Final Exam Flashcards
(24 cards)
What is the Lyon hypothesis?
Give an example of X-chromosome inactivation.
One of two X-chromosomes in each somatic cell of females (XX) is randomly inactivated during embryonic development.
Example: Female cats have one X with the orange allele and one X with the black allele.
What was the effect of deoxyribonuclease in the Avery et al experiment?
Transformation did not occur when DNA was destroyed.
How did Avery et al interpret the results of their experiment?
Only when DNA was destroyed did the transformation cease to occur.
What components are involved in the formation of a transcription initiation complex in eukaryotes?
Promoter and protein factors such as TBP-TATA and RNA polymerase.
What was Korana’s experiment with synthetic mRNA UCUCUCUC?
The mRNA is considered to be a dipeptide, meaning a short chain of two amino acids (Leu, Ser).
What conclusion could be drawn from Korana’s experiment?
It could be translated into a dipeptide.
Why is there a lagging strand in DNA replication?
The lagging strand runs 5′ to 3′ toward the replication fork, necessitating synthesis away from the fork in short fragments.
How was the lagging strand experimentally observed?
Most newly synthesized DNA was found in short fragments (~1000–2000 nucleotides).
Explain the statement: ‘Somatic cell mutations in two types of genes often combine, leading to cancer.’
Tumor suppressor genes and oncogenes.
What is the composition of the envelope surrounding certain animal viruses?
Cell membrane and viral protein.
What is the importance of the envelope surrounding certain animal viruses?
Infection or immunity.
What is the function of translation factor EF-Tu?
EF-Tu binds GTP and transports tRNA into the A-site.
What are the key steps in mammalian transgenesis for producing biomedically useful protein in goat milk?
- Mammary-specific promoter
- Coding sequence of the therapeutic protein
- Inject transfected ES cells into blastocoel.
Define antigenic shift in influenza virus.
Reassortment of viral genes.
Define antigenic drift in influenza virus.
Mutation in HA and NA.
Why is a different influenza vaccine needed every year?
Due to antigenic drift, which alters the virus antigen.
What is the Sanger DNA sequencing method?
Single-stranded DNA template is prepared for sequencing.
How is Sanger DNA sequencing automated?
It is automated through fluorescent labels or capillary electrophoresis.
What type of bond is responsible for the α-helix protein secondary structure?
Hydrogen bonds between backbone atoms of the polypeptide chain.
What corresponds to transformant clones in Illumina flow cell technology?
Each cluster on the flow cell originates from a single DNA molecule amplified in place.
How does Illumina design lead to greater throughput than Sanger sequencing?
It enables massive parallel sequences, leading to high throughput and fast data generation.
How are all the CODIS STRs from a crime scene DNA sample analyzed in a single run?
Using multiple PCR combined with capillary electrophoresis for multiplex detection.
What is 45(X) and why is it the only viable human monosomy?
It has only one copy of a particular chromosome, known as Turner syndrome female.
Describe the gene therapy treatment for sickle cell anemia.
It targets a mutation in the HBB gene, which encodes the β-globin subunit of hemoglobin.
