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2 years ago

How does an antibiotic act as a selective agent in promoting bacterial resistance? quilzlet

1 answer:

8 0

Answer: Frequent antibiotic use over long periods of time puts selective pressure on bacteria, and causes resistance to spread. When an antibiotic is used to treat a typical bacterial infection, most bacteria are killed. Sometimes, however, a bacterium with an advantage lives.

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Suppose that extra fingers and toes are caused by a recessive trait, but it appears in only 60% of homozygous recessive individu

Ainat [17]

Answer:

<h2> (1/4 * 60) </h2><h2>The probability. that child will have extra fingers and toes are = 0.15 </h2>

Explanation:

As given; extra fingers and toes are caused by a recessive trait.

Penetrance= 60%.

Parents are heterozygous, assume Ff and Ff

F is dominant over f, and ff are homozygous recessive.

Ff crossed with Ff

Progeny are; FF, Ff, Ff and ff.

ff are homozygous recessive, as given that extra fingers and toes are caused by a recessive trait, so 1/4 will show the trait.

But according to 60% penetrance the trait will occur in = (1/4 * 60) =15% or 0.15 progeny will show the trait .

The probability, that child will have extra fingers and toes are = 0.15

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3 years ago

During production of a drug, all work area surfaces must be disinfected using sterilized disinfectants. Which of the following s

Ede4ka [16]

Answer: The correct options are

--> Disinfectants are used to inhibit or destroy pathogens,

--> Disinfection can occur by physical or chemical means,

--> Endospores and viruses can resist disinfectant treatment.

Explanation:

To prevent infectious diseases from spreading or to sterilise work area surfaces during the production of drugs, chemicals known as disinfectants as used. These are chemicals that kill or inhibit the growth of pathogens. Other chemicals such as antiseptics can also kill and prevent the growth of mainly pathogenic microorganisms. However, disinfectants are stronger chemicals than antiseptics and so are often used on non-living things and surfaces.

Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores (endospores) and viruses, so it is less effective than sterilisation.

There are generally two methods of disinfection:

--> The chemical method: A typical example of a chemical disinfectant is the carbolic acid. It is used for disinfecting lavatories and floors.

--> The physical method: here, physical agents are use to disrupt and damage the pathogenic organisms on work surfaces. Some typical example include: UV irradiation, heat, sunlight exposure, sonic or hydrodynamic pressure and radiation.

3 0

3 years ago

1.scientist refer to a biological community and the abiotic parts of the environment that affects the community as _______?

laila [671]

The answer is B. Ecosystem

8 0

3 years ago

why does the sky looks blue in the daytime and looks red during sunset because in of brownian movement be cause of the suspense

d1i1m1o1n [39]

Answer:

due to the refraction of light from sea.

Explanation:

the sky looks blue in the daytime and looks red during sunset because in of brownian movement be cause of the suspense is particles the air see because the tyndall effect because the of the particles a directly

8 0

3 years ago

Akira creates a reaction without a catalyst, then repeats the reaction with a catalyst.

Romashka [77]

Answer:

Akira turns in a written lab report to his science teacher. ... Akira writes in his notes that adding a catalyst sped up the chemical reaction because the catalyst lowered the activation energy needed to start the reaction.

6 0

3 years ago