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3 years ago

Why is HCl poured on the DNase test agar plates that you inoculated last period?

Biology

2 answers:

astra-53 [7]3 years ago

8 0

Answer:The right option is A( to cause intact DNA to precipitate,so the activity of DNase can be determined.

Explanation:

Deoxyribonuclease(DNase) test is used to determine the ability of an organism, usually of bacteria origin, to hydrolyse

DNA ( deoxyribonucleic acid). The organism uses the DNA present as a source of carbon and energy for growth. The DNase medium is grouped as a differential medium as it helps distinguish organisms able to produce DNase from non producing organisms. The medium is pale green in colour because of the DNA- methyl green complex. Methyl green( the indicator) is a cation which binds to the negatively charged DNA.

When an organism is inoculated onto the medium, if the organism that grows in the medium produces DNase,DNA will be broken down leading to the release of free methyl green cation in the medium. The green colour of medium fades and the colony is surrounded by a colourless zone.

But when the DNase agar is prepared without an indicator (methyl green), HCL is used for easy identification of the DNase activity.

tia_tia [17]3 years ago

4 0

Answer:

A. To cause intact DNA to precipitate, so the activity of DNase can be determined.

Explanation:

The presence of DNase is special feature for some species of bacteria and can be used for identifying them. During DNase test, diluted hydrochloric acid (HCl) can be poured onto the agar plates so that there will be a clear zone close to the bacteria colonies. Each nucleotides are soluble in diluted HCl. But DNA is not soluble in the diluted HCl, thereby making the DNA to precipitate in the rest of the plate.

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3 years ago

An action potential causes the release of neurotransmitters by:________.

seraphim [82]

Answer:

b) opening calcium pores in the membrane

Explanation:

The opening of calcium ions channels facilitates the migration of vesicles containing neurotransmitters in the pre-synaptic neurons to the tip of the post-synaptic membrane. at the neuromuscular junction These neurotransmitters can either be cholinergic or non-chorlinergic. At the tip of the pre-synaptic membranes the vesicles empty their neurotransmitter contents into the synapse.

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3 years ago

0.005 m3 x 8.900 kg/m3

olga2289 [7]

Answer:

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Explanation:

I multiplied the values together. The m^3 cancelled out.

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3 years ago

Form a hypothesis about the relationship between vegetable mass and salinity of the solution

mihalych1998 [28]

Answer:

HYPOTHESIS: IF the salinity of the solution decreases, THEN the vegetable mass increases.

Explanation:

Hypothesis, in an experiment, is a testable explanation or prediction made to solve an observed problem or answer a question. It shows how one variable called independent variable affects another variable called dependent variable. It is usually written in the "IF, THEN" format.

In this case, the question states that there is a relationship between vegetable mass and salinity of the solution. This means that the question has been asked that "Why is the vegetable's mass affected by salinity of a solution". Hence, a hypothesis can read:

IF the salinity of the solution decreases, THEN the vegetable mass increases.

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3 years ago