Hydrothermal Vent Origin of Life Model

Question 1

7 stage of fluid movement at hydrothermal vents

Answer 1

1) cold water seeps into crustal cracks
2) O and K removed from seawater
3) Ca, (SO4)2-, and Mg removed from fluid
4) Na, Ca, K from crust added to fluid
5) Fluid at hottest temp = Cu, Z, Fe, S from crust added to fluid
6) hot fluid rises, carrying dissolved metals through crust
7) cold-oxidated- and hot-reduced- waters mix, forming black metal-sulfide minerals

Question 2

What is serpentinization?

Answer 2

Hydration and metamorphic transformation of ultramafic rock

Question 3

why is serpentinization important?

Answer 3

it produces hydrogen gas, which reacts with CO2 to create organics

Question 4

Where is inorganic carbon dominant at hydrothermal vents?

Answer 4

Center of vent, where the temperature is hottest

Question 5

Where is organic carbon dominant at hydrothermal vents?

Answer 5

flanks of the vent, where the temperature is cooler

Question 6

What is a Fischer-Tropsch reaction

Answer 6

two step conversion of CO into organic carbon

Question 7

What are the two steps in a Fischer-Tropsch reaction?

Answer 7

1) H2 and CO2 convert to water and CO
2) CO and more H2 convert to Methane and water

(there are other steps two possibilities)

Question 8

How does Hydrothermal Vent theory address dilute concentrations in seawater?

Answer 8

Mineral Templates , surface metabolism model
(mineral surfaces collect dissolved species, causing them to concentrate and act as catalyst)

Question 9

How does mineral surface catch dissolved species?

Answer 9

1) the surfaces are not fully bonded,
2 ) oxygen in water will fill those gaps in the surface
3) hydrogen will rearrange to create hydroxyl (OH-)groups

Question 10

What charges are possible on a oxide mineral surface?

Answer 10

positive, neutral, negative

Question 11

What determines the charge on a oxide mineral surface?

Answer 11

pH
more acidic = positive charge
more basic = negative charge

Question 12

Why is charge of an oxide mineral surface important?

Answer 12

It allows different anion and cations to concentrate on the surface

Question 13

What charges will clay surfaces have?

Answer 13

net negative, potential for sections of positive due to hydroxyl groups at edges sites

Question 14

What causes changes in clay surfaces charges?

Answer 14

net negative areas = vacancies/holes due to elemental substitutions
edge sites = pH of solution

Question 15

What are two ways that ice connected to origin of life theories?

Answer 15

1) small lenses of liquid water trapped in the ice allow for very concentrated solutions
2) chirality

Question 16

what is chirality?

Answer 16

non-superimposable mirror-image (like hands)

Question 17

How is chirality connected to life?

Answer 17

Some molecules that life as we know it uses heavily (D and L sugars) have chirality.

Question 18

What is one theory that explains how chiral molecules used in biological systems formed?

Answer 18

Chiral molecules are optically active (react to polarized light that has specific directionality). Ice polarized light. So the polarized light could have hit molecules as they were synthesizing such that they would become chiral.

Question 19

RNA World theory

Answer 19

that life with just RNA existed prior to the current system of RNA, DNA and proteins

Question 20

Why is RNA World theory viable?

Answer 20

RNA can do all the jobs:
catalyze reactions (protein’s job)
store information (DNA’s job)
utilize information (RNA’s job)

Question 21

Why change from RNA World?

Answer 21

DNA and protein complete their roles more efficiently than RNA
DNA is more stable
variety of proteins make them more flexible