MMBio Chap 12 – Flashcards

Unlock all answers in this set

Unlock answers
question
Alu element
answer
is a short stretch of DNA originally characterized by the action of the Alu restriction endonuclease. These are the most abundant mobile elements in the human genome. Is a retrotransposon
question
conservative site specific recombination
answer
is a type of genetic recombination in which DNA strand exchange takes place between segments possessing only a limited degree of sequence homology.
question
cut and paste transposition
answer
Theses transpositions are catalyzed by various types of transposase enzymes. The enzyme makes a staggered cut, producing sticky ends, cuts out the transposon, and ligates it into the target site. DNA poly. fills in the resulting gaps, DNA ligase seals the nick
question
excisionase (Xis)
answer
manages excision and insertion of phage genome into the hosts genome.
question
insertion sequence
answer
is a short DNA sequence that acts as a simple transposable element. They have two characteristics- they are small (700-2500 bp) and only code for proteins implicated in the transposition activity (means they are different from transposons which have accessory genes)
question
inverted repeat
answer
is a sequence of nucleotides that is the reversed complement of another sequence further downstream.
question
mobile genetic element
answer
are a type of DNA that can move around within the genome- they include
-transposons
-retrotransposons
-Plasmids
-bacteriophage elements (Mu)
-Group II introns
question
replicative transposition
answer
is a mechanism of transposition in molecular biology in which the transposable element is duplicated during the reaction so that the transposing entity is a copy of the original element
question
resolvase
answer
any group of enzymes that repress transposases
question
transposable element
answer
the things that can move inside a cell
question
transpoase
answer
is an enzyme that binds to the ends of a transposon and catalyzes the movement of the transposon to another part of the genome by a cut and paste mechanism or a replicative transposition mechanism.
question
tranposition
answer
the process of transposons moving themselves to new positions within the genome.
question
transposon
answer
are sequences of DNA that can move or transpose themselves to new positions within the genome of a single cell.
question
What are the two ways transposons can move?
answer
Cut and past transposition (in which the element is directly moved to a new location.) or by replicative transposition (copy and paste- a copy of the transposon is left at the donor site.)
question
How are transposons used in molecular genetics?
answer
They allow the position of the insertion to be determined genetically or by PCR. They can also be engineered in a number of ways to make them a powerful tool for mutagenesis and for studying gene regulation.
question
What are the simplest transposons?
answer
Insertion sequences
question
Insertion sequences contain what (simplest transposons)?
answer
A transposase gene and inverted repeat sequences that include transposase binding sites and cleavage sites
question
Transposons have ___ _______ ______elements flanking intervening DNA that contains additional genes.
answer
two insertion sequences
question
In _____ and _____ transposition, the element is directly moved to a new location and a copy is left at the original location.
answer
cut and paste
question
In ______ transposition, a copy of the element is left at the donor site.
answer
replicative
question
________ elements tend to target certain sequences and may target certain biological processes.
answer
Transposable elements
question
_____ can be used for mutagenesis and offer the advantage that the insertions can be easily mapped genetically or by PCR.
answer
Transposons
question
Transpsons have been engineered to enhance their utility as a genetic tool by incorporating ____ genes and reporter genes
answer
drug resistant
question
What are transposons
answer
Elements of DNA which can move within the genome.
question
Many transposons code for ____, an enzyme which allow them to cut and paste themselves.
answer
Transposase
question
______ worked in the area of chromosome biology using maize and suggested segments of the chromosome could jump to another location.
answer
Barbara McClintock
question
How can cut and past transposons create multiple copies of themselves?
answer
During DNA replication, the transposon removes itself from a chromosome that has already been replicated and inserts into a chromosome that has not yet been replicated
question
What is one way in which transposons may be harmful to an organism.
answer
transposons can insert themselves in the middle of genes and disable them
question
The simplest mobile elements in bacteria are called
answer
insertion sequences
question
Why might transposons be beneficial to the host organisms?
answer
They may pass on phenotypic characteristics that are preferred in natural selection, such as antibiotic resistance in bacteria.
question
Transposons and other mobile elements are valuable to genetic researchers because
answer
They maybe be used to insert genes into a n organism and thus can serve as tools for gene therapy
question
In conservative site-specific recombination,
answer
two DNA segments n homologous chromosomes exchange places at a specific recognition site.
question
Transposition is a process in which a discrete DNA entity can move between DNA sites that lack homology using a self encoded protein called a
answer
Transposase
question
True or False. coordinated breakage and joining events occur during transposition.
answer
true
question
T or F- Transposons are found at various levels of complexity in bacteria
answer
True
question
Transposases that use extensive DNA replication to leave one copy of the element behind in a process called
answer
replicative transposition
question
True or False- Transposons in eukaryotes are mechanistically different from bacterial transposons
answer
False
question
T or F- when transposons move to reproduce and to distribute to new hosts, the process of transposition inevitably jeopardizes the host organism
answer
Can be both but probably false
question
T or F- transposons are known as selfish DNA because their only apparent purpose is to replicate themselves.
answer
True
question
T or F- Transposons always require an RNA intermdiate
answer
False
question
T or F- Ligase is required to seal the nicks caused by transposition
answer
true
question
What DNA sequence feature is diagnostic for the presence of transposons and how is this feature produced?
answer
Short repeats on both ends of the strand
question
The presence of mobile genetic elements can not easily be detected by
answer
gel filtration chromatography
question
The general term for sequences that can change location within the genome is
answer
mobile genetic elements
question
Bacterial elements that have inverted terminal repeats and do not contain coding sequences are called
answer
insertion sequences
question
SINEs are
answer
(Short interspersed elements)-short DNA sequences that represent reverse transcribed RNA molecules originally transcribed by RNA polymerase III- rely on other mobile elements for transposition
question
What are retrotransposons?
answer
are genetic elements that can amplify themselves in a genome and are ubiquitous components of the DNA of many eukaryotic organisms.
question
What is the general process of retrotransposons?
answer
They copy themselves in two stages. First from DNA to RNA by transcription, then from RNA back to DNA by reverse transcription. The DNA copy is then inserted into the genome in a new position.
Get an explanation on any task
Get unstuck with the help of our AI assistant in seconds
New