DNA & RNA Structure

What is the role of DNA?

DNA stores genetic information

What is the role of RNA?

RNA transfers genetic information from DNA to ribosomes for protein synthesis

What are ribosomes made of?

Ribosomal RNA and proteins

What type of molecules are DNA and RNA?

Polymers of nucleotides

What are the three components of a nucleotide?

A pentose sugar, a nitrogen-containing base, and a phosphate group

What sugar is found in DNA nucleotides?

Deoxyribose

What sugar is found in RNA nucleotides?

Ribose

Which bases are found in DNA?

Adenine, cytosine, guanine, thymine

Which bases are found in RNA?

Adenine, cytosine, guanine, uracil

What bond joins nucleotides together?

Phosphodiester bond

How are phosphodiester bonds formed?

By condensation reactions

What is a dinucleotide?

Two nucleotides joined by a phosphodiester bond

What is a polynucleotide?

A long chain of nucleotides joined by phosphodiester bonds

Where does the phosphodiester bond form?

Between the sugar of one nucleotide and the phosphate of another

What is the structure of DNA?

A double helix of two polynucleotide strands

What holds the two DNA strands together?

Hydrogen bonds between complementary bases

What is the structure of RNA?

A relatively short single polynucleotide chain

Which bases pair together in DNA?

Adenine with thymine, guanine with cytosine

How many hydrogen bonds form between adenine and thymine?

Two

How many hydrogen bonds form between guanine and cytosine?

Three

Why is DNA a stable molecule?

The phosphodiester backbone protects the bases

How do hydrogen bonds increase DNA stability?

More hydrogen bonds increase overall stability

Why does a higher C–G content increase DNA stability?

C–G pairs have three hydrogen bonds instead of two

Where are the nitrogen-containing bases located in DNA?

On the inside of the double helix

What forms the outside of the DNA molecule?

The phosphodiester backbone