Concept explainers
Because there was no oxygen in the earliest atmosphere, the first cells must have derived energy by __________
To review:
The given blank space in the statement, “because there was no oxygen in the earliest atmosphere, the first cells must have derived energy by _______________ metabolism of organic molecules. Oxygen was introduced into the atmosphere when some microbes developed the ability to ___________ and released oxygen as a byproduct. Oxygen was ___________ to many of the earliest cells, but some cells evolved the ability to use oxygen in ___________ respiration, which provided far more _______________.”
Introduction:
Oxygen is one of the most abundant elements on the earth. It is a major constituent of all the living organisms. The first cells found on the earth were prokaryotes, for example, cyanobacteria (blue-green algae). Its genetic material does not contain a nucleus. The origin of oxygen came into existence due to the evolution of prokaryotes.
Explanation of Solution
The evolution of oxygenic photosynthesis during the archean eon was one of the most important events in the history of life on Earth. The release of molecular oxygen by oxygenic Cyanobacteria had major consequence for the geochemistry of Earth’s surface as it involves the redox state changes which modified the bioavailability of redox sensitive metals such as iron, molybdenum, and copper. The first cells obtained energy by absorbing organic molecules from the environment because there was no oxygen present in the environment. The prokaryotes metabolized the organic molecules anaerobically.
When these microbes developed the ability to synthesize food in the presence of sunlight, it led to the release of oxygen as a byproduct and the use of carbon dioxide and water. This process is known as photosynthesis. Oxygen is also necessary for many cells because they perform aerobic respiration. In this process, more and efficient energy is obtained.
Because there was no oxygen in the earliest atmosphere, the first cells must have derived energy by anaerobic metabolism of organic molecules. Oxygen was introduced into the atmosphere when some microbes developed the ability to photosynthesis and released oxygen as a byproduct. Oxygen was harmful to many of the earliest cells, but some cells evolved the ability to use oxygen in aerobic respiration, which provided far more energy.
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Chapter 17 Solutions
Biology: Life on Earth
- Photosynthesis carried out by one group of ________ resulted in Earths first increase in atmospheric oxygen levels. a. archaea c. protists b. bacteria d. algaearrow_forwardThe first organisms that oxygenated the atmosphere were ______. a. cyanobacteria b. phootrophic organisms c. anaerobic organisms d. allof the abovearrow_forwardA rise in oxygen in Earths air and seas set the stage for the evolution of _______. a. aerobic respiration c. photosynthesis b. fermentation d. sexual reproductionarrow_forward
- Cyanobacteria was responsible for the increase in oxygen levels billions of years ago. They play a decisive role in changing the earth’s environment. Explain how are Cyanobacteria related in changing the early earth’s environment which later suitable for the development of other organisms.arrow_forwardOriginal cells were anaerobic and prokaryotic cells Eukaryotes evolved Multicellular organisms evolved Autotrophs evolved Aerobic organisms evolvedarrow_forwardMitochondria and chloroplasts contain some DNA, which more closely resembles prokaryotic DNA than (eukaryotic) nuclear DNA. Use this information to suggest how eukaryotes may have originated.arrow_forward
- The first forms of life on Earth were thought to be_____. a. single-celled plants b. prokaryotes c. insects d. large animals such as dinosaursarrow_forwardWhich statement about spontaneous generation is false? A. It addresses the formation of living cells from previously nonliving material. B. This was a common belief for during the Middle Ages. C. Pasteur demonstrated that it does not occur under normal laboratory conditions. D. It occurs every time a new species evolves from a preexisting species. E. It apparently occurred at least once – when life on Earth began.arrow_forwardCompare and contrast mitochondria and chloroplasts in relation to the Endosymbiotic Theory.arrow_forward
- The first living cells on earth would most likely resemble whichof these?a. a cyanobacterium c. a gram-positive cellb. an endospore former d. an archaeonarrow_forwardMitochondria are located in the _ and serve as _ ? A. Cytoplasm; the energy producers of the cell B. Cytoplasm; protectors to fight off bacteria and intruders C. Nucleus; instruction givers from DNA to assemble protein D. Nucleus; transcribersarrow_forwardMake a time line of the development of microbiology from the 1600s totodayarrow_forward
- Concepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax CollegeHuman Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning