Gene Function: Transcription Flashcards
What is the role of genes in RNA transcription?
Genes are the key regions that lead to RNA
Genes can be encoded in the genome on the 5’ strand or 3’ strand.
In which organelles are genes present in eukaryotic cells?
Nucleus and mitochondria
Genes are found in various organelles in eukaryotic cells.
Are genes evenly distributed across chromosomes?
No, genes are not evenly distributed over the chromosomes
Eukaryotic chromosomes have regions such as the centromere and telomeres which are gene-poor.
What is the relationship between telomere length and aging?
Telomere length relates to aging as they erode and wear down over an animal’s lifetime
Shorter telomeres are associated with cellular aging.
What are the two types of chromatin states?
- Euhromatin - lightly packed
- Heterochromatin - condensed packing
Define a gene.
A DNA sequence that has the ability to encode a product (usually a protein)
Genes are fundamental units of heredity.
What is a pseudogene?
A DNA sequence that has lost the ability to encode a product due to mutations
Pseudogenes are often remnants of evolutionary history.
What characterizes a repetitive sequence?
A DNA sequence that contains a repeated base pair pattern
Examples include microsatellites, transposons, and retrotransposons.
How many genes are present in horses?
20,499 genes
Only a fraction of these genes are transcribed in any one cell.
What are the three dynamics of transcription?
- Location
- Time
- Response to signals
What happens to RNA after it is transcribed from DNA?
It contains introns and undergoes maturation, including the removal of introns
The process of removing introns is called RNA splicing.
What are introns and what functions do they serve?
Introns are non-coding regions that can contain enhancer sequences and allow for alternate splicing
Small genes inside introns can produce non-coding RNAs.
What is required for RNA synthesis?
A polymerase
RNA synthesis requires specific RNA polymerases depending on the type of RNA.
What are the three types of RNA polymerase in eukaryotes?
- Pol I -> Ribosomal RNAs
- Pol II -> mRNA for translation into protein
- Pol III -> small RNAs
What are the three steps of gene transcription?
- Initiation
- Elongation
- RNA processing and termination
What is required for the initiation of transcription in eukaryotes?
A series of proteins/complexes to aid RNA polymerase II
Transcriptional activators and general transcription factors are critical.
What is the role of transcriptional activators?
They bind to enhancer sequences of the DNA and recruit other proteins to the site
They do not interact between DNA strands.
What is the function of general transcription factors?
Proteins that control the rate of transcription by binding to specific DNA regions
They are involved in all Pol II transcription.
What does TFIID do in transcription?
Recognizes the TATA box in the promoter
It is one of the general transcription factors.
What is the function of TFIIH?
Contains a DNA helicase
It is involved in unwinding DNA during transcription.
What occurs after general transcription factors bind to the promoter?
RNA polymerase binds to the promoter region of the gene.
What is required for the elongation of transcription?
Chromatin remodeling to initiate and keep transcribing
Involves histone methyltransferases, acetyltransferases, and demethylases, as well as chromatin-remodeling complexes that reposition nucleosomes.
Which types of dogs are more prevalent for osteosarcoma?
Middle-aged dogs, specifically golden retriever, Rottweiler, and greyhound
Osteosarcoma is a type of bone cancer that is notably common in these breeds.
What mutation is associated with cancer in dogs?
SETD2 mutation
SETD2 is a histone methyltransferase involved in regulating gene expression.
