In The Beginning Flashcards
What does LUCA stand for?
Last Universal Common Ancestor
What are the characteristics of life?
Growth, Response, Reproduction, Heredity, Homeostasis, Metabolism and Cells
When was life thought to have first evolved?
4000Ma
What are the characteristics of LUCA?
A cell membrane (lipid bilayer), RNA, DNA, Ribosomes.
What are the 7 kingdoms of life?
Bacteria, Archaea, Protista, chromista, Plantae, Fungi and Animalia
What are the 3 domains of life?
Bacteria, Archaea and Eukarya
What is Taxonomy and who developed it?
It is the science of naming and sorting things and was developed by Carl Linnaeus.
What is the 2nd law of thermodynamics?
The total entropy of an isolated system can only increase over time.
What was the Urey-Miller experiment and why was it important?
A chemical simulation of the early Earth was set up and energy was added via heat and a spark. This showed that the formation of the molecules required for life could have been spontaneously created.
Which molecule is thought to have been the first to play a role in storing biological information?
The central dogma is that DNA makes RNA which makes protein. However, RNA itself has the ability to act as a catalyst and is directly involved in protein synthesis (as tRNA and rRNA). DNA is more stable and less chemically reactive and is thought to have evolved later, as a long term storage of information.
What was the chemiosmotic theory proposed by Peter Mitchell?
The chemiosmotic theory states that electron transport results in the movement of positively charged ions from one side of a membrane to another. Those ions then move back through the membrane, down a concentration gradient, through an ATP synthase, generating ATP from ADP and phosphate. In this way, electrical energy is converted to potential energy (gradient) and then into chemical energy (ATP).
How does an electron transport chain work (ETC) and what are its benefits?
Electrons flow from high energy reduced sources to low energy oxidised receptors, in doing so they turn the ‘water wheel’. This system is highly adaptable as it can be used to rotate multiple ‘wheels’ and in different directions giving life great adaptability.
What system did Archaea such as Halobacteria develop to capture light energy?
Halobacteria use retinal (vitamin A) instead of chlorophyll. Retinal is bound to a membrane (bacteriorhodopsin) and a long chain of double bonds (conjugated system) that allows the absorption of (blue-green) light via cis-trans isomerisation.
What limits the Archaea system for capturing light energy compared to the bacterial system?
It doesn’t produce a reducing power whereas the bacterial system does.
How does the bacterial system of photosynthesis work?
Photosynthetic reaction centres contain a dimer (two core proteins) and a special pair, The special pair of chlorophyll absorb light and enter a highly reducing state. This gives an electron to a quinone on the other side of the dimer (charge separation) converting light energy into chemical energy and producing chlorophyll and quinone molecules. These molecules then regenerate themselves by oxidising or reducing themselves.
