Nucleic Acids | Genetics and Evolution - Biology IB23

Nitrogenous Bases

Nitrogenous Bases

- Adenine | A
- Thymine | T
- Cytosine | C
- Guanine | G
- Uracil | U

DNA

Deoxyribonucleic Acid

DNA Function

Holds the code for protein synthesis within a cell, called genes. Processes of protein synthesis is called “transcription” and “translation”.

It’s able to copy itself for cell division called replication within the S-phase of the cell cylce.

DNA Structure

It’s a double helix, it’s double strands are attached to each other by hydrogen bonds which are twisted into a spiral. The backbones are made of phosphate and sugars while the rungs are composed of nitrogenous base pairs.

These nucleotides are composed of phosphate, 5 C-sugar/deoxyribose and a nitrogenous base.

Nitrogenous Bases: Adenine, Thymine, Guanine & Cytosine.

RNA

Ribonucleic Acid

RNA Function

There are several functions:
mRNA - Copy of a gene that leaves the nucleus and carries the message into the cytoplasm and to a ribosome for protein synthesis.

tRNA - Reads the mRNA and carries amino acids to the correct ribosome.

RNA Structure

It only has a single strand of nucleotides which are composed of 5-C sugar ribose.

Nitrogenous Bases: Adenine, Guanine, Cytosine & Uracil.

Nucleotides

In a chain connected to each other by covalent bonds, meaning electrons are shared between atoms.

Complementary nucleotides are held together by hydrogen bonds which are weak bonds where there’s a proton in one atom while the other one is an electron.