Expert answer:CRISPR in my thought
Solved by verified expert:Reaction to Update: CRISPRList to the Radiolab Podcast called Update: CRISPR. The link to the audio is provided in th Chapter 17: Viruses folder. After listening to the episode, write a two-page (NOT including references) written response about your thoughts and reactions to what was presented in the podcast. Upload this document via Blackboard for grading. Additionally, take a stance on this issue. Do you support the use of CRISPR in biomedical research? Why or why not? Identify two different instances in the podcast that you use as evidence to support your stance (cite at what time in the podcast this occurred in the text of your response). You must also find one additional news article about CRISPR to include in your discussion that must be referenced. You must use the Chicago Manual of Style for referencing formatting (link also in the Chapter 17 folder). Formating:Double-spaced, size 11 font, 1 inch marginsTitle and by-line should be one line at the top You will be graded on this assignment. You will not be graded on the position you take, but rather what evidence you used to come to your decision, your ability to find a news source to discuss, grammar, and structure. You will also be graded on using the appropriate reference format. Please visit the student resource center to help with spelling, sentencing, grammar issues if you need help. Email with any questions. chicago manual of style https://owl.english.purdue.edu/owl/resource/717/04…http://www.radiolab.org/story/update-crispr/ This is the link to the podcast episode you need to listen to for the written assignment.
crispr.pptx
viruses_lecture_10_2_17.pptx
Unformatted Attachment Preview
The Reign of CRISPR
Ledford et. Al., Nature, 2017.
Bacterial Defenses Against Phages
• Natural selection favors mutant bacteria with surface proteins that
are not recognized by a particular phage
• Phage DNA is often identified as foreign and cut up by restriction
enzymes (DNAse, RNAse)
• The bacterium’s own DNA is methylated in a way that prevents attack
by its own restriction enzymes
• The CRISPR-Cas system consists of clustered regularly interspaced
short palindromic repeats and nuclease enzymes called Cas, CRISPRassociated proteins
• When a phage infects a bacterium with this system, the phage DNA is
integrated between two repeat sequences
• If the cell survives the infection, any further attempt at infection of
this cell or its offspring triggers transcription of the CRISPR region
• Transcription of the CRISPR region leads to the resulting RNA being
bound by Cas proteins
• The RNA is used to target the corresponding DNA, which is then cut
and degraded
• In this way, the bacterial cell and its offspring are protected against
further infection by the same type of phage
Phage
BACTERIAL CELL
DNA from previous
infection by the same
type of phage
DNA from
invading phage
DNA from previous
infections by other
phages
CRISPR region
of DNA
Transcription
Repeats
RNA transcript
Processing
Complementary
RNA
RNA
transcribed
from repeat
Cas protein
RNA
Active sites
that cut DNA
5
3
DNA from
invading phage
5
Complementary
RNA
3
5
Resulting cut
in phage DNA
Degraded
phage DNA
Phage
BACTERIAL CELL
DNA from previous
infection by the same
type of phage
DNA from
invading phage
DNA from previous
infections by other
phages
CRISPR region
of DNA
Transcription
RNA transcript
Repeats
RNA transcript
Processing
Complementary
RNA
Cas protein
RNA
RNA
transcribed
from repeat
Active sites
that cut DNA
5
5
3
DNA from
invading phage
Complementary
RNA
3
5
Resulting cut
in phage DNA
Degraded
phage DNA
The CRISPR System of Immunity
Applications of CRISPR
Combating Disease
Forensics
Crop Science
Editing the Human Genome
Viruses!
Overview: A Borrowed Life
• A virus is an infectious particle consisting of little more than genes
packaged into a protein coat
• Viruses lead “a kind of borrowed life,” existing in a shady area
between life-forms and chemicals
Viruses replicate only in host cells
• Viruses are obligate intracellular parasites, because they can replicate
only within a host cell
• Each virus has a host range, a limited number of host cells that it can
infect
• -this is determined by the viral proteins found on the capsid or envelop
General Features of Viral Replicative Cycles
• Once a viral genome has entered a cell, the cell begins to
manufacture viral proteins
• The virus makes use of host enzymes, ribosomes, tRNAs, amino acids,
ATP, and other molecules
• Viral nucleic acid molecules and capsomeres spontaneously selfassemble into new viruses
• These exit from the host cell, usually damaging or destroying it
Attachment
Attachment
Entry of phage
DNA and
degradation
of host DNA
Attachment
Entry of phage
DNA and
degradation
of host DNA
Synthesis of
viral genomes
and proteins
Attachment
Entry of phage
DNA and
degradation
of host DNA
Phage assembly
Self-assembly
Head
Tail
Tail
fibers
Synthesis of
viral genomes
and proteins
Attachment
Release
Entry of phage
DNA and
degradation
of host DNA
Phage assembly
Self-assembly
Head
Tail
Tail
fibers
Synthesis of
viral genomes
and proteins
Lytic vs lysogenic life cycles of viruses.
Lytic viruses:
Common cold
Influenza
TMV
SARS
Rabies
Lysogenic viruses:
HIV
HPV – herpes
Hepatitis B
Chicken Pox
Is Ebola lytic or lysogenic?
Types of viruses – function determined by their features.
• Bacteriophages, also called phages, are viruses that infect bacteria
• They have the most complex capsids found among viruses
• Phages have an elongated capsid head that encloses their DNA
• A protein tail piece attaches the phage to the host and injects the
phage DNA inside
Feature 1: The viral structure.
RNA
Capsomere
DNA
Membranous
envelope
RNA
Capsid
Head
DNA
Tail
sheath
Capsomere
of capsid
Tail
fiber
18 250 nm
Glycoprotein
Glycoproteins
70–90 nm (diameter)
80–200 nm (diameter)
50 nm
50 nm
80 nm
(a)Tobacco mosaic
virus
(b) Adenoviruses
(c) Influenza viruses
80 225 nm
50 nm
(d) Bacteriophage T4
RNA
Capsomere
DNA
Capsomere
of capsid
Glycoprotein
18 250 nm
70–90 nm (diameter)
Nature Reviews Microbiology 13, 471–483 (2015)
80 nm
(a) Tobacco mosaic virus
(b) Adenoviruses
50 nm
Feature 2: The viral genome influences the functions of the virus.
Why would a segmented viral genome be advantageous?
Feature 3: The viral envelop.
Glycoprotein
Viral envelope
Capsid
RNA (two
identical
strands)
HIV
Reverse
transcriptase
HOST
CELL
Viral RNA
RNA-DNA
hybrid
DNA
Reverse
transcriptase
Feature 3: The viral envelop.
NUCLEUS
Chromosomal
DNA
RNA genome
for the
mRNA
progeny
viruses
New virus
Provirus
Feature 3: The viral envelop.
Why
might an
envelope
be
useful?
HIV
Membrane of
white blood cell
0.25 m
HIV entering a cell
0.25 m
HIV entering a cell
0.25 m
New HIV leaving a cell
0.25 m
New HIV leaving a cell
0.25 m
New HIV leaving a cell
HIV
Membrane of
white blood cell
0.25 m
HIV entering a cell
New HIV leaving a cell
Which of the following characteristics determine a
virus’s host range?
A) the enzymes carried by the virus
B) whether its nucleic acid is DNA or RNA
C) the proteins in the host’s cytoplasm
D) the proteins on its surface and that of the host
Which of the following processes can be effective in
preventing the onset of viral infection in humans?
A) taking vitamins
B) getting vaccinated
C) taking antibiotics
D) applying antiseptics
Which of the following responses correctly lists the order of
events in a generalized viral replicative cycle?
A) enzymes transcribe the viral genome into mRNA, the virus
enters the cell, host enzymes replicate the viral genome
B) the virus enters the cell, host enzymes replicate the viral
genome, enzymes transcribe the viral genome into mRNA
C) host enzymes replicate the viral genome, enzymes transcribe
the viral genome into mRNA, the virus enters the cell
D) the virus enters the cell, enzymes transcribe the viral genome
into mRNA, host enzymes replicate the viral genome
If scientists are trying to use what they know about HSV to
devise a means of protecting other people from being infected,
which of the following would have the best chance of lowering
the number of new cases of infection?
A)vaccination of all persons with preexisting cases
B) interference with new viral replication in preexisting cases
C) treatment of the HSV lesions to shorten the breakout
D) medication that destroys surface HSV before it gets to neurons
…
Purchase answer to see full
attachment
How it works
- Paste your instructions in the instructions box. You can also attach an instructions file
- Select the writer category, deadline, education level and review the instructions
- Make a payment for the order to be assignment to a writer
- Download the paper after the writer uploads it
Will the writer plagiarize my essay?
You will get a plagiarism-free paper and you can get an originality report upon request.
Is this service safe?
All the personal information is confidential and we have 100% safe payment methods. We also guarantee good grades