北京大学：《微生物学》课程PPT教学课件（英文版）Arrangement of DNA in Prokaryotes

Arrangement of DNA in Prokaryotes Vertebrates Algae uno Free-living prokaryotes Obigately parasitic Bacteria Chloroplasts Mitochondria Viruses 15x100101102103104105105107108105 Genome size(kilobase pairs of DNA per organism)

Arrangement of DNA in Prokaryotes

DNA SU upercoilin g To package the A into the cell requires that the dna be supercoiled Proteins There are over 50 supercoiled domain domains in the Open ciro E. coli chromosome they are stabilized by association with the Supercoil structural proteins

DNA Supercoiling To package the DNA into the cell requires that the DNA be supercoiled. There are over 50 supercoiled domains in the E. coli chromosome, they are stabilized by association with the structural proteins

The Nucleus The nucleus is both a storehouse and a processing factory for genetic information The process of protein synthesis occurs in the cytoplasm

The Nucleus The nucleus is both a storehouse and a processing factory for genetic information. The process of protein synthesis occurs in the cytoplasm

Chromosomes and DNA Double-stranded DNA Histones are spaced along the DNA double helix at regular intervals the dna itself b g Histone H1 Nucleosome wound around each histone molecule. The packing forms a discrete structure called a nucleosome Nucleosomes aggregate and form a fibrous material called chromatin. Chromatin itself can be compacted by folding and looping to Core histones eventually form an intact oN chromosome

Chromosomes and DNA Histones are spaced along the DNA double helix at regular intervals, the DNA itself being wound around each histone molecule. The packing forms a discrete structure called a nucleosome. Nucleosomes aggregate and form a fibrous material called chromatin. Chromatin itself can be compacted by folding and looping to eventually form an intact chromosome

Mitosis(有丝分裂 During cell division. the nucleus 装3 divides following a doubling of the chromosome number. a process called mitosis, yielding two cells. each with a full complement of chromosome Metaphase: chromosomes are paired in the center of the cell 需 Anaphase: chromosomes are separating

Mitosis (有丝分裂) • During cell division, the nucleus divides following a doubling of the chromosome number, a process called mitosis, yielding two cells, each with a full complement of chromosome. • Metaphase: chromosomes are paired in the center of the cell. • Anaphase: chromosomes are separating

Organelles: Mitochondria and Chloroplasts Eukaryotic cells have a number of important functions localized in discrete bodies called organelles: Mitochondria: in which energy meta bolism is carried out Chloroplasts: in which the process of photosynthesis is carried out in plants and algae

Organelles: Mitochondria and Chloroplasts • Eukaryotic cells have a number of important functions localized in discrete bodies called organelles: • Mitochondria: in which energy metabolism is carried out, • Chloroplasts:in which the process of photosynthesis is carried out in plants and algae

Structure of the mitochondrion A bilayer of phospho lipid with embedded proteins. Cristae(脊): sites of enzymes involved in Inner membrane respiration and ATP production and of Matri specific transport proteins that regulate the passage of metabolites into and out of the matrix of the mitochondrion Cristae Matrix(基质): contains a number of enzymes involved in the oxidation oforganic Outer membran compounds(TCa cycle)

Structure of the mitochondrion A bilayer of phospho￾lipid with embedded proteins. Cristae(脊): sites of enzymes involved in respiration and ATP production and of specific transport proteins that regulate the passage of metabolites into and out of the matrix of the mitochondrion. Matrix(基质)：contains a number of enzymes involved in the oxidation of organic compounds (TCA cycle)

Structure of the chloroplasts Chloroplast Thylakoids(类囊体): the thylakoid membrane is highly impermeable to ions and other metabolites because its function is to establish the proton motive force necessary for ATP synthesis

Structure of the chloroplasts • Thylakoids(类囊体):the thylakoid membrane is highly impermeable to ions and other metabolites because its function is to establish the proton motive force necessary for ATP synthesis

Detailed structure of the chloroplasts Outer Stacked thylakoids membrane Stroma forming grana Thylakoid Inner membranes membrane Stroma contains large amounts of the enzyme ribulose bisphosphate carboxylase(RubisCO) that convert Co2 to organic form

Detailed structure of the chloroplasts Stroma contains large amounts of the enzyme ribulose bisphosphate carboxylase (RubisCO) that convert CO2 to organic form

Relationships oforganelles to bacteria SPRSAYINPAIC C AMNPAIRYNMH- WAy It was suggested that. Evidences mitochondria and Mitochondria and chloroplasts are descendents of ancient chloroplasts contain proKaryotic organisms DNA Endosymbiosis theory:. Mitochondria and Eukaryotes arose from chloroplasts contain the engulfment of a their own ribosomes prokaryotic cell by a Antibiotic specificity large cell Phylogeny

Relationships of organelles to bacteria • It was suggested that mitochondria and chloroplasts are descendents of ancient prokaryotic organisms. • Endosymbiosis theory: Eukaryotes arose from the engulfment of a prokaryotic cell by a large cell. • Evidences: • Mitochondria and chloroplasts contain DNA, • Mitochondria and chloroplasts contain their own ribosomes • Antibiotic specificity • Phylogeny