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Advocard [28]
3 years ago
7

When the first antibiotics became available in the late 1940s and early 1950s, these antibiotics were effective against all bact

erial infections. Today however, there are a multitude of antibiotic resistant bacterial infections. What conclusion can be drawn? A) Antibiotics of today are not as strong as those in the past. B) Antibiotics cause DNA mutations in bacteria, and over time, this has led to resistance. C) Over time, bacteria have turned into viruses, and antibiotics have no affect over viruses. D) Bacteria have become resistant to antibiotics over time due to evolution by means of natural selection.
Biology
2 answers:
kirza4 [7]3 years ago
8 0
The correct answer would be D.

After many generations, only those with genes suitable to live in harsh environments can live. These genes are passed onto their offspring and then we see a rise in antibiotic resistant strains of bacteria such as Methicillin Resistant Staphylococcus Aureus (MRSA).
Dmitry [639]3 years ago
6 0
Answer is D. how do i no? i got it right on USA test prep. 
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Which choice best describes the antimicrobial activities in the mouth?
kykrilka [37]

The antimicrobial activities in the mouth are hydrochloric acid denatures proteins and killing many microbes.

The capability of an hydrochloric acid activating pathogen-killing compounds is not a part of insect immunity,There has recently been an increase in interest in trehalose metabolism for therapeutic applications due to trehalose's relevance in numerous pathogenic species.The most significant biosynthetic process is the enzyme TPP (trehalose-6-phosphate phosphatase) (OtsAB).

Here, five important nematode and bacterial pathogens' recombinant TPPs, including three new members of this protein family, are compared for their enzyme characteristics.

The kinetics of the hydrolysis of trehalose-6-phosphate show that all five enzymes display burst-like kinetic behaviour, which is characterised by a decrease in enzymatic rate beyond the pre-steady state.

The observed super-stoichiometric burst amplitudes can be explained by many global conformational changes that occur in members of this enzyme family during substrate processing.

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7 0
1 year ago
In what part of the mrna does degradation generally begin?
noname [10]
When the mrna has done it's job for the celll and is no longer of any use, it starts to degeneate
3 0
3 years ago
It takes a plane 1.5 h to travel between city A and city B. How far apart are the two cities if the cruising speed of the plane
Andrew [12]
D. 1,200

This is because if it takes 1 and a half hours **1.5** to travel through city a and city b , and the plane goes 800km per hour and 400km is half of that it then the answer has to be d.
4 0
3 years ago
Read 2 more answers
Ozone in the troposphere is necessary to protect Earth's surface from harmful UV radiation.
romanna [79]

Answer:

False

Explanation:

In the troposphere, near the Earth's surface, human activities lead to ozone concentrations several times higher than the natural background level. Too much of this ground-level ozone is 'bad' as it is harmful to breathe and also damages vegetation.

The stratosphere or “good” ozone layer extends upward from about 6 to 30 miles and protects life on Earth from the sun's harmful ultraviolet (UV) rays.

7 0
2 years ago
explain how repressible and inducible operons differ and how those differences reflect differences in the pathways they control
Sonja [21]

Answer

Operons are cluster of coordinated genes, including structural genes, an operator gene, and a regulatory gene.

Explanation:

In the The repressible operons, The transcription is usually on and repressor is in inactive form, So the specific genes are transcribed. While a regulatory molecule act as corepressor and binds to repressor protein to activate it. The repressor protein cause the inactivation of repressible operon (as the name indicate). E.g., Tryptophan Repress the trp operon.

A high level of product act as regulatory molecule (Corepressor) and turn off the operon, So anabolic pathways or synthesis of essential components are controlled by repressible operon.

In the Inducible operons, the transcription is usually off and repressor is in active form. So there is no transcription of genes. Specific Metabolite cause the activation of operon  e.g lactose cause the induction of lac operon.

As a metabolite induces the operon, So they control the Metabolic pathways or breakdown of a neutrient.

7 0
3 years ago
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