Tags & Description
What is the name for ordinary matter?
Baryonic matter
What forms protons and neutrons?
Quarks
What is a nucleon?
Protons and neutrons
What is kB?
Boltzmann constant
Equation linking kB, energy and temperature
E = kBxT
What is plasma?
Hot ionised gas
What are the CHNOPS elements?
Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur
Why is Silicon not found in life?
Bonds strongly to Oxygen
Where is Silicon found in life?
Phyloliths in plants (provides stability)
Are amino acids in life right or left handed?
Left (except glycine)
Are sugars in life right or left handed?
Right
Why might ammonia be a good solvent for life?
Dissolves chemicals, high heat of vapourisation, high heat capacity
How big are eukaryotes?
10-100 um
How big are prokaryotes?
1-10 um
Why is having only one phylogenetic tree sig?
Suggests life only evolved once (life is unusual)
What is the 'mesh' called that protects cells?
Peptidoglycan
What enzyme unwinds the DNA dbl helix?
topoisomerase
Why are microbes not 'simple life'?
have chemotaxis, can move, same evolution period
What shows an absorption on a graph?
A dip/trough
What is an emission spectra?
photons produced by an energised gas, element or molecule
What is a protoplanetary disk?
Planet forming regions of dust around stars
How hot is the outer disk of a protoplanetary disk?
10K
How hot is the inner disk of a protoplanetary disk at 10AU?
100K
How hot is the inner disk of a protoplanetary disk at 1AU?
1000K
What happens at the inner disk of a protoplanetary disk?
Ice evaporates
What is present on the outer disk of a protoplanetary disk?
Frozen molecular gas on dust grains
What type of molecules are formed in protoplanetary disks?
Complex molecules (sugars and bases)
What evidence is there for the formation of complex molecules in protoplanetary disks?
Molecules present on asteroids (left over material from planet formation)
What are grains in space?
Solid silicaceous/carbonaceous material with ice on exterior
Why are grains significant for chemistry?
Solid surface for reactions
Why is chemistry difficult in space?
Low temperatures and pressures
What are PAH's?
Polycyclic aromatic hydrocarbons
Why are PAH's significant?
Stable
What can PAH's react to form?
Complex, ringed carbon compounds (e.g. fullerenes and quinones)
Define catabolism
Process of an organism obtaining energy and raw materials from nutrients.
Define anabolism
Process of an organism using energy and raw materials for biosynthesis
Define metabolism
Processes of catabolism and anabolism
Prefix for organisms that obtain energy from light
Photo
Prefix for organisms that obtain energy from chemical compounds
Chemo
Prefix for organisms that obtain Carbon from CO2
Auto
Prefix for organisms that obtain Carbon from organic compounds
Hetero
Prefix for organisms that obtain Carbon from both CO2 and organic compounds
Mixo
What order are proteins in the ETC in?
Increasing electronegativity
What does electron movement generate?
Free energy
What is pmf?
Proton motive force
Equation linking pmf, water potential, R, T, F and pH?
pmf=△waterpot. - (2.3RT/F)(△pH)
How is pmf generated?
Pumping protons across a membrane
What is the final electron acceptor in anaerobic respiration?
Inorganic Molecules (not oxygen)
What is the final electron acceptor in aerobic respiration?
Oxygen
Example of an organism uses nitrates as its final electron acceptor?
Pseudomonas
What is another name for a chemoautotroph?
Chemolithotroph (rock eater)
What does anoxygenic photosynthesis use?
Sulfur (or sulfide)
Example of an organism that uses anoxygenic photosynthesis
Chlorobium
What is the word used to describe a reaction with a negative free energy change?
Exergonic (energy given out)
What is the word used to describe a reaction with a positive free energy change?
Endergonic (energy taken in)
What is the word used to describe a reaction with a free energy change of zero?
Equilibrium
Equations for Gibbs Free Energy change
△G = -nFE and △G = -2.303(pE)
What is pE analogous to?
pH
Equation for pE
pE = EF/2.303RT
Where on the electron tower are the best electron donors (oxidisers) found?
Top/higher (more negative value)
Define phylogeny
Evolutionary history of a species or group of species.
What area of science classifies organisms and determines their evolutionary relationships?
Systematics
Define analogy
Similarity due to convergent evolution
Define homology
Similarity due to common ancestry
What is a good molecule to analyse to determine evolutionary relationships?
rRNA (highly conserved)
What can phylogenetic tree branches represent?
Number of genetic changes OR chronological time
What is the name for the technique that allows predictions about features of a common ancestor?
Phylogenetic bracketing
What are the three methods of horizontal gene transfer (HGT)?
Transformation, transduction and conjugation
Where does genetic info come from in transformation HGT?
Environment
Where does genetic info come from in transduction HGT?
Microbes via an agent (e.g. a virus(bacteriophages))
Where does genetic info come from in conjugation HGT?
A pilus from one bacterium to another (usually plasmids)
What can HGT lead to?
Antibiotic resistance
What domain are most extremophiles from?
Archea
What temperature range can Tardigrades endure?
151 to -200 degrees celcius
What pressure range can Tardigrades endure?
Vacuum to 1200x atm
How long can Tardigrades survive without water?
10 years
What radiation can Tardigrades endure?
1000x more ionising
What are organisms that live in hot environments called?
Thermophiles (50-80 degrees), Hyperthermophiles (80+ degrees)
What are organisms that live in salty environments called?
Halophilic
What is an adaptation to a hot environment?
Modified cell membrane compositions to prevent increased fluidity
What is an adaptation to a cold environment?
Double bonds to prevent close packing and so increase membrane fluidity
What is an adaptation to a saline or dry environment?
Control of water loss and cell dormancy to overcome issues with osmotic pressure and water availability
What are most extremophiles (energy and carbon source)?
Chemolithotrophs
What is the name for organisms that live in multiple extreme environments?
Polyextremophiles
How could extremophiles be used in space?
Oxygen production, nitrogen fixation
Why are hydrogen bonds used between bases in DNA?
Require little energy to overcome (replication easier)
What type of bonds are more common in extreme environments?
Covalent and Ionic (strong)
Why is water's negative melting curve on phase diagrams significant?
Ice floats so water environment more stable below
What is degenerate matter?
Free, non-interacting particles (more dense than a solid)
Where is degenerate matter found?
White dwarfs, neutron stars
Why is carbon the basis of life?
Bonds to itself (chains), stable bonds
Why is water a good solvent?
Polar (dissolves ions), abundant, stable
Why is radiation important for chemistry?
Transfers energy
Why does HGT make building phylogenetic trees difficult?
Gene transfer between non-related organisms