UNIT 2 ORIGINS OF LIFE Flashcards

1
Q

What are the 7 characteristics that all forms of life share?

A
  • They have a display order (cell being the fundamental unit of life)
  • Harness and utilize energy
  • Reproduce
  • Respond to stimuli
  • Do homeostasis
  • Grow and develop
  • They evolve
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2
Q

What are the 3 main ideas of the cell theory?

A
  • All organisms are composed of one or more cell
  • Cell is the smallest unit that has the property of life
  • Cells are from growth and division of preexisting cells only.
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3
Q

What was the type of atmosphere in early atmosphere?

A

Reduced atmosphere

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4
Q

What is a reduced atmosphere?

A

Lack of oxygen or other oxidizing gases, leads to the production of complex organic molecules.

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5
Q

Early atmosphere constitutants?

A

Large amount of water, hydrogen sulphide, carbon dioxide, ammonia and methane.

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6
Q

What is an oxidizing atmosphere?

A

02 rich atmosphere that oxidizes surface compounds.

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7
Q

What is the atmosphere we have today?

A

Oxidizing atmosphere

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8
Q

Miller-Urey experiement?

A

Confirmed the reducing atmosphere created building blocks for the creation of life.

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9
Q

How did the mille-Urey experiment worked?

A

They placed the components of a reducing atmosphere in a closed environment and exposed them to an energy source. After a week they found lots of organic compounds in water.

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10
Q

What are protobionts?

A

The first cell. Are abiotic.

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11
Q

What is the Oparin-Haldane hypothesis?

A

Earth was a reducing atmosphere having a lot of electrons that can easily be donated.

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12
Q

What are ribozymes and what do they do?

A

They are a group of RNA molecules that can catalyze reactions on the precursor RNA molecule that leads to their own synthesis.

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13
Q

What did RNA served for in primordial earth.

A

Both the information and the catalyst

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14
Q

First energy releasing reaction in primitive cells?

A

Oxydation-reduction reactions.

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15
Q

Exemple of an oxidation-reduction reaction.

A

We oxidize food molecules to release energy and reduce other molecules like those needed for protein synthesis.

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16
Q

What is panspermia?

A

The hypothesis that simple forms of life are present in space and could have seeded early earth.

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17
Q

Panspermia points?

A
  • too little of a window to create life between the cooling of earth and first evidence of life.
  • The presence of extremophiles
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18
Q

Prokaryotes are 2 organisms?

A

Archea and bacteria

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19
Q

What are the properties of prokaryotes?

A

They have a plasma membrane and a cytoplast consisting of cytosol. Organelles, electron transport chain, chromosomes and DNA in nucleoid.

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20
Q

Are prokaryotes 10 times smaller than eukaryotes?

A

Yep

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21
Q

Prokaryotes have a high metabolic flexibility meaning that:

A

They can use a variety of substances as a source of energy and carbon source and they synthesize almost all their organic molecules from raw inorganic materials.

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22
Q

The evidence of atmospheric increase in CO2 about 2.5 million years ago is shown by what?

A

Banded iron.

23
Q

How is banded iron formed?

A

In the sediments of lakes and oceans as dissolved oxygen reacted to dissolved iron which formed rust.

24
Q

What causes our atmosphere to have CO2 now?

A

Cyanobacteria. Could harness electrons from water and by doing so was forming CO2 that was released. With time the CO2 accumulated in the atmosphere.

25
Q

What is oxygenic photosynthesis?

A

Photosynthesis that relies on oxydation of water and releases CO2.

26
Q

Ho does eukaryotes distinguish from prokaryotes?

A

They have a nuclear enveloppe, cytoplasm has membrane bound compartiments with specialized functions (mitochondria, chloroplasts, endoplasmic reticulum, Golgi complex) they also have motor proteins to move cells.

27
Q

What is an endomembrane system?

A

Collection of internal membrane sacs that divides the cell into functional compartments called organelles.

28
Q

The endomembrane system is derived from the plasma membrane how?

A

Pockets of plasma membrane extended inwards and surrounded the nuclear region, forming the nucleus. The remaining of those membranes formed ER and the Golgi complex.

29
Q

What is the endoplasmic reticulum?

A

interconnected network of channels and vesicles.

30
Q

What is lumen

A

the space inside a vesicle

31
Q

Rough ER.

A

Contains many ribosomes on it’s outer surface.

32
Q

Smooth ER.

A

Doesn’t contain any ribosome on its surface.

33
Q

Where is the Golgi complex located?

A

Between the rough ER and the plasma membrane.

34
Q

What is the theory of endosymbiosis?

A

That mitochondria and choloroplasts evoked from ingested prokaryotes.

35
Q

Evidences of the theory of endosymbiosis?

A
  • Morphology, mitochondria ressembles aerobic prokaryotes while chloroplasts resemble cyanobacteria.
  • Reproduction, Only derived from preexisting.
  • They both have DNA
  • Generates ATP from electron transport chains.
36
Q

Cytoskeleton

A

system of protein, fibers and tubes that extend through the cytoplasm

37
Q

Function of cytoskeleton?

A

reinforces the plasma membrane and helps the cell stay in shape and maintain their internal organization. Also gives mechanical support to carry division and movement.

38
Q

3 structural elements of cytoskeleton?

A

-microtubules,
-Intermediate fillamanents
-microfillaments
All interlinked.

39
Q

Plant cytoskeleton contains only

A

microtubules and microfillamanet

40
Q

Structure of motor protein

A

one end is attached to the cell, the other end walks along a microtubule or microfilament and then releases. It Neds ATP.

41
Q

Cytoplasmic streaming

A

Active flowing motion of cytoplasm

42
Q

What is a flagella?

A

La queu. Helps in movement of the cell.

43
Q

Flagella in prokaryotes

A

Made of a protein called flagellin

44
Q

Flagella in eukaryotes

A

Constitute of microtubules.

45
Q

Analogous structures

A

same functions but not the same evolution history

46
Q

Homologous structures

A

same evolutionary history

47
Q

Why eukaryotic cells are larger than prokaryotes?

A

The size of the cell is determined by the surface being able to supply it’s volume with necessary metabolic requirement. They have a large area of internal membrane structures.

48
Q

Multicellular eukaryotes

A

Cells are not identical in structure and function, they help each other to benefit the entire organism.

49
Q

Cell colony

A

group of cells that are only one type

50
Q

How long did it take for eukaryotes to develop from prokaryotes ?

A

1.3 billion years.

51
Q

Approximate age of planet?

A

4.6 billion years

52
Q

What is RNA

A

Ribonucleic acid. translate the genetic code to proteins from DNA with the help of ribosomes.

53
Q

What is DNA

A

The molecule that contains the genetic code of an organism.