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Banded iron formations indicate

A) THE FORMATION OF RED CYANOBACTERIA

B) THE FORMATION OF FREE OXYGEN IN THE ATMOSPHERE FOR THE FIRSTTIME

C) THE PRESENCE OF SIGNIFICANT OXYGEN IN THE ATMOSPHERE

D) ANOXYGENIC PHOTOSYNTHESIS

E) THE PRESENCE OF OZONE

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Nelly Stracke
Nelly StrackeLv2
29 Sep 2019
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Related questions

There are two hypotheses for the archean "red beds" (banded iron formations). One hypothesis attributes these formations to oxygen produced by early cyanobacteria, reacting with ferrous iron to form iron oxides. The other hypothesis attributes red beds to the activity of photosynthetic bacteria. Explain the role of ferrous iron in the metabolism of photosynthetic (purple non-sulfur) bacteria, and write out the equation for this form of photosynthesis. Would you expect these organisms to be growing autotrophically (explain)? Is there any place on earth where this process occurs today? รขย€ยจ

Phototrophs need an electron source like H2S orH2O. Where do the electrons from these sources go?(Assume the organism is growing autotrophically as well astophototrophically.)

O2 and CO2

O2 only

CO2 only
Sulfate or oxygen
Inorganic various molecules, depending on cellular needs.
2. Which of the following statements about chlorophyll istrue?
It is a good electron acceptor in its oxidized form.
It is a good electron donor in its reduced form when energizedby light.
It contains magnesium.
It is a tetrapyrrole.
All of the above
3. The unifying feature of all photosynthetic organisms isa(n)
electron transfer chain.
electron donating system to generate NADPH.
ATP-generating system.
light-gathering system.
All of the above
4. Evidence suggests that banded iron formations are due to
chemical oxidation of reduced iron, Fe2+.
aerobic reduction of insoluble ferric iron, Fe(OH)3.
anaerobic oxidation of soluble ferrous iron,Fe2+.
Both a and b
Both a and c
5. In addition to their ability to harvest light in the 400 to 500nm range, carotenoids also
eject electrons from the reaction center.
function as a tetrapyrrole.
intercept toxic single-state oxygen.
transfer electrons to ubiquinone.
raise electrons to a higher energy state.
6. Ribosomal RNA and other cell features affirm that living cellsshould be divided into three groups called domains.
True
False
7. Microbes have started to evolve recently.
True
False
8. The ________ was essential for the evolution of oxygenicphotosynthesis.
evolution of cyanobacteria
development of photosystem I
ability to extract electrons from CO2
ability to extract electrons from H2O
ability to use oxygen as the terminal electron acceptor
9. What do oxygenic phototrophs use as an electron source?
Oxygen
Sulfide
Water
Organic compounds
CO2
10. Three domains of organisms have been established basedprimarily on size and other structural features of the cells.
True
False

Many bacteria, including E. coli, are capable of growing under both anaerobic and aerobic conditions. some mutations are introduced into an E. coli strain that inactivate several enzymes involved in DNA repair. The mutant strain grows normally when kept in a incubator with a 100% nitrogen gas atmosphere. however, the strain dies when exposed to a normal labroratory atmosphere. why?

a. nitrogen stabilizes the enzyme responsible for DNA repair, while oxygen destabilized these enzymes

b. reactive oxygen species generated during normal aerobic metabolism from free radicals are a major source of DNA damage

c. deamination of cytosine, which introduces mismateched nucleotides, occurs at a higher frequency in aerobic conditions compared to anaerobic conditions.

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