Week #2 Flashcards
Molecule of DNA complexed with specific proteins responsible for storage and transformation of genetic information
Chromosome
Chromosomes are made up of
Chromatin
Chromatin is made up of what repeating octomer
Nucleosome
Nucleosome is the basic unit of DNA packaging, made up of 8 _ proteins, and DNA (___bp) wrapped around _x
Histone, 146, 2
An organism’s complete set of DNA
Genome
Genome is present in all cells, except RBC because
RBC lack a nucleus and don’t need to divide, grow, perform complex function
Specific DNA sequence that encode blueprint for protein
Gene
Genes can vary in length 5386bp () to 3 billion bp ()
Phi-X 174, Humans
Genes comprise only _% of human genome
2
DNA Structure: 5’ end of DNA _ Group, 3’ end of DNA _ Group
Phosphate, Sugar Group
What type of bonds between bases?
Hydrogen
Smallest genome (473 genes) of independent organism
Syn 3.0
Major Components of Gene
5’ - Regulatory Region, Promoter, Exons, Intron - 3’
Region of DNA involved in gene expression control, towards the 5’ region of the sense strand
Promoter
Core Promoters, sites for transcription factor binding, recruit and bind RNA polymerase
TATA, CAAT, GC Box
Core promoter that is initiation site and specifies direction of transcription
TATA box
Two Types of promoters
Constitutive, Cell Specific promoter
Constitutive promoter is active in what cell type
All cell types
Cell specific promoter is active in what cell type
Specific cell types
Region that can be upstream or downstream from promoter, contains silencer, enhancer and insulator regions
Regulatory Region
Regulatory Region Element that binds co-regulatory proteins (repressors) to decrease rate of transcription
Silencer
Regulatory Region Element that binds co-regulatory proteins (activators) to increase rate of transcription
Enhancer
Regulatory Region Element that is anti-enhancer and anti-silencer activity
Insulator
Coding region of gene
Exon
Non-coding region of gene, important for DNA structure, allows for alternative splicing of genes, regulate gene expression
Intron
Central Dogma
Replication, Transcription, Translation
Two Steps/Levels of Gene Expression
Transcription, Translation
DNA vs RNA
DNA - Double stranded, deoxyribose sugar backbone
RNA - Single stranded, ribose sugar backbone
DNA Strand 5’ - 3’
Top/Sense/Coding Strand
DNA Strand 3’ - 5’
Bottom/Antisense/Template Strand
Newly transcribed mRNA Strand 5’ - 3’ is transcribed from which strand?
Bottom/Antisense/Template Strand
During Transcription from DNA to mRNA, _ replaces _
U, T
Post-Transciptional Regulations
- Poly-A Tail
- RNA interference by siRNA
- RNA interference by miRNA
Consists of 50-250 adenosine monophosphates, located at the 3’ end of most mRNA, added post-transcriptionally on pre-mRNA in the nucleus (PAP+ cleavage factors bind to poly A signal (AAUAAA) and GU/U-rich motfis on RNA transcript and PAP enzyme adds adenosine monophosphates)
Poly-A Tail
Roles of Poly-A Tail
1) Facilitate export of mRNA from the nucleus
2) Increase mRNA stability
3) Enhance translation
How does addition of Poly-A Tail enhance translation?
eIF4 complex interacts with both the 5’ end of mRNA (via eIF4E) and the poly-a tail (via PABP) and recruits the 43S ribosomal subunit (via eIF3
21-23 nucleotide RNA molecules produced from cleavage of long double stranded DNA (dsDNA) by dicer enzyme. Cause sequence specific post-transcriptional gene silencing mechanisms
Small Interfering RNA
Degrades mRNA with complementary sequences to siRNA
RNA Interference
