Chapter 21 - Transcription And Rna

A segment of DNA that is transcribed into a RNA molecule that has a function within the cell

All the information specifying the amino acid sequence of a polypeptide

Before becoming fully functional

The process of converting DNA into RNA

By immobile protein complexes that reel in the DNA

A protein coding segment

The removal of introns and joining of exons in an RNA molcule

Consensus sequences

(Usually) short sections of DNA/RNA that are common at different locations and important for specific functions

A region of a gene, upstream of the transcribed section, where RNA polymerase binds, and transcription will begin

Proteins that facilitate binding of RNA polymerase by altering the structure/form of DNA at the promoter and bind to consensus sequence

DNA sequences

Protein

Bind to enhancers to promote the transcription of a gene

Set of functionally related genes under the control of one promoter and only found in prokaryotes

Bacteria

An enzyme, unwinds and separates double-stranded DNA at the position where transcription occurs

At promotors

Prokaryotic operons

Eukaryotic promotors

Eukaryotic promotors

When transcription factors unwind DNA

Many transcription factors

Enhancers and activators

Upstream of the promotor

Eight

Transcription to produce noncoding RNA

1. mRNA

2. rRNA

3. tRNA

They are not translated into protein

Messenger RNA - encodes for polypeptide sequences

Ribosomal RNA - aids in polypeptide synthesis

Transfer RNA - carries amino acids to the ribosome

Small Interfering RNA

Micro Interfering RNA

Complementary RNA and target it for destruction/degredation or block translation

Translation (ribosomal structure and catalytic activity)

Delivery of amino acids to ribosome during translation

Sequence-specific inactivation of mRNA

rRNAs

RNA polymerase II

RNA polymerase III

True

False

The acetylation of histones

Negatively

The action of the chromatin-remodeling complex

DNA is loosened from the histone so that it can slide along the nucleosome

1. Hairpin loop

2. Rho

Immediately translated

Needs to travel from nucleus to cytosol (location in the ribosomes)

1. mRNA can be modified ("processed")

2. Variety of gene products can be generated gene

3. Expression can be regulated

1. Addition of 5' methyl cap

2. Addition of 3'm poly (A) tail

3. Splicing

Eukaryotic mRNAs receive a 5' methyl cap

Protection from exonucleases that would attack the 5' end

The 3' end receives a poly (A) 3' tail

Attachment of poly (A) binding proteins

Protection from exonucleases that would attack the 3' end

A binding protein bound to poly (A)

A consensus sequence triggers poly (A) polymerase to create the poly (A) tail that is then bound to poly (A) - BP

Before transcription ends

Prior to translation, introns needs to be removed and exons joined together

Splicing is the removal of introns and joining of exons in an RNA molecule

It is controlled by consensus sequence that are recognized by the spliceosome

Complex made of snRNA and proteins

Alternative splicing

Alternative splicing

mRNA turnover

Large intervening noncoding RNA

Small nuclear RNA

Small nucleolar RNA

Transcriptional control

RNA splicing

Sequence-specific methylation of rRNA

Disrupt the synthesis of proteins by either degrading mRNA or blocking translation

RNA interface

Regulation of gene expression

20 - 25 nucleotides (small)

1. siRNA

2. miRNA

Therapeutic strategy

Effective delivery to target sites

RNA is subject to nuclease degradation

RNA is unable to cross cell membranes

Direct delivery (injection at target site)

Chemical modifications

Lipid or polymer based nanocarriers

Need to optimize for delivery to target site, uptake of nanocarrier, and release of RNA once in the cells

False

Proteins

Can catalyze reactions

Can adopt complex tertiary structures

Watson-Crick base pairing

Nonstandard base pairing