Chapter 1: End of Chapter Review Questions
1. Explain the apparent contradictions in defining microbiology as the study of
microscopic organisms or as the study of single-celled organisms.
Most single- celled organisms require a microscope to be viewed, but not all.
Some species are actually large enough to see with the naked eye. Many microbes
form multicellular communities that render them visible. Two examples of these
are mushrooms and biofilms. There are also some multicellular organisms that are
microscopic, but do not fall into the category of a microorganism.
2. What is the genome of an organism? How do genomes of viruses differ from those of
cellular microbes?
The genome of an organism is the total genetic information contained in the
organism’s chromosomal DNA. For most cellular organisms it contains all the
information necessary for the organism’s self- replication.
The genome of a virus is not always DNA. Furthermore, the viral genome does
not contain all the information needed for self- replication. It relies on the cell
machinery and its genome typically contains information to take over host cell
processes to generate more virus particles.
3. Under what conditions might microbial life have originated? What evidence
supports current views of microbial origin?
The early Earth environment was composed mainly of highly reduced
compounds. Living cells may have formed from spontaneous reactions sparked by
UV absorption or electrical discharge.
Miller found that when reduced compounds were subjected to an electrical
discharge, several amino acids were observed.
Oró did a similar experiment and found the production of adenine. There is still
debate as to where the first cells came from. Some scientists believe life has an
extraterrestrial origin.
4. List the ways in which microbes have affected human life throughout history
Probably the first thing that will come to mind is a microbe’s disease- causing
properties. Microbes have been used in food production, mining, for their
insecticidal activity, and for antibiotic production, to name just a few uses. We
also rely on organisms to cycle compounds such as carbon and nitrogen
5. Summarize the key experiments and insights that shaped the controversy over
spontaneous generation. What key questions were raised, and how were they
answered?
Spontaneous generation means that life arises spontaneously, without parental
organisms. In the 1600s, Redi showed that maggots appearing on decaying meat
were actually the offspring of flies. When flies could not gain access to the meat,
no maggots were observed.
This study source was downloaded by 100000899606396 from CourseHero.com on 10-09-2025 17:20:42 GMT -05:00
https://www.coursehero.com/file/49519307/Chapter-1-end-of-chapter-questionsdocx/
1. Explain the apparent contradictions in defining microbiology as the study of
microscopic organisms or as the study of single-celled organisms.
Most single- celled organisms require a microscope to be viewed, but not all.
Some species are actually large enough to see with the naked eye. Many microbes
form multicellular communities that render them visible. Two examples of these
are mushrooms and biofilms. There are also some multicellular organisms that are
microscopic, but do not fall into the category of a microorganism.
2. What is the genome of an organism? How do genomes of viruses differ from those of
cellular microbes?
The genome of an organism is the total genetic information contained in the
organism’s chromosomal DNA. For most cellular organisms it contains all the
information necessary for the organism’s self- replication.
The genome of a virus is not always DNA. Furthermore, the viral genome does
not contain all the information needed for self- replication. It relies on the cell
machinery and its genome typically contains information to take over host cell
processes to generate more virus particles.
3. Under what conditions might microbial life have originated? What evidence
supports current views of microbial origin?
The early Earth environment was composed mainly of highly reduced
compounds. Living cells may have formed from spontaneous reactions sparked by
UV absorption or electrical discharge.
Miller found that when reduced compounds were subjected to an electrical
discharge, several amino acids were observed.
Oró did a similar experiment and found the production of adenine. There is still
debate as to where the first cells came from. Some scientists believe life has an
extraterrestrial origin.
4. List the ways in which microbes have affected human life throughout history
Probably the first thing that will come to mind is a microbe’s disease- causing
properties. Microbes have been used in food production, mining, for their
insecticidal activity, and for antibiotic production, to name just a few uses. We
also rely on organisms to cycle compounds such as carbon and nitrogen
5. Summarize the key experiments and insights that shaped the controversy over
spontaneous generation. What key questions were raised, and how were they
answered?
Spontaneous generation means that life arises spontaneously, without parental
organisms. In the 1600s, Redi showed that maggots appearing on decaying meat
were actually the offspring of flies. When flies could not gain access to the meat,
no maggots were observed.
This study source was downloaded by 100000899606396 from CourseHero.com on 10-09-2025 17:20:42 GMT -05:00
https://www.coursehero.com/file/49519307/Chapter-1-end-of-chapter-questionsdocx/
