The structure of DNA and RNA

Nucleotide structure

5 carbon pentose sugar, hydrophobic nitrogenous base, a hydrophilic phosphate group

What does the sugar and phosphate form

Sugar phosphate backbone

How does the sugar, base and phosphate group join together

By a condensation reaction releasing two water molecules

Purine bases (two nitrogen containing rings)

Adenine

Guanine

Pyramidine (a single nitrogen containing ring)

Cytosine

Thymine

Uracil

Complementary base pairing

A pyramidine pairing with a purine

What does complementary base pairing ensure

Ensures DNA is the same width

Guanine pairs with

Cytosine

Adenine pairs with

Uracil or thymine

Nucleic acid

Two or more mononucleotides joined together

How do nucleotides joined together

By condensation reaction

What is the bond between nucleotides

A phosphodiester bond between the 3C sugar of one nucleotide and the phosphate group of the next

DNA and RNA similarities

Both have a phosphate group

Both have bases G, C, A

Both have hydrogen bonds between nitrogenous bases

Both have phosphodiester bonds between nucleotides

DNA features

Deoxyribose sugar

Double helix and strands are anti parallel

Has a thymine base

Located only in the nucleus

RNA features

Ribose sugar

Single strand structure

Has a uracil base

Located in the nucleus and cytoplasm

Types of RNA

mRNA, tRNA, rRNA

How many hydrogen bonds are between guanine and cytosine

3 hydrogen bonds

How many hydrogen bonds are between adenine and thymine

2 hydrogen bonds