TEST 3 Flashcards
dmitosis results
-Results in two diploid (two copies of each chromosome)
daughter cells
meiosis results
-results in four haploid gametes
Cristae of mitochondria
-folded internal membranes
-Contain enzymes needed for respiration and ATP production
Matrix of mitochondria
-innermost area of mitochondrion
-Contains citric acid enzymes
Thylakoids in chloroplast
-flattened membrane discs contain
chlorophyll and ATP synthetic components, form proton motive force
rubisco
-key enzyme for calvin cycle
-found in inner membrane of mitochondria
Endosymbiotic hypothesis
-Mitochondria and chloroplasts descended from respiratory and
phototrophic bacterial cells, that were enveloped and used with nonphototrophic eukaryal hosts
-mitochondria utilized before chloroplasts
eukaryote origins
-fusion of archaeal host and mitochondrial precursor
Microtubules
hollow tubes made up of a & b tubulin
25nm
-Maintain cell shape, moves cell chromosomes and organelles
microfilaments
polymer of actin
7nm
-Maintain and change cell shape
Intermediate filaments
fibrous keratin proteins
8-12nm
-Maintain cell shape and position organelles
golgi complex
-stacks of membrane-bound sacs
modifying ER products
lysosomes
-membrane-enclosed compartments
containing digestive enzymes and recycling cell
components
Endoplasmic reticulum
-a network of membranes continuous with nuclear membrane
-rough and smooth
-rough has ribosomes; processes glycoproteins
-smooth does not; processes lipids
flagella composition
-Bundle of nine pairs of microtubules surrounding a central pair of microtubules
-Dynein is attached and uses ATP to drive motility
-eukarya and prokarya flagella are different
first phototrophs
anaerobic
Stromatolites
fossilized bacterial communities
ozone shield
-02 gave rise to collection of 03 in atmosphere
-03 in atmosphere blocks suns harmful radiation (UV)
-allows for organisms to colonize land
Phylogeny
-Evolutionary history of related DNA
sequences
bacteria and archaea divergence in relation to eukarya
before the emergence of eukarya
bacteria and archaea divergence time
3.7bya
eukaryas divergence from archaea divergence time
1.5-2.7bya
-oxygen may have spurred evolution
last eukaryotic common
ancestor LECA characteristic
-4000 genes
2/3 from bacteria (metabolic)
1/3 archaea (info processing)
70% are genes only in eukaryotes
evidence for endosymbiont theory
-Chloroplasts and mitochondria about the same size as bacteria
and independently replicate
-Both contain their own genomes of bacterial genes and are
circular
-Both contain bacterial ribosomes
-16S rRNA are characteristic of Bacteria
-Antibiotics inhibit both bacterial and organelle ribosome function
Eukaryotic genes for DNA replication
derived from archaea
archaea is ancestor
Lokiarchaeota
-Genomes with eukaryotic features
-eukaryotic-like cytoskeleton
-ability to synthesize intracellular
membranes,
-which may have facilitated stable integration of an
endosymbion
Hydrogen hypothesis
-Eukaryotic cells arose from an H2-
producing bacterium and an H2- consuming Archaea
Symbiogenesis
-Eukaryotic cell arose from symbiotic
relationship between Bacteria and Archaea; bacterial
partner was engulfed to form mitochondria
Serial endosymbiosis
hypothesis
mitochondria and chloroplasts integrated into protoeukaryote after nucleus formed
Genetic drift
a random process that can cause
gene frequencies to change over time, resulting in
evolution in the absence of natural selection
mutation
changes in DNA sequence over time
evolution
change in allele frequency over time
Rhodobacter
anoxygenic phototrophic purple bacterium
rhodobacter loss of function example
-rhodobacter who have lost photoactivity do better in dark environments
-rhodobacter who keep photoactivity do better in light environments
duplication and deletions effects on genome
-regulates genome size
-regulates gene content, removing non essential genes and expanding functions
Homologous genes
-Genes that all descended from a single ancestral gene
Orthologs
-Homologus genes sharing the same function
Paralogs
-A single gene that diverges to many different functions in different organisms
deletion frequency compared to insertion/duplication
much more
horizontal gene transfer pathways
transformation, transduction, conjugation
Gene conversion
-homologous recombination results in replacement of recipient copy with donor copy
Mobilome
-Consists of all mobile genetic elements in a genome
-can shuffle genes between species (recombination between host genome and plasmid that is transfered to another species)
Insertion sequences
-Simple mobile elements made of transposase
-flanked by inverted repeats
Transposons
-mobile genetic elements
-have terminal inverted repeats and transposase
-gene
Integrons
-contain integrase gene which integrates extra chromosomal DNA into chromosome
Systematics
-Study of organisms and their relationships, links phylogeny with taxonomy
(characterizes, names, classifies organisms)
3 methods of approach to taxonomy
-phenotypic
-genotypic
-phylogenetic
sequence alignment
-positioning of codons is important
-establishes gaps in homologs
Homoplasy
-convergent evolution
-complicates phylogeneitc approach to taxonomy
horizontal gene transfer in relation to the phylogenetic approach to taxonomy
-complicates phylogenetic approach
phylogenetic taxonomy tests
-analyze SSU rRNA
-Multilocus sequence analysis
Average nucleotide identity
-estimates overall relatedness by aligning ~1000 bp fragments and
calculating average nucleotide identity
reduction potential
ability of a molecule to accept or donate an electron
fementation
-doesn’t need external electron acceptor
-excretes metabolic intermediates
respiration
-need external electron acceptor
-uses 02 as final electron acceptor
Assimilative
-integrates inorganic nutrients into cells which are the electron acceptors
-uses ATP
Dissimilative
-process conserves energy
-electron acceptor is reduced then excreted
-02 in respiration
Mixotrophs
-can utilize 2 different metabolism pathways for energy (photosynthesis and respiration)
-(autotroph and heterotroph)
autotrophs
-creates their own energy using inorganic materials usually sunlight or chemicals
calvin cycle
-most widespread pathway that fixes C02
-used by all oxygenic phototrophs
-uses rubisco
calvin cycle requirements
12NADPH & 18 ATP
calvin cycle products
fructose 6 phosphate
Carboxysomes
-Protein compartments filled with RubisCO
reductive calvin cycle
-reverse of calvin cycle
-24H & 10 ATP
photosynthesis
-Use of light energy to drive
biosynthesis
-those that use this pathway are photoautotrophs
-origininated in bacteria
-requires light sensative pigments such as cholorphyll to absorb light and convert energy
Tetrapyrroles
cytocrhome with magnesium at center instead of iron
chlorophylls absorb what colors
-red and blue
-transmits green as it doesnt absorb that color
Bacteriochlorophyll
-found in anoxygenic phototrophs
Antenna pigments
-absorb and capture and funnel the light, transferring it to reaction centers
Reaction centers
-where photosynthetic process take place
-where the light energy is transformed into chemical energy
thylakoid lumen
-space inside thylakoid
-creates pmf
thylakoid stroma
-surrounding matrix of thylakoid
Chlorosomes
-capture low light intensities
-in bacteria
-contains bacteriochlorophyll
Carotenoids
-most widespread accessory pigment
-yellow red brown or green
-absorbs blue light
-can transfer light to reaction center
-protects cell from photooxidation
Phycobiliprotein
-main light harvesting system in cyanobacteria and red algae
-red or blue/green tetrapyrroles
-allows cells to grow at low light intensities
oxidation of sulfur product
S04^-2
Sox system
-reduces sulfur to sulfate
-acidifies envrionment
Primary fermentation
-break down and ferment carbohydrate, protein, fat polymers and monomers to reduced products
Secondary Fermentation
-break down and ferment volitile fatty acids
Major substrate of fermentation in nature?
lactate
Syntrophy
-Two different microbes cooperate to perform
a reaction neither can do alone
-usually secondary fermentations
direct syntrophy
direct contact between cells to allow for syntrophy
Mediated syntrophy
diffusion of metabolic prodcuts allows for syntrophy
Metabolic diversity
L
Ecological diversity
-microbial interactions between organisms and
their environments
Phylogenetic diversity
-evolutionary relationships between organisms
Gene loss
-trait is present in a common ancestor is
lost during divergence over time
Convergent evolution
-trait has evolved independently in different lineages and is not encoded by homologous genes
Photosystem 1
-FeS in center of oxygenic phototroph
-can do photosynthesis w/o help from ps2 through anoxygenic photosynthesis
Photosystem 2
-Quinone in center of oxygenic phototroph
-transfers energy (electrons) to photosystem 1 in Z scheme
-oxidizes water into oxygen
-reduces hydrogen for pmf
phototrophic bacteria hydrogen produced per o2 in photosynthesis
12H+ per 02 molecule
cyanobacteria aquired ps1 & ps2 how?
through horizontal gene transfer