CBG Lecture 1: Prokaryotes and Eukaryotes Flashcards by Helen Panteli

what is an UTR

untranslated region, found at 3’ and 5’ mRNA

targeting sequences that are temporal and spatial: how long and where mRNA should stay/go

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how to change DNA code from plus sense to - sense

leave labels but reverse the letters, the complementary base pair

eg. 5’ CGT 3’ DNA (+) as written
1. swap labels and reverse: 5’ TGC 3’
2. complementary base pair 5’ ACG 3’

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how many possible codons are there

64 - 3 stop, 61 aa coding, start codings

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what is the central dogma of biology

sequential info in protein cant flow back to nucleic acid
TRANSLATION IS IRREVERSIBLE
phenotype back to protein is irreversible
no such thing as an anti ribosome

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what is a prion

an infectious agent composed of protein in a misfolded form. there is no nucleic acid element to their structure
prions disease
(protein and infection)

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what are planctomycetes

a phylum of aquatic bacteria that tend to enclose tehir nuclear material within a double membrane

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what is reverse transcription

RNA back to DNA

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what are planctomycetes

a phylum of aquatic bacteria that tend to enclose their nuclear material within a double membrane

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compare nucleus and time of arising in proks and eukaryotes

o PROK: no nucleus, arose 3000MYA

EUKS: nucleus, arose 1500MYA

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outline prokaryotic cell structure

simple cell structure, naked DNA with a simple path from DNA to proteins
circular chromosome in nucleoid (area within the cytoplasm holding the DNA)
only essential organelles: ribosome, mitochondria
rotating flagellum
binary fission
small and diffusion limited:1micrometre
have plasmalemma
have pilli
have capsule

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what is a nucleoid

where found

area within the cytoplasm holding the DNA

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what can prokaryotes be divided into

bacteria and archaea

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what subdivision of prok’s is related closer to eukaryotes

archaea

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outline PROK’s molecular biology

'junk' free genome (most is transcribed and translated)
nacked DNA lacking histones
one RNAP using sigma factor
tRNAi formylmethionine start codon
small 70s ribosomes

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what is S (wrt. ribosome size)

sedimentation coefficient in Svedbergs

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outline EUKARY’s cell structure

linear chromosomes in nucleus - with ssSNA ends (telomeres)
complex endomembranes and endosymbionts
prominent cytoskeleton and up-down flagellum (9+2 tubulin rubbing)
complex mitotic division (using microtubule tracks)
large cytplasmic screening 100micrometre

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outline eukaryotic molecular biology

junk in genome
dna bound by histones into nucleosomes
3 RNAPs using TBP (TATA binding protein)
tRNAiMETHIONINE start codon
large 80s ribosomes

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what size ribosomes present in EUKS

80s

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how does DNA packaging in EUKS compare to PROKS

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no DNA packaging in PROKS, but DNA bound by histones into nucleosomes in EUKS

what tRNAi start codon do EUKS use

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methionine

what tRNAi start codon do PROKS use

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formylmethionine

what RNAPs do EUKS use? and use what initiate transcription

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3 type RNAPS and TBP (TATA binding protein)

what RNAPs do PROKS use? and use what initiate transcription

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one type RNAP use sigma factor

what did Woese propose

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3 domains of life based on rDNA sequences - bacteria, archaea, eukarya
the prokaryotes are not a monophyletic group and are sometimes split into archaeabacteria and eubacteria
archaea are a polyphyletic group

what is rDNA

the DNA that encodes rRNA - these genes tend to be highly conserved and mutate rather slowly becaUSE theyre so essential to the cell

why did Woese base domain theory on rDNA

because the genes encoded tend to be highly conserved and mutate rather slowly, as they are essential to the cell

what grp (phylogenetically) are archaea

polyphyletic group

what relation exists between archaea and eukaryotes

archaea are eukaryotes in a bacterium's clothing

why are archaea said to be eukaryotes in a bacterium's clothing

they have a prokaryotic cell structure (no nucleus/no endosymbionts/no skeleton) but they have eukaryotic molecular biology (histone bound DNA, tRNAmet start codon, RNAP using TBP)

give example of an archaea

halobacterium

what did Margulis propose

that eukaryotes contain endosymbionts of bacterial origin - -> Mitochondria (proteobacteria : Rickettsia) - -> Plastids (cyanobacteria) the mitochondria merged from the bacteria line into the eukaryotic line, hence the commonalities between them

why is it not sensible to say that archaea are more closely related to eukaryotes than bacreria

due to gene transfer from the endosymbiont to the host nucleus. if you look at individual genes, some of the eukaryotic genes are of clearly (proteo/cyano-)bacteria origin: the eukaryotic genome is loads of genes from different sourcesa

what is the following archaea feature more similar to BACTERIA or EUK?? aa attached to initiator tRNA

eukaryote

what is the following archaea feature more similar to BACTERIA or EUK?? start codon identification by ribosome

bacteria

what is the following archaea feature more similar to BACTERIA or EUK?? binding of RNAP to promoter

euk

what is the following archaea feature more similar to BACTERIA or EUK?? number of different RNAPs

bacteria

what is the following archaea feature more similar to BACTERIA or EUK?? cytoskeletal architecture and composition

bacteria

what is the following archaea feature more similar to BACTERIA or EUK?? dna packaging

eukaryotes

what is the following archaea feature more similar to BACTERIA or EUK??presence/absence of introns

absence of introns - bac

what is the following archaea feature more similar to BACTERIA or EUK?? no. rRNAs in large subunit

bacteria

how does flagellum of bacteria move? | give an exception

movement by PMF | Oscillatoria: use gliding for movement, lack flagellum

how does flagellum of EUKS move?

rotating flagellum-structurally similar to bacterium but analogous

what is max size bacteria can grow? why not bigger?

1 micrometre | size is limited by the fact they rely on diffusion for nutrients and survival so cant grow bigger

why can eukaryotic cells be bigger than archaea/bac

the cytoskeleton allows mixing up of the cytosol which means substances can be transported intracellularly easily therefore can grow bigger also, cytoskeleton forms a framework for movement of organelles

what is ENCODE

Encyclopedia of DNA Elements 30 research papers, decade long project hypothesized that around 80% of genome serves a biochemical purpose

what were the main outcomes of the ENCODE project

showed DNA bases not only define proteins but 1. specify landing spots for proteins that influence gene activity 2. strands of RNA have many roles 3. places where chemicals

CBG Lecture 1: Prokaryotes and Eukaryotes Flashcards

(46 cards)