1. The hydrogen bonds between the two polynucleotide DNA strands are broken by the enzyme DNA helicase
2. The original single strand acts a template for a new strand.
Free-floating DNA nucleotides are joined together by the enzyme DNA
polymerase; hydrogen bonds form between the exposed bases following the
base pairing rule.
Semi-conservative replication
DNA contains genes which are instructions for protein
A gene is a sequence of DNA nucleotides that codes for a protein
Protein are made from amino acids
Different proteins have a different number and order of amino acids
It's the order of nucleotide bases in a gene that determines the order of amino acids in a particular protein
Each amino acid is coded for by a sequence of three bases in a gene
Different sequences of bases code for different amino acids
Protein Synthesis
DNA carries the instructions to make proteins
Transcription
1.The hydrogens bonds between the two polynucleotide DNA strands are broken temporally by the enzyme DNA helicase
2. RNA polymerase reads the unzipped strand and produces mRNA
3. mRNA leaves the nucleus via the nuclear pores
DNA molecules are too large to move out of the
nucleus
Translation
The process of converting
mRNA codon into a sequence of
amino acids
1. Initiation- A ribosome attaches to the mRNA
usually AUG, sometimes GUG or UUG
2. Elongation- tRNA brings the corresponding amino acid to each codon as the ribosome moves down the mRNA strand
3. Termination- Reading of the final mRNA codon (aka the STOP codon), which ends the synthesis of the
peptide chain and releases it.