Lecture 1 - Terminology, The concept of Prokaryote & Eukaryote PDF

TERMINOLOGY, THE CONCEPT OF PROKARYOTE & EUKARYOTE Prof. Dr. Ahmet CARHAN 1 2 ORGANIZATION WITHIN AN ORGANISM Atoms are organized into molecules In multicelled species, cells are organized into tissues, organs, and organ systems All organisms consist...

TERMINOLOGY, THE CONCEPT OF PROKARYOTE & EUKARYOTE Prof. Dr. Ahmet CARHAN 1 2 ORGANIZATION WITHIN AN ORGANISM Atoms are organized into molecules In multicelled species, cells are organized into tissues, organs, and organ systems All organisms consist of one or more cells Emergent properties: Life emerges at the cellular level 3 LEVELS OF ORGANIZATION 4 LEVELS OF ORGANIZATION 5 KEY CONCEPTS: LEVELS OF ORGANIZATION We study the world of life at different levels of organization, from atoms and molecules to the biosphere “Life” emerges at the level of cells 6 ECOSYSTEM: ENERGY FLOW AND MATERIAL CYCLİNG Organisms require energy and materials to sustain their organization and activities 7 OVERVIEW OF LIFE’S UNITY Organisms grow and reproduce Based on information encoded in DNA Inheritance transmits DNA from parents to offspring through reproduction mechanisms Development transforms first cell into an adult 8 DEVELOPMENT 9 KEY CONCEPTS All organisms are alike in key respects: Consist of one or more cells. Live through inputs of energy & raw materials. Sense and respond to changes in their external and internal environments. Cells contain DNA (molecule that offspring inherit from parents; encodes information necessary for growth, survival, and reproduction). 10  Cell is the smallest unit capable of carrying out the processes associated with life Classical Properties of How cells fulfill these criteria of Living Organisms: Living Organisms: Reproduction Cell replication Nutrition Nutrition Respiration Respiration Excretion Excretion Irritability/respond Respond to environment Movement Movement within and Growth externally Grow in number and size 11 GENUS AND SPECIES Species: One kind of organism Each species has a two-part name First part: Genus name Combined with the second part, it designates one particular species 12 DOMAINS Current classification groups all species into three domains Bacteria (single-celled prokaryotes) Archaea (single-celled prokaryotes) Eukarya (protists, plants, fungi, and animals) 13 BACTERIA AND ARCHAEA Bacteria Archaea 14 EUKARYA 15 TWO MAIN TYPES OF CELLS… 1. Prokaryotes 2. Eukaryotes 16 AGE Prokaryotes: Older- 3.8 billion yrs Eukaryotes: Younger- 2.7 billion yrs 17  THE SIX KINGDOMS Prokaryotic Eukaryotic (before nucleus) (true nucleus) 1. Eubacteria 1. Animals 2. Archaebacteria 2. Plants 3. Fungi 4. Protist 18 ORGANISMS CAN BE DIVIDED INTO 2 GROUPS Single Cellular Multi-cellular Procaryote Bacteria - Eucaryote Fungi Fungi Protozoa Algae Algae Plants Animal 19 PROKARYOTES Only a few types of cell parts Prokaryotic cells exist in two major kingdom: Eubacteria Most of the common bacteria that are found everywhere Archaebacteria (archae=ancient or old) Ancient bacteria that live in very extreme conditions only found in certain places on Earth. 20 21 PROKARYOTIC CELLS 1-10 um in diameter, just visible with light microscopes Lack a membrane bound nucleus and organelles. Genetic material is naked in the cytoplasm Ribosomes are only organelle 22 CELL WALL Bacterial cell wall Rigid structure Surrounds cytoplasmic membrane Determines shape of bacteria Holds cell together Prevents cell from bursting Unique chemical structure Distinguishes Gram positive from Gram-negative 23  PLASMA MEMBRANE Layer of phospho-lipids and proteins that separates cytoplasm from external environment. Regulates flow of material in and out of cell. 24 RIBOSOMES Translate the genetic code into proteins Free-standing and distributed throughout the cytoplasm Composed of large (50S) & small (30S) subunits 25 NUCLEOID Region of the cytoplasm where chromosomal DNA is located. Usually a singular, circular chromosome Smaller circles of DNA called plasmids are also located in cytoplasm. They are not essential for growth and reproduction Bacterial chromosome is not directly interact with the proteins such as histones 26 Here you can see pili and flagellae 27 28 PROKARYOTES Prokaryotes can survive in a wide range of environments -can withstand extreme temperatures -extreme pH levels -can live in areas of no oxygen or no water obtain their energy in a variety of ways -some can make their own food (autotrophs) -some have to find their food (heterotrophs) 29 PROKARYOTES 30 ARCHAEBACTERIA 31 Shared with Bacteria Shared with Eukaryote Unique to Archae No nucleus or membrane No peptidoglycan Cell wall (for example, some archaeal cell bound organelles wall contain pseudomurein) Circular genome DNA associated with Cell membrane containing ether-linked histones lipids Genes grouped in Operon Translation initiated with Flagellin protein structure methionine No intron or RNA processing Similar RNA polymerase, Ribosomal structure (characteristics promoters, other shared with both Bacteria and Eukarya) transcriptional machinery Polycistronic mRNA Similar DNA replication tRNA sequence and metabolism and repair Cellular size (> 100 fold Similar ATPase (Type V) No fatty acid synthetase enzyme smaller than eukaryotes) Single RNA Polymerase More than 1 RNA More than 1 RNA Polymerase Polymerase Note: Operon is also found in some eukaryotes (D.melanogaster, C.elegans & some 32 chordates)  POLYCISTRON Before RNA Processing (before mRNA) Exon I Intron Exon II After RNA Processing Ekzon Exon II Ekzon ExonIIII β-galactosidase, permease & transacetylase  COMPARISONS EUCARYOTE BACTERIA Larger Smaller Simple wall structure Peptidoglycan wall Sterols in membrane 2 + (9x2) flagella Usually no sterols in memb. True nucleus Flagellin in helix Histones No nucleus, instead nucleoid Several chromosomes Membrane-bound No histones organelles One chromosome 80S ribosomes No membrane-bound organelles 70S ribosomes 34 35 MAKE COMPARISON BETWEEN BACTERIA & MITOCHONDRIA BACTERIA MITOCHONDRIA 1 chromosome Multiple copies No membrane-bound no membrane-bound organelles organelles 70S ribosomes 70S ribosomes Replicates autonomously Replicates autonomously About 1- 8 m About 1 m Peptidoglycan wall No wall Mostly no sterols in Minute amount membrane sterol membrane No nucleus No nucleus No histones No histones 36  Questions & Comments: Prof. Dr. Ahmet CARHAN e.mail: [email protected] 37  Questions & Comments: Prof. Dr. Ahmet CARHAN e.mail: [email protected] 37