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Prokaryotes vs. Eukaryotes

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rahozoku's version from 2016-03-08 08:25

Cellular Structure

Question Answer
Prokaryotic cellular components vs Eukaryotic cellular componentsno membrane-bound organelles (has a nucleoid), ribosome 70s (30s and 50s subunits) ; nucleus, nucleolus, endoplasmic reticulum (smooth and rough), golgi apparatus, mitochondria, peroxisome, lysosome, ribosome 80s (40s & 60s subunits)
Prokaryotic external structure vs. Eukaryotic external structureflagellum rotates like screws to create propulsion; flagellum possess a 9+2 structure, which lashes back and forth to create propulsion
Prokaryote plasma membrane vs Eukaryote plasma membraneCell membrane: outside the lipid bilayer is a rigid cell wall composed of peptidoglycan, a complex polymer unique to prokaryotes, which provides support for the cell and prevents lysis due to osmotic pressure; cell membrane: phospholipid bilayer
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DNA Structure

Question Answer
Prokaryote DNA structure vs Eukaryote DNA structure single, circular, and naturally supercoiled DNA that is contained in a region called a nucleoid; multiple linear chromosomes, chromatin is the basic structure composed of DNA and histones forming the appearance of "beads on a string," heterochromatin: densely coiled chromatin, euchromatin: diffusely coiled chromatin
Prokaryote plasmid vs Eukaryote plasmidcircular double-stranded DNA molecules separate from the chromosomal DNA; not present in eukaryotes ljljjljl
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DNA Replication

Question Answer
Prokayote DNA replication mx vs Eukaroyte DNA replication mxsingle origin of replication in which DNA replication proceeds via theta replication; Each chromosome has several originas of replication in which DNA replication proceeds via replication bubbles
Prokaryote DNA polymerase fx vs Eukaryote DNA polymerase fxDNA Pol recognizes and binds to the start signals for replication called origins of replication (ori); DNA Pol recognizes and binds to the start signals for replication called origins of replication (ori)
Prokaryote DNA polymerase mx vs Eukrayote DNA polymerase mxDna Pol 1: primarily remove primer and puts DNA in its place; 5' to 3' exonuclease activity (adds dNTP), 3' to 5' exonuclease activity (proofread), DNA Pol II: function unknown, DNA Pol III: 5' to 3' polymerase activity (adds dNTP), 3' to 5' exonuclease activity (proofread); DNA Pol: removes primer and puts DNA in its place, 5' to 3' polymerase activity (adds dNTP), 3' to 5' exonuclease activity (proofread)
Prokaryote other enzymes fx in DNA replication vs Eukaryote other enzymes fx in DNA replicationHelicase: separates the two strands of nucleic acid double helix, DNA gyrase: uses ATP to supercoil DNA, Primase (RNA Pol): makes primer, DNA ligase: not needed since prokaryotes possess a single circular DNA that is replicated via theta replication; Helicase: separates the two strands of nucleic acid double helix, DNA Topoisomerase: uses ATP to supercoil DNA, Primase (RNA Pol): makes primer, DNA ligase: catalyzes formation of phosphodiester linkages that join okazaki fragments
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DNA Transcription

Question Answer
Prokaryote Transcription enzyme vs Eukaryote Transcription enzymeEukaryote Primase (RNA polymerase): make primer
Prokaryote site of occurrence vs Eukaryote site of occurrence (Transcription)cytoplasm; nucleus
Prokaryote RNA polymerase fx vs Eukaryote RNA polymerase fxRNA Pol recognizes and binds to the start signals for transcription called Promoters (P); RNA Pol recognizes and binds to the start signals for transcription called Promoters (P)
Prokaryote modification of mRNA vs Eukaryote modification of mRNA (Transcription)no modification of mRNA, mRNA is translated shortly after transcription (both transcription and translation occur in the cytoplasm); 5' G-cap (methylated guanine nucleotides), 3' Poly-A tail (string of adenine nucleotides), splicing of introns/exons
Prokaryote transcription enzyme structure vs Eukaryote transcription enzymesCore is composed of 4 sub units (alpha, alpha, beta, beta prime), sigma factor, holoenzyme = complete (alpha, alpha, beta, beta prime, sigma); RNA pol I: transcribes rRNA, RNA pol II: transcribes mRNA, RNA pol III: transcribes tRNA
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Regulation of Transcription

Question Answer
Prokaryote other notes regulation of transcription vs Eukaryote other notes regulation of transcriptionregulation of transcription is the primary method of regulation of gene expression, transcription and translation often occur at the same location and same time; regulatory control during both transcription and translation, transcription and translation occur at different locations
Prokaryote regulation of transcription enzyme vs Eukaryote regulation of transcription enzymePromoter: DNA sequence located in the -10 ("Prinbow Box") and -35 regions, Constitutive: genes that are continuously expressed (i.e. always turned "on"), Inducible (lac Operon): the presence of a substrate (i.e., lactose) induces the formation of new enzymes capable of metabolizing that substrate, Repressible (trp Operon): the presence of the products of an enzyme action (i.e. tryptophan) represses enzyme synthesis; Promoter: DNA sequence, typically contain a sequence of bases TATAA ("TATA Box") located at about the -50 region, Enhancer: located thousands of base pairs away from promoters, these DNA sequences serve to increase the rate of transcription, Silencer: located thousands of base pairs away from promoters, these DNA sequences serve to decrease the rate of transcription
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Translation

Question Answer
Prokaryote initiation translation vs Eukaryote initiation translationfirst amino acid: fMet (formylmethionine), initiatior tRNA: fMet-tRNAfmet; first amino acid: Met (methionine), initiator tRNA: Met-tRNAmet
Prokaryote site of occurrence translation vs Eukaryote site of occurrence translationcytoplasm; nucleus
Prokaryote important notes translation vs Eukaryote important notes translationprokaryotic mRNA is typically polycistronic, which means mRNA often codes for more than one polypeptide; eukaryotic mRNA is typically monocistronic, which means that mRNA codes for only one polypeptide
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Cellular Respiration

Question Answer
Prokaryote glycolyis location vs Eukaryote glycolysis locationcytoplasm; cytoplasm
Prokaryote krebs cycle/tricarboxylic acid cycle location vs Eukaryote krebs cycle/tricarboxylic acid cycle locationcytoplasm; mitochondria matrix
Prokaryote electron transport & oxidative phosphorylation location vs Eukaryote electron transportion & oxidative phosphorylationcell membrane; inner membrane of mitochondria
Prokaryotes important notes about cellular respiration vs Eukaryote important notes about cellular respirationProkaryotes do not have membrane-bound organelles so no energy is expended to transport NADH to where it can be oxidized. Hence, bacteria produce two more ATP from aerobic respiration than do eukaryotes; During aerobic respiration, energy is expended to transport cytosolic NADH into mitochondrial matrix
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Reproduction

Question Answer
Prokaryotes method of reproduction vs Eukaryotes method of reproduction Binary fission: asexual reproduction; Mitosis: asexual reproduction, Meiosis: sexual reproduction
Prokarytes method of genetic recombination vs Eukaryotes method of recombinationTransduction: transfer by a lysogenic virus of a portion of a host cell genome to a new host, Transformation: DNA released from one bacterium that is taken up by another, Conjugation: a form of genetic recombination in bacteria in which plasmid and/or genetic DNA is transferred from one bacterium to the other through a conjugation bridge (bacterial sex); Meiosis
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Viruses

Question Answer
Prokaryote viruses type/kind vs Eukaryote viruses type/kindBacteriophage (abbreviated to "phage"); Animal virus
Prokaryote virus life cycles vs Eukaryote virus life cycles Lytic cycle, Lysogenic cycle; Productive cycle (retroviruses such as HIV)
Prokaryote virus route of infection vs Eukaryote virus route of infectionAttachment/Adsorption: binding to exterior of bacterial cell, Penetration/Eclipse: injection of viral genome into host cell (because bacteria contain cell walls); Many animal viruses possess an envelope that surrounds the capsid and virus can enter host cell via fusion with plasma membrane or receptor mediated endocytosis
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