Bacterial Physiology (Micr430) Lecture 1 Overview of Bacterial Physiology (Text Chapters: 1 and 2)
Bacterial Physiology • Study of how bacteria function including such processes as nutrition, growth, reproduction and locomotion
CELL STRUCTURE • The typical bacterial cell (most knowledge is from studies of Escherichia coli)
CELL STRUCTURE • The Cell Surface: the interface between bacterial cell and its external environment. It consists of: • Cell Wall • Membranes • Capsules • Organs of Locomotion • Pili or Fimbriae
Cell membrane Cell, 2006
The glycocalyx: layers of matrix outside cell wall.
CELL STRUCTURE • The Cytoplasm: the space within the cellular membranes. It consists of: • Ribosomes: protein synthesis • Soluble (invisible) proteins: metabolism • Nucleoid: site of genetic material - DNA
SYNTHESIS OF DNA, RNA AND PROTEIN • DNA • replication
SYNTHESIS OF DNA, RNA AND PROTEIN • Transcription & translation
MICROBIAL GENETICS • Definitions to review: • Gene: a heritable unit of function composed of a specific sequence of purine and pyrimidine bases, which in turn determines sequence of the corresponding RNA and proteins. • Genotype: sum total of all of the hereditary units of genes. • Phenotype: the observed expression of the genetic determinants.
MICROBIAL GENETICS • Define following terms: • Alleles. • Mutagenesis. • Wild-type. • Spontaneous mutations.
CHEMICAL SYNTHESIS • Chemical composition of cell • 55% protein • 3.1% DNA • 16.7 rRNA • 3% tRNA • 0.8% mRNA • 9.1% lipids • E. coli cell can make a perfect copy of itself in 40 min in minimal glucose media
CHEMICAL SYNTHESIS • Energy • Substrate-level phosphorylation: ATP production during carbohydrate catabolism • Oxidative phosphorylation: ATP production using energy conserved in electrical and chemical gradient (PMF) across cell membrane • PMF: Proton motive force is formed during electron transport through a series of electron carriers on the membrane