Exam 2 Flashcards
What is the order of the transcription steps?
- RNA polymerase II binds to the promotor
- DNA helix is unwound and RNA is synthesized
- Transcription is stopped by a hairpin loop
What two roles are played by the RNA polymerarse II during transcription?
- Binds to protein
2. unwinds the DNA helix and synthesizes RNA
The formation of what ends transcription?
Hair pin loop
List the three steps involved in processing RNA.
1) Add 5 prime Guansine triphosphate cap
2) Add a 3 prime Poly A tail
3) Splice out introns and rebond exons
What is the function of the spliceosome?
Removes introns
What is the order of the schematic nucleotides?
GU, A, AG
What is alternative splicing?
Allows the intron to become an exon
What is the difference between exons and introns?
Both are Transcribed
Exons are translated
Introns are never translated
What happens in the Aminoacyl site in translation?
Link an amino acid on a tRNA to a codon
What are the functions of the three types of RNA required for translation to take place?
mRNA- codes for protein
tRNA-serves as a link between AA and codon
Ribosomal-Peptide bond between amino acid
What is the start codon?
AUG
What are the Stop Codons?
UAG, UGA, UAA
Transcription factors bind two DNA sequence and one protein to increase expression of a gene. What are the DNA sequences and proteins?
Enhancer, Promotor and Polymerase II
The enhancer may be located tens of thousands of nucleotides away from the promotor. How does the transcription factor bind to the enhancer and promotor simultaneously to increase gene expression.
The DNA is flexible and can loop back to the enhancer
List the order of microRNA processing in the correct order.
1) Immature microRNA is transcribed from DNA
2) Drosha removes the hair pin loop
3) Dicer removes the loop in the hair pin loop
4) RISC removes the miRNA-star
What role does Drosha play in processing?
Cuts off the hairpin loop from the sequence
What role does Dicer play in microRNA processing?
Binds and degrades the hair pin loop
What role does the RNA-induced silencing complex play in microRNA processing?
Removes the miRNA
Compare and contrast repressor proteins and transcription factors in regulating gene expression
Both change gene expression
Repressors down regulate-sits on the promotor and blocks transcription, only binds to promotor
Transcription factors- up regulate-bind to enhancer and promotor
How does microRNA decrease gene expression when the microRNA is:
1) Completely complementary to mRNA
2) Partially complementary
1) RISC cleaves the mRNA
2) RISC can’t cleave but can sit on the sequence and prevents ribosome from translating
Define epigenetic.
Affects the expression of a gene but doesn’t change the actual genetic sequence.
What happens to a gene when it becomes highly methylated?
Can begin silencing the gene by tightly wrapping around itself and down regulates expression
What happens to a gene when it becomes un-methylated?
Gene relaxes and uncoils and allows gene expression to increase
An increase in what can cause increased gene expression?
histone acetylation
What about genetics can change with time?
Epigenome
What causes changes to an individual epigenome?
Environment, Diet and Stress
What is transgenerational epigenetic inheritance?
Changes in DNA methylation that can be transmitted across generations
What is the purpose of gel electrophoresis?
To ensure PCR worked, assists in determining size of DNA strands
What is the purpose of PCR?
PCR allows us to zoom in and observe the gene sequence. It amplifies the DNA by increasing magnitude
Name three reagents that are needed for completion of the polymerase chain reaction and the purpose of each reagent?
DNA-must be added for it to be amplified
Primers-DNA sequence that binds to the gene to amplify
Nucleotides-Must be able to make many copies
What happens at the different temperatures of a PCR cycle?
95 degrees-Denature, unwinds the helix-allows primers to enter
50-60 degrees- temp allows primers to bond
72 degrees- Replication
What size DNA fragments are expected to move through the gel faster?
Small
How does the polymerase chain reaction amplify DNA?
Exponentially
Are DNA fragments negative or positively charged?
Negative
What is the difference between Taq DNA polymerase and DNA Polymerase III?
Taq is thermal protected and can with stand the 95 degree C heat
DNA polmerase III would denature at 95 degrees C
How is the size of a DNA fragment determined on a gel?
The gel has a DNA ladder system, Known DNA is placed in one well and all other DNA is measured against it
What is a SNP Chip?
Test that can genotype thousands of SNPs at one time
How can a SNP chip be used in the livestock industry?
Can predict the genetic merits of an animals traits
Can also be research
Why is the efficiency of cloning low?
Because methylation marks werent reprogrammed correctly is the most common issue seen
What is imprinting?
A gene from one parent (mother or father) is epigenetically silenced when transferred to the offspring
List one advantage and one disadvantage of cloning in livestock
Disadvantage-Lacks genetic pool
Advantage-Maintain valuable genetic merit
Why would a producer choose to use sex semen?
If they wanted to produce more bull or heifer calves
Why is sex semen used more in the dairy industry than the beef industry?
In dairy the females make the money so youd want more heifers. Dairy also uses more AI than beef.
Explain how the Cas9-CRISPR targets a gene for modification.
The guide RNA leads the Cas9 to the target and the CAS9 unwinds and cuts the helix. The sequence then attempts to match with replacement
What needs to be added to the Cas9-CRISPER system to modify with the right sequence that has genetic change?
Must be provided with the right sequence that has the genetic change
The Cas9-CRISPR system exists in bacterial cells. What is its function in bacterial cells?
Protect the bacteria from viruses
What is the change inAquaBounty Advantage salmon?
They grow twice as fast and help reduce the costs of production
What does PCR stand for?
Polymerase Chain Reaction
What is the difference between a cloned animal and a gene edited animal?
Cloned will have the exact same genome and creates the same animal
Gene edited animals will change the actual genetic code
Explain how Cas9-CRISPR has the potential to revolutionize the field of gene editing in livestock.
Can make multiple genetic changes at one time
List two examples of how gene editing could benefit livetstock.
1) Feed efficiency
2) Carcaus Quality
3) Environment Impact
List two concerns of opponents of gene editing in livestock
1) Cost
2) Unintended consequences
3) Public Preception
Describe Enviro Pig
They had a phytase gene changed in their salivary glands to degrade phosphate to decrease the environmental impact
Describe the steps involved in cloning an animal by somatic cell nuclear transfer.
1) Isolate donor cells from the animal to be cloned and the egg donor
2) Remove and discard the nucleus from the egg cell
3) Transfer somatic cell nucleus to the egg cell-rest
4) Stimulate cell division
5) Implant embryo in surrogate mother
6) Deliver the baby
