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1. wk > origin o life > Flashcards

origin o life Flashcards

1
Q

What do we know about the earth?

A
  • Earth is about 4.65 billion years old (from geological evidence)
  • For the first billion years, we have no record of life on the planet.
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2
Q

Gases in the early atmosphere?

A
  • H2 CO2 N2 H2S H2O CH4 NH3

- may have been unable to sustain life

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3
Q

Were organic macromolecules able to form under the conditions on the early Earth?

A

-Aleksandr Oparin’s hypothesis says YES
-There is no fundamental
difference between a living
organism and lifeless matter.
-characteristic of life must have arisen in the process of the evolution of matter

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4
Q

What did Stanley Miller prove?

A
  • it is possible that organic molecules (which appear in creatures) can be created in early atmosphere
  • in the 1950s
  • after one week 18% of methane molecules convert into biomolecules
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5
Q

What is the phylogenetic tree?

A

-phylogenetic tree or evolutionary tree is a branching diagram or “tree” showing the evolutionary relationships among various biological species or other entities

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6
Q

Name some procaryotes and eukaryotes

A
  • prokaryotes= bacteria, archaea

- eukaryotes= protists, plants, fungi, animals

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7
Q

What is closer to humans? Fungi, animals, bacteria

A

-human> animals> fungi> bacteria

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8
Q

How were the Earth’s only organisms (for the first two billion years)?

A

-microscopic, unicellular (einzellig) and aquatic

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9
Q

How does the first fossil look like?

A
  • 3.5 billion years old

- Resembling Bacteria, embedded in rocks from Western Australia

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10
Q

What are some rich sources for early prokaryote fossils?

A

-Stromatolites: fossilized layered microbial mats

Sediments from ancient hydrothermal vent habitats (alten hydrothermalen Abzugsgebiete)

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11
Q

What was the earth like 3.5 to 4.0 billion years ago?

A
  • very hot from excessive volcanic activity
  • numerous meteor impacts
  • high solar radiation
  • very little oxygen-consequently no ozone layer to protect from…
  • high ultraviolet (UV) radiation
  • atmosphere of H2O, H2, CH4, NH3, CO2, CO,N2, H2S
  • A reducing atmosphere = electron-adding
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12
Q

What is reducing atmosphere?

A

-A reducing atmosphere is a gaseous environment with a lessened amount of oxygen as a free-form vapor (Dampf) as a single unit or in a mixture. It often contains other reactive gaseous elements or compounds such as hydrogen or nitrogen.

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13
Q

Name important steps in creation of life

A
  • Nonbiological synthesis of organic compounds in nonoxidizing atmosphere
  • Polymerization by removal of water from chemical joints of monomers
  • Survival advantage of protocells that can make polymers
  • Evolution of metabolic chains from back-to-front
  • Natural selection for objects that have genetic apparatus (nucleic acids) for remembering metabolic recipes that can pass down that apparatus (DNA) to daughter cells
  • Importance of sex, eukaryotic cells, and cell differentiation
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14
Q

What was the Aristotle’s idea?

A

-Proposed the theory of spontaneous generation
(abiogenesis):
->Idea that living things can arise from nonliving matter
( lasted almost 2000 years)

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15
Q

Give examples for abiogenesis

A
  • muddy soil gave rise to the frogs

- mice came from the moldy grain (schimmeliges Getreide)

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16
Q

How was the disproving of the spontaneous generation?

A

-Francesco Redi (1668)
-Unsealed – maggots on meat
Sealed – no maggots on meat
Gauze (Drahtgeflecht) – few maggots on gauze, none on meat

17
Q

What did Anton Leeuwenhoek find (1674) ?

A
  • began making and looking through simple microscopes
  • examined water and visualized tiny animals, fungi (Pilze), algae, and single celled protozoa; “animalcules” then called microbes
18
Q

What did John Needham (1745) show?

A
  • Showed that microorganisms flourished (aufblühen) in various soups that had been exposed to the air
  • Claimed that there was a “life force” present in the molecules of all inorganic matter, including air and the oxygen in it, that could cause spontaneous generation to occur
19
Q

What was the problem with John Needham’s thesis?

A

-People didn’t realize bacteria were already present in Needham’s soups
-Needham didn’t boil long enough to kill the microbes
(-broth appeared clear after boiling (but only till you wait))

20
Q

Describe Lazzaro Spallanzani’s experiment (1765)

A
  • heated broth let it cool and open , waited and bacteria appeared
  • heated broth let flask sealed , waited nothing grew, opened flask -> bacteria appeared
21
Q

How do microbes appear (history)?

A
  • By 1860, Paris Academy of Sciences offered a prize for any experiments that would help resolve this conflict
  • The prize was claimed in 1864 by Louis Pasteur (disproved spontaneous generation in microscopic organisms)
22
Q

How do microbes appear (describe the Pasteur’s problem)?

A
  • Hypothesis: Microbes come from cells of organisms on dust particles in the air; not the air itself
  • Pasteur put broth into several special S-shaped flasks ( no growth
  • boil+ break stem -> microbial growth
23
Q

What is the result of Pasteur*s problem?

A
  • Pasteur’s S-shaped flask kept microbes out & let air in
  • Proved microbes only come from other microbes (life from life) -> biogenesis
24
Q

Which came first, proteins

or nucleic acids?

A 
-Need proteins to perform 
polymerization reactions
in presence of water; need 
nucleic acids to remember
how to make proteins.
-Many researchers feel that
answer might be RNA, which
is capable of self-polymerization
25
Q

How does synthesizing abiotically of shot polymers of ribonucleotides work?

A
  • first RNA monomers
  • formation of short RNA polymers
  • assembly of a complimentary RNA chain (pairing rules are G with C and A with U)
  • complementary chain serves as template for making copy of original “gene”
26
Q

Was is meant with RNA world?

A
  • Small RNA molecules can form abiotically by polymerization of free nucleotides
  • RNA molecules can self-replicate
  • RNA can fold into 3D structures that act as simple enzymes
27
Q

Name the characteristics fo living organisms

A
  • living things need air, water and food
  • can grow, develop
  • can move on their own
  • can respond to stimuli (changes around them) because they are sensitive
  • they respire (breathe)
  • they excrete (ausscheiden)
  • they reproduce
  • have a definite life- span
  • different levels of organization
  • made up of cells
  • obtains& uses Energy
28
Q

What is a ribozyme?

A

-an RNA molecule capable of acting as an enzyme

1. wk (11 decks)

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