Central Dogma and Gene Expression Overview

Central Dogma

The process of DNA to RNA to Protein.

Transcription

The process of converting DNA to RNA.

Translation

The process of converting RNA to Protein.

Splicing

Process where introns are removed, and exons are joined together.

Anticodons

Sequences found in tRNA that pair with codons in mRNA.

tRNA

Transfer RNA that carries amino acids to the ribosome.

Leading strand

The DNA strand synthesized continuously in the 5' to 3' direction.

Lagging strand

The DNA strand synthesized in Okazaki fragments.

Topoisomerase

Enzyme that relieves tension by untangling DNA.

Helicase

Enzyme that unwinds and unzips DNA.

DNA polymerase

Enzyme that synthesizes new DNA strands.

Semi-conservative replication

Each new DNA molecule consists of one old strand and one new strand.

5' to 3' DIRECTION

The direction in which DNA and RNA strands are synthesized.

mRNA

Messenger RNA that carries genetic information from DNA to the ribosome.

mRNA Processing

The addition of a 5' cap and 3' poly-A tail for protection and removal of introns.

Operons

Genetic regulatory systems found in bacteria.

Repressors

Proteins that prevent RNA polymerase from transcribing by blocking it.

Repressible operon

Operon that is always on, such as the tryptophan operon.

Inducible operon

Operon that can be turned on, such as the lactose operon.

Transcription factors

Proteins that bind to promoters and are specific to cell type.

Enhancers

Sites upstream of genes that activate transcription.

Histones

Proteins that package and order DNA into structural units.

Acetylation

Modification of histones that loosens DNA for transcription.

Methylation

Modification of histones that condenses DNA, preventing transcription.

EPA Sites

Ribosomal sites: E (Exit), P (Peptidyl), A (Aminoacyl) for tRNA.

Polypeptide Chain Growth

Ribosome links amino acids into a polypeptide chain.

Himalayan rabbits

Example of gene regulation influenced by temperature.

Point Mutations

Mutations that involve a change in a single nucleotide.

Insertion

A point mutation where an extra nucleotide is added.

Deletion

A point mutation where a nucleotide is removed.

Substitution

A point mutation where a single nucleotide is changed.

Frameshift mutations

Mutations that disrupt codon groupings due to insertions or deletions.

RNA World Hypothesis

The theory that the first genetic material was RNA.

Conjugation in Bacteria

The process where bacteria exchange plasmids, spreading traits.

mRNA to Protein Calculation

Formula: (# of amino acids * 3) + 3.

Start codon

The codon AUG, which codes for Methionine.

Telomeres

The ends of eukaryotic chromosomes that shorten with every replication.