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a lab assistant needs to mix up the following reaction to prepare dna for an experiment:
25ul of a dna sample
25ul of enzyme
50ul of reaction buffer
400ul of water
the smallest size tube that will hold the entire reaction is [0.05, 0.5, or 5] ml:
which of the following pipetting devices most likely would not be used by the lab assistant to measure the needed volumes? ? [p20, p200, p1000]?
the enzyme comes as a concentrated solution of 20 units of activity per ul. therefore, the reaction mix will have total units of the enzyme at a working dilution of units/ul.

The smallest size tube that will hold the entire reaction is 0.5ml

Explanation:

25ul (DNA sample) + 25ul (enzyme) + 50ul (buffer) + 400ul (water) = 500ul total

since 1000ul=1ml, then 500ul = 0.5ml

The device that mostlikely would not be used P20

Explanation:

P20 is a pipette used to measure and sample volumes of 20ul maximum.

The reaction mix will have 400 units of the enzyme.

The working dilution will be 0.8 Units/ul.

Explanation:

The mix has 20ul of the enzyme which is 20Units/ul. Then we have 20ulx20Units/ul= 400 Units of enzyme in the mix.

Since the final volume is 500ul, the final concentration 400Units/500ul=0.8 Units/ul.

b) chemical ( the chemical breakdown of food is accomplished by enzymes. )

- officialprodixy ☕

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.