Nucleotides / DNA / RNA

What are the three parts that are nucleotides consisted of?

• Five carbon sugar molecule – pinto sugar

• Base attached to the sugar molecule – nitrogenous base

• Negatively charged phosphate group attached to other side of sugar molecule

What elements are consisted in nucleotides?

Carbon, hydrogen, oxygen, nitrogen, and phosphorus

What’s a nucleotides used to make?

Molecules DNA and RNA

What is a pentose sugar in DNA called?

Deoxyribose

What is the pinto sugar and RNA called?

Ribose

What are the four different bases found in DNA?

Adenine, Thymine, Guanine and Cytosine

What two bases have a double ring structure and what are these called?

Adine and Guanine - Purines

The other two bases have a single ring what are they called?

Thymine and Cytosine- Pyrimidines

What base does RNA not contain and what is it replaced by?

Thymine replaced by Uracil

How is a Polynucleotide formed?

A bond forms between the phosphate group of one nucleotide and the hydroxyl group on carbon 3 of the pentose sugar of the other nucleotide.

What is the bond between two nucleotides called?

Phosphodiester bond

What type of reaction is it and what else is formed

Condensation reaction and a molecule of water is formed. The molecule form is a nucleotide

The purine on one strand always bind with a pyrimidine on the opposite strand, what does this mean?

The distance between the sugar phosphate backbone is constant all down the DNA molecule.

Are the two polynucleotide strands in DNA parallel or anti parallel?

Antiparallel – they run in opposite directions

How many hydrogen bonds to go in the cytosine form?

3 hydrogen bonds

How many hydrogen bonds do adenine and thymine form?

2

Where is RNA found?

In the cytoplasm – plays a key role in production of proteins

Is RNA shorter or longer than DNA?

Shorter

What is the first stage of DNA replication?

Enzyme DNA healer case attaches to DNA molecule and causes the hydrogen bonds between the complementary basis to break which causes the two polynucleotide strands to separate from each other

What happens now? ( Nucleotides)

Three nucleotides lineup with their complementary basis on the DNA strand, the free nucleotides are only held in place by hydrogen bonds between the complementary bases they are not bonded to each other by phosphodiester bonds. The free nucleotides are activated nucleotides.

What is the difference between a normal nucleotide and an activated nucleotide?

Activated nucleotide contains 3 Phosphate groups while a normal nucleotide only contains 1

What happens in stage 3 (polymerase)

DNA polymerase moves down the molecule and catalyses formation of phosphodiester bonds between the activated nucleotides – condensation reaction. When Phosphodiester bonds form the activated nucleotides lose their extra two phosphate groups. When these phosphate groups leave it provides energy for the reaction.

What is semiconservative DNA replication?

Each new DNA molecule consist of one original strand and one newly synthesised strand.

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