In the previous chapter we studied the sequence of events that might lead to the formation of polymers. Chapter 5 will illustrate how polymers would form:
- Cells themselves were able to develop, and
- Life was eventually able to arise.
In the first pages of this chapter you will find a quick description of different ways to make a living on our planet, such as under anaerobic (in absence of oxygen, or anoxic) and aerobic (in presence of oxygen, or oxic) conditions, and as autotrophic or heterotrophic organisms.
The chapter then goes on by describing how modern metabolism developed through four different stages.
This chapter may seem complex at first but it can really be synthesized and reduced to a few essential points. My suggestion is to first read the chapter as a whole, and then go back to the beginning and start extracting the significant concepts.
What information do you need to get out of this chapter?
As usual, you do not need to know the biological or chemical details of what is being explained, but rather the facts: how and why cells began, what are the essentials of life, what strategies did the early organisms adopt in their fight for life, who won and how, where is the energy for life coming from?
Following is the list of paragraphs from this chapter. All of the questions on the next quiz will come from these paragraphs:
- How Did Cells Begin?
- The Essentials Of Life
- know the "Necessities and Strategies of Life" figure (figure 5.6, page 148). You do not need to memorize chemical formulas in here, but you need to know what is going on, how and why. You need to know the four kinds of metabolism listed in the left column of this figure. You need to understand that there is a different outcome, in terms of energy units, between the "advanced" and the "primitive" strategies of life.
- know the role of purple bacteria and cyanobacteria in the birth of the modern eukaryotic cell, explained on pages 148 and 149, and illustrated in figure 5.7, page 149 (these concepts should be used to strengthen the understanding of Chapter 3 from your textbook).
- Life's Earliest Way To Make A Living
you do not need to know the details of figure 5.9, page 154; just know what this paragraph is about
- Air And Light: A New Source Of Glucose
- Why Do We Breathe Oxygen?
- The Four-Stage Development Of Modern Metabolism
This paragraph represents a very nice summary, detailing all the different steps that lead to oxygen-breathing heterotrophic organisms. These are the most important concepts that you need to get out of this chapter. You will find out that these concepts are essential in order to understand the materials in the next chapters. There will definitely be questions about these materials on both the quiz and the second exam.
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