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3 years ago

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Alpha helices are a type of secondary structure in proteins. What is the length of a 27.0 kDa single‑stranded α‑helical protein

segment? Assume a mean residue mass of 110 Da .

1 answer:

iogann1982 [59]3 years ago

8 0

Answer : The length of protein will be, 36.8 A⁰

Explanation :

First we have to calculate the amino acid residue.

$\text{Amino acid residue}=\frac{\text{Length of single strand of protein}}{\text{Mean residue mass}}$

Given:

Length of single strand of protein = 27.0 kDa

Mean residue mass = 110 Da

$\text{Amino acid residue}=\frac{27.0kDa}{110Da}=\frac{27000Da}{110Da}=245.4$

Now we have to calculate the number of turns in protein.

$\text{Number of turns in protein}=\frac{\text{Amino acid residue}}{3.6\text{amino acid per turn of the alpha-helix}}$

As there are 3.6 amino acid per turn of the alpha-helix.

$\text{Number of turns in protein}=\frac{245.4}{3.6}=68.17$

Now we have to calculate the length of the protein.

$\text{Length of protein}=\text{Number of turns in protein}\times \text{Length of each turn}$

As, we know that the length of each turn = 0.54 A⁰

$\text{Length of protein}=68.17turns\times 0.54\AA=36.8\AA$

Thus, the length of protein will be, 36.8 A⁰

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3 years ago

Two types of heterogeneous mixtures are suspensions and colloids.<br>true or false<br><br>

scoray [572]

<h2>Answer:True</h2>

Explanation:

Heterogeneous mixture is a mixture with non-uniform composition.

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3 years ago

Determine the rate law, including the values of the orders and rate law constant, for the following reaction using the experimen

olga55 [171]

Answer: Rate law= $k[A]^1[B]^2$ , order with respect to A is 1, order with respect to B is 2 and total order is 3. Rate law constant is $3L^2mol^{-2}s^{-1}$

Explanation: Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.

$Rate=k[A]^x[B]^y$

k= rate constant

x = order with respect to A

y = order with respect to A

n = x+y = Total order

a) From trial 1: $1.2\times 10^{-2}=k[0.10]^x[0.20]^y$ (1)

From trial 2: $4.8\times 10^{-2}=k[0.10]^x[0.40]^y$ (2)

Dividing 2 by 1 : $\frac{4.8\times 10^{-2}}{1.2\times 10^{-2}}=\frac{k[0.10]^x[0.40]^y}{k[0.10]^x[0.20]^y}$

$4=2^y,2^2=2^y$ therefore y=2.

b) From trial 2: $4.8\times 10^{-2}=k[0.10]^x[0.40]^y$ (3)

From trial 3: $9.6\times 10^{-2}=k[0.20]^x[0.40]^y$ (4)

Dividing 4 by 3: $\frac{9.6\times 10^{-2}}{4.8\times 10^{-2}}=\frac{k[0.20]^x[0.40]^y}{k[0.10]^x[0.40]^y}$

$2=2^x,2=2^1$ , x=1

Thus rate law is $Rate=k[A]^1[B]^2$

Thus order with respect to A is 1 , order with respect to B is 2 and total order is 1+2=3.

c) For calculating k:

Using trial 1: $1.2\times 10^{-2}=k[0.10]^1[0.20]^2$

$k=3 L^2mol^{-2}s^{-1}$ .

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3 years ago

An unknown gas is contained in a sealed container. Over time, the gas is gradually cooled until it becomes a solid. Determine wh

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3 years ago

Read 2 more answers

What are the names of the following three compounds (see attached)

balu736 [363]

Answer:

1. 4-ethyl-1-heptene

2. 6-ethyl-2-octene

3. 1-butyne

Explanation:

The compounds are named according to IUPAC rules.

Compound 1:

Identify the longest carbon chain. This chain is called the parent chain.
Identify all of the substituents (groups appending from the parent chain).
The parent chain is numbered so that the multiple bonds have the lowest numbers (double has the priority over alkyl substituents).
The longest chain contains 7 carbon atoms, so taken the name hept.
The double bond between C1 and C2, so take no. 1 and add the suffix ene to hept "1-heptene".
The ethyl group is the alkyl substituent on position 4.
So the name is 4-ethyl-1-heptene.

Compound 2:

Identify the longest carbon chain. This chain is called the parent chain.
Identify all of the substituents (groups appending from the parent chain).
The parent chain is numbered so that the multiple bonds have the lowest numbers (double has the priority over alkyl substituents).
The longest chain contains 8 carbon atoms, so taken the name oct.
The double bond between C2 and C3, so take no. 2 and add the suffix ene to oct "2-octene".
The ethyl group is the alkyl substituent on position 6.

So the name is 6-ethyl-2-octene.

Compound 3:

Identify the longest carbon chain. This chain is called the parent chain.
Identify all of the substituents (groups appending from the parent chain), there is no substituents.
The parent chain is numbered so that the multiple bonds have the lowest numbers (Triple bond here take the lowest number).
The longest chain contains 4 carbon atoms, so taken the name but.
The triple bond between C1 and C2, so take no. 1 and add the suffix yne to but "1-butyne".

So the name is 1-butyne.

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3 years ago