BIS 2B Midterm: Practice 2011 1st Midterm

right-spiraling common DNA form

referencing the opposite orientation of hydrogen-bonded DNA strands

viral particle whose natural host is a prokaryote

universal holding that the number of purines always equals the number of pyrimidines

nucleic acid base sequences able to form a double-stranded structure by virtue of matching base pairs

5’→ 3’ or 3’→ 5’

nuclease able to cleave phosphodiester linkages in the DNA backbone

the structure formed by two DNA strands twisted around a common axis in a spiral

bacterial cycle of phage- infected cells resulting in cell destruction and viral release

main access site for proteins that recognize specific DNA sequences

a cytosine modification favoring Z DNA formation

nucleic acid monomer consisting of a sugar, a phosphate group, and a nitrogenous base

connects two nucleic acid sugar molecules via an ester bond

hydrolyzes peptide bonds linking amino acids

U or C in RNA

a pentose sugar

an enzyme that breaks down RNA

either of the two nucleotide chains of a double helix

a pyrimidine able to hydrogen bond with adenine

a DNA configuration favored by high ionic strength and GC repeats

protease

lysis

double helix

bacteriophage

complementary

Chargaff’s rule

B DNA

major groove

nucelotide

antiparallel

RNAse

directionality

phosphodiester linkage

ribose

Z DNA

pyrimidine

methylation

DNAse

uracil

strand

Step 1.

Step 2.

Step 3.

Step 4.

Step 5.

Step 6.

Step 7.

Step 8.

Step 9.

Step 10.

Step 11.

Step 12.

Step 13.

Step 14.

Step 15.

Step 16.

Don appropriate personal protective equipment (PPE).

Aseptically transfer 1 mL from dilution tube 2 to dilution tube 3 and mix well. This is a 10^-5 cumulative dilution.

Aseptically transfer 1.0 mL from dilution tube 4 to dilution tube 5 and mix well. This is a 10^-7 cumulative dilution.

Aseptically transfer 0.1 mL from dilution tube 1 to dilution tube 2 and mix well. The cumulative dilution of the culture is 10^-4.

Allow the inocula to soak into the plates before proceeding.

Aseptically transfer 0.1 mL from dilution tube 2 to plate A₁. Using the spread plate technique, disperse the sample evenly over the entire surface of the agar.

Aseptically transfer 1 mL from dilution tube 3 to dilution tube 4 and mix well. This is a 10^-6 cumulative dilution.

Obtain eight plates, organize them int four pairs and label them A₁, A₂, B₁, B₂, etc.

Keep accurate records in your lab notebook.

Clean up the lab benches, doff PPE, and wash hands.

Repeate the procedure with plate A₂ and label both plates "10^-5mL of original sample," or simply "10^-5"

Notice that transferring 0.1 mL counts as a dilution!! The tube was a 10^-4 dilution, but the plate is a 10^-5 dilution!!

Invert the plates so they are "agar up" to prevent condensation from ruining the plates.

Repeat the aseptic transfer, spread plate technique, and label schematic for dilutions tubes 3, 4, and 5, and plates B, C, and D.

Incubate the plates at 35℃ for 24 to 48 hours.

Obtain five dilution tubes and label them 1–5, respectively. Make sure they remain covered until needed.

Aseptically add 9.9 mL sterile water to dilution tubes 1 & 2. Cover when finished. Aseptically add 9.0 mL sterile water to dilution tubes 3, 4, and 5. Cover when finished.

Mix the broth culture an aseptically transfer 0.1 mL to dilution tube 1. Mix dilution tube 1 well. This is a 10^-2 dilution