Early Life Test: Conditions Of Early Earth And The Synthesis Of Hereditary Information

Question 1

Nucleic Acids

Answer 1

Macromolecules containing H O N C P that are assembled from nucleotides
They store and transmit Genetic Info DNA and RNA

Question 2

Nucleotides

Answer 2

Made of a 5 carbon sugar a phosphate group and a nitrogenous base
Joined by covalent bonds to make nucleic acids
Ex ATP holds and transfers chemical energy

Question 3

Proteins

Answer 3

Macromolecules that contain N C H O

Amino acids are joined by peptide bonds to make a polypeptide polypeptides make proteins

Question 4

Atmosphere of early earth

Answer 4

Little oxygen mostly carbon dioxide water vapor nitrogen with a little carbon monoxide hydrogen sulfide hydrogen cyanide
H2O H2 CH4 NH3

Question 5

Could organic molecules assemble under the conditions of early earth

Answer 5

In 1953 Stanley Miller and Harold Urey tried to answer that question

Question 6

Steps to Experiment

Answer 6

1. Water is heated Water vapor forms
2. Mix of methane ammonia and hydrogen is added to atmosphere
3. Circulating gases are bombarded by sparks of electricity
4. Cold water cools chamber causing droplets to form
5. After a week liquid is collected containing amino acids and other organic compounds.

Question 7

Chemical evolution theory made by who

Answer 7

J.B.S. Haldane and A.I. Oparin

Question 8

Chemical evolution theory

Answer 8

1. Abiotic synthesis of organic monomers ex amino acids and nucleotides
2. The joining of these monomers into polymers ex proteins and nucleic acids
3. The abiotic grouping of these macromolecules into protobionts
4. The origin of genetic material

Question 9

Two difficulties scientists face in explaining how the first monomers combined how does clay solve these

Answer 9

The monomers were too far apart to spontaneously combine together and there were no enzymes to catalyze the reaction
clays solves these because the solutions containing the monomers would drip onto the clay the water would then evaporate leaving the monomers the zinc and iron in the clay catalyze the reaction
monomers bond to charged sites on clay molecules

Question 10

What is a protobiont how do they share characteristics with modern organisms

Answer 10

A protobiont is a self organized aggregate of abiotically produced molecules
Protobionts maintain a stable internal environment reproduce they respond to their environment and they metabolize

Question 11

How is the transmission of genetic information different from the process of growing and splitting

Answer 11

In growing and splitting, unique traits become more and more diluted and there is no chance for evolution
Genetic information makes it possible to transmit instructions for making more of those key molecules

Question 12

Why is RNA a good candidate for the first molecule capable of self replication

Answer 12

Currently we have a system of DNA to RNA to protein but this is too complicated to have appeared all at once. RNA came before DNA because it is less complex and RNA is autocatalytic

Question 13

Why might DNA have eventually replaced RNA as the repository of hereditary material

Answer 13

DNA is more stable and less likely to break down while still allowing some variation

Question 14

What is panspermia does it contradict the theory of chemical evolution why or why not

Answer 14

Panspermia is the idea that organic molecules were brought to earth via comet or meteorite
It doesn’t contradict the theory of chemical evolution it just requires that the first step happened on a different planet

Question 15

Do you think life is restricted to earth

Answer 15

No

Question 16

Earth

Answer 16

4.6 Billion years ago

Question 17

Life

Answer 17

3.5 Billion years ago

Question 18

Oxygen

Answer 18

2.6 Billion years ago