All categories

3 years ago

Select the true statements about protein secondary structure.

Chemistry

1 answer:

netineya [11]3 years ago

7 0

Answer:

The α‑helix is held together by hydrogen bonds between the amide N−H and C=O groups.

Disulfide bonds stabilize secondary structure.

Explanation:

Proteins have primary, secondary, tertiary and quartinary structures.

The secondary structure of a protein is the regular, recurring sequence of amino acid in a polypeptide chain. Secondary structure of proteins give rise to the folding observed in the structure of a protein.

The major secondary structures of a protein are α-helices and β-structures.

You might be interested in

Picric acid has been used in the leather industry and in etching copper. However, its laboratory use has been restricted because

olchik [2.2K]

Answer:

0.3023 M

Explanation:

Let Picric acid = $H_{picric}$

So, $H_{picric}$ + $H_2}O$ ⇄ $H_3}O^+$ + $Picric^-$

The ICE table can be given as:

$H_{picric}$ + $H_2}O$ ⇄ $H_3}O^+$ + $Picric^-$

Initial: 0.52 0 0

Change: - x + x + x

Equilibrium: 0.52 - x + x + x

Given that;

acid dissociation constant ( $K_a$ ) = 0.42

$K_a = \frac{[H_3O^+][Picric^-]}{H_{picric}}$

$0.42 = \frac{[x][x]}{0.52-x}}$

$0.42 = \frac{[x]^2}{0.52-x}}$

0.42(0.52-x) = x²

0.2184 - 0.42x = x²

x² + 0.42x - 0.2184 = 0 -------------------- (quadratic equation)

Using the quadratic formula;

$\frac{-b+/-\sqrt{b^2-4ac} }{2a}$ ; ( where +/- represent ± )

= $\frac{-0.42+/-\sqrt{(0.42)^2-4(1)(-0.2184)} }{2*1}$

= $\frac{-0.42+/-\sqrt {0.1764+0.8736} }{2}$

= $\frac{-0.42+\sqrt {1.0496} }{2}$ OR $\frac{-0.42-\sqrt {1.0496} }{2}$

= $\frac{-0.42+1.0245}{2}$ OR $\frac{-0.42-1.0245}{2}$

= $\frac{0.6045}{2}$ OR $-\frac{1.4445}{2}$

= 0.30225 OR - 0.72225

So, we go by the +ve integer that says:

x = 0.30225

x = [ $H_3}O^+$ ] = [ $Picric^-$ ] = 0.3023 M

∴ the value of [H3O+] for an 0.52 M solution of picric acid = 0.3023 M (to 4 decimal places).

6 0

3 years ago

Naming Organic compounds

Oduvanchick [21]

i don't know but try putting this diagram into a question on google. you should be able to get some type of answer if not the right answer. good luck and * hint* you can make a really good question out of the sentence on top of the DIAGRAM. I hope this was helpful. please let me know in the comments: )

7 0

3 years ago

Help me please !! is it A,B,C, or D ???

Nata [24]

Ok, after doing an immense amount of research I came up with the most logical answer.

A. Is indicated by a negative enthrall sign.

Reasoning: an endothermic reaction is ice melting and the energy being more than its surroundings. Not specified to ice but as an example, ice is endothermic. That puts d and b out of the running leaving you left with a and c.

When I searched up enthalpy, it said “When a substance changes at constant pressure, enthalpy tells how much heat and work was added or removed from the substance.” Which is similar to c, right? Yeah, meaning both a and c are similar in that aspect.

The reason I decided to go with a is because heat is NOT released into the surrounding, exothermic reactions release energy and heat into the surrounding.

5 0

3 years ago

How many pounds of ice are required to absorb 4900 kJ of heat as the ice melts? The heat of fusion of water is 0.334 kJ/g.

Goshia [24]

Answer:

m = 32.34 pounds of ice.

Explanation:

In this case we need to use the following expression of heat:

q = m * ΔHf (1)

Where:

q: heat absorbed in J or kJ

m: mass of the compound in g

ΔHf: heat of fusion of the water in kJ/g

We are asked to look for the mass of ice in pounds, so after we get the grams, we need to convert the grams to pounds, using the following conversion:

1 pound --------> 453.59 g (2)

So, we have the heat and heat of fusion, from (1) let's solve for the mass, and then, using (2) the conversion to pounds:

q = m * ΔHf

m = q / ΔHf

m = 4900 / 0.334 = 14,670.66 g of ice

Now, the conversion to pounds:

m = 14,670.66 g * 1 pound/453.59 g

<h2>m = 32.34 pounds of ice.</h2>

Hope this helps

5 0

3 years ago

What three tests must all theories pass to be considered a "proven" theory?

VladimirAG [237]

In order to become a scientific theory the three categories that it must pass are the following:

1) Can the phenomena be recreated in a laboratory setting?

2) Can variables be changed, yet still result in like observations?

3) Is the phenomena truly natural or was it the result of a man-made force enacting upon it?

7 0

3 years ago