The Prokaryotes: Flashcards
About how many years ago did the first prokaryotic cells evolve, according to the fossil record?
Earliest prokaryotic fossils about 3.5 BYA.
In the Precambrian Era.
What is the basic idea behind the Oparin-Haldane hypothesis? (1938)
That life arose through abiogenic molecular Evolution
In what ways were Oparin and Haldane’s ideas similar?
-That early Earth was very inhospitable, due to its primitive atmosphere, with intense heat, also agreed sunlight provided the energy with its intense UV.
In what ways were Oparin and Haldane’s ideas different?
- Oparin: atmosphere lots of methane,, water vapor, ammonia and hydrogen gas; intense heat of volcanoes, lightning and sunlight provide the energy; (the formation of coaverates)
- Haldane: atmosphere had water vapor, carbon dioxide, and ammonia; Intense UV from sun since no ozone layer, which provided the energy; (the formation of organic molecules, in a “hot dilute soup,” covering Earth [premordial soup]
Stanley Miller’s 1953 Experiment were designed to test what hypothesis?
his experiments were designed to test Oparin-Haldane Hypothesis, using conditions of early Earth suggested by Oparin
What conclusions did Miller draw from the results of the experiments (1953)?
- Concluded that 15% of Carbon incorporated into 4 kinds of amino acids (which builds proteins), Urea, and fatty acids (which build lipids) [The 15 % is coming from the methane (CH4)]
- Also concluded, the experiment doesn’t work when the atmosphere contains O2, implying early Earth had no oxygen in it (it came later).
what was the key difference between Fox’s “Protobionts/Protocells” and actual living cells?
“Protocells” are like cells, however they can’t reproduce and/or replicate itself/themselves.
Why would it be more likely that nucleic acids evolved before enzymes evolved in living systems? Explain why scientists think that is true:
It is more likely that nucleic acids evolved before enzymes because nucleic acids are easier to build
Which type of Nucleic Acid probably evolved first: RNA or DNA? why do scientists think this is true?
We believe RNA came first, since its easier to build, because you only need 1 strand of nucleotides (which its also a template on how to build a protein)
What is the geographic range of bacteria?
Bacteria are ubiquitous meaning they are found everywhere, all over the place
3 Basic shapes of bacteria cells?
1-Coccus (plural=cocci)—->Round
2-Bacillius (plural=bacilli)—-> hot dog/rod shaped
3-Spirillium (plural=spirillium)–> spiral (corkscrew)
What are Bacteria’s most common Arrangements?
- 1–Strepto–Meaning “chains”/ Chained together
- 2–Staphylo–Meaning “grape-like clusters
- 3–Diplo–Meaning “pairs”
- 4–Sarcina–Cuboidal (packets of 4, 8)
The method of reproduction for bacteria:
- No Mitosis and No Meiosis
- They do a process to replicate itself called Binary Fission (all have same DNA)
What are the Principle differences between Prokaryotic cells and Eukaryotic cells?
- Prokaryotes do not divide by mitosis, instead through binary fission.
- The organization of the genetic material differs, since the DNA of prokaryotic cell is not organized within a membrane enclosed nucleus, they have smaller DNA molecules called Plasmids, and DNA is often circular.
- prokaryotes have none of the membrane-enclosed cytoplasmic organelles—(mitochondria, Golgi apparatus, and others, that are found in most Eukaryotes)
What are the 2 Domains of prokaryotic cells? Which domain is more closely related to Eukaryotes?
- 2 Domains: Bacteria and Archaea
- Eukaryotes share a more recent common ancestor with Archaea, than they do with bacteria.
What roles (other than “disease-causing”) do bacteria play in the human environment?
- Environmental applications: composting, bio-leaching of minerals, bio-remediation, sanitary landfill, sewage treatment.
- Food Production: Yogurt, cheese, Intestinal bacteria (e. coli), normal skin flora
The size of bacteria:
They’re really small:
-requires staining and really good (light) microscope lenses to see them.
The best way of telling/classifying bacteria is?
by looking at the cell wall
