BMSC 240 lecture 6-7 Flashcards
Beer Lambert Equation
A = elc
– e is molar absorptivity in L/mol cm – l is path length in cm
– c is concentration in mol/L
indirect Protein Assays: Bradford Assay
MeasurementofcolorchangewhenCoomassie Blue dye binds protein
Indirect protien assays: Biuret Assay
Measurement of color change when Copper II Sulfate (CuSO4) reacts with proteins under alkaline conditions. Solution turns purple. Amax=540nm
Common bacterial shapes
coccus=circle. bacillus=rod. Vibrios, spirillas, spirochetes=long and bendy
The bacterial cell wall
Protects cells from mechanical and osmotic forces
Gram negative stains what colour?
red
Gram positive stains what colour?
Blue
What is the cell wall structure
threads of a repeating carbohydrate (NAG-NAM)
• Glued together with proteins
• These sugars and proteins form a compound called peptidoglycan
Corss-linking makes cell walls more durable. What enzyme does this?
Transpeptidase.
what drug blocks transpeptidase?
penecillin
Gram positive cells
- Multiple layers of peptidoglycan (up to 80 nm thick) • Teichoic acids aid in keeping the layers together
- Also increase the (-) charge of the cell wall
Gram negative cells
• A single layer of peptidoglycan (about 8 nm thick)
• A second phospholipid membrane outside the peptidoglycan
– This membrane helps to repel some immune system factors, block entry of antibiotics and can contain toxic compounds
Glycoalax
Outside the cell wall
• Increases pathogenicity
• Composed of sugars & proteins
Endospores
dormant daughter cell which is formed inside the main cell
• Resists drying out, heat, chemicals, radiation
• Is not “alive”, all cellular processes are halted
What is aseptic technique?
Prevention of contamination when cultivating microorganisms
