A2.1 origin of cells Flashcards

Question

fluorescence miscroscopy

Answer 1

When the dye is added to the sample it will preferentially attach to certain structures. As in immunofluorescence, the labelled areas will appear as brightly coloured spots, allowing visualisation of the target molecule throughout the specimen.

Answer 2

complex netowrk of fibres made of 3 proteinaceous elements microfilaments intermediate filaments microtubules

Answer 3

protein subunits- actin strucutre- two intertwined strands functions- maintain cell shape, motility, contraction, cytokinesis can grow or shrink as actin subunits added or taken away

Answer 4

protein subunits= fibrous protein eg.keratin strucutre- fibres wound into thicker cables functions- maintai cell shaoe, anchor nucleus and organelles form dense network help anchor nucleus into place

Answer 5

protein subunits- a and b tubulin dimers strucutre- hollow tubes functions- maintain cell shape, motilit, move chromsomes, move organelles largest cytoskeletal component, grows and shrinks as tubulin subunits added or removed

Answer 6

all help maintain cell shape

Answer 7

can move and change alter cell shape meaning materials can move in and out of ell, and cell itself can move

Answer 8

secretory vesciels

Answer 9

centrioles

Answer 10

the smaller the organelle the highest its speed

Answer 11

last universal common ancestor all living organisms originated from one common ancestor LUCA- gave rise to prokarayotic eukarayotic prokarayotic give rise to; -eubacteria -archae eukarayotic give rise to; -protist -fungi -plant -animal

Answer 12

1- infolding of the prokarayotic cell membrane- creates internal micro-enviornments, advantage= increase efficiency 2- theory of endosymbiosis -early eukarayotic cells engulfed aerboic bacteria but did not digest them, led to the origin of mitpchondria -early eukarayotic cells engulfed photosynthetic bacteria, did not digest them, led to origin of chloroplast

Answer 13

1.ancestral prokarayote (lacks internal membrane compartmentalisation) 2.given enviornmental or abiotic changes prokarayotic cells adapted their structure by forming invaginations of cell membrnae 3. this internal folding formed a vesicle that trapped dna round in the cytoplasm forming nucelar membrane 4. those primitive eukarayotic cells evolved by forming other membrnae bound organelles that originiated from the infolding of plasma membrane

Answer 14

1. formation mitochondrion eukarayotic cells engulfed ancwestor aerobic bacteria evidence for this, it that mitochondira had an internal membrane composed of proteins found in abcteria cells + an external membrane composed of proteins found in eukarayotic cells 2. formation chloroplasts same thing but engulfmenet of photosyntheticn bactertia note// fluidity of membrane allows endocytosis to occur

Answer 15

- same approcimate site and shape as prokarayotes -mitochondria and chloroplast, double membrane, inner is from prokarayotic and outer membrane from eukarayotic -both have 70s ribosomes while eukarayotes has 80s ribosomes

Answer 16

-circular naked DNA like prokarayotic cells, eukarayote= linear- dna wraped histone proteins -share common DNA sequences with bacterial cells

Answer 17

-move independetly without support cytoskeleton, move independently with eukarayotic cell -reproduce independetly of host cell through process similar to binar fission -are inhibited by antibiotics as are prokarayotes

Answer 18

because one cell livid with the other and became increasingly interdependet until the unit could only exist as a whole

Answer 19

first cells must have arisen from non living material

Answer 20

independently proposed nearly identical hypothesis for steps of how life was created

Answer 21

= prebiotic formation of carbon compounds inroganic compounds -> organic compounds (condition early earth led to formation carbon compounds eg. amino acids, nitrogenous bases -> polymer (monomers may have been able to spontaneously form polymers an early earth via anabolic reacions creating proteins and RNA strands ->self-replication (formation nucleis acid polymer (likely RNA) that can encode hereditary info, self replicate and catalyze chemical reactions ->formation of cell (protocell), (packaging molecules into membranes with an internal chemistry different from surroundings. Fatty acids can spontaneously form spherical bilayers, perhaps encapsulating the slef replicating molecules -formation of protocells that carry out metabolic reactions within an enclosed system is the final step of oparin haldane hypothesized process for origin of life

Answer 22

1- spontaneous formation of simple organic molecules from inorganic compounds 2-assembly of carbon compounds into polymers 3- formation of polymer that can self replicat (enabling inheritance and variation) 4-packaging of molecules into compartments with an internal chemistry different from the surroudnings

Answer 23

-difficult to directly test hypothesis related to origin of cells because it happened billions of years ago as a result; -conditions on earth were very different -its not possible to replicate with certainty the conditions that would have ecisted on early earth -well preserved fossils are rare -the methods used to estimate dates of the first living cells have ranges of uncertainty

Answer 24

atmosphere- "reducing atmosphere"; with higher porportion of reactive gases such as ammonia and hydrogen, very little oxygen temperature- significantly warmer than today due to heat from asteroid collisions and accretion (coming together/ formation of the planet) uv radiation- no ozone layer to block radiation from the sun so intense UV radiation reached the surface volcanic activity- volcanic eruptions released gasses (H2O and CO2) into the atmosphere asteroid bombardment- constant bombardment by asteroids as the solar system was forming

Answer 25

hydrogen nitrogen waper vapous methane ammonia hydrogen sulfide these gases came from volcanic activity, did not contain oxygen only ntil plants started photosynthesising

Answer 26

test served to test hypothesis of whether simple carbon compounds can be formed from iorganic compounds they simulated earth conditions, earths water cycle - heat source- simulate volcanic activity -water- simulate primodial ocean this water evaporised electrodes- simulate lightning -gas inlet with ammonia, methane, hydrogen, carbon dioxide and water vapour- simulate atmosphere cooling jackets condensed water into a primodial soup, after resting for a week soup found to contain simple amino acids and comples oily hydrocarbons

Answer 27

polymerization second step in oparin haldane hypothesis small molecules (monomers) combine chemically to produce large molecules (polymer) anabolic reaction, condensation reaction

Answer 28

genesadapted to organisms enviornments, genes likely to have been present in LUCA are clue about where and how LUCA lived genes indicated LUCA; -obligate anaerobe -chmoautotroph , obtain eneergy from hydrogen and converting co2 and nitrogen into essential organic compounds -able to live extreme heat -likely to have been raised from hydrothermal vents, issue supply reduced iroganic chemicals

Answer 29

formation of polymer that can self replicate once formed small organic molecules may have been able to spontaneously form polymers on early earth

Answer 30

-amino acids can spontaneously link togehter to form proteins -fatty acids could have been concentrated sufficiently to assemble into membranes -RNA nucleotides can link together when exposed to a catalyst found in clay or in water

Answer 31

-RNA first molecule to pass genetic info between generations -DNA very stable and effective stroing info but not able self-replicate, enzymes recquired -RNA can store info + self replicate, can catalyse formation of copies of itself -RNA that function as catalyst= ribozymes -in ribosomes RNA is found in catalytic site and plays role in peptide bond formation

Answer 32

ribosomes contain ribozyme, forms peptide bond between amino acids during translation all cells have ribosomes, ribosome used in translation to built polypeptide from an mRNA code

Answer 33

evidence RNA arose before DNA found in chemical differences between them -ribose easily produced lab to attempt to simulate conditions primative earth -deoxyribose harder to make, produced from ribose in reaction catalyzed by protein enzyme, suggests ribose predates deoxyribose in cels -DNA replaced RNA as more stable repository of genetic info -deoxyribose in DNA makes it more stable than chains RNA so that much greater lengths of DNA can be maintained -hydrogen bonds holding double helical strucutre of DNA add to stability -use of thymine instead uracil enhances DNA stability. Thymine much less succeptible to mutation

Answer 34

formation of membranes to package organic molecules membranes can exist as vesicles, micelles or bilayers early cell membranes may have been formed from fatty acids, structurally simpler than phospholipids formation of an internal enviornment (due to bilayer) means optimal can be maintained

Answer 35

fatty acids in watery solution, attracted to each other, will spontaneously form spherical strucutres= micelles shape micelle tucks hydrophobic tail together, away from water solvent under high conc, under appropriate PH conditions, can form vesicles instead of micelles

Answer 36

chemist mixed glycerol+phosphate+many fatty acids put mixture in mixture gases (earths atmoshpere), phospholipids formed spontaneously phosphoilipids attarcted to eachother form membrane

Answer 37

chemist included aminoa cids _ nucleic acid in mixture they were trapped inside membrane compartments spontaneously shows molecules likely existed on early earth could spontaneously give rise to membrane spheres and could trap randomly nearby molecules inside

Answer 38

fatty acids spontaneously coalesced to form spherical bilayers double layer of lipid molecules that encloses a space

Answer 39

created a physical seperation where the interior of a vesicle would have been able to provide a chemical enviornment with a different chemsitry to its external enviornment this allows the cell to control and maintain a precise set of conditions for proper cell functioning including ph and solute concentration

Answer 40

it was the 1st genetic material, rna was the basis for formation of first cell-like structure acts as both genetic material and catalyst

Answer 41

rna formed from inorganic sources able to replicate using ribozymes able to catalyze protein synthesis membrane compartmentailization ocurred inside the cell rna was able to produce both protein and dna dna took over as main genetic material because it is more stable proteins took over as catalytic form (enzymes) because they are more capable of variability

Answer 42

short rna sequences shown to be able to duplicate other molecules of rna demonstrating that rna can self replicate rna has some catalytic activity acts as genetic material and enzymes of earliest cells ribozymes in ribosome are still used to catalyse peptide bond formation during protei synthesis

Answer 43

existed depp in ocean in alkaline hydrothermal vents, rich in hydrogen, dissolved materials (sulfur, methane, iron) which was used as lucas energy source was anaerobic, fits lack of oxygen in early atmosphere autotrophic, combinign inorganic carbon with hydrogen to produce carbon dioxide and formic acid

Answer 44

thye had high temp, this provided energy needed for formation of complex organic molecules recquired for cellular formation

A2.1 origin of cells Flashcards

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