The titration curve for glycine is shown below. The key points are designated I to V.

Select the the point on the titration curve where the average net charge of glycine is zero

Question

The titration curve for glycine is shown below. The key points are designated I to V.

Select the the point on the titration curve where the average net charge of glycine is zero

BlackTom AI · Accepted Answer

To determine where the average net charge of glycine is zero, we should consider glycine's amino and carboxyl groups and their pKa values. As the molecule is titrated, the net charge passes through zero at its isoelectric point (pI).

Option I: This point occurs at very low OH- equivalents and corresponds to a highly protonated species with a positive net charge, not zero.

Option II: This location aligns with the first deprotonation step (carboxyl group losing a proton), giving glycine a negative charge but not yet neutral overall; the net charge is still not zero here.

Option III: This point sits around pH 5.97, which is the pI of glycine. At this pH, the average net charge of glycine is zero because the molecule has equal populations of positively and negatively charged forms when the two ionizable groups balance each other.

Option IV: This region corresponds to a higher pH where the amino group begins to deprotonate and the molecule carries a negative charge, so the net charge is not zero.

Option V: At very high pH, both groups are deprotonated, giving a strongly negative net charge, far from zero.

In summary, the net charge is zero at the isoelectric point, which for glycine occurs near pH 6 and corresponds to point III on the curve.

The titration curve for glycine is shown below. The key points are designated I to V. Select the the point on the titration curve where the average net charge of glycine is zero单项选择题

类似问题

The isoelectric point of casein:

The isoelectric point of a molecule can be calculated from the pKa values of its ionisable groups.Calculate the isoelectric point of the molecule below. Give your answer to one decimal point.

The isoelectric point of a molecule can be calculated from the pKa values of its ionisable groups.Calculate the isoelectric point of the molecule below. Give your answer to two decimal points.

The isoelectric point of a molecule can be calculated from the pKa values of its ionisable groups. Calculate the isoelectric point for the molecule below. Give your answer to one decimal point.

Which one of the following amino acids has the highest isoelectric point? (all amino acids are shown at the same pH)

The pI is the pH where a molecules charge is overall neutral . This is sometimes at near pH 7.

What is the pI of the given amino acid?

The titration curve for glycine is shown below. The key points are designated I to V. Click on the region of the titration curve that represents the isoelectric point (pI) of glycine

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单