G11) 1.3 Nucleic acids

Each nucleotide is made up of:

a 5 carbon sugar (eg: pentose)

a phosphate group

a nitrogenous base (one or two rings)

How do nucleotides form DNA chains

The phosphate group of one nucleotide attaches to the pentose (at carbon 3) of another nucleotide via a phosphodiester bond (covalent bond).

Whats the backbone of DNA comprised of

the sugar and the phosphate

Complementary Base Pairing

In DNA, T pairs with A; G pairs with C;

RNA, U pairs with A and G pairs with C

This allows genetic information to be expressed and replicated.

What are the 4 bases

Adenine, Thymine, Guanine, Cytosine

Which two bases swap in RNA

Thymine as uracil

What bond holds the two DNA bases together

hydrogen bond

Pyrimidines

Cytosine and Thymine (have one ring)

Purines

Bases with a double-ring structure.

Adenine and Guanine

Which bases experience triple bonding?

Guanine and Cytosine

Which bonds experience double bonding

Adenine and thymine/uracil

The differences between DNA and RNA

DNA:

- double-stranded

-thymine

- doesnt leave nucleus

- deoxyribose sugar

RNA:

- single-stranded

- Uracil

- leaves nucleus

- ribose sugar

3 types of RNA

mRNA, rRNA, tRNA

5 prime and 3 prime definition in DNA

5' means that it ends with carbon bond 5 ontop

3' means it ends with carbon bond 3 at the top

DNA diagram

Genetic code

collection of codons (groups of 3 bases) of mRNA, each of which directs the incorporation of a particular amino acid into a protein during protein synthesis

antiparallel DNA strands

One strand of DNA runs from the 5' carbon to the 3' carbon, and then the other side will be upside down, thus going from the 3' carbon to the 5' carbon; the 5' end has a phosphate group attached and the 3' end has a hydroxyl group that is attached to the sugar