pro and eu cell structure

Eukaryotic and Eukaryotic and Prokaryotic CellsProkaryotic Cells

AHMP 5406AHMP 5406

Objectives:Objectives:

1.1. Discuss the key differences between prokaryotic and Discuss the key differences between prokaryotic and eukaryotic cellular componentseukaryotic cellular components

2.2. Describe the basic structure of mammalian eukaryotic Describe the basic structure of mammalian eukaryotic cellscells

3.3. Discuss the different nutritional classesDiscuss the different nutritional classes4.4. Explain the endosymbiotic theory and development of Explain the endosymbiotic theory and development of

organelles in the Euk. cellorganelles in the Euk. cell5.5. Compare and contrast the genome organization of Compare and contrast the genome organization of

prokaryotes versus eukaryotesprokaryotes versus eukaryotes6.6. Compare the different ways new genes are generated Compare the different ways new genes are generated

from existing genesfrom existing genes7.7. Explain why the human genome is complexExplain why the human genome is complex

Features All Cells ShareFeatures All Cells Share

Hereditary info stored in DNAHereditary info stored in DNAProteins are used as catalysts Proteins are used as catalysts DNA replication occurs through templated DNA replication occurs through templated polymerizationpolymerizationHereditary info transcribed into RNAHereditary info transcribed into RNARNA translated into proteinRNA translated into protein

Later we will discuss these things in Later we will discuss these things in greater detailgreater detail

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From DNA to ProteinFrom DNA to Protein(Why is this eukaryotic?)(Why is this eukaryotic?)

Prokaryotic cells:Prokaryotic cells:No membrane bound organellesNo membrane bound organelles

Simple genome organizationSimple genome organization

Genes usually do not have intronsGenes usually do not have introns

Between 500 and 4000 genesBetween 500 and 4000 genes M. genitaliumM. genitalium has 477 genes has 477 genes

Great degree of diversityGreat degree of diversity

UnicellularUnicellular

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MycoplasmaMycoplasma genitalium genitalium

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Eukaryotic cellsEukaryotic cells

All organelles are membrane-boundAll organelles are membrane-boundComplex genome organizationComplex genome organizationLarge genome sizeLarge genome sizeBetween 6,000 and 30,000 genesBetween 6,000 and 30,000 genesGenes have intronsGenes have introns Where is the genetic diversity?Where is the genetic diversity?

Large amount of regulatory DNALarge amount of regulatory DNA To control gene expression To control gene expression

High degree of genetic redundancyHigh degree of genetic redundancyUnicellular or multicellularUnicellular or multicellular

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General eukaryotic cellGeneral eukaryotic cell

1 and 2

Cells can be powered by different Cells can be powered by different energy sourcesenergy sources

I eat other living things!I eat other living things! OrganotrophicOrganotrophic

AnimalsAnimals Protists etc. Protists etc.

I need a tan?I need a tan? PhototrohpicPhototrohpic

BacteriaBacteria PlantsPlants AlgaeAlgae

I eat dirt?I eat dirt? LithotropicLithotropic

ArcaebacteriaArcaebacteria

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Eukaryotic cell may have been Eukaryotic cell may have been predatorspredators

The primordial eukaryotic cell may have The primordial eukaryotic cell may have survived by eating other cellssurvived by eating other cells

This would require:This would require: A large cellA large cell A flexible membraneA flexible membrane An elaborate cytoskeletonAn elaborate cytoskeleton Protected DNA (in an organelle, which one?)Protected DNA (in an organelle, which one?)

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4 Dinidium is a cilliated protozoan

Lunch!

He looks hungry

Genome organization in Prok. and Genome organization in Prok. and Euk.Euk.

ProkaryotesProkaryotes Circular DNACircular DNA

mtDNA very similarmtDNA very similar

EukaryotesEukaryotes Linear DNALinear DNA nuclear DNAnuclear DNA

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Prokaryotic DNAProkaryotic DNA

Eukaryotic DNAEukaryotic DNA

DNA packaged in a DNA packaged in a chromosomechromosome

Linear DNALinear DNA

Associated proteinsAssociated proteins

More details laterMore details later

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Ways to generate new genes from preexisting genesWays to generate new genes from preexisting genes

Intragenic mutationIntragenic mutation Simply a mutation in the sequenceSimply a mutation in the sequence

Gene duplicationGene duplication Whole gene is just recopied into different part of the genomeWhole gene is just recopied into different part of the genome

DNA segment shufflingDNA segment shuffling Similar genes may exchange segmentsSimilar genes may exchange segments

Horizontal transferHorizontal transfer Cell to cell transfer of genetic materialCell to cell transfer of genetic material

e.g. Plasmidse.g. Plasmidsancient mitochondrial genesancient mitochondrial genesVirusesVirusesSexSex

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Gene FamiliesGene Families

Created by generation of different genes Created by generation of different genes from a precursorfrom a precursor

Speciation results in orthologous genesSpeciation results in orthologous genes An organismal phylogeny is producedAn organismal phylogeny is produced

Gene duplication can result in paralogous Gene duplication can result in paralogous genesgenes A gene phylogeny is producedA gene phylogeny is produced

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The human genome is complex:The human genome is complex:7

Partly because of duplications

Regulatory Regulatory DNA is DNA is

everywhere everywhere in eukaryotic in eukaryotic

genomesgenomes

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mRNA StructuremRNA Structure7

7Comparative Genome Sizes

pro and eu cell structure

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