes enclosing compounds, looking at compartments of living organisms that are bounded by semipermeable membranes. It discusses how organic compounds are immiscible with water and tend to associate in aqueous solution, which is exploited by cells with the use of compounds and lipids to form the basic structures of cell membranes. It also develops an awareness of the intrinsic chemistry of phospholipids. The chapter analyses the membranes found in biological systems. These are formed by the spontaneous association of relatively small organic molecules called lipids. It explains that membrane structures arise because of the amphiphilic nature of lipid molecules, wherein one end is hydrophilic and the remainder is a hydrophobic tail.

Chapter

Cover Foundations of Chemical Biology

The chemicals of biological systems  

This chapter provides a background on the chemistry processes that take place in the cells of living organisms, noting that cells consist of a semipermeable membrane that encloses an aqueous solution rich in a diverse range of chemicals. It describes cells as sophisticated machines that undertake a wide range of chemistry in an organized fashion. It also refers to the chemicals present in cells that appear to have been selected by the processes of evolution for their chemical utility. The chapter shows that many cellular processes can be understood in simple molecular terms. It introduces a series of examples to exemplify principles that are important for understanding the chemistry of cells.

Chapter

Cover Biological Science

The Structure of Living Organisms  

This chapter focuses on the structure of living organisms. The basic units of life, particularly when it comes to cells and the organelles inside them, are enclosed structures bounded by membranes. Biochemistry helps in unveiling and investigating the structure and function of cells, which are identified to be self-contained units of life. The chapter then details differentiation as the process of cell specialization. This happens even though all cells in an organism have similar genetic composition. It explores the link between the tissues of multicellular animals and multicellular plants while explaining that both require mechanisms for the internal coordination of cellular activity based on chemical signals and electrochemical transmissions conducted by nerve tissues.

Chapter

Cover Biological Science

The Emergence of Life on Earth  

This chapter explains how life emerged and looks at the subsequent development of understanding life. All modern living organisms are cellular, and looking at the characteristics of cells provides some ideas about the locations where and when life may have originated, and when this might have occurred. Geochemistry shows how some of Earth's dominant global features are the result of its formation history and accretionary environment. The chapter discusses the notion that life is based on aqueous organic chemistry. The chemistry of carbon is a known example of functioning biology. It also covers the correlation between DNA, RNA and functional proteins.

Chapter

Cover The Ecology of Plants

Photosynthesis and Light  

This chapter begins by looking at the interactions plants make with their environment by considering the process by which plants acquire energy and carbon: photosynthesis. It examines how plants capture the energy of sunlight and incorporate carbon from the atmosphere in photosynthesis, their adaptations to the light environment, their water relations, and the mineral nutrients they get from the soil. These processes in turn can play out at the larger scope of ecosystem processes. The chapter also takes a look at the structures in which some of these processes take place and some of the biochemistry involved. It focuses first on processes occurring at the small scale of a cell, a leaf, or an individual plant. Finally, the chapter considers the importance of the forest, where plants have evolved and live in an ecological context. It studies the physical conditions that a plant experiences, determined by the physical features of the environment and by other living organisms in that habitat.

Chapter

Cover Thrive in Cell Biology

Introduction to cell biology  

This chapter recounts the first discovery of living cells by the Dutch linen merchant Leeuwenhoek, who observed unicellular organisms in pond water, and later blood cells, oral bacteria, and spermatozoa. It mentions the first use of the term ‘cell’ in 1665 by a curator of the Royal Society of London, who described the empty cell walls of a cork. It also considers cells as the basic structural and functional unit of all organisms, which are grouped into archaea, eucarya, and bacteria. The chapter cites the theory that life began with a group of molecules that were capable of catalyzing their self-replication. It explains that cells are largely composed of water and a variety of inorganic minerals and organic constituents.

Chapter

Cover The Evolution of Life

The Tree of Life  

This chapter examines how all living organisms are related to one another and describes how these relationships can be worked out. Evolution is the process by which organisms become modified over time. New organisms do not appear spontaneously, of course: they are produced by old organisms. The basic unit that undergoes modification is thus the lineage—the long succession of parents and offspring, extended over time. Three fundamental aspects of organisms are the following: individuals, populations, and lineages. Lineages vary between strictly tree-like and entirely web-like, with any intermediate state being possible according to the degree of mingling of lineages during descent. With the advent of evolutionary biology in the mid-nineteenth century, classification was revolutionized by the use of relatedness, rather than similarity, as the basis for grouping species together. The fact of evolution makes it possible to construct a natural classification that expresses the genealogical relationships among all kinds of organisms.