BIO SCI 99 Lecture Notes - Lecture 1: Central Dogma Of Molecular Biology, Cyanine, Telomere

74 views6 pages

redcockroach754

4 May 2020

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

The below questions are examples of problems that you should be capable of completing prior to each lecture. These questions do not cover all topics in the reading and are only meant to provide you with a means to test your understanding. Answers to these questions will not be released. Feel free to discuss them with your classmates, on the message board, in office hours, etc. How does the cell prevent supercoiling? (use figure 9-18 as a reference to answer such questions: does topoisomerase require atp or any kind of triphosphate to ensure its reaction with. What property of topoisomerase (chemically) allows for it bypass the use of triphosphate: if telomerase ceased to exist, what would be the biochemical consequence for our coding. Week 4 friday (lecture 12: describe the different types of responses to a strand break (fig 13-1), the recombination process described in fig 13-2 relies on many of the dna replication principles we currently discussed.

Related Questions

1. Which two of the following mutational changes would you predict to be the most deleterious to gene function?

a. Insertion of a single nucleotide near the end of a coding sequence.

b. Removal of a single nucleotide near the beginning of a coding sequence.

c. Deletion of three consecutive nucleotides in the middle of a coding sequence.

d. Deletion of four consecutive nucleotides in the middle of a coding sequence.

e. Substitution of one nucleotide for another in the middle of a coding sequence.

2. Which type of RNA chain encodes for proteins?

3. What are the pieces of RNA that are removed from the final, mature RNA chains by the process of splicing called?

4. There are three fundamental differences between RNA and DNA. List two of these differences.

5. What is the central dogma of molecular biology and what are the names of the processes that transmit the genetic information between the key components of the dogma?

indigocaribou576

Class 6: Viruses (and Cells, continued)

Making connections: viruses and microbes Match the cell biology concept (on page 1) with an important application of that concept (on page 2). Then answer the follow-up questions at the bottom of page 2.

Cell Biology concepts
1. Bacteria that cannot construct new cell wall material become fragile and break down.
2. During influenza infection, the viral enzyme neuraminidase is required to release new viruses from the host cell in which they were made. Once released, the new viruses can infect many additional cells.
3. Thermus aquaticus is a bacterium found in hot springs and can live at temperatures up to ~80Â°C (175Â°F). It has adapted so that its enzymes are most functional at the elevated temperatures, compared with many organismsâ enzymes that function best ~37Â°C (98Â°F).
4. Until the isolation and investigation of retroviruses, scientists thought that RNA could be copied from DNA, but DNA could not be copied from RNA. Research on this class of viruses led to an update to this âCentral Dogmaâ of biology.
5. Some bacteria have adapted, so that the enzymes involved in making cell wall materials have a slightly different shape and can no longer be bound by certain drugs.
6. Rhizobia are bacteria that colonize the roots of certain plants (legumes, including beans and peas). The host plant benefits from the prokaryotesâ ability to âfixâ nitrogen, converting N2 from the atmosphere into a form that is usable by the plant.
7. Many species of bacteria contain the enzyme cellulase. More than 10 billion such bacteria and other symbiotic microbes may be found in a single milliliter of material from inside the digestive system of ruminant mammals.
8. Fungi, including those that cause athleteâs foot, use ergosterol to maintain healthy membranes. Animal cells do not make ergosterol, they use a similar lipid â cholesterol.
9. During retrovirus infection, a DNA copy is made of the virusâs RNA genome. A cut is made in the host cellâs DNA and the DNA copy of the viral genome is pasted into the host chromosome by a viral enzyme called integrase.
10. Prokaryotic cells contain smaller ribosomes (â70Sâ ribosomes) than eukaryotic cells (â80Sâ ribosomes). Both types of ribosomes synthesize proteins, but the macromolecules they use to do it are somewhat different.

2
Applications
_______ Oseltamivir, also called Tamiflu, binds and inhibits the viral protein neuraminidase.
_______ Clotrimazole is a drug that is used to treat certain infections. It interferes with synthesis of ergosterol, a lipid involved in phospholipid membranes.
_______ Penicillin is a drug that interferes with synthesis of peptidoglycans (these are biological molecules that are part protein and part carbohydrate) that are present in certain cell walls.
_______ HIV is often treated with several drugs that inhibit different parts of the viral replicative cycle. Raltegravir is an example of a drug that interferes with the integration of viral genes into the host cellâs chromosome.
_______ Cows, like other vertebrates, lack the ability to breakdown cellulose. Yet they are able to live on a diet of grass and other vegetation high in cellulose.
_______ Enzymes isolated from extremophiles have been very useful in laboratory research. For example, Taq polymerase facilitates PCR, a revolutionary technique for production of DNAs of particular sequences, which requires cycling reactions through high temperatures.
_______ Plants and animals require nitrogen to make biological macromolecules, however theyâre unable to convert atmospheric nitrogen (N2) into a biologically useful form.
_______ Azithromycin is a drug that binds to 70S ribosomes and blocks synthesis of any new proteins.
_______ Methicillin-Resistant Staphylococcus aureus (MRSA) can cause life-threatening infections of the skin and bloodstream. One of the reasons MRSA infections are so serious is that they are resistant to treatment by many antibiotics, including methicillin and penicillin.
_______ The enzyme reverse transcriptase, isolated from retroviruses, is an important tool in molecular biology research. Scientists interested in learning what genes are turned on in particular cells use it to make DNA copies of RNAs they are studying (The DNA copies are useful because they are more stable).

When you have completed the matching activity, answer these follow-up questions:
â¢ What types of infections can be treated with the following drugs?
o Penicillin
o Clotrimazole
o Azithromycin
o Tamiflu
o Raltegravir
â¢ Why are these drugs (above) safe for you to take? That is, why donât they kill your cells?
â¢ Cancer cells are your own human cells that have become deregulated so that they divide and pile up in an uncontrolled way. Many chemotherapy drugs treat cancer by interfering with cell division and other cell processes.
o Why are there so many more side effects for individuals undergoing chemotherapy than for individuals taking antibiotics?

1. A mutation in the gene encoding the integrase enzyme rendersthe protein non-functional. How would the affect the HIV infectioncycle?

Formation of the provirus would bestopped.

Reverse transcription would nolonger be possible.

The gp120 glycoprotein would nolonger be able to bind to the CCR5 receptor.

Cutting and assembling the capsid would be halted.

2. If the viral gene is AUGCCCAGG and the mRNA used to make theviral protein is UACGGGUCC, then the virus is a :

Negative strand RNA virus

Double stranded DNA virus

Retrovirus

Positive strand RNA virus

3. Would treating prions with enzymes that digest nucleotides bean effective neutralization method?

No, prions lack amino acids.

Yes, prion nucleic acids would besusceptible to enzymatic digestion.

No, prions lack phosphodiesterbonds and would not be subject to digestion by these types ofenzymes.

Yes, the bonds between the amino acids would be hydrolyzed.

4. Most Americans born before 1970 have a permanent scar ontheir shoulders from the smallpox vaccine. Why don't youngerAmericans have one?

Smallpox has been eradicated by aworldwide vaccination program.

Smallpox is no longer lethal.

A safer less damaging vaccine wasdeveloped in the early 1970's.

The vaccine is no longer effective due to antigenic shift.

5. What kind of pathogen would retain its ability to causeinfections after being treated with powerful proteolytic chemicalsthat would destroy all proteinaceous material?

A viroid

6. Select all of the false statements concerning AIDS.

AIDS kills the patient.

Patients die as a result ofopportunistic infections.

AIDS shuts down the immunesystem.

HIV therapy (HAART) can clear thevirus from the bloodstream.

HIV therapy (HAART) can clear the virus from the patient'sbody.

7. Why do viruses only infect specific types of cells?

Viruses only attack epithelialcells, such as the cells lining the lungs.

If a host cell is weakened, viruseshave an easier time infecting it.

The initial choice is random butonce a cell type is chosen it becomes the preferred host.

The host cells have the correctsurface receptor that the virus can fit into.

Viruses infect the first cells they encounter.

8. Nucleotide analogs are a class of drugs that are highlyeffective against many types of viruses. They work by halting thereplication of viral genes. They are equally effective at stoppingthe spread of prion diseases.

True

False

9. An experimental chemical has been shown to selectively cleavephosphodiester bonds. How would the affect a virus?

Dissociate the envelope

Fragment the genome

Hydrolyze the protein coating

Alter the host binding site

Digest the capsid

10. HIV uses cell surface receptors to enter host cells. Whydoes switching from a CCR5 co-receptor to a CXCR4 co-receptoreventually shut down the immune system?

	Macrophages have CCR5co-receptors.
	T-helper cells have CXCR4co-receptors.
	T-helper cells are not involved incoordinating immune responses.
	Only macrophages are killed byHIV.

crimsonsalmon160

BIO SCI 99 Lecture Notes - Lecture 1: Central Dogma Of Molecular Biology, Cyanine, Telomere

Document Summary

Get access

Related textbook solutions

Molecular Cell Biology

Biology: Science for Life with Physiology

Concepts of Biology

Biology

Essentials of Biology

Related Documents

BIO SCI 99 Study Guide - Midterm Guide: Dna Replication, Reaction Mechanism, Leaving Group

BIO SCI 99 Study Guide - Quiz Guide: Edward Tatum, George Beadle, Semiconservative Replication

BIO SCI 99 Lecture Notes - Lecture 10: Gc-Content, Ampicillin, Isotopes Of Nitrogen

Related Questions