BIOL 1020 Lecture Notes - Lecture 13: Separase, Chromatin, Plant Cell

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BIOL 1020 Full Course Notes

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There is a parent cell that creates two genetically identical daughter cell; daughter cells are genetically identical to each other and the parent cell. Each daughter cell receives an exact copy of the hereditary info. Definition: differentiate- to become different from one another. At one time it was thought that as cells went from an immature stage to a mature stage, differentiated, they lost specific genetic information. A unite of inheritance is referred to as a gene. Genes are certain stretches of the dna molecule, found on the chromosome. Others thought that the reason for cell differentiation was that certain genes were turned on and certain genes were turned off; these cells remained totipotent. Frog example: start with a tadpole (has an intestine and epithelial cells (cells are differentiated))=> an experiment where scientists removed the nucleus from an egg, they then put the adult nucleus of an epithelial cell into the egg cell.

Related Questions

Every year, the viral strains included in vaccinations for the flu are slightly different, based on the prevalence of the strains present the previous year. Which of the following statements is TRUE regarding the vaccinations and the treatment of viral infections like the flu?

	A.	When someone who is vaccinated encounters the virus they were vaccinated for, antigens are produced triggering destruction of the virus.
	B.	Antibodies are built up in response to viral antigens, making those with vaccines more susceptible to viral infection.
	C.	Viruses mutate quickly due to overuse of antibiotics.
	D.	Vaccinations involve introducing an antigen of a virus into the immune system, which stimulates the production of antibodies.

Recall that HIV is a retrovirus. Based on that, which of the following would NOT be an effective drug target for treatment of HIV?

	A.	Translation inhibitors
	B.	Integrase inhibitors
	C.	Reverse transcriptase inhibitors

The type of horizontal gene transfer that specifically requires a virus to transfer DNA from donor to recipient is called:

	A.	transformation.
	B.	conjugation.
	C.	transduction.
	D.	binary fission.

Binary fission differs from mitosis in that

	A.	binary fission occurs in prokaryotes, and mitosis happens in eukaryotes.
	B.	binary fission does not have a step to duplicate the genetic information, and mitosis does.
	C.	binary fission creates daughter cells that are genetically identical to the parent cell, while mitosis introduces genetic variation.
	D.	binary fission does not have a step to separate the parent cell into two daughter cells, and mitosis does.

Bacteria contain ______ in their cell walls, while Archaea contain _____ in their cell walls.

	A.	chitin; peptidoglycan
	B.	peptidoglycan; pseudopeptidoglycan
	C.	pseudopeptidoglycan; peptidoglycan
	D.	peptidoglycan; chitin
	E.	cellulose; chitin

Question: Think about these questions, and post your thoughts on the use of cloning. Specifically, think the about the use of human cloning and discuss the potential impact on society.

Background Discussion: The scientific research terms, cloning means making exact copies of genes, a cell, or an organism. Therefore, cloning has been around for a long time. Identical twins are clones of a single zygote. When a single bacterium reproduces asexually on a petri dish, a colony of cells results, and each member of the colony is a clone of the original cell. Through biotechnology, bacteria now produce clone copies of human genes.

Through recent advances in science, it is possible to produce a clone of a mammal- and perhaps even one day, a human. The parent need not contribute sperm or egg to the process. During the so-called reproductive cloning, a nucleus (which contains the genetic material of a person) from one adult cell is placed in an enucleated egg. That egg is then allowed to develop. The developing embryo is placed in the uterus of a surrogate mother, and when birth occurs, the clone is an exact genetic copy of the original parent (of course the clone is younger). The process of cloning whole animals, and certainly humans, has not been perfected. Until it is, therapeutic cloning is more likely to become widespread.

Suppose it were possible to put the nucleus from a cell of a burn victim into an enucleated egg that is forced to become skin cells in the laboratory. These cells could be used to provide grafts of new skin that would not be rejected by the recipient. Would this be a proper use of cloning in humans?

Now, suppose parents want to produce a child free of genetic diseases. Scientists produce an embryo though in vitro fertilization, and then they clone the embryo to produce several embryos. Genetic engineering is then used to remove the genetic defect, and the defect free embryos are implanted into the uterus of a surrogate where they are allowed to grow to term. Would this be proper use of cloning in humans?

What if later scientists were able to produce children with increased intelligence or athletic abilities using the same technique? Would this be an acceptable use of cloning in humans?

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?

BIOL 1020 Lecture Notes - Lecture 13: Separase, Chromatin, Plant Cell

BIOL 1020 Full Course Notes

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