why is the Dna molecule able to open up and close?

Answers

Answer 1

Answer:

The breaking of the hydrogen bonds due to the force relieves the torsional stress stored in a double helix. As a result, the nucleotide strands rotate more freely about the axis of a helix and start unwinding. ... The DNA unzipping and the DNA unwinding result in a structural transformation from dsDNA to ssDNA.


Related Questions

Cho các dung dịch: Glucozơ, glixerol, fomanđehit, etanol. Có thể dùng thuốc thử nào sau đây để phân biệt được cả 4 dung dịch trên?

A. Cu(OH)2; B. Dung dịch AgNO3 trong NH3;

C. Na kim loại; D. Nước brom.



Xem thêm tại: https://loigiaihay.com/bai-2-trang-25-sgk-hoa-hoc-12-c55a8069.html#ixzz71KH6guhm

Answers

Answer:

chắc là câu B í

Explanation:

How much water will the measuring cup have if you poured 1/2 of it out?

Answers

The cup will be filled up halfway

I need help with question 5

Answers

Answer:

B a spring being stretched

Please help me
will give the brainliest!​

Answers

Explanation:

a) The presence of sulfate ions in a solution can be confirmed by the reaction of barium chloride in an acidic medium.

The balanced chemical equation of the reaction is shown below:

[tex]BaCl_2(aq)+CuSO_4(aq)->CuCl_2(aq)+BaSO_4(s)[/tex]

Hence, the white precipitate is barium sulfate and its formation with the ionic equation is shown below:

[tex]Ba^2^+(aq)+SO_4^2^-(aq)->BaSO_4(aq)[/tex]

b) The presence of copper (II) ions can be confirmed by the following test:

Add potassium iodide solution to copper (II) solution.

Then a white ppt of cuprous iodide along with the liberation of iodine is observed and the entire solution attains brown color.

The chemical equation of the reaction is shown below:

[tex]2CuSO_4(aq)+4KI(aq)->Cu_2I_2(s)+I_2(s)+2K_2SO_4(aq)\\[/tex]

c)(i)Due to this reaction, the blue color of the solution becomes white.

Reddish-brown copper is deposited at the bottom of the container.

(ii)In this reaction, zinc is oxidized.

d) (i) Copper is produced at the cathode.

(ii)[tex]Cu^2^+(aq)+2e^-->Cu(s)[/tex]

(iii) The reaction that takes place at the cathode is reduction.

Reduction is gaining of electrons.

True or false, The universal gas constant, R, is . 0821 when we use mm Hg as our unit for pressure

Answers

Answer:

False

Explanation:

R = gas constant = 0.0821 atm•L/mol•K

mention two factors which affect pressure due to liquid contained in a vessel​

Answers

Answer:

depth of the liquid and nature of liquid affects the pressure due to liquid contained in a vessel

Answer:

Two factors influence the pressure of fluids. They are the depth of the fluid and its density. A fluid exerts more pressure at greater depths

A pupil has drawn the electronic structure of fluorine and the diagram is shown below. However,
mistakes have been made. State three mistakes that have been made.

Fl atomic number: 9
Fl atomic mass: 10

(ps i have two of these but can’t figure out the last)

Answers

Answer:

The number of electrons in the orbit is wrong they have to be 9 and not 10since flourine is in group 7 the number of electrons in the outer most shell has to be 7 and not 2the first shell has 8 instead of 2 electrons

I hope this helps

When it’s summer in the northern hemisphere what Season is it in the Southern Hemisphere

Answers

Answer:

Winter

Explanation:

I dont know but whatev

Answer:

Winter

Explanation:

The seasonal cycle in the polar and temperate zones of one hemisphere is opposite to that of the other. Therefore, When it is summer in the Northern Hemisphere, it is winter in the Southern, and vice versa.

hope it helps :)

How many atoms of hydrogen are there in 36 g of NH4?

Answers

Answer:

hope it helps you

Explanation:

please like and mark me brainlist

The formula mass of ammonia is 14 + 1 3 = 17. The number of moles in 36 g ammonia is 36/ 17 = 2.11mol. A mole is 6.02 10, so the number of hydrogen atoms in a 2.11 moles of ammonia is 2.11 *6.02*10^23 = 1.27 *10^24 atoms .


Hope it helps!

The world is made up of ​

Answers

Answer:

Explanation:

           The world is made up of ​living beings .    

Describe weighted average

Answers

Answer:

Explained below

Explanation:

In simple average, we just add all the given data variables and divide it by the number of data given.

However, when it comes to weighted average, what we do is that we multiply each given variable by their weights and then divide the sum of that by the sum of the weights.

Thus, if the variables are denoted by x and their weights are denoted by y, then we have;

Weighted average = Σ(xy)/Σy

Which is another word for 10 meters in the metric system?

Answers

Answer:

Dekameter

Explanation:

1.Which of the following forms only Ionic Bond?
1)Ca 2)C 3)Si 4)P

2.How many atoms of Na are present in 92 a.m.u of it?
a)4 b)5 c)6 d)7​

Answers

The Answer is A)4 atoms of NA are present in 92 a.m.u

How are the vapor pressure and boiling point of alkynes affected as the chain length increases?

Answers

Answer:

Answer to the following question is as follows;

Explanation:

Alkynes' vapour pressure and normal boiling points are altered when chain length grows, since vapour pressure rises while boiling point falls.

Vapour pressure always include pressure entered by vapour with its condensed phase, pressure include molecules force of attraction include vapour

Is this population more likely to grows slowly or quickly in the next 10 years

Answers

nobody can say it is uncertain but in my opinion it will grow quickly in the next 10 years

Which element has 2 valence electrons in the 2s sublevel?

Answers

Answer:

beryllium is the answer.

I hope this will help you

QUICK CHECK
Use the periodic table to select which type of bond is present and which of the listed properties is most
likely for each substance.
Substance
Type of bond
Likely property
A А
B
A
Cuzm
Ba
lonic
DO
covalent
02
С
D
metallic

Answers

Answer:

Coppell zinc,ironic bond

Explanation:

lt will give away two zinc atoms

Answer:

I will go with Sodium chlorine NaCl

write any two conditions at which a body of certain mass weightless​

Answers

Answer:

A body becomes weightless in a zero-gravity scenario and when a force is applied to a body that is equal and opposite to the force of gravity. If the body is falling only under the influence of gravity.

Answer:

A body becomes weightless in a zero-gravity scenario and when a force is applied to a body that is equal and opposite to the force of gravity.If the body is falling only under the influence of gravity.

the text of oxygen gas in the laboratory ​

Answers

Explanation:in testing for oxygen a glowing splint is used.

the glowing splint is brought in the presence of the test tube containing the gas

the glowing splint rekindles or lights up showing that oxygen is present.

this is a positive test because oxygen supports burning or combustion

how much energy is required to melt 2kg of aluminium

Answers

800kj----------




800kj----------

How many moles of KOH are there in 27.5 mL of 0.250 M KOH?

Question 2 options:

4.31 × 10−3 mol KOH


6.88 × 10−3 mol KOH


7.24 × 10−3 mol KOH


8.13 × 10−3 mol KOH


9.21 × 10−3 mol KOH

Answers

Answer:

6.88 × 10^-3mol

Explanation:

Molarity = number of moles (n) ÷ volume (V)

According to this question, there in 27.5 mL of 0.250 M KOH, the number of moles of KOH can, therefore, be calculated as follows:

number of moles = molarity × volume

Volume of KOH = 27.5mL = 27.5/1000

= 0.0275L

n = 0.0275 × 0.250

n = 0.006875 mol

n = 6.88 × 10^-3mol

2.0 kilograms of lithium hydroxide can “scrub”, or remove, how many liters of carbon dioxide at standard conditions?

Answers

Answer:

0.94 L

Explanation:

The equation of the reaction is;

2LiOH + CO2 -----> Li2CO3 + H2O

Number of moles LiOH = 2.0/23.95 g/mol = 0.084 moles

2 moles of LiOH scrubs 22.4 L of CO2

0.084 moles of LiOH scrubs 0.084 moles × 22.4/2

= 0.94 L

Can you help me on this. I will support your correct answer​

Answers

Iron+ nitric acid = Ferrous nitrate
Zinc+ sulphuric acid= Zinc sulphate

Magnesium chloride, Magnesium nitrate, magnesium sulphate

Please mark brainliest

what is the organic molecule

Answers

Answer:

kinetic energy is the molecules

Explanation:

A molecule of the kind normally found in living systems. Organic molecules are usually composed of carbon atoms in rings or long chains, to which are attached other atoms of such elements as hydrogen, oxygen, and nitrogen.

Plants in forests take up carbon dioxide from the atmosphere during photosynthesis. They transform the carbon dioxide into plant material. When plants die, their organic matter is often worked into the soil by decomposers. Some of this organic matter remains within the soil and forest floor, and some of it is taken up by other living things.

Based on this information, what role do forests play in the carbon cycle?
A.
Forests are carbon sinks because they store carbon.
B.
Forests are carbon sinks because they do not absorb carbon dioxide when plants die.
C.
Forests are carbon sources because they emit carbon.
D.
Forests are carbon sources because they can be burned to emit carbon dioxide.

Answers

Answer is A

Because Trees store carbon and make it oxygen

Answer: B. forests are carbon sinks because they store carbon

Explanation:forests take up carbon from the atmosphere through photosynthesis and from organic matter through decomposition. so, forests are carbon sinks because they store carbon

Is FeS iron (ll) sulfide or iron (lll) sulfide?

Answers

Answer:

the valence of S is -2. For FeS to be neutral the valence of Fe used must be +2

and since Iron (II) has its valency 2, FeS will be Iron (II) Sulfide.

difference between Nitrogen 1 oxide and Oxygen​

Answers

Answer:

one atom of oxygen is not equal to oxygen

Which among the following mixtures will show tyndal effect?
i) copper sulphate solution
ii) sand in water.
iii) milk.
iv) starch solution ​

Answers

Answer:

milk and starch solution are the colloids, hence these will show the tyndall effect

Answer:

milk and starch solution

Explanation:

Tyndall effect is shown by colloidal solutions. It is not shown by true solutions or suspensions.

Milk and starch solution are colloidal solutions. They show tyndall effect. On the other hand, common salt and copper sulphate solution are true solutions. They do not show tyndall effect.

What is the pressure in atm exerted by 1.8 g of H2 gas exert in a 4.3 L balloon at 27ºC? R = 0.821(L*atm) / (mol*K)

Answers

kakamc cjdismxsjxj xjcodmd xksowmd x

The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm

What is Ideal gas law ?

The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).

Let's convert grams to moles (via molar mass).

Molar Mass (H₂) :  2 (1.008 g/mol)

Molar Mass (H₂) :  2.016 g/mol

1.8 grams H₂               1 mole

----------------------  x  ----------------------  =  0.893 moles H₂

                                2.016 grams

The Ideal Gas Law equation looks like this:

PV = nRT

In this equation,

P = pressure (atm) V = volume (L) n = moles R = Ideal Gas Constant (0.0821 L*atm/mol*K)T = temperature (K)

After converting Celsius to Kelvin, you can put the given values into the equation and simplify to find the pressure.

P = ? atm                                R = 0.0821 L*atm/mol*K

V = 4.3 L                               T = 27 °C + 273.15 = 300.15 K

n = 0.893 moles

PV = nRT

P (4.3 L) = (0.893 moles) (0.0821 L*atm/mol*K)( 300.15 K)

P (4.3 L) =  22.0021

P = 5.12 atm

Therefore, The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm

Learn more about Ideal gas here ;

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A sample of gas has a volume of 20 cm³.The pressure is changed to 90 kPa at constant temperature,while the volume increases to 75 cm³.What was the original pressure of the gas?​

Answers

Answer:

337.5kPa ~ 338kPa

Explanation:

Using the ideal gas law PV=nRT we have the following definitions from the problem:

V(initial) = 20cm³

P(initial) = ?kPa

V(final) = 75cm³

P(final) = 90kPa

Since we know that the number of moles of the sample did not change, nor did the temperature, nor does the ideal gas constant (R) we can rewrite this equation to state:

P(initial)V(initial) = nRT =P(final)V(final) ~  P(initial)V(initial) = P(final)V(final)

Rearranging this equation as we are solving for the initial pressure we find that:

P(initial) = (P(final)V(final))/V(initial)

P(initial) = ((90kPa)(75cm³))/20cm³

P(initial) = 337.5kPa ~ 338kPA

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