Lec 2 Flashcards by Jasmine Marta

Eon where the first cellular life belongs and formation of crust and oceans/ earth

Hadean

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Eon where purple and green bacteria belongs

Archaean

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What does LUCA stands for?

Last Universal Common Ancestor

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– The first cells arose out or primodial soup (“On the origin of species” Darwin)
– Temperature fluctuations, meteor impacts, dust clouds, intense UV radiation make a surface origin for life unlikely.

Surface origin hypothesis

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– Life originated at hydrothermal springs on he ocean floor.
– More stable than surface

Subsurface origin hypothesis

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What are the five kingdoms according to the Whitaker scheme?

– Animalia, Plantae, Fungi, Protista, and Monera

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This kingdom is comprised of prokaryotes

Monera

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Goal: ________
* In order to understand relatedness, organisms must be viewed at the ____ level

Evolutionary classification
DNA

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*
– Ribosomal RNA genes cannot afford to mutate much

Carl Woese and 16S rRNA

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he began using molecular sequences of rna to study the evolutionary history of life on earth

Carl woese (1969)

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All _______ are not phylogenetically closely related
______ are actually more closely related to Eukarya than to Bacteria
The ______ shows that LUCA resides very early within the Bacteria domain

prokaryotes
Archaea
universal tree of life

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– groups organisms based on mutual similarity of phenotypic characteristics
– may or may not correctly match evolutionary grouping
– Example: Group flagellated (motile) organisms in one group, non-motile organisms in another group

Phenetic system

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– groups organisms based on shared evolutionary heritage
* But evolutionarily they are similar

Phylogenetic system

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For example: Use a variety of characteristics: e.g., Gram stain, cell shape, motility, size, aerobic/ anaerobic capacity, nutritional capabilities, cell wall chemistry, immunological characteristics, etc. – Relies on similarity coefficients and then match organisms
Ex. A and B share 8 characters out of 10: similarity coefficient Sab is 8/10 = 0.8
Can use many such values to establish similarity matrix
_______ help display this information clearly

Numerical Taxonomy
Dendrograms

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Basic assumptions:
-Genes mutate randomly
Many mutations are “neutral” – do not lead to any obvious disadvantage to the strain
Once a mutation is established, all progeny of parent cell carry that particular mutation

Molecular taxonomy

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– descended from a single organism – different isolates may be same species but are different strains; often have slight differences

strain:

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– the first strain isolated or best characterized
– often more fully characterized than others
– standard by which other strains thought to be the same can be compared
– only those strains very similar to the type of strain are included within species

type strain:

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variants that are characterized by biochemical or physiological differences

BIOVARS

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variants that differ morphologically

MORPHOVARS

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variants that have distinct antigenic properties

SEROVARS

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used to identify genera of enteric bacteria

Metabolic / Physiologic characteristics

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Universal Criteria for Naming and Classification (bacteria) Clue: 6 items

-Morphological / Cultural Characteristics
-Chemical Composition
-Metabolic Characteristics
-Genetic Characteristics
-Serology / Antigenic / Immunological characteristics
-Ecological Characteristics

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genetic system studied at the molecular level
likeness or homology bet DNA of cells

Genetic Characteristics

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Homology studies can be determined by ____
Clue: 5 items

Study These Flashcards

-DNA Base composition
-DNA hybridization
-DNA fingerprinting
-rRNA sequencing
- PCR

PCR stands for?

Polymerase Chain Reaction

constant characteristics of a particular species -expressed as the mole % of guanine and cytosine (G+C) pf the moles of the total base

DNA Base Composition

-measures the ability of DNA strands to hybridize with DNA strands of another organism -the greater the degree of hybridization, the greater the degree of relatedness

DNA Hybridization

Complete hybridization=_____ Partial Hybridization=_____ ______=organism unrelated

organism identical organism related No Hybridization

-analysis of DNA using electrophoresis -DNA is sequenced -separate DNA component by electric current -for detection of microbial pathogen

DNA Fingerprinting

What type of characteristic? * Slide Agglutination Test –______ results when the bacteria are mixed with antibodies that were provided in response to the same strain –positive test is indicated by the presence of agglutination

Serology / Antigenic Characteristics agglutination

______ most powerful, most direct - used in determining diversity and in phylogenetic relationships similarities are detected using association coefficient represented by % similarity.

rRNA sequencing

is used since most microorganisms don't form fossils unlike eukaryotes

RNA

What are the 3 fossilized microbes

✓ marine protist- England ✓ Stromatolites filamentous bacteria (1.5 B yrs. Ago) ✓ cyanobacteria- 3 to 3.5 B yrs. Ago; in Australia

_______ to make multiple copies of DNA in a short period of time, especially if the DNA sample is only few

PCR

-3 cycles of pcr??

(denaturation, annealing and extension)

a problem where Unrelated bacteria develop similar physical and biochemical traits

Convergent evolution

precipitates of clay, metal sulfides, silica and carbonates

Mound

Problem of bacterial taxonomy – no sexual reproduction – no interbreeding

concept of species

Eukaryotes: * mitochondria are nearly universal among eukaryotic cells – Some anaerobic eukaryotic microorganisms lack mitochondria and instead contain _______ * ________are found only in phototrophic cells.

hydrogenosomes chloroplasts

– Unicellular eukaryotes with many different characteristics. Also studied by Parasitologists. – Some cause human disease

* Protists

– Yeasts and molds, studied by Mycologists – Several types can cause human disease

* Fungi

– Parasitic worms; studied by Parasitologists

* Animals

* Most are unicellular. * Most are freeliving organisms that live in soil and water. * Ingest other organisms or organic material. * Do not have a cell wall.

Protozoa

Protozoan Life Cycle – _________ * Motile, feeding, dividing stage. – ______ * Dormant, survival stage.

Trophozoite Cyst

Tsetse flies in the genus Glossina transmit the protozoan pathogens that cause ____________ (Trypanosoma gambiense and T. rhodesiense).

African sleeping sickness

* Asexual reproduction of Protozoan: – ___________ * produces 2 daughter cells. – ____________ * Multiple nuclear divisions before cytoplasmic divisions. * Results in more than 2 daughter cells.

Binary fission Schizogony

* Sexual reproduction in protozoan – ____________ * 2 haploid gametes which fuse to form a diploid zygote.

Gametocyte production

* Major groups of Protozoan Based on method of locomotion – _______ * Pseudopodia – ________ * Possess flagella – ______ * Possess cilia

Amoebae Flagellates Ciliates

– Nonmotile protozoa Called ________

sporozoa

Unicellular Algae * _______ – Freshwater and marine environments. – Cell walls contain silicon dioxide (glass). – Used in filtration systems, insulation, and abrasives (like toothpaste).

Diatoms

Unicellular Algae * _______ * Usually photosynthetic. * Some produce light and are often called fire algae. * Responsible for “red tides” or algal bloom

Dinoflagellates

Unicellular Algae * ________ – Group of green algae. – Can photosynthesize. – Ex. _____ * Has algal and protozoan characteristics. * Has a primitive mouth. * Does not have a cell wall. * Has an eyespot. * Has flagellum. – Ex. _______ * Filamentous algae.

Desmids Euglena Spirogyra

Multicellular Algae * ____________ – Usually found in ocean water. – Are a source of algin, which is a thickener in ice cream. * ____________ – Found in deeper ocean water than brown algae. – One type of red algae (Gelidium) is the source of agar.

Brown Algae Red Algae

__________ * Unicellular or multicellular eukaryotes. * Reproduce asexually and sexually. * Lack chlorophyll. * Have a cell wall made of chitin. * Are _______ – “garbage disposers” of nature

Fungi saprophytes

_______ * 3-8 µm in diameter. * Found in soil and water and on skin of many fruits and vegetables. * Reproduce by an asexual process called budding. * Results in the production of a type of asexual spore called a _______. * Responsible for beer, wine, leavened bread. * Some species are human pathogens (i.e. Candida albicans).

Unicellular Yeast blastospore

______ * Possess hyphae – A ____is a tubelike cell. * A mass of hyphae forms a mycelium. * _______ have cross walls or septations. * _________ coenocytic lack cross walls or septations.

Multicellular Fungi hypha Septate hyphae Non-septate hyphae/

Fungi classification * _______ – Zoospores * Sexual spores * flagellated * ________ – Food spoilage * ________ – Mycorrhizal fungi

Chytridiomecetes Zygomecetes Glomeromycetes

Fungi classification * _________ – Produce asci (ascus) cells – Ascospores (haploid); ascocarp (fruiting body) * ________ – mushrooms

Ascomycetes Basidiomycetes

Lec 2 Flashcards

(58 cards)