Suppose you had an organic molecule such as cystine, and you chemically removed the --nh2 group and replaced it with --cooh. Dra
w the structural formula for this molecule and speculate about its chemical properties. Is the central carbon asymmetric before the change? After?
1 answer:
Cystine is dimer of Cystein amino acid formed by oxidation reaction. Its main function is to provide mechanical strength to proteins and allow them to retain their 3-D structures and also serves as a substrate for the cystine-glutamate antiporter.
As shown in figure cystine has two amino groups (highlighted blue) and two carboxylic groups (highlighted green). In its original structure cystine is neutral in nature as it has equal number of basic (NH₂) and acidic (COOH) moieties along with two chiral centers (asymmetric carbons) highlighted with red spots.
When one -NH₂ group is replaced by -COOH group the cystine is converted into an acidic compound with three COOH groups and a NH₂ group. Also, one asymmetric carbon will convert into a symmetrical carbon with a loss of one chiral carbon.
In second step, when another NH₂ is replaced by COOH, the acidic strength of resulting compound will increase along with conversion of last chiral carbon into symmetric carbon.
Therefore, the final structure will be acidic in nature with zero chiral carbons as shown in figure attached below.
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Answer:
1.83moles
Explanation:
Given parameters:
Mass of methane given = 29.2g
Unknown:
Number of moles = ?
Solution:
To find the number of moles in this mass of a compound;
Number of moles =
Molar mass of CH₄ = 12 + 4(1) = 16g/mol
Now;
Number of moles = = 1.83moles
Answer:
964ug
Explanation:
The problem here involves converting from one unit to another.
We are to convert from ounces to micrograms.
1ug = 1 x 10⁻⁶g
1oz = 28.35g
So we first convert to grams from oz then take to ug:
Solving:
1oz = 28.35g
3.4 x 10⁻⁵oz will then give 3.4 x 10⁻⁵ x 28.35 = 9.64 x 10⁻⁴g
So;
1 x 10⁻⁶g = 1ug
9.64 x 10⁻⁴g will give = 9.64 x 10²ug or 964ug