Answer:
When patient takes in antibiotics the resistance bacteria gets a competitive survival advantage over the normal sensitive bacteria and hence grows faster.
Explanation:
- Bacteria can acquire resistance by taking in plasmids containing MDR (Multi-Drug Resistance) gene cassettes. The MDR genes produces proteins that can:
- Render the antibiotic ineffective to act on its target by inducing chemical modifications on the drug.
- Promote efflux of the drug from the bacterial cell so that the drug cannot act upon its target.
- When a healthy person ( having no prior exposure to the antibiotic) is infected by bacteria ( both sensitive and resistant varieties):
- A competition develops for the host cells and nutrients between the sensitive and the resistant variety.
- This mutual competition restricts either of the sensitive or resistant bacterial strain to grow profusely.
- When a person (having prior antibiotic exposure), gets infected by bacteria ( both sensitive and resistant varieties) and is exposed to the same antibiotic:
- The sensitive variety, due to its sensitivity towards the drug, gets killed.
- The resistant variety, due to its MDR genes, bypasses the lethal effect of the drug and survives.
- These surviving resistant bacteria can now infect all the available host cells and utilise all the available nutrients without facing any competition and multiply rapidly.
Answer:
D. 0.60
Explanation:
If the population is in Hardy-Weinberg equilibrium, the genotypic frequencies are:
- freq AA = p²
- freq Aa = 2pq
- freq aa = q²
<em>p</em> is the frequency of the Rh positive allele (A) and <em>q</em> is the frequency of the Rh-negative allele (a).
If 84% of the population is Rh-positive, then 16% is Rh-negative and has the genotype <em>aa</em>. Therefore:
q² = 0.16
q = √0.16
q=0.4
And because p+q=1,
p = 1 - 0.4
p = 0.6
The frequency of the Rh-positive allele is 0.6
Cancer, other antigens, diseases, blood type
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