Lecture 4: Gene Regulation Flashcards
Proteins
- building blocks are amino acids that have R groups, amino groups, and a carboxyl group
- AA differs in R-Groups- unique behavior
- mRNA translated from 5’ to 3’ protein is synthesized from the amino end (N-terminus) to the carboxy end (C-terminus)
Primary Proteins
Sequence of a chain of amino acids connected by peptide bond
Second Proteins
Sequence of amino acids that are linked by weak hydrogen bonds into one or two structural forms
Tertiary Proteins
a 3D structure produced from alpha helixes and beta helixes attractions
Functions of Proteins
They are catalysts, transporting and storing molecules, provide mechanical support and immune protection, generates movements, transmit nerve impulses, and control cell growth and differentiation
Post Translational Modifications
Hydroxylation, methylation, lipidation, acetylation, phosphorylation, glycosylation, ubiquitination, disulfide bond, and SUMOylation
Mutations
Changes in nucleotide sequence of DNA and can occur spontaneously as errors during DNA replication or caused by environmental agents. It is the major cause of genetic diversity and disease. In bioprocessing, mutations can affect the production levels and quality of protein production. Insertion or deletion of 3 nucleotides causes no extensive frameshift.
Point Mutations
Consists of one DNA base change
ex: silent mutation, missense mutation, and nonsense mutation
Silent Mutation
No effect on the amino acid sequence- base pair substitution
Missense Mutation
Changes in amino acid coded for
ex: sickle cell anemia which reduces the oxygen-carrying capacity of RBC is due to missense mutation in one of the hemoglobin peptides
Nonsense Mutation
Creates stop codon
Deletion
Frameshift causing extensive missense
Insertion
Frameshift causing immediate nonsense
Promoters
DNA sequence found 5’ upstream of gene sequences to which RNA polymerase binds to initiation transcription. Activation of promoters => amount of mRNA.
Operons
Regulate gene expression in response to their nutrient requirements, and other cell needs/processes. Operons are several genes located on after another, in the same direction.
Operator
Region within promoter where transcriptional repressor protein binds. NOT FOUND IN EUKARYOTES.
Activator Proteins
Promote expression of specific genes by binding to enhancer regions. It may require other non-protein inducers (testosterone, estrogen). In eukaryotes, the same activator proteins that bind to specific control elements can regulate multiple genes simultaneously.
Epigenome
- Are modifications in chromatin that do not involve changes in DNA sequence. Some are heritable while some are not. Some or reversible and some persist longer. They can differ between tissue types: role in embryonic development and cancer cells.
- Chemical modifications can be in histones or on DNA
Histones
Highly Alkaline proteins found in eukaryotic cell nuclei that package and order the DNA into structural units called nucleosomes
