Energy carrier, Nucleotide, Contains phosphate connected by high energy bonds
Anabolism
1. Biosynthesis of amino acids and nucleotides
2. Biosynthesis of sugars and polysaccharides
3. Biosynthesis of fatty acids and lipids
Amino group
Usually derived from inorganic nitrogen source
Purines
Constructed from key compound, inosinic acid
Pyrimidines
Constructed from key compound, uridylate
Polysaccharides
Synthesized from either uridine diphosphoglucose or adenosine diphosphoglucose
Fatty acid biosynthesis
1. Fatty acids biosynthesize 2 C atoms at a time using acyl carrier protein (ACP)
2. ACP holds fatty acids as its being synthesized
3. Each 2 C unit derived from a 3 C compound (malonate)
4. Most common fatty acids contain C12-C20 fatty acids
5. Lipid formulation occurs when fatty acids are added to glycerol
Respiration
1. Anaerobic (includes glycolysis and fermentation)
2. Aerobic/catabolism (includes glycolysis and Krebs cycle)
Glycolysis
Converts glucose to pyruvate, producing ATP and NADH
Krebs cycle
Series of biochemical reactions in which large amounts of potential chemical energy is released, through a series of oxidations and reductions that transfer the potential energy to electron carrier coenzymes
Metabolism of fatty acids
1. Fatty acids are broken down to acetic acid
2. If fatty acids are the sole source of carbon, bacteria utilize a modified Krebs cycle (glyoxylate cycle) which is not generally found in animal cells
Gene expression
DNA is expressed by synthesis of specific RNAs and proteins (transcription and translation)
Bacterial genomes vary in size
Regulation of gene expression
Induction and repression enable bacteria to regulate production of specific gene products
Operon
A group of contiguous genes that is transcribed as a single unit and translated to produce the corresponding gene products, can be induced or repressed
Regulon
Alters expression of a groups of genes and operons
Inducible genes
Genes whose expression is turned on by the presence of some substance, e.g. Lactose induces expression of the lac genes
Catabolite repression
Many inducible operons are controlled by inducers and regulatory genes, AND the level of glucose in the environment
Repressible genes
Genes whose expression is turned off by the presence of some substance (co-repressor), e.g. Tryptophan represses the trp genes
Attenuation
In many repressible operons, transcriptions initiated at the promoter can terminate prematurely, called premature termination
Plasmids
DNA molecules that encode traits not essential for bacterial viability, such as resistance, production of toxins, and synthesis of cell surface structures
Two types: stringent (replicate only when the chromosome replicates) and relaxed (replicate on their own)
Bacteriophages
Viruses that infect bacteria.
Either DNA or RNA, obligate intracellular parasites in bacteria, extracellular phage particles are metabolically inert
Mutations
Heritable changes in the genome
Genetic interactions between microbes
Enable genomes to evolve much more rapidly than by mutation alone
Processes in bacteria involving transfer of genetic information
1. Transformation
2. Transduction
3. Conjugation
Transposons
Segments of DNA that can move, can cause mutations, mediate genomic rearrangements, function as portable regions of genetic homology, and acquire new genes and contribute to their dissemination, but are not self-replicating genetic elements
Polysaccharides:
Synthesised from either uridine diphosphoglucose or adenosine diphosphoglucose
Bacterial DNA is:
Double stranded
Free in the cytosol
Attached at mesosome to cell wall
lac i: regulatory gene that codes for regulatory proteins
lac o: operator and where the protein attaches to
What happens when a protein attaches to a gene?
steric interference occurs causing gene to not be readable
lac p: promoter, aids in RNA polymerase binding
lac z: β - galactosidase, enzyme that catalyses the hydrolysis of β - galactosidase
lac y: permease, a protein present in cell wall that allows lactose to be brought into the cell
lac a: transacetylase
alolactose: isomer of lactose, attaches to regulatory gene and it falls off so gene can now be read
Transformation: a donor bacterium lysis and the fragments of DNA released are taken up directly from the extracellular environment by recipient bacteria
Transduction: bacteriophages act as vectors to introduce DNA from donor bacteria into recipient bacteria
Conjugation: direct contact between donor bacterium and recipient bacterium via a conjugation pili, allowing genetic information to transfer fromndinor bacterium to recipient bacterium
Breakage and joining of parental DNA molecules: forms hybrid, recombinant molecules