BIO1130 Mid2 Keywords

8/10/2019 BIO1130 Mid2 Keywords

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Midterm 2 KEY words

Modern Theory:

Adaptive radiation - cluster of closely related species that are each adaptively specialized to a

specific habitat or food source.

- groups of organisms filling ecological niches

Advanced characters - a new version of a trait found in the most recent common ancester of a

group.

-more recently evolved

-opposite of primitive characters

- "derived" character

Allopatric speciation a reproductive isolating mechanism that results from geographical

separation between two populations

-a prezygotic mechanism

- Populations evolve independently and diverge into different species

-caused by glaciers, continental shifts, etc

Behavioural isolation -a prezygotic isolation process

-2 species do not mate because of differences in courtship behavior

-also known as ethological isolation

-ex: songs of bullfrogs, fireflies example used in class (sequences of bursts of

light vary for different species of fireflies within males and females)

Biological species the concept of a species based on the ability of populations to interbreed

and produce fertile offspring

-basically a reproductively isolated gene pool

-no universal agreement to what it is

-problems with the concept: how do you define a fossil species?

how do you define populations that reproduce asexually? (ex archaea and

bacteria)

Cladogram a dichotomous phylogenetic tree that branches repeatedly

- end points of branches represent different species

Diploid an organism that contains 2 sets of chromosomes

-grow through cell division (mitosis) and reproduce by meiosis (production

of gametes)

-ex: animals

Ecological isolation a prezygotic isolation mechanism

-species that live in the same geographic region occupy different habitats

-thus making it difficult for them to mate with one another

-ex: a marsh species vs. a woodland species

Ecological species the species concept where a group of organisms is adapted to a particular

set of resources (niche) in the environment

-the ecological & evolutionary processes that control how resources are

divided up produce these clusters

-good for ecological foodwebs

-PROBLEM: the observations are just as subjective as the morphospecies

concept


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Gametic isolation -prezygotic reproductive isolating mechanism

-is the incompability of the sperm of one species and the egg of another

species to join together

-ex: giant clams/ sponges/organisms that release their egg and sperm into

the water column recognize only each other and dont end up combining

with other species

Hybrid breakdown a post zygotic isolation mechanism

-hybrids are capable of reproduction, but the offspring have reduced

fertility or reduced viability (fitness)

-the hybrids eventually die out from the population

-this ensures speciation b/c the species in the long run do not mix

successfully

Hybrid viability whether or not the hybrid organism will be able to come to term

-the zygote may form, but may end up being destroyed

-if the hybrid is inviable, this ensures speciation because the hybrid will

never exist

-or the hybrid will survive, but not to a reproductive age

-this is because the developmental programs of the parent organisms areincompatible

Ex: goats and sheep can fertilize each other but their ova will never come to

term

Hybridization when 2 species interbreed and produce fertile offspring

-can be the interbreeding between 2 homozygous individuals that creates a

heterozygote

-ex: more hardy and disease resistant crops can be formed from

hybridization

-leads to speciation

Mechanical isolation pre-zygotic reproductive isolation mechanism

-differences between reproductive organs make it physically impossible forthe sperm and egg of different species to join (this also applies to undesired

species ex what type of insect will pollinate a certain flower)

ex: the comet orchid has its reproductive organs behind the petals --12

inch long tube so only a month with a 12 inch long tongue will be able to

fertilize it

Microevolution small-scale genetic changes within populations

-often in response to shifting environmental circumstances or change

events

-this type of evolution occurs only in ONE species

-i.e. the frequency of alleles in a population changes

-ONLY genetic changes

-due to: genetic drift, gene flow, mutation, natural selection, non-randommating

Monophyletic - group of organisms that includes a single ancestral species and all of its

descendants

*** Morphospecies - Species, distinguishable from others ONLY by morphology

- E.g. Yellow Throated Warbler vs. Yellow Rumpled Warbler

Parapatric speciation Speciation between populations with adjacent geographic distributions.


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-Evolution, like allopatric speciation without geographical speciatioin.

-SUBSTANTIAL reproductive isolation b/w spatially adjacent populations

have LIMITED gene exchange

-population on outskirts of zones

Phylogenetic species A group of organisms bound by unique ancestry

- smallest branch at the end of a cladogram- can place fossils bacteria and archaea

-branches can be neverending, subspecies, etc. (Are they species, families,

orders?)

Phylogeny evolutionary history of a group of organisms

***Plesiomorphy - Sharing a character state with an ancestral clade

- Primitive

Postzygotic isolation

mechanisms

A reproductive isolating mechanism that acts after zygote formation.Hybrid inviability, hybrid sterility and hybrid breakdown

Prezygotic isolation

mechanisms

A reproductive isolating mechanism that acts prior to the production of a

zygote, or fertilized egg.

Ecological/habitat, temporal, behavioural, mechanical and gametic

Reproductive

isolation

A biological characteristic that prevents the gene pools of two species from

mixing.

Ex: genitalia of a bird do not match that of a horse

Ring species A species with a geographic distribution that forms a ring around an

uninhabitable terrain.

Gene flow between distant population occurs only through intermediary

populations

Example: Salamanders of California, rattle snake

Still capable of interbreeding on border between zones (transition zone)

These become different sub species, each zone is a different sub species,

but the all under the same species

Speciation Species formation

3 types:

Allopatric (isolation)

Parapatric (barrier spanning)

Sympatric (contiguous/touching populations)

Ex. Rape seed oiltoxic seed removed creating the subspecies, Canola Oil.

***Subspecies Taxonomic subdivision of speciesLocal variants of a species

Sympatric speciation Speciation that occurs without the geographic isolation of populations,

based on environmentSympatric = Species that occupy the same space at the same time

Evolves between distinct subgroups that arise within one population

Ex. Hybrid offspring has a lower fitness and generations eventually die off

Temporal isolation A prezygotic reproductive isolating mechanism

Species live in the same habitat (and sometimes could interbreed)

Breed at different times of day or different times of year


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Hadean eon and Archean eon:

Viroids

Pathogens without a protein component,

they are pure RNA. They are small

molecules of RNA that act as RNAsilencers. They silence mRNA translation

into proteins therefore proteins cannot be

produced and the cell begins to die.

Human viroid: Hepatitis D. AccompaniesHep B virus, replicates and packages itself

when Hep B does. Hides inside the capsidof Hep B.(virus that can replicate itself and is

composed of RNA {RNA world})

Prion

Pathogens that do not have any heritablecomponent ( RNA or DNA) Prions exist

as a protein with a tertiary structure andcan invert itself into the

aberrant/pathogenic form which is mostly

composed of pleated sheets. The aberrantform will induce normal prions to invert

into the aberrant form. As it invertsproteins, they stick together and formbranching fibres. The ends of the fibres

act as catalytic sites and can invert normal

prions. The fibres gown spontaneouslyand manifest themselves in vacuoles or

spaces between cells. They can become

large enough to push cells apart. Mainlyeffects the nervous system, pushes nerve

cells apart and destroys neural function

(mad cow disease)

In the aberrant form they are very stableand immune to protease.

Heterotroph

Organisms that grow/build using carbon

that already exists as part of an organic

carbon-carbon bond/

Absorbtive heterotroph

Organism which excretes enzymes into its

external environment to digest organic

materials which are then absorbed ( ex.

Vicariance The fragmentation of a continuous geographic distribution by non-

biological factors. Allopatric by speciationSpecies become completely separated

Results in the formation of new species

Ex. marsupials


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fungi, many protista and monera)

Ingestive heterotroph

An organism or protist that obtains its

nutrients by injestive organic material and

then digesting it.

Autotroph

Organism with a metabolic process that is

capable of building organic carbon usingatmospheric carbon dioxide.

Chemolithoheterotroph

Organism that use inorganic redox pairs as

a source of energy and use inorganic

carbon.

Chemolithotrophs,

Organisms that use inorganic redox pairs (

iron oxide) to trap the high energy

electron and use the energy.

Chemoorganoheterotrophs,

Organisms that use inorganic redox pairs

as a source of energy and use organiccarbon source.

Chemoorganotrophs,

Chemoorgano-Organisms or metabolismsthat use high energy organic bonds.Chemoorganotrophs -organisms that use

covalent bonds in organic chemicals as a

source of energy.

Chemoorganoheterotrophs-organisms thatuse covalent bonds in organic chemicals

as a source of energy and use organic

carbon.

Phototrophs

Organisms that use light energy to buildcarbon-carbon bonds (light energizes

electrons into a higher state, the energy istransferred through redox pairs-used tobuild a gradient or high energy molecules

( NADH etc))

PhotoheterotrophsOrganisms that use light energy as anenergy source and use organic carbon as a

carbon source.

Bacterial flagellum

The structure used by bacteria for

locomotion, the same structure is presentin all bacteria who have a flagellum. The

flagellum itself (the tail/whip) isthousands of copies of just one protein.The flagellum is connected to the

motor(basal structure) by the hook. The

motor is composed of a series of proteinsthat span the plasma membrane to form

rings. The number of rings depends if the

bacteria is gram-negative or gram-


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infecting another bacterium, that DNA is

injected into the cell which the bacterial

can incorporate into its own DNA.

Transformation

A bacterium can absorb a DNA strandfrom the external environment and splice

it into its own DNA. Sometimes theprocess is successful and a new genesequence is inserted and becomes active.

Sometimes, the new DNA is degraded and

salvaged for nucleotides.

Methanogens

Anaerobic bacteria. They combine

hydrogen and carbon dioxide to build

organic in a process which results in

methane as a by-product. Abundant in theArchean eon and were trapped in pockets

of water in the earths crust, they continued

metabolizing and producing largequantities of methane gas which is storedas methane hydrates.

Can recycle organic material and produce

fuel.

Bacterial cell wall

Composed of peptidoglycan which is a

series of repeating units of two different

sugars that form dimers which are strungtogether. Every second sugar contains a 4

amino peptide which allows 2 different

peptidoglycan fibres to interact. An

enzyme forms a covalent linkage betweenthe 2 terminal amino acids of the small

peptide chains of 2 different

peptidoglycan molecules.

Gram-positivePeptidoglycan layer is thick and onoutermost surface of bacterium and can be

stained.

Gram-negative

Peptidoglycan layer is thin andsandwiched between an inner and outer

plasma membrane(periplasm between the

membranes) the additional outer

membrane prevents staining and oftencontains endotoxins. The outer membrane

also prevents penicillin from damaging

peptidoglycan.

Viral Infections

Virus infects host cell and insert own

genetic material. Genetic material

compromises replication, transcription

and translation machinery. Viral DNA is


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replicated and viral protein parts are

created by host cell and assembled

together into viral cells inside the host cell

and they burst out by lysing the host cell(lytic cycle)

In the lysogenic cycle, the Viral DNA isinserted into bacterial chromosome andremain dormant for long periods of time

and is replicated along with host cell

DNA. Spontaneous induction occurswhere viral DNA is released from host

DNA and then completes the lytic cycle.

Enveloped virus

During infection makes proteins

associated with viral parts. Inserts proteinsinto plasma membrane of the host cell,

performs exocytosis and wrapping itself

in host membrane. When infecting, theyfuse their plasma membrane with hostplasma membrane.

Non-enveloped virusNot covered with a membrane. Use their

capsid to attach themselves to host cell.

Key words Hadeon Eon

AdhesionThe ability of a substance to stick to anunlike substance

Bio monomers

Identical or nearly identical subunits that

link together to form biological polymersduring polymerization ( glucose, amino

acids...)

Amino acids, pyruvate, basic hydrocarbons,glucose, nucleotides etc.- Believe to be created from Interstellarorganics or Prebiotic soup- Miller-Urey Apparatus proved that it ispossible to produce these organic compounds

biopolymers/macromolecules

-polymers produced by living organisms+

biodegradable-monomer units covalently

bonded(repeatingly) to form larger

structures-polynucleotides( DNA/RNA),

polypeptides (short polymers of amino

acids) , polysaccharides ( glucose,

fructose, galactose)


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-have well defined structures, shapes

(how they fold) determines function

Macromolecules: proteins, lipids,carbohydrates, nucleic acids- Created through chemical evolution: the

binding of biomonomers- Questions: panspermia, ribozymes,importance of clays (+ive andive charged)

Building phase of the earth

-Explosion that formed the sun propelled

lighter materials (gases) to the outer edges

of the solar system and the heavier

materials (iron) stayed near the sun. As aresult, the inner planets have iron cores

while outer planets are mainly composed

of gases.-Planets, asteroids, and otherextraterrestrial material crashing around,

creating the formation seen today.

Formation of the moon from a chunk ofthe earth that was blown off due to a

collision with an other body.

Stabilizing phase of the earth

-once orbits of planets stabilized,meteorites, asteroids and other

extraterrestrial bodies were not being

thrown about as violently and frequently.

Though impacts still occurred on earth,they did not cause global damage. Dense

iron core remained molted and lighter

gases escaped into the atmosphere throughout-gassing. Initial atmosphere composed

of methane gases, sulphur gases and no

oxygen. As the earth cooled, water vapor

began to liquify and rain down, the planetwas covered in a blanket of water but the

earth could not sustain life due to sterility

of water and the extreme heat from core

of planet.

Carbon

-universal building block. forms perfect

tetrahedron. can be stitched together into

any form. most abundant element onearth.

Essential element in all organic compounds,very abundant- Perfectly symmetrical, stable tetrahedral


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bonds- Excellent for forming chains, only othercandidate is less abundant silicon

Cenozoic

Chemical evolutionorganic molecules associated with lifehave to be created

Central Dogma

DNA ----> RNA --->Proteins

The central dogma basically states thatProteins are derived from RNA which is

derived from DNA. But the question is

what was the first self-replicating

molecule? For DNA to be the first self-replicating molecule is problematic

because DNA is too complex a molecule.

Through the discovery of HIV Aids,

which was the first RNA virus, it was alsodiscovered that RNA could replicate itself.

RNA can turn itself into DNA and has

catalytic abilities, ribozymes.

RNA worldRibozymes: strands of RNA with catalytic

properties and can replicate themselvesand make proteins. It can be suggested

that the first self-replicating molecule was

an RNA strand with catalytic ability to

assemble nucleotides and replicate itself.The strand can fold itself to form an active

site where the nucleotides would bestitched together. If somehow, during thisprocess, catalytic RNA began stitching

together amino acids and makes proteins

with a catalytic site, that protein can beused to make more RNA strands. This

process separates the coding from thework. RNA can use this process to

assemble nucleotides into base-pairs,

creating DNA strand for storage purposes.This makes RNA the intermediate with

ribozomes controlling everything.

1) Replication DNA copies itself to makemore DNA

2) Transcription Parts of DNA copied intoRNA strands

3) Translation RNA codes translated byribosome to produce a protein


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Clays

Superfine sediments with charged groups

on them. Clay molecules interact with

each other to form lattices. Clays areorganizers of charged substances. If the

primordial soup is placed on clays, theclays will align the amino acids head totail, in sequence. In the shallows of the

oceans or perhaps where water splashed

on land, nucleotides were likely beingstitched together on clays.

This could potentially be the source of the

first RNA strand.

Cohesion

- The attraction between polar andnon-polar parts of water

molecules. Form H-bonds with

itself. Water molecules, as a result,try to lock into one another ( evenin liquid form ) and form a spongy

matrix on which a small degree of

weight can be applied. Thisproperty is called surface tension,

when a small weight is placed on

it, the water molecules will pushback with equal force, holding the

object that is applying weight in

place. This is how some insects are

able to walk on water.Behaviour of water molecules to stick together- Result of the polarity of the molecule,hydrogen bonds form between molecules- Creates a surface tension across surface ofwater (can support some insects)

Crystal lattice of water

-as water freezes, it forms a uniformlattice that is less dense than liquid water.

therefore, it rises to the top (ex. icebergs

float in water). During periods of intense

cold (ice ages) the surface oceans would

be completely covered with ice but therewould be water present deep beneath the

ice. The ice acts as an insulator andcreates and environment in the water

beneath that could sustain life. therefore,

during ice ages, some species were able to

survive and from them, the earth would berepopulated again.


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Solid H2O (ice) has a crystalline structure anda lower density than liquid H2O (water)- At 4

oC, water arranges itself with

neighboring molecules into a honeycombshape

- This is due to hydrogen bonds, in liquid thelattice breaks, in ice the lattice is solid- Biological importance: Ice (less dense) formsat tops of bodies allowing the lower volume ofliquid water to continue supporting life

Emergence

-a property that comes about from

interactions between substances (ex.

molecules, proteins etc.) that is notpresent in the substances in themselves.

ex. the ability to produce and utilize

energy, in living organisms is the product

of the interactions between proteins,sugars, enzymes and all the other factors

that make the energy productionmechanism in living organisms.

Complex systems and patterns arise out ofrelatively simple interactions- Examples: swarming of animals, chemicalbonds to produce complex organics- Life is a major source of complexity, andevolution is the major principle or driving forcebehind life

Eukaryote

-living organisms that posses cells with

the genetic material contained inside a

separate unit called the nucleus.

Mesozoic

Geological time scale

Habitable zone

-Earth's distance form the sun allows arange of temperatures that allows water to

remain in the liquid state, liquid water is

the fundamental prerequisite for the

development of life.

-because of the size of the planet, earth'sgravitational pull is strong enough to hold

an atmosphere around the planet.

Hadeon eon

-the first eon, characterized by earth'sinitial formation. The planet was initially

solid and water was present on large

celestial bodies.Dust and gasses were gradually


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accumulating on the planet and there were

frequent collisions with extraterrestrial

bodies (this released extreme amounts of

heat, keeping the planets surface moltenfor period of time), there was intensive

volcanic and seismic activity. Overtimeheat was radiated off and the surfacelayers of gasses, dust and molten rock

cooled and formed the crust. At the end of

Hadean eon, first forms of life wereappearing.

The Nice Model (late heavy

bombardment)The initial solar system was somewhat

unstable and ordered as Jupiter, Saturn,

Neptune, and Uranus with J in more orless in it's present orbit and the positionsof Neptune and Uranus inverted from the

present ordering. The asteroid belt (

composed of icy bodies) was in orbitoutside U. Interactions between the orbits

of the planets altered their orbits little by

little. When the orbits of J and S came into2:1 resonance, the orbital forces ( of J + S)

exerted disrupted the orbits of N and U,

inverting them(to where they are now)

and dispersing the asteroid belt.

Dispersion of the asteroid belt results in

the bombardment of the inner planets.Called the late heavy bombardment, it is

also how water originated on Earth; it was

carried by an asteroid(s). Craters on theplanets and the moon also believed to

have resulted from the bombardment.

Archean Eon

-Second eon, began with the formation ofthe earth's crust. The environment was

completely anoxic; all the oxygen on the

earth's surface was bound in water. Thefirst bacteria arise and all are anaerobic.

Special anaerobic cyanobacteria arose that

could oxidize water to generate protonsand high energy electrons to produce ATP


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with oxygen gas being a waste product,

this is the most efficient way of gaining

electrons. Oxygen gas produced escapes

into the atmosphere where it oxidizesminerals. For a period of time, all the

surface of the earth was rusted, causingmassive changes to the strata.

Archean oceans likely formed by the

condensation of water vapour from theout-gassing of volcanoes. The iron

released by the out-gassing combined with

oxygen to form ferric iron hematite (

Fe2O3) which resulted in banded ironformations on the flanks of volcanoes

unique to the Archean eon.

Green house gas effect:The concentration of carbon dioxide in the

atmosphere reached extremely high levels

due to out-gassing from volcanoes,causing a green house gas effect. Warming

the surface of the planet and likely

preventing the development of glaciation.

Reducing Atmosphere

Hypothesis that claimed that the early

atmosphere was a reducing atmosphere

due to the lack of any oxygen and the

presence of large quantities of methane,ammonia, hydrogen and carbon dioxide.

These molecules an abundance of

electrons and hydrogen and would havereacted with one another to yield larger,

more complex molecules. The lack of any

oxygen also meant that their was no ozone

layer, UV rays from the sun were thenalso available to provide energy(along

with lightning) for reactions.

Miller-Urey experiment

Components of a reducing atmosphere,

hydrogen, methane, ammonia and watervapour were added to a closed apparatus,

and energy was provided in the form of

sparking electrodes. The electrodesmimicked lightning, in primordial earth

there was a lot of volcanic activity which

is always accompanied by lightningtherefore light would have been a major


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source of energy for chemical reactions.

This mixture was heated and cooled (

water vapour) and allowed to cycle

for a week. The resulting concoctioncontained many organic compounds,

including amino acids, lactic acid, formicacid and ascetic acid. 15% of the carboninitially in methane had be converted into

organic molecules essential for life. The

addition of formaldehyde and hydrogencyanide resulted in the formation of amino

acids, fatty acids, purine and pyrimidine,

sugars and phospholipids.

This was the first experiment todemonstrate the abiotic formation of

molecules critical to life.

Results in the early oceans being aprimordial soup of organic molecules:provides an environment in which an

extraterrestrial LUCA could have

metabolized.

CO2 + H2O + CH4 + SO2 + other inorganicsorganic compounds- Evidence of how life may have originated,pre-biotic soup

Hydrothermal vents

Complex organic molecules could have

occurred under the sea at the site of deepsea vents. At the level, weight of the water

column keeps water in liquid formdespite extremely high temperatures.

Reduced gases such as methane,

ammonia, hydrogen sulfide, are producedby the crack in the ocean floor. The

extreme temperature and pressure could

provide the environment necessary toreact the gases and form basic organic

molecules.

Vents at the bottom of ocean that spew outhot noxious gases, such at SO2- Contingent for the origin of life due to highenergy and presence of organics

Extreme bacteria-thermophile-are known

to thrive in these environments. They

posses the criteria necessary for space


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travel and potentially enhance the

feasibility of LUCA being extraterrestrial.

Hydrophilic

Charged/polarized molecules, can be

dissolved in water and other polarsolvents.

Hydrophobic

Non-polar molecules that prefer neutraland non-polar solvents. Tend to formclusters in water ( lipids). Do not dissolve

in water.

Panspermia

The hypothesis that "seeds" of life existalready all over the Universe- Life on Earth may have originated throughthese "seeds"- Other habitable bodies may have had lifedelivered to them as well

Extraterrestrial origins for life on earth.

Small bacteria can be found on asteroidswith morphological forms similar tobacteria on earth. Possible it arrived on

earth on an asteroid that collided with

earth during the late heavy bombardment.

Liposome

when lipids are fragmented and mixed

with water, they cannot come back

together into their original form but

instead, form a sphere composed if abilayer of lipid molecules containing

aqueous environment inside.

Micelles: sphere composed of a singlelayer of lipid molecules.

Prokaryote

Living organisms with cells that do not

have genetic material contained inside a

nucleus.

Probionts/protocells

Precursors to prokaryotic cells.

A group of abiotically produced organic

molecules that are surrounded by amembrane or membrane-like structure.

Reverse transcriptaseEnzyme that functions as an RNA

dependant DNA polymerase.

Proterozoic eonStable continents appeared. First evidenceof oxygen build-up in atmosphere. Fossils

of living organisms from this eon are good

Specific heat

The amount of heat that is required to

raise the temperature of a substance byone degree.

Spontaneous originsAll life appeared on earth as is.The idea that life spontaneously was created


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by no physical-chemical means

Surfactant

Compounds that lower the surface tension

between two liquids or between a liquid

and a solid. Includes detergents, wetting

agents, emulsifiers.

Wetting agents that lower the surface tensionof a liquid, amphiphilic- Allows for easier spreading, and lower theinterfacial tension between two liquids

Eons Largest division of time

Eras Division of eons

Or

Absorbtive

heterotroph

Aerobic Aerobic - Requirement of oxygen- Usual necessity for oxygen is in the respiration processes- Oxygen acts as an electron acceptor

process by which molecules are oxidized to produce ATP via an

electron transport chain and ATP synthase.

- Chemoorganoheterotrophs, break chemical bonds and use them for

energy via glycolysis, kreb cycle, they all trap energy and use it to

build sugars

Algae

Anaerobic No requirement of oxygen- Usual dependence on oxygen is from the organisms metabolicprocesses- Other inorganic molecules, such as sulphur, can be used as electronacceptors

process by which molecules are oxidized to produce ATP via an

electron transport chain and ATP synthase.

- Chemoorganoheterotrophs, break chemical bonds and use them for

energy via glycolysis, kreb cycle, they all trap energy and use it to

build sugars

Animalia - The taxonomic Kingdom that includes all living and extinct animals

Antibody - highly specific soluble protein molecule that circulates in the blood

- recognizes and binds to antigens to clear them from body.

Antigen - foreign molecule that triggers an immune response.

- antibodies bind to these molecules.

- ex: the antigens on the surface of blood cells

Antibiotic resistance - Type of drug resistance where microrganisms are able to survive

exposure to antibiotic

- Spontaneous or induced genetic mutation in bacteria may confer


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resistance to antimicrobial drugs

- genes that resist can be transfer between bacteria horizontally by

conjugation, transduction, or transformation.

- Gene for antibiotic resistance which had evolved via natural

selection may be shared.

Archaea - Unusual group of bacteria, that can survive in extreme conditions

(extremophiles)- single celled microorganisms

- have no nucleus or any other membrane-bound organelles w/ in

their cells.

-Phototrophs, chemolithotrophs, chemorganotrophs

- No peptidoglycan, plasma membrane=branched w/ ether links, has

operon genes, translation via complex RNA polymerase, no nuclear

envelope, circular chromosome, DNA histones

One of the three domains, from Linnaeus taxonomic hierarchy- These prokaryotic organisms can survive in extreme conditions,extremophiles- Survives as either Halophiles, Thermophiles, can also be

methanogens

ATP synthetase

(synthase)

- enzyme that provides energy for the cell by using ATP (most common

energy currency)

- Formed from ADP+Pi

- in glycolysis, and kreb cycle

- E coli atp Synthase is the simplest from of Atp synthase

Membrane-spanning protein complex, couples reactions:- Energetically favouring transport of protons across a membrane withthe synthesis of adenosine triphosphate (ATP) from adenosinediphosphate (ADP) and a phosphate group

Autotroph - makes energy from the sun or light photons- produces complex organic compouns like carbs from inorganic

compound (photosynthesis)

- inorganic chem reactions chemosynthesis

- Algae and plants

- Phototrophs and lithotrophs

- Get carbons from carbon oxides

An organism that produces its own food from CO2, simple inorganics,and energy- The energy could come from the sun, photo, or from the oxidation ofother organic, organo, or inorganic litho compounds

Bacteria (Eubacteria) Multicellular

- Metabolism (photo, chemolitho,organothrops)

- Gram-positive bacteria very dormant and resistant endospores

One of the three domains, from Linneaus taxonomic hierarchy- These prokaryotic organisms are the most metabolically diverse- All six -troph options are possible

Bacterial flagellum - Motor embedded in gram negative

- Motorized by the flow of H+ ions, protons nudge ATP synthase-like


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molecules that spin the flagellum. (tail spins)

- Powered by ATP

- Flagellum = bio chem motor

-shaft sits against molecular motor at bottom

- hook: sleeve that attaches shaft and flagellum

- different than animal flagellum

Bacteriophage - Number of viruses that infect bacteria- Consist of outer protein capsid enclosing genetic material

- Lytic or lysogenic cycle

- Viron assembly

Binary fission - subdivision of a cell into two or more parts and regeneration of

those parts into separate cells.

- Asexual reproduction and cell division used by prokaryotes and

some eukaryotes

- Results in reproduction of a living prokaryotic cell

- Takes place without spindle fibres

- DNA mol replicates, then attaches each copy to different part of cell

membrane to build identical clones

One mode of prokaryotic reproduction- DNA replicates in cell, and cell splits in half- This method yields no genetic variation from parent to daughter cells

Capsin protein

Capsule

Cellular Respiration

- may be a polysaccharide or polypeptide

- ex. Bacillius or streptococci

- detected by special stain

- antigenic

- antiphagocytic determines virulence of many bacteria

Cellular respiration - The process by which high-energy molecules are

converted to ATP- Takes place aerobically or anaerobically, depending on organism andenvironment- Takes place in all living organisms

Chemolithotrophs

Chemorganohetrotrophs

- consume carbon already in inorganic compound

- Use sulfur and ammonia to get energy

- Carbon fixation

Class of organisms that fix their own source of carbon- These organisms get energy from the oxidation of inorganiccompounds- These organisms can only be bacteria

Class of organisms that consume other organisms as a source ofcarbon- These organisms get energy from the oxidation of organiccompounds- These organisms can be bacteria, some protists, fungi, or animals

Chemoorganotrophs - Break C-c bonds to make energy

- Pull together CO2 to make organic compounds

- Ex. Bacillius


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Class of organisms that fix their own source of carbon- These organisms get energy from the oxidation of organiccompounds- These organisms can only be bacteria

Chitin - Polymer derived from glucose- Cell wall of fungi and exoskeleton of athropods (crabs, squids,

octopods, lobsters, shrimps) mollusks

Circular genome

Conjugation - Transfer of genetic material between bacterial cells by direct cell to cell

contact

- Donor cell provides a conjugative or mobile genetic element that is most

often a plasmid or transposon

- plasmid replicates and through the pilli, some plasmid migrates to the

other cell.

- may take a bit of the genome by accident, creating a unique new cell

- plasmid is the key in recombinant DNA

- Mechanism of horizontal gene transfer as are transformation and

transduction- Genetic material transferred is often beneficial to the recipient.

- Benefits may include antibiotic resistance

One mode of prokaryotic reproduction- Part of DNA of a donor cell moves through a cytoplasmic bridge intorecipient cell- Genetic recombination occurs and yields genetic variation- In ciliate protozoa, this is the form of sexual reproduction

Cyanobacteria - obtain energy through photosynthesis

- blue-green algae

- capable of splitting H2O molecule and taking CO2 to make C-C bonds

- perform oxygenic photosynthesis by reducing atmosphere into anoxidizing one

- rocks and minerals became oxidized and began to rust.

A phylum of bacteria that obtain their energy through photosynthesis - Due to its high efficiency, these bacteria flourished filling theatmosphere with O2- Involved in the marine nitrogen cycle and a primary producer in areasof the ocean

Daughter cell - cell resulting from the replication and division of a single parent cell

- genetically identical

- only in eukaryote cells

Domains - Highest taxonomic category- group of cellular organisms w/ distinct characteristics that set it apart

as a main branch of evolutionary tree.

Electron donor - donates electrons to another compound (reducing agent)

- thus it is oxidized

- transfer of an electric charge during cell respiration

- results in release of energy

- microorganisms like bacteria obtain energy in ET processes

A molecule which has easily relievable electrons (electron pair)


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Lithotrophs - an organism that uses inorganic substrate (minerals) to obtain carbon

fixation or energy by anaerobic respiration

- utilize inorganic compounds as energy sources

- deep sea worms and plastids

- often extremophiles

Lytic cycle - phage inserts its DNA into the host cell

- the virus takes over the cells replication machinery to reproduce viralDNA and proteins

- Viral particles are assembled inside

- The cell lyses, erupting and freeing the new phages

Methanogens - microbes that produce methane as a metabolic byproduct in anoxic

conditions

- responsible for the methane content in belching

- some are extremophiles found in hot springs

- in anaerobic environments remove excess hydrogen produced by other

forms of anaerobic respiration

Monera - A kingdom that includes all prokaryotes

- Unicellular organisms without a nucleus

- Cyanobacteria classified under monera

Nitrogen fixation - at beginning of the planet, N was only available as a gas. - natural process, either biological or abiotic, by which nitrogen in the atm

is converted into ammonia

- Fixed nitrogen is part of essential subunits (DNA, A.A, proteins)

- cyanobacteria play key role in the nitrogen cycle of the biosphere

use inorganic sources of combined nitrogen

A metabolic process in which molecular nitrogen is converted toammonia- Certain bacteria, specifically cyanobacteria, perform this- Can take form of a symbiotic relationship with a plant that uses theammonia

Nonenveloped virus - A virus that is not encased in host cell phospholipid bilayet.-

Nucleoid - area with a prokaryote cell where majority of the genetic material is

found

The central region of a prokaryotic cell where DNA is located- No membrane bounds this region- Replication and transcription occur here

Oxidized - loses an electron

- reducing agent is oxidized

Process of a substance losing electrons

- Occurs during oxidation reactions- These substances are called reducing agents

Pandemic -widespread occurrence of a disease

Pathogen - virus bacterium prion or fungus that causes disease in its animal or

plant host

- small amount of bacteria actually harmful

- cause infectious diseases ex. Tuberculosis

- which is causes by other bacterias like streptococcus and

pseudomonas and food borne illnesses


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a biological agent that causes disease or illness to its host- could be viral, bacterial, fungal, or prionic- Not all pathogens are negative

Penicillin - Group of antibiotics derived from penicillium fungi

- First drug that was affective in fighting many diseases- Ex. Syphilis

- Still widely used today even though many bacteria now resistant

- Used in treatments of gram-positive bacteria

Peptidoglycan - Polymer of sugars and aminoacids formas a mesh like layer outside

the plasma membrane of bacteria (not archaea)

- In the bacterial cell wall is a crystal lattice structure

- Formed by linear chains of two amino sugars

- interacts with stains

The primary structural molecule of bacterial cell walls- A polymeric substance formed from a polysaccharide backbone +short polypeptides

Periplasm - Space between the peptidoglycan cell wall and the inner membrane of

gram negative bacteria

- Space outside the inner membrane for gram-positive bacteria

- May be 40% of total cell volume in gram negative and significantly less

in gram-positive

- Includes nutrient binding transport and alteration of substances toxic to

the cell.

- Clinical importance when considering antibiotic resistance

Phage - bacteriophage

- virus particle made up of a head unit (a capsid), a tail unit and and a

strand or two of nucleic acids.

- to infect, it injects its DNA into a host cell.

- looks like an alien space pod.Photoheterotrophs - Break carbon carbon bonds as a source of carbon

- Use photonic energy from light to do this

Class of organisms that consume other organisms as a source ofcarbon- These organisms get energy from the sun- These organisms can only be bacteria

Photosynthesis - Conversion of light energy (in the form of photons) to chemical energy

(in the form of sugars and other organic molecules).

- Can occur in species with chloroplasts

- Occurs in autotrophs

Highest efficiency method of carbon fixation and energy capture- CO2 + H2O (CH2O)n + H2O + O2- Used in plants and cyanobacteria

Phototrophs - Light as source to generate high energy electrons

- Transfer electrons from inorganic carbons

- Ex. Plant

- See them in proterozones and bacteria do this too


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Class of organisms that fix their own source of carbon- These organisms get energy from the sun- These organisms can be bacteria, certain protists, or plants

Pilli - Hair like structures found on the surface of many bacteria

- Composed of proteins

- Some bacterial viruses attach receptors on pili at the start of theirreproductive cycle

- They are antigentic

Plantae - A kingdom that includes multicellular plant organisms

Plasmid - DNA molecule that is separate from, and can replicate

independently of the chromosomal DNA

- They are stranded and in many cases circular

- Occur naturally in bacteria

- Sometimes found in eukaryotic organisms

Separate DNA molecule in certain prokaryotes, usually circular ordouble stranded- Often contains gene which supplement those in the nucleoid

- Replicates independent of nucleoid DNA

Prions - Pathogen that does not involve nuclear material

- Infectious protein molecules

- has an aberrant form: a flipped orientation that induces normal protein

to flip into aberrant/pathogenic form.

- aberrant form sticks together forming a fibrous chain that flips other

proteins and pushes other cells (ex: neurons) apart.

- Ex: mad cow disease

Prokaryote -

- organisms that lack a nucleus and othe membrane-bound organelles

- most are unicellular

- no nucleus ex: mitochondria etc

- no organelles- belong in two taxonic domains: archaea and bacteria

Protista - Kingdom that includes several groups of unicellular eukaryotes

- single celled organisms

- animal like protists (protozoans)

- plant like protists (algae)

Proton gradients - gradient of protons (duh)

- Used to power ATP synthase

- sources include: splitting H2O molecules

Protozoa - organisms of the Protozoa group

- a phylum/group of phyla that includes single celled microscopic

animals, (including amebas, flagellates, ciliates, etc)

- belong to kingdom Protista

Redox pair - 2 species between which an electron is gained or lost. - gain= reduction

- loss= oxidization

- ETC creates p+ gradient that can then generate ATP via ATP synthase

Reduced - Gain of electrons

- Oxidizing agent gets reduced

Process of a substance gaining electrons- Occurs during reduction reactions


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- These substances are called oxidizing agents

Reverse transcriptase - An enzyme that uses RNA as a template to make a DNNA copy of the

retrotransposon

- used to make DNA copies of RNA in test tube reactions.

Ribosome - location of protein production

- Three binding sites for tRNA- builds chains of amino acids

Saprophytic - organism that lives on dead or decaying matter.

Stromatolites - layers formed in shallow water by trapping, binding, and

cementation of sedimentary grains by biofilms of microorganisms,

especially cyanobacteria

- found on shorelines

- provide some of the most ancient records of life on earth

- fossil record

Thermophiles - type of extremophile that thrives at high temps between 45 to 122

Celsius

- found in various geothermally heated regions of the earth ex: hot

springs and deep sea vents- their enzymes allow then to function at such high temps

- Ex. DNA polymerase, TAQ polymerase

Transduction - (related to topic) virus: a protein container w/ pieces of DNA.

- protein shuts down transcription/translation of cell

- lands, injects, destroys. Protein copies, makes cases, lysis.

- sometimes bacterial fragments survive.

- these fragments can end up in other cells from injection, increasing

biodiversity.

One mode of prokaryotic reproduction- DNA is transferred from a donor to a recipient by means of abacteriophage

- This method yields variable genetic variation- The DNA may kill the bacteria and reproduce more bacteriophages or- The DNA may combine with host cell DNA and the message will bepassed on

Transformation - bacteria can take chunks of DNA from the external environment

and add it into the genome.

- uptakeintegrationeither stableor unsuccessful

transformation

One mode of prokaryotic gene transfer- Bacterial cell can intake DNA from the surrounding environment- The DNA may prove useful or useless and be passed on or

- The DNA may prove detrimental and kill the bacteria- This method yields genetic variation depending on survival of bacteria

Vaccine - creates antibodies in out body

- we inject a small amount of capsid protein so that our body recognizes it

as a foreign particle

- we create antibodies so that if the virus enters our system, the virus can

be destroyed

Virion - a complete infective form virus particle outside of the cell


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Viroids - Pure RNA in circular loops

- Plant pathogens.

- RNA silencerssilence mRNA in cells and inhibit transcription.

- Ex: Hepatitis D

- virus that has a function made of RNA

Virus - NOT cells (non living) [no membrane, ribosomes, mitochondria, DNA is

wrapped in a protein coat]- virus: a protein container w/ pieces of DNA.

- only reproduces by injecting into cells

- protein shuts down transcription/translation of cell

- lands, injects, destroys. Protein copies, makes cases, lysis.

- characterized initially based on morphology

Proterozoic eon:

9+2 organization - Orientation of cilia and flagella in eukaryotes- Position of 9 microtubules surrounding two central ones- Differs from prokaryotic flagella which acts as a micro motor

Alternation of generations - Life cycle that switches between haploid and diploid betweengenerations- Haploid generation: haploid spores undergo mitosis making haploid gametophytes

- Diploid generation: gametophytes fertilize zygote sporophyte meiosis

Amoeboid movement - Type of protist locomotion where pseudopods use actin and myocin tomove- ATP can change the density of the protein solution to solid or liquid states- The solid ectoplasm makes the outer structure of the pseudopod for liquidendoplasm channel to flow through causing movement

Antibody - Type of protein found in the blood plasma- Binds to specific antigens found of cell surfaces, or foreign invaders

- Destroys the cells with the antigen markers as a part of our immune system

Antigen - Substances which prompt the production of antibodies- Surface markers on cells

Archaea - One of the domains of life- Extremophile prokaryotes with many biochemical similarities with eukarya- Believed to be one of the first organisms on earth due to extremophility

Asexual reproduction - Process of self-reproduction- No genetic variation occurs through this method- Single organism gives rise to offspring without genetic input from another

Bacteria - One of the domains of life- Consists of the most metabolically diverse prokaryotes- Also the most reproductively diverse domain

Bacteriophage - A complex virus that infects bacterial, prokaryotic cells, not eukarya- Consists of a protein capsid surrounding genome as well as characteristic tail andsheath for bacterial cell wall penetration- These viruses are enveloped, meaning they have a phospholipid bilayer surrounding

Capsid protein - Protein coat which protects genome


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- Found in all viruses- May or may not be enveloped

Chloroplast - Unique organelle in plants and plant-like protists- Contains photosynthetic pigments used to capture energy from light- Origin results from endosymbiosis of ancestral protists of cyanobacteria

Cilia - Motile extension of the cellsurface- Structurally identical to flagella in eukaryotes (9 + 2 organization or microtubules)- Used for cell locomotion in protists, and sweeping of debris or other cells

Contractile vacuole - Specialized cytoplasmic organelle that is used for locomotion or feeding- Pumps fluid in cyclical manner from inside the cell to outside- Alternately fills and contracts vacuole at various points on cell surface

Diploid - Organism or cell with two copies of each chromosome in nucleus- Common to most kingdom life cycles at some point

Diplontic - Life cycle of animal-like protists- Consists of purely diploid asexual reproductive phase

- And partially haploid sexual reproductive phase (gametes are haploid)

Ectoplasm - Insoluble protein solution in pseudopods used for stability and walls of channel

Endomembrane system - System of interconnected membranous sacs in eukaryotes- Nuclear membrane, endoplasmic reticulum, Golgi apparatus, and derived elements

Endoplasm - Soluble protein solution in pseudopods used in amoeboid channel for locomotion

Endosymbiosis - Engulfing of an organism leads to symbiotic relationship as opposed topredation- Hypothetical scenario supported by mitochondrial and plastid organelles

Enveloped virus - Virus surrounded by a phospholipid bilayer for easy entrance/exit of cells- Envelop surrounds capsid of virus

Epidemic - Widespread disease

Eukarya - One of the domains of life- Consists of all organisms with eukaryotic cells- Has the 3 kingdoms of multicellular life: animals, plants, fungi {+ protists}

Flagellum - Long, threadlike, cellular appendage responsible for movement- Possible derivative of composed cilia- Found in both eukaryotic and bacterial cells, but with different structures

Gametocyte (phyte?) - Gametophytes are individuals from the alteration of generation life cycle- Haploid individuals produced as spores (n) undergo mitotic divisions- Can be male and develop sperm or female and develop eggs

Haploid - Organism or cell with one copy of chromosomes- Common to all life cycles at some point

Haplontic - Life cycle of fungal-like protists- Consists of purely haploid asexual reproductive phase- And partially diploid sexual reproductive phase (zygotes are diploid)


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Histone proteins - Small positively charged protein that complexes DNA in formation ofchromosomes- DNA literally wraps around 8 histones (twice wrapped in a 2x2x2 arrangement)

Host - Any cell with its own functioning genetic material, nutrients, taken over by another- Species is fed upon by parasites (or viruses)

Immune system - The combined defences, acquired or innate, that a body uses to eliminateinfection- Consists of while blood cells as well as other phagocytotic cells- Intrinsically controlled in all organisms; extrinsically or intrinsically compromised

Latent viral phase - Phase of viral life cycle where its genome replicates with host cell s- Viral protein are not synthesized at this stage

Lysogenic replication - Viral replication where virus first remains dormant for a period of time- As viral gene replicates with host cell, number of infected cells increase- At a point, genome separates and proteins and synthesized, many host cells die

Lytic replication - Virus is never dormant

- Viral gene immediately takes over host cell and viral proteins synthesized- Ends, as with lysogenic cycle, with lysis of host cell and virus spreads

Malaria - Disease caused by the parasite Plasmodium sp.- Causes high fever, sweating, which attracts mosquitoes- Protist parasite has life cycle in mosquito and human liver and red blood cells

Meiosis - Eukaryote gamete production- The division of diploid cells into haploid progeny- Consists of two round of nuclear and cellular division

Merozoite - During the life cycle of Plasmodium sp. these are the reproducing form- Found in human red blood cells

Metachronal wave - Synchronized wave motion of cilia on a ciliate- This motion produces a power and recovery stroke, though power stroke isstronger, it is not 100% efficient as protist moves back slightly

Mitochondria - Membrane bound organelle responsible for synthesis of ATP in eukaryotic cells- Possible origin through endosymbiosis by ancestral protist of a bacterium

Mitosis - Nuclear division that produces daughter nuclei- These nuclei are exact genetic copies of the parental nucleus- This process precedes cytokinesis where the cytoplasm divides

Nonenveloped virus - Virus with no phospholipid bilayer surrounding its capsid

Nuclear envelope - Membrane separating cytoplasm from the nucleus- Continuous with the rough endoplasmic reticulum- Possible origin through inward extension of plasma membraneParasite - An organism that feeds on, or otherwise exploits its host

Peptidoglycan - A polymeric substance formed from a polysaccharide backbone tied together byshort polypeptide- The primary structural molecule of bacterial cell walls- Can be stained in gram-tests, testing gram-positive, indicating no capsule


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Phage - Synonymous with bacteriophage

Phytoplankton - General name for microscopic, free-floating aqueous protists and plants

Planar flagellar beat - Motion of flagella on some flagellated protists- Flagellum moves back and forth along a plane in space- This primitive motion eliminates problem of recovery stroke in ciliated protists

Plasmodium - The composite mass of plasmodial slime moulds- Individual nuclei are suspended in common cytoplasm- Surrounded by single membrane

Plastid - Chloroplastdouble membrane bound organelle- Contain pigment chlorophyll responsible for capturing energy from the sun- Possible origin through endosymbiosis

Primary consumers - A member of the second trophic levels- Usually herbivores, consumers of the primary producers

Primary producers - A member of the first trophic level- Autotrophic, usually a photosynthetic organism

Proterozoic- Third major eonof earths history(2,500550 Ma) - Oxygen atmosphere, single celled aerobic organisms- Introduction of first eukarya, the protists

Protist - Organism classified in the kingdom protista- Unicellular eukaryotes which are likely ancestors of all multicellular life- Diverse kingdom with animal, plant, and fungal-like properties

Pseudopod (Pseudopodium) - A temporary cytoplasmic extension of a cell- Concept used by amoebas for locomotion

Reverse transcriptase - An enzyme that uses RNA as a template to make a DNA copy of theretrotransposon- Paradox of the central dogma in that RNA is producing DNA

RNA polymerase (simple and complex) - An enzyme that catalyzes the assembly of nucleotidesinto an RNA strand

Secondary endosymbiosis - A non-photosynthetic eukaryote engulfed a photosynthetic eukaryote- The smaller photosynthetic protist, algae, formed a symbiotic relationship

Sexual reproduction - The mode of reproduction in which male and female parents produceoffspring

- Offspring arise as zygotes from fertilization of an egg by a sperm from a male- This method allows for genetic variation

Spiral flagellar beat - Motion of flagella on some flagellated protists and spirillium bacteria- Flagellum moves in a corkscrew motion propelling cell through space- This motion is the most efficient method of individual cell locomotion

Sporozoite - During Plasmodium sp. life cycle, these are the form which enter human bloodthrough mosquito saliva


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Trophozoite - During Plasmodium sp. life cycle, these are the form which live and feed in humanred blood cells

Vaccine - Substance administered which is a weaker form of a pathogen to patients- Purpose is to raise their immunity by getting used to form and antigens

Virion - A complete virus particle

Virus - An infectious agent that contains either DNA or RNA surrounded by a capsid

Zooplankton - Small, usually microscopic animals that float freely in aquatic habitats

Zygote - A fertilized egg

or

Proterozoic eon

Autapomorphies

Origins of Mitochondria

The primitive eukaryotic cell was only

capable of anaerobic metabolism to

generate ATP, one of the intermediates ofwhich is 3 carbon organic molecule

pyruvate. Bacteria was used as a food

source and would normally be digested

but for some reason, one bacterium wasnot digested and it continued metabolizing

inside the eukaryotic cell. The bacteriaused the pyruvate molecules produced bythe cell to produce ATP and any surplus

ATP would diffuse out of the

mitochondria and could be used by the

eukaryotic cell as an energy source. Asymbiosis developed in which the

eukaryotic cell would provide pyruvate

and mitochondria would provide ATP.This high efficiency energy production

system allowed the eukaryotic cell to

dedicate more energy to growth and

development, one of the reasonseukaryotic cells are so large.

The mitochondrial DNA sequence has

been preserved for long periods of timedue to its efficiency. The membrane

surrounding mitochondria is characteristic

of prokaryote membrane and its DNA is


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characteristic of prokaryote DNA.

Endomembrane System

Invaginations of the plasma membrane to

increase surface:volume ratio and create

complex endomembrane system that hasspecialized organelles and surfaces for

different cellular activities.. Providescompartments within the cell which areseparate from the cytoplasm. System

contains nuclear envelopes, endoplasmic

reticulum, golgi comples, vesicles andlysosomes.

The genetic material was first to be

wrapped in endomembrane system. The

invagination creates a double lipid bilayerwith pores in it used for communication

and transport of ribosomes and RNA. The

genetic material, events of the genome,transcription were separated from the restof the cellular components and were given

a specialized cellular component. This

allows for the modification of mRNA(removal of introns) before translation.

Chromosomes

Storage of genetic material in multiple

linear strands rather than in a singlecircular loop. This characteristic allows

fast replication of a large genome because

there are replication points on multiple

chromosomes rather than only onereplication point on a single bacterial

chromosome.

Centrosome

Important role in mitosis and meiosis.

System of microtubules extending fromthe centrosome pull the chromosomes

apart. The cytoskeleton is also composed

partly of microtubules.Microtuble networks extend throughout

the cell from the centrosome and are

responsible for positioning the nucleus

and other organelles, also creates overallpolarity of the cell. The centrosome

implements the cell's 3D architectural

plan which is encoded in the centriole ofthe centrosome and passed to the daughter

cells when they duplicate. Molecular

motors (kinesin and dyenin) move alongthe microtubles and are responsible for


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intracellular transport. They can speed

materials across the cell which overcomes

the limitations of passive diffusion.

Kinesin and dyenin

Molecular motors that interact withtubulin dimers in cytoskeleton. Burns ATP

and moves down the tubulin, also has abinding site on which things attach as theymove down the fibres they move things

around. Kinesin moves towards the

centrioles and dyenin move away.Transport vesicles and increase the speed

of functions happening in the cell.

Origin of cellular mobility

Cell gliding. The centrioles build

cytoskeleton at one end and retract at theother end with motors transporting

cytoplasmic material.

Endosymbiosis

Chloroplast (plastid) arose byendosymbiosis, a photoautotroph, likely acyanobacteria, was internalized by a

eukaryote. There's a double plasma

membrane around the plastid ( bacterialmembrane and eukaryote membrane) The

plastid contains bacterial DNA and

bacterial ribosomes. In some algae, theplastid still has traces of peptidoglycan.

Certain algal groups have a third lipid bi-

layer membrane surrounding the plastid.

This would have resulted from asecondary endosymbiotic event in which a

small eukaryote algae is engulfed by a

larger eukaryote.

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