Answer:
Antibiotic resistance is a consequence of evolution via natural selection. The antibiotic action is an environmental pressure; those bacteria which have a mutation allowing them to survive will live on to reproduce. They will then pass this trait to their offspring, which will be a fully resistant generation.
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.
spider has no tail and has no stinger
The correct option is 3.
Enzymes are biological catalysts which speed up the rate of biochemical reactions inside the cells. Enzymes are very specific in action and they require specific conditions called optimum conditions for them to function optimally.
When the optimum conditions are not met, an enzyme's activity will be lowered or totally stopped.
Conditions that affect the optimum activity of an enzyme include: temperature, pH level and regulatory activity of regulatory enzymes and hormones.
Answer:
Active transport requires energy from ATP while facilitated diffusion does not
Explanation:
Active transport and facilitated diffusion with the use of channel and carrier proteins are both ways by which ions, polar and large molecules cross a selectively permeable membrane.
The major difference is that; Active transport transport these particles from a low to high concentration, which is against concentration gradient and hence, energy is required to perform the task
Facilitated diffusion transport from a high to low concentration, which is through a concentration gradient and hence, no energy is required to perform the task.
