Final Pt 1 Flashcards by Hanna Song

Life as we know it on earth relies on two fundamental polymers: _____ aka RNA and DNA, and _____ aka proteins. These two compounds are interwoven in ____

polynucleotides, polypeptides, metabolism

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A chain of nucleotides linked together by dehydration reactions between the phosphate group of one and the sugar residue of the next

polynucleotides (ex. RNA)

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Two polynucleotide strands held together by H bonds between adjacent bases that store the genetic code

DNA

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The difference between DNA and RNA are that DNA contains _____ vs _____, ___ vs ___ and is ___ instead of _____ stranded

deoxyribose, ribose, thymine, uracil, double-stranded, single stranded

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DNA can be thought of as strings of _____. Units are 3 letter ____ representing a particular __ ___, Ordered succession of codons results in ____

letters, codons, amino acid, proteins

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mutations cause ___ within species. Some have __ __, most are ____ and in very rare occasions are ___.

diversity, no effect, detrimental, beneficial

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During transcription, only a ___ of one DNA strand is duplicated. ______ carries the information on how to build proteins. ____ have 3 base pairs on one end and at its other end displays a specific sequence of 3 nucleotides (____). In other words, RNA acts as a _____.

section, mRNA, tRNA, anticodon, catalyst

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Proteins have the diversity to allow them to perform the various functions necessary to maintain the living organism such as ___, __ ___ and signalling, ____ (enzymes), ______ _____, and _____ actions

structures, molecular recognition, catalysis, molecular transport, mechanical actions

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We know that life requires C-based macromolecules such as ___, ___, ___ and ___ ___. The smallest living units of life are __

lipids, carbohydrates, proteins, nucleic acids, cells

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Looking at present day biology and extrapolating backwards towards the simplest living entities

top down approach

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making the complex building blocks of life (organic macromolecules) and putting them together

bottom up approach

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Mycoplasma genitalium has the smallest known genome of free living organisms, with about ___ protein-coding genes and over ____ nucleotide pairs

480, 582,000

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Carsonella rudii has the smallest known genone of any living organism with ____ genes and about ___ nucleotide pairs. It is probably missing genes essential for life

182, 160,000

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There are corresponding segments of the gene for ____ rRNA (_____ nucleotides, coding for ribosome) for different organisms such as __, ___ and ____. Sites where the nucleotides are identical between species are indicated by a ___ ___. Genetic information has been _____ since the beginnings of life. By looking at the differences in the 165 rRNA we can identify the __ domains of life.

165, 1500, archaea, eukarya, eubacteria, vertical line, conserved, 3

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DNA has information to ___ itself but needs proteins to ____ the reaction. Oppositely, proteins can catalyze the reaction but need DNA to ____. It is unlikely that all compounds would from exactly _____ at the same time, so how did they come about

replicate, catalyze, replicate, spontaneously

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The RNA world hypothesis is that RNA is an ____ ___ like DNA, and can act as ____ unlike DNA. Thus the DNA/protein world may have evolved from an RNA world

information carrier, catalysts

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The problems with the RNA world are in terms of _____, whereby we don’t know how RNA type strings of nucleotides get produced without _____, as well as the ____ problem, where we don’t know how RNA type nucleotides find each other so as to combine into the first RNA type molecules that can _____

energy, life, dilution, replicate

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It could be that RNA could form, simple molecules started to form from simpler ______ ____ ___ via ____ cycles. Once these cycles were established, it began to produce ever more ___ compounds. These entities could be subject to a primitive form of ___ eventually giving rise to ___.

metabolically active entities, autocatalytic, complex, selection, RNA

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The primordial soup theory is that life began in a warm ____ or ___ from a combination of basic building blocks of life (______ ______), which grew into ever more complex molecules such as ____ and some early versions of ____.

pond, ocean, organic molecules, proteins, RNA

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Almost all organic C that we observe today is produced _____ via _____. A ____ gas mixture does not produce organic molecules on its own, so where did these organics come from before there was life?

biologically, photosynthesis, CO2

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In the Milley-Urey experiment, it was found that a ___ __ breaks the chemical bonds in ___, ___ and ____. The C, N, H, and O atoms can then recombine into various molecules such as ___, and ____, ___ ___, and other simple ____ molecules that eventually end up in the ___.

spark discharge, CH4, NH3, H2O, HCN, H2CO, amino acids, organic, ocean

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There is debate over the presence of large amounts of __ and ___ in the early atmosphere as used in the Miller-urey experiment. Additionally, in a ____ rich atmosphere, organic production by spark discharge is not very ____. If the ___/____ ratio is less than ___, there is essentially no organic production. If an atmosphere is dominated by CO2, the most abundant radical after spark discharge or ____ is ___. The products would be __, __, __ and ___.

NH3, CH4, CO2, efficient, CH4/CO2, 0.1, photolysis, O, NO, CO, NO2, H2O

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Organic molecules could have also been produced in hydrothermal vents, as they were likely to be present in the ____ _____. Organic synthesis requires only ___, ___, __ ___ and heat, and occurs through ______ or ___ _____.

prebiotic environment, CO2, H2O, silicate rocks, serpentinization, spinel polymerization

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Its also possible that organics were ___ and brought from ____. About _____% of chondrites are ____ which contain ___ ____, ____ and ____. However, these were not a good source of organic compounds. The native chondrite supported ___ ___, while the ___ chondrite was inhibitory and resulted in a decline of microbial cell concentration. ____ ____ particles provided a constant, ____ ___ of organic compounds to the surface of the earth.

synthesized, space, 5, carbonaceous, amino acids, hydrocarbons, fullerenes, microbial growth, pyrolyzed, interplanetary dust, steady flux

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The problem with extraterrestrial organic delivery is that they could only provide ____ organics, no large ____. Similarly, it is hard to accumulate necessary ___ of carbon for the concentrated ___ ____. Additionally, most organic matter is physically ____ ___ to be taken up directly by heterotrophic microorganisms. Consequently, many heterotrophs secrete _____ that break down large molecules outside the cell into smaller molecules.

simple, macromolecules, mass, prebiotic soup, too big, exoenzymes

Phosphorous is a very ____ element in the universe. On earth it is found as ___ ___ ____, which are not readily taken up and usually are not found in ____. The ratio of C:N:P in modern marine biomass typically showed limited variation around the canonical redfield ratio, which is ____C:___N: ___P

rare, insoluble phosphate minerals, water, 106, 16, 1

Phosphorous plays essential roles in phosphate groups in ___ and ____, ____, and ____.

DNA, RNA, ATP, phospholipids

Meteorites contain two forms of phosphorous, ____ and _____. The latter rusts in the presence of water to form a __ and ___ P.

apatite, schreibersite, soluble, reactive

Phoshorylation, which is the addition of a ___ group, it vital for the cellular storage and ___ of ____ ___ using energy carrier molecules.

PO3, transfer, free energy

ATP, the most abundant energy carrier molecule, has two high energy ____ bonds that can be broken to release free energy or vice versa added to ___ to store it as ___ energy for later use. We find that in general, ____, ___ and ___ are N poor and P rich compared with nearby stars. However, the dearth of P abundance data, which exists for only ___% of all stars and ___% of exoplanet hosts, makes it difficult to deduce clear trends in the stellar data let alone the role of P in the evolution of an exoplanet

phosphate-phosphate, ADP, chemical, plankton, earth, mars, 1, 1

It is possible that the primordial soup was probably too _____ in simple monomers to form very ___ molecules.

dilute, long

Ancient rocks are rare because they are ___, ___, ____ or ___ into space. The surviving rocks are changed by ____ (pressure and ___), strongly affecting fragile _______ ____. Moreover, not every rock can contain evidence for life, for example ____ rocks. Additionally, single-celled _____ did not have any ___ or ____, and may have been very different from life today. The last issue is that there may have been _____ from younger rocks mixing with older rocks

buried, eroded, subducted, ejected, metamorphism, heat, biological signatures, igneous, prokaryotes, bones, shells, contamination

C13 is common in ___ material from ___ ___. Natural carbon is a mix of ___ and ___. Photosynthesis prefers __ to ____

abiotic material, outer space, C12, C13, C12, C13

preserved remains of microbial organisms

microfossils

Microfossils can be as small as a few tens of __. They are either simple ___, or simple ___. They are best preserved in ___ (fine grained sedimentary rock that resists weathering and metamorphosis.

microns, spheroids, filaments, cherts

Sometimes ___ ___ or _____ can be interpreted as microfossils such as ____ _____ because of their dark, ______ ____ shape

crystal ghosts, contaminants, cyanobacterial microfossils, curved filament

Stromatolites are ___ ____ structures accreted as a result of ___ growth. They represent fossils of ____ ___ ____ (cyanobacteria) that build ___ similar to corals.

laminated sedimentary, microbial, colonial photosynthesizing microbes, reefs

Certain ____ molecules found in ancient organic matter like ___ or ___ are recognizable derivatives of biological molecules. They are hard to measure and ___ is a big problem

hydrocarbon, kerogan, oil, contamination

all terrestrial life require ___, __ and __ ___. All terrestrial multicellular life also requires high ___ and some protection from ___

nutrients, energy, liquid water, O2, UV

The stratospheric ozone is ____km in altitude, and contains ____% of the atmospheric ozone. The current issues are the long term global ___ trends, as well as the springtime ___ __ ___ each year. The stratospheric ozone absorbs parts of the ____ spectrum where other gasses do not absorb, which is beneficial for us

15-30, 90, downward, antarctic ozone hole, UV

The tropospheric ozone contains ___% of the atmospheric ozone and has ____ effects on humans and vegetation. Current issues are the episodes of high surface ozone in __ and ___ areas

10, toxic, rural, urban

Both O2 and O3 are important to the biosphere but ___ cannot form without O2. While volcanic gasses contain ___, ___ and ____, there is no O2. Today the major source of O2 is ____

O3, CO2, H2O, SO2, life

Oxygen abundance in the atmosphere is a result of the balance between ___ and ____. The atmosphere doesn't have much ___, thus any change in the balance of sources vs sinks results in the ____ changes in atmospheric oxygen

sources, sinks, mass, rapid

a region around any star where a planetary body can maintain liquid water on its surface

circumstellar habitable zone

The fraction of incident sunlight that is reflected

albedo

Using the earth's albedo of ____, the mean surface temperature is calculated to be ____°C colder than what we observe. This is because this doesn't take into account the difference between the surface temperature and ___ ____ due to the _____ effect

0.30, 33, emission temperature, greenhouse

_____% of visible light is absorbed by the ground. The greenhouse effect is when this absorbed radiation is re-radiated in the _____, then ____ by some ___ in the atmosphere. This radiation radiates back to the ____, causing the surface to be ___ than without the greenhouse gasses

70, infrared, absorbed, re-emitted, gasses, planet, warmer

Greenhouse gases must have a total or internal ___ ____, absorb energy in the ___ portion of the EM spectrum, and due to this, increase the ___ and ____ of the molecules. The gain of this kinetic energy may be transmitted to other molecules such as __ and ____ and cause a general heating of the atmosphere.

dipole moment, UV, vibration, rotation, Oxygen, nitrogen

Non greenhouse gasses have an __ ____ that is distributed equally over the atoms in the molecule. They also cannot be ___ to have a dipole moment

electron cloud, made

The outgoing IR radiation includes Earth's radiation but also the __ part of the reflected solar spectrum. The magnitude of the greenhouse effect depends on the ___ of greenhouse gasses.

IR, abundance

The water content of the atmosphere varies about ____ fold between the hot humid tropics and the cold and ___ polar ice deserts. ____ ___ is the main absorber of radiation in the atmosphere, accounting for ____% of all atmospheric absorption of radiation, mainly in the ____.

100, dry, water vapor, 70, IR

Liquid water and ice droplets are also present in the atmosphere as ____. These reflect ____ which cools the earth, and trap heat in the same way as ____ ____, and thus warm the earth. ___, ____ clouds have a high albedo, reflecting more sunlight, while ____, ___ clouds have a low albedo, letting most solar radiation through

clouds, sunlight, greenhouse gasses, low, thick, high, thin

The point at which the planet can avoid a runaway greenhouse effect

the inner edge of the habitable zone

The runaway greenhouse effect likely happened on Venus, as venus' atmosphere has a very high _____ ratio, ____x higher than earth's and any other body in the solar system, suggesting a huge ___ loss

D/H, 120, H

The distance from the sun at which even a strong greenhouse effect would not allow liquid water on the planetary surface

the outer edge of the habitable zone

In the past, the habitable zone was ___ to the sun, and over time, it ____ ___. This is due to the increase in ___ __ with time, and thus the decreasing ___ in the boundaries of the habitable zone

closer, expanded outwards, solar luminosity, range

The ____ the fossil record gets, the more difficult it is to read it and the ____ samples that are available. Thus, indirect evidence such as ____ changes in ____ are used.

older, less, isotopic, 13C

After a mass extinction _____ and ____ are dominated by opportunistic species like __ and ____. There is also a rapid ____, and ____. ___ ____ will not survive

floras, faunas, weeds, pests, reproduction, diversification, apex predators

Sea levels changes alter the area of ____ __ or land available for colonization. The ____ of species is correlated to the physical area of habitat available. The more that is available, the more ___ can be accommodated.

continental shelf, diversity, species

During a supernova explosion calculated to occur using the solar system's ____ million year orbit around the galaxy, will result in ____ _____ ____, which are intense and very ____ bursts of radiation. These are possibly caused by collisions between ____ ___, and could cause changes in ___ ___ if they occurred close enough. The major problem with assigning these events as causes of _____ ___ is the difficulty of linking the events with changes in the __ ___

250, gamma ray bursts, distant, neutron stars, atmospheric conditions, mass extinctions, rock record

The K/Pg boundary shows evidence of a mass extinction and divides the age of ___ from the age of ____. There is dramatic change in the types of ____ deposited on either side of this boundary. there is a lot of evidence of a ____ impact.

dinosaurs, mammals, fossils, asteroid

shocked quartz has a ____ structure that is different from normal quartz. Under the intense _____, the crystalline structure of quartz is ___ along planes inside the crystal. These planes which show up as lines under a microscope, are called _____ _____ _____, or ___ ____. Shocked quartz was discovered following ___ ___ ____ testing which generated the intense pressures

microscopic, pressure, deformed, planar deformation features, shock lamellae, nuclear weapons testing

microscopic glassy particles formed from molten rock ejected from the impact craters

spherule layer (microtektites)

The rate at which impacts produce craters on the moon is used to ___ ages in planetary science. Earth should have also received similar numbers of impacts, but many craters have been hidden by ___, ____ ___, etc. Mazrouei et al used ____ images of the moon to estimate the ages of young lunar craters, and found that the impact rate increased within the past ____ million years. The similarities between the lunar and ___ distributions suggests that the inferred increase in terrestrial impacts is not a ____ ____.

callibrate, erosion, ice sheets, infrared, 500, terrestrial, preservation bias

During the end of the cretaceous, there was evidence for large scale ___ activity associated with rising __ ____ from the mantle. The ___ ___ in India record the eruption of large amounts of lava over prolonged time periods.

volcanic, heat plumes, deccan traps

volcanism has been proposed for other mass extinctions. For example the massive ___ ____ in Siberia are associated with the _____ extinction and these have been proposed as a contributor to major ___ ___. There appears to be a correspondence between some but not all ___ __ and major volcanic episodes.

flood basalts, end-permian, climate change, mass extinctions

Other mass extinctions aren't associated with big ___ ___ or _____ indicators. There are no major extinctions associated with other large ___ on earth. There are many _____, but we don't quite know what triggered most mass extinction events

iridium spikes, impact, craters, hypotheses

Organisms (mostly microbes) that thrive in (and sometimes require) extreme conditions; earliest living organisms on earth

Extremophiles

Organisms have upper temperature limits, as ___, ___ and __ ___ denature at high temperatures. ____ also have optimal temperatures for activity, and ____ at low temperatures. Additionally, the ___ of gasses goes down as the temperature goes ____. At low temperatures, water ___ and ____, and crystals can then break up _____.

chlorophyll, proteins, nucleic acids, enzymes, slow, solubility, up, freezes, expands, membranes

high pressures can make ___ ___ relatively impermeable for _____. The current upper limit is greater than ______ atm.

cell membranes, nutrients, 1000

Within the cell, pH levels must be ___, as proteins ___ at very low pH

neutral, denature

Extreme salinity prevents ____ ____, as proteins are ___ soluble at high salt concentrations.

protein aggregation, less

Extreme desiccation can cause ____ ___ changes to lipids, proteins and ___ ___.

irreversible phase, nucleic acids

How efficiently the water present in a system can take part in a reaction or in a physical process

water activity

Any new ___ ___ contains new life forms. Deep sub-seafloor biosphere is the least explored habitat on earth, yet it may make up ___ to ____ of the earth's living biomass. This may help us look for life beyond earth.

hydrothermal vent, 1/10, 1/3

Final Pt 1 Flashcards

(75 cards)