CH.6-Origin of Life/Earth's Geological History Flashcards
Did Earth’s prebiotic atmosphere have oxygen?
No
What was Earth’s prebiotic atmosphere composed of?
CO2
Water vapour
Nitrogen gas (N2)
Methane (CH4)
Ammonia (NH3)
Hydrogen gas (H2)
Carbon monoxide CO
Hydrogen sulfide (H2S)
Did Earth’s prebiotic atmosphere have an ozone layer?
No
T or F: Earth’s atmosphere today has ozone layer
True
What are the steps that may have led to origin of first simple unicellular organisms?
1) Abiotic synthesis of small organic molecules (monomers) ==> Amino acids, nucleotides
2) Creation of macromolecules (polymers) from monomers ==> Proteins, nucleic acids
3) Packaging macromolecules into lipid membranes (protocells)
4) Self-replicating molecules within protocells
What is the Primordial Soup Hypothesis and who made it? What were the requirements?
By Oparin and Haldane - Conditions on Earth were good for formation of small organic molecules IF AND ONLY IF:
1) No O2 available to create reducing environ. to promote addition of electrons to form larger molecules
2) Source of E
3) Chemical building blocks: water, ions, dissolved gases
What experiment performed to test Primordial Soup? Successful? Why?
Miller and Urey - Yes, bc simple organic molecules were formed (amino acids)
Since Oparin & Haldane:
1) Volcanic-atmosphere hypothesis
2) Meteors transporting organic molecules from space
3) Deep sea hydrothermal vents
T or F: Polymers from Monomers - Polymers will form w/o help from enzymes if temp is high enough for rx
True
Packaging organic polymers into protocells: What are vesicles
Simple lipid membranes
Packaging organic polymers into protocells: Simple lipid membranes (___) may have formed around _____. This would have created the ____
vesicles - organic polymers - first intracellular environment
T or F: Living organisms don’t need to be able to replicate themselves
False
What was most likely encoded as RNA in first living organisms?
Genetic info
RNA is key to synthesis of…
Proteins
Can some RNA molecules perform enzymatic fcts?
Yes
As RNA sequences become longer, they become less ___
Stable
RNA is more stable than DNA?
No. DNA is more stable
Order in chronological order:
a) First prokaryotes (single-celled)
b) First multicellular eukaryotes
c) Cambrian explosion (increase in diversity)
d) Colonization of land by fungi, plants, animals
e) First eukaryotes (single-celled)
a) First prokaryotes (single-celled)
b) First eukaryotes (single-celled)
c) First multicellular eukaryotes
d) Cambrian explosion (increase in diversity)
e) Colonization of land by fungi, plants, animals
Name Energy source and carbon source for:
1) PhotoAUTOTROPH
2) ChemoAUTROTROPH
3) PhotoHETEROTROPH
4) ChemoHETEROTROPH
1) PhotoAUTOTROPH =
Light (energy), CO2 and HCO3- (carbon)
2) ChemoAUTROTROPH =
Inorganic chems (H2S, NH3), CO2 and HCO3-
3) PhotoHETEROTROPH =
Light, Organic compounds
4) ChemoHETEROTROPH =
Organic compounds, organic compounds
Oldest known fossils of living organisms are: prokaryotic or eukaryotic
Prokaryotic
What is the oldest known fossils of living organisms? Were they prokaryotic?
Stromatolites (formed by ancestor of cyanobateria) - prokaryotic
What are the cause of modern-day stromatolites?
Cyanobacteria
In the proposed biological timeline, what took up most of it? How does it compare to humans?
Prokaryotes - Humans were small portion
First living organisms?
Prokaryotes
T or F: The 1st prokaryotes were all autotrophic and their first source of carbon was organic
False, first source of carbon was INORGANIC
Oxygen levels increased bc of:
Photoautotrophic prokaryotes
The presence of ___ in the atmos allowed for evolution of single celled aquatic ____
Oxygen - eukaryotes
Single celled eukaryotes evolved from ___
prokaryotic ancestor
Mitochondria are found in all ___ cells
eukaryotic
Mitochondria have double membrane: name them
Smooth outer
Complex inner
T or F: Mitochondria don’t have their own DNA and ribosomes
False
Function of mitochondria
Cellular respiration
How does mitochondria perform cellular respiration?
1) Use E from glucose, fatty acids, amino acids
2) Make adenosine triphosphate ATP
Are chloroplasts in all eukaryotic cells?
No, in plants and some protists (algae)
T or F: Like mitochondria, chloroplasts have 2x membrane and own DNA and ribosomes
True
What pigment is chloroplast? Where is it found?
Chlorophyll found in internal structures “Thylakoids”
Function of chloroplast and how
Photosynthesis - Transform light E into bond E forming glucose molecules
What is Endosymbiont Theory? What does it prove?
Cell living withing another cell - Proves that Mitochondria & Chloroplasts (organelles in euk cells) have OWN DNA AND RIBOSOMES different from ones in cytoplasm
Endosymbiont Theory proved that it occured 2 times: what are they?
1) Bacterium that could perform aerobic cellular respiration (became euk mitochondria)
2) Bacterium could perform photosynthesis (became euk chloroplasts)
The additions in mitochondria and chloroplasts are 2 distinct ___ gene transfer
Horizontal
What is the oldest known fossil of multicellular eukaryotes?
Red algae
Choose and fill in blank: The first animals were aquatic/inaquatic invertebrates similar to ___ modern day ___
Aquatic - sponges
What made the diversity of aquatic animals increase?
Cambrian explosion
Majority of life was in ___ habitats
water/moist
What helped liv. orgs. colonize land?
1) Formation of ozone layer (reduce UV radiation)
2) Evolution of traits to reduce reliance of water
What is the sequence of events?
1) Prokaryotes
2) Atmospheric oxygen
3) Single-celled eukaryotes
4) Multicellular eukaryotes
5) Animals
6) Land plants
7) Paleozoic
8) Mesozoic
9) Cenozoic
10) Humans
Land plants are before animals. T or F
False - animals then plants
Order: Cenozoic, Paleozoic, Mesozoic
1) Paleozoic
2) Mesozoic
3) Cenozoic
We can examine genetic diversity at many levels: Population, ___, and 3 domains: __, __, ___
species - Archaea, bacteria, eukarya
Which are autotrophic organisms: Producers, consumers or decomposers
producers
Which are heterotrophic organisms: Producers, consumers or decomposers
Consumers & decomposers
Producers, consumers or decomposers: Make up the base of a food web by synthesizing organic molecules from which all other organisms will depend upon (O2 and organic mutriends for consumers AND organic nutrients for decomposers)
Producers
Producers, consumers or decomposers: Must ingest producers/consumers to acquire carbon and energy
Consumers
Producers, consumers or decomposers: Digest organic molecules left by living organisms and absorb the breakdown products to acquire carbon and energy
Decomposers
