Bacterial Physiology (Micr430)

Lecture 1Overview 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 surfaces of Gram- and Gram+ bacteria

Cell membrane

Cell, 2006

The glycocalyx:layers of matrix outside cell wall.

Capsule of Streptococc

us pneumoniae

Flagella and fimbriae

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

Metabolic and

Genetic

Regulation

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

Major pathways

of carbohydratemetabolism

Biosynthetic pathways

leading to the amino acids and others

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

Nitrogen Assimilation

ENDOSPORES

GROWTH CURVE