Lecture 7 Flashcards
(15 cards)
What do most restriction enzymes recognize?
Palindrome sequences
Restriction enzymes are proteins that cut DNA at specific sequences.
What is the role of T7 expression vectors in gene cloning?
Cloned genes are placed under control of the T7 promoter
T7 expression vectors are used to express target genes in bacteria.
What is the function of T7 RNA polymerase?
Only recognizes T7 promoters and transcribes cloned genes
T7 RNA polymerase is highly active and uses most RNA precursors.
What are reporter gene fusions used for?
To study regulation by assaying reporter under different conditions
Reporter genes allow monitoring of gene expression and regulation.
What is genome editing?
Use of CRISPR/Cas9 system to alter eukaryotic genomes in living cells
CRISPR/Cas9 is a powerful tool for gene editing in various organisms.
How does the Cas9 protein function in CRISPR systems?
Acts as an endonuclease guided by CRISPR RNAs to target nucleic acids
Cas9 cuts DNA at specific sites determined by the guide RNA.
What is a significant risk associated with genetically modified organisms (GMOs)?
They may spread genes to wild-type populations
This can lead to unintended ecological consequences.
What is the estimated age of Earth?
~4.5 billion years
Earth formed approximately 4.5 billion years ago, making it suitable for life.
What are anoxygenic phototrophs?
Organisms that perform photosynthesis without producing oxygen
They use electron donors like H2S for CO2 fixation.
What major evolutionary event allowed the rise of oxygen in the atmosphere?
Evolution of cyanobacteria that used H2O for photosynthesis
This led to significant changes in Earth’s atmosphere and allowed aerobic respiration.
What theory explains the origin of organelles in eukaryotic cells?
Endosymbiotic Theory
This theory posits that mitochondria and chloroplasts originated from free-living bacteria.
What are homologous genes?
Genes that all descended from a single ancestral gene
These genes can have similar or different functions in different organisms.
What are orthologs?
Homologous genes sharing the same function
Orthologs arise from speciation events and retain the same function across species.
What are paralogs?
Homologous genes that diverge to have different functions
Paralogs arise from gene duplications within the same genome.
What role do transposons play in genome evolution?
They are mobile genetic elements that promote horizontal gene transfer
Transposons can carry genes that enhance adaptability and evolution.
