Nucleic Acids - chemistry

What are the primary functions and the location of DNA and RNA?

• DNA’s main function is to store genetic information and acts as the blueprint for life

• DNA is found in the nucleus

• RNA’s main function is to transfer the information from DNA to ribosomes for protein synthesis

• RNA is found within all parts of the cell

What are the structural composition of a nucleotide and nucleoside?

• Nucleoside has a nitrogen-containing base (a purine and pyrimidine molecule) and a five carbon sugar that is deoxyribose in DNA and ribose in RNA that is linked together by a glycosidic bond

• Nucleotide has a nitrogen-containing base (a purine and pyrimidine molecule) and a five carbon sugar that is deoxyribose in DNA and ribose in RNA with an additional phosphate group that is covalently attached to the 5’ carbon of the sugar

What is the classification of the heterocyclic bases found in nucleic acids as either pyrimidine or purine?

• Purine - adenine and guanine

• Pyrimidines - cytosine, thymine, and uracil

What kind of molecule is this? It is purine or pyrimidine

Guanine

• purine

What kind of molecule is this? It is purine or pyrimidine

Adenine

• purine

What kind of molecule is this? It is purine or pyrimidine

Uracil

• pyrimidine

What kind of molecule is this? It is purine or pyrimidine

Thymine

• pyrimidine

What kind of molecule is this? It is purine or pyrimidine

Cytosine

• pyrimidine

What is the primary nucleic acid structure of DNA?

• the order in which the bases are stacked together

• Made up of a deoxyribose sugar and a phosphate backbone

• Has nitrogen-containing bases that are connected via hydrogen bonds

• Contains guanine, cytosine, adenine, and thymine

• Read from the beginning of carbon 5 to the end of carbon 3

What is the primary nucleic acid structure of RNA?

• The way bases are stacked together

• Linked together via phosphodiester bonds

• Has a sugar (ribose) phosphate backbone

• Includes guanine, cytosine, or uracil

• Read from the beginning of carbon 5 to the end of carbon 3

Define nucleic acid.

Unbranched polymers made up of nucleotide monomers

What is a nucleotide?

A molecule with three subunits: sugar that is bonded to both a phosphate group and a heterocyclic base

What base is found in ONLY DNA?

Thymine

What base is found in ONLY RNA?

Uracil

What bases are found in BOTH RNA and DNA?

• adenine

• cytosine

• guanine

What are nucleosides?

A molecule that only has a sugar and a base that are bonded together

• The base is always attached to carbon 1 on the sugar

How are nucleotides formed?

Nucleoside reacts with the phosphate group

• The base is always attached to the carbon 5 on the sugar

What are the bonds of the sugar molecules called?

Phosphodiester bonds

What is the importance of the negative charge on the phosphate group?

It gives the nucleic acids its acidic property

How do we read the sequence of DNA and RNA?

Read sequence from the 5' carbon end to the 3' carbon end.

List the forces that stabilize DNA.

• hydrogen bonds between complementary base pairs

• base stacking interactions (including van der Waals forces)

• hydrophobic interactions

• electrostatic interactions with the surrounding solvent

Identify a complementary DNA sequence for a given sequence

• double helix that contains two DNA strands that around each other

Describe the steps involved in DNA replication

•   1.) Separation of the template strand is achieved through the DNA helicase that unzips the DNA

•   2.)  Nucleotides are added to the template strands that are held together by hydrogen bonds

• 3.) creation of a continuous strand that is made by DNA polymerase, which can only work from 5’ to 3'. It leads to a strand that can grow continuously, and the lagging strand grows in segments

•   4.) Okazaki fragments are joined together by DNA ligase

Match the enzymes involved in DNA replication to their function.

• DNA helicase - unwinds the DNA strand

• DNA polymerase - causes the continuous growth of the DNA strand

• DNA ligase - binds Okazaki fragments together

What are the possible pairs of complementary bases, and how many hydrogen bonds do they form?

• Adenine and thymine w/ creates 2 hydrogen bonds

• cytosine and guanine w/ creates 3 hydrogen bonds

True or false: complementary bases are found in equal amounts of DNA.

True

What is base stacking in DNA?

Helps stabilize the double helix that lies in the same plane

• can interact with the base above and below it by Van der Waals forces (a type of London dispersions forces)

What is the secondary structure of RNA?

Single strand molecule that is normally shorter than DNA

• contains adenine, guanine,, cytosine, and uracil

What are Okazaki fragments?

Fragments that are created through the lagging of the continuous growth of s strand