Because enzymes connect to their substrate through a lock-and-key system, where the shape of the substrate and the enzyme has to fit like puzzle pieces. Then only the enzymatic reaction can occur.
A person going to bed because she feels sleepy is an example of a _VOLUNTARY__ response to an _INTERNAL___ stimulus.
Answers: Voluntary; Internal
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Answer:
The correct answer is D. production of new cell-surface proteins with a different molecular structure by each new generation
Explanation:
Trypanosomes infections is famous for evading the immune response of the body because it has the ability to make change in its variant surface glycoprotein having different molecular weight and this phenomenon is called antigenic variation.
So adaptive immune system is not able to recognize the trypanosome by its glycoprotein because the old surface glycoprotein against which the memory cells were produced previous time is now changed.
Therefore the immune system will not recognize the new generation of trypanosome with different variants of cell surface glycoprotein. Therefore the right answer is D.
Answer:
A hypertonic environment will result in cell shrinkage due to osmosis. However, this question is unclear because it's not the lack of water that causes shrinkage, it's the loss of cell water due to there being more concentrated aqueous particles outside of the cell vs. inside of the cell. I would still go with hypertonic though.
Factors that must be kept constant in the experiment to obtain valid results are option (c) i.e, type of antibiotic, nutrient agar, and temperature.
<h3>what are antibiotics?</h3>
A particular class of antimicrobial agents that works against bacteria is an antibiotic. Antibiotic drugs are frequently employed in the treatment and prevention of bacterial infections because they are the most effective type of antibacterial agent for doing so. Bacteria may be killed or have their growth suppressed.
They could harm the bacterial cell directly by attacking the cell wall. These cells can no longer do additional harm to the body since the bacteria cannot attack it. Other antibacterials, such as tetracycline and erythromycin, prevent the germs from multiplying or growing.
Antibiotics limit bacterial growth and replication by interfering with the bacterial cell wall. Because many types of bacteria have cell walls but human cells do not, antibiotics can kill bacteria while sparing human cells.
To know more about antibiotics refer to: brainly.com/question/10868637
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