Mechanisms by which meiosis would introduce genetic variability in a population

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Preparation Task 1:

Describe the mechanisms by which meiosis would introduce genetic variability in a population.  If one diploid yeast cell was heterozygous for an allele with a Dominant mutation on it, what proportion of its offspring could be expected to carry that dominant mutation after mating? (Assume it mates with a cell that is homozygous for the normal, recessive allele.)

Interestingly, yeast switch to sexual reproduction when they are under conditions of stress.

For the purposes of this task, assume yeast populations follow this simplified rule: When yeast are reproducing sexually, they will be found as diploid cells that can go through meiosis (or mitosis), while populations that are producing asexually will include only haploid cells undergoing mitosis. Remember that chromosomes can be counted using karyotypes as seen in your text Figure 9.3.

During Meiosis-I at Prophase-I of pachytene stage crossing over or recombination occurs between two non-sister chromatids of homologous chromosomes resulting in exchange or reshuffling of genes. This process is universal among sexually reproducing organisms and is responsible for all types germinal variations that are passed on from parents to offspring. 50% of offspring would be carrying dominant mutation when the heterozygous is crossed with homozygous recessive. For example, Aa x aa the result will be Aa, Aa, aa, aa 1:1 ratio

Preparation Task 2:

 

Explain why sexual reproduction could be advantageous to a population under stressful conditions. Relate this to the process of natural selection.

If an organism is under stressful condition sexual reproduction could be advantageous because:

Sexual reproduction increases variation. So, the organism can make various variants. In sexual reproduction we know we get one set of chromosomes from father and one from mother. And there are also crossing over during gamete formation. So sexual reproduction creates many variations.

It makes variants that are different from parental population. So, if the parental population is in stress then the variants created by sexual reproduction could survive the changing environment. Some variation should have advantages upon the changing environment, so they have better chance to survive in nature.

Thus, sexual reproduction also prevents the extinction of that organism.

Preparation Task 3:

 

Consider the differences between mitosis and meiosis. Examine the figure “A Simplified Model of Yeast Reproduction” above and identify ways in which you could determine whether a yeast cell was going through mitosis or meiosis.

Organisms, including yeast, find a variety of environmental conditions stressful. We can grow yeast in a laboratory under either stressful or non-stressful conditions.

Conditions or chemicals that damage organelles (Chapter 3), interfere with transporting nutrients (Chapter 4), or affect the processes of aerobic or anaerobic respiration (Chapter 6) would “stress” these organisms. Environments that affect protein folding (Chapter 2) or enzyme regulation (Chapter 4), are also stressful environments.

Mitosis is an equational division where the chromosomes double up and then divide into two. So, the mother cell divides into 2 daughter cells, each having the equal number of chromosomes as the mother cell. The yeast cell in picture performs asexual reproduction wherein its haploid cell undergoes mitosis producing 2 cells with ploidy N.

When stressful conditions arrive, the yeast cell in the picture undergoes sexual reproduction. The diploid cell with 2N ploidy gives 2 daughter cells with half the number of chromosomes. Hence meiosis is also called as reductional division, as the chromosome number reduces to half.

Preparation Task 4:

Revisit these sections in your textbook if needed and propose at least two specific situations or conditions (that you could control) that yeast may find stressful. Include a citation (your textbook or other sources you may consult)

 

 

 

 

 

 

Preparation Task 4:

Revisit these sections in your textbook if needed, and propose at least two specific situations or conditions (that you could control) that yeast may find stressful. Include a citation (your textbook or other sources you may consult)

Gen Ed Assignment Tasks

Task 5 Define a problem or pose a question:

Define a question you could investigate that links a stressful scenario you identified in Preparation Task 4 to sexual reproduction in yeast.

Task 6 Formulate a hypothesis:

Formulate a hypothesis that could be tested regarding your question. Include your reasoning that led to this hypothesis.

Task 7 Designing an experiment:

Outline an experiment you could use to test this hypothesis. Include and identify the following 6 key elements of your experiment:

1. the experimental versus control group

2. the dependent variable

3. the independent variable

4. the standardized variables

5. adequate replication/sample size

6. materials and methods

Task 8 Drawing Conclusions:

(Defining results that would support or refute your hypothesis.)  Complete both A +B.

A) Describe a possible result from your experiment that would support your hypothesis. You will to describe the results for both the experimental and the control groups to draw a valid conclusion. Provide an explanation for your conclusion. Your explanation should demonstrate the connection between your results and the support of your hypothesis.

B) Describe a possible result from your experiment that would refute your hypothesis. You will to describe the results for both the experimental and the control groups to draw a valid conclusion. Provide an explanation for your conclusion. Your explanation should demonstrate the connection between your results and how they refute your hypothesis.

Task 9 Envision future directions:

Imagine that you have discovered a new species of yeast. Describe how your method, process, or solution could be applicable to this new situation.

 
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BIO 235 Microbilogy

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Instructions:

 

Please answer the following with minimum 75-100 words for each question. Must include references with answer in APA. Must be 100% original work. Thanks

 

 

1.      A 40 year old bird handler was admitted to the hospital with soreness over his upper jaw, progressive vision loss, and bladder dysfunction.  He had been well 2 months earlier.  Within weeks he lost reflexes in his lower extremities and subsequently died.  Examination of CSF showed lymphocytes.  What etiology do you suspect? What further information do you need? (20 points)

 

2.      Please watch the film on Polio and comment.  Also OPV is no longer used for routine vaccination.  Provide the rationale for this policy. (10 points)

http://www.youtube.com/watch?v=XP2iUz4JzMY

 

3.      Nearly 70% of the patients seen in STI clinics are men.

a.       Offer a reason men are more likely to seek treatment than women

b.      Why is it important that women seek treatment for STIs? (15 points)

 

4.      Pneumonia is diagnosed by the presence of fluid (dark shadows in an X-ray image) in the alveoli.  Given that pneumonia usually is caused by a microorganism, what causes the fluid accumulation? Name a bacterium, a virus, a fungus, a protozoan and a helminth that can cause pneumonia (15 points)

 

5.       A 31 year old man became feverish 4 days after arriving at a vacation resort in Idaho.  During his stay he ate at two restaurants that were not associated with the resort.  AT the resort he drank soft drinks with ice, used the hot tub and went fishing.  The resort is supplied by a well that was dug 3 years ago. He went to the hospital when he developed vomiting and bloody diarrhea.  Gram-negative, lactose-negative bacteria were cultured from his stool.  The patient recovered after receiving intravenous fluids.  What microorganism most likely caused his symptoms? How is this disease transmitted?  What is the most likely source of his infection and how would you verify the source? (15 points)

 

6.      The tropical skin disease called yaws is transmitted by direct contact.  Its causative agent, Treponemapallidumpertenue is indistinguishable from T. pallidum.  One theory is that syphilis epidemics in Europe coincided with the return of Columbus from the New World.  How might T. Pallidumpertenue have evolved into T. Pallidum in the temperate climate of Europe? (15 points)

 

7.      Research the disease Ebola.  How would you feel as a nurse being assigned to a patient with this disease and do you think that patients should be brought to this country with the disease, but remember that the two patients that are coming are both American citizens. (10 points)

 

 

 
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2420-Lab 7- Microbial Growth

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2420-Lab 7- Microbial Growth: Temperature, Oxygen and Osmotic Balance

Directions:

Answer following questions after reading the information and watching the video from the link below. Use color RED or BLUE for your answers. Submit the completed document on eCampus for grading. Refer to

· the textbook chapter 4 (sections 4.1, 4.3 and 4.4) (Nester- McGraw Hill)

· Lab Manual by Dr. Su, pages (optional)

· Link: Environmental Influences of Bacterial Growth, Virtual Edge Experiment- 5A-B

· pH Requirement of bacteria

Bacterial Growth:

Read the information from textbook from chapter 4 review sections 4.1, 4.3 and 4.4 to answer the following questions.

Watch the following video:

· For background: Bacterial Growth

1. Label the phases of growth on the following curve:

2. What happens to bacteria in the phases labeled as A, B, C and D in the above figure?

A:

B:

C:

D:

3. If we add more nutrients and space at the end of the exponential phase for a growing bacterial culture, what will happen?

Oxygen Requirement of bacteria

Read the information from textbook from chapter 4 review sections 4.3-4.4 to answer the following questions.

Watch the following videos:

· For background: Oxygen Requirement of bacteria

· For experiment: Oxygen requirement of bacteria using soft agar

Results of the bacterial oxygen requirement of bacteria:

4. Why can only some organisms tolerate oxygen?

 

5. Describe the kind of bacteria shown in the figure above in terms of oxygen (concentration) requirement and special enzymes.

 

6. Which oxygen related enzymes are present or absent in the bacteria from tubes A-E?

 

Temperature Requirements of Bacteria:

Read the information from textbook from chapter 4 review sections 4.3-4.4 to answer the following questions.

Watch the following videos:

· For background: Temperature Requirement of bacteria

· For experiment: Temperature Influence on bacterial growth

Temperature tolerance of bacteria

Write the correct term for bacteria growing under the following conditions

7. Most medically important bacteria

8. Bacteria growing on or inside your body

9. Bacteria growing in your refrigerator

10. Bacteria growing in the arctic ocean in winter

11. Bacteria growing in hot springs in Arkansas

12. Bacteria growing in geysers

13. Why are bacteria not able to grow at temperature higher than the maximum tolerance limit?

14. Do bacteria grow at the temperatures lower than the minimum tolerance limit? Why or why not? Explain

Osmotic Balance Requirements of Bacteria:

Read the information from textbook from chapter 4 review sections 4.3-4.4 to answer the following questions.

Read the following:

· For experiment: Osmotic Influences

Osmotic tolerance of bacteria

Halophiles : On human body, Staphylococcus aureus is known to tolerate sweat. These bacteria may cause skin infections if athletic gear is shared among athletes without proper sanitization. In nature we will find bacteria, algae and fungi in water bodies or soil with higher salt concentrations. These organisms come under a group called “halophiles”.

Habitat : Halophiles are usually found in salt lakes, salt marshes, subterranean salt deposits, dry soil, salted meat and hypersaline seas.

3 groups based on the salt concentration tolerance :

· Halophiles-2-5% salt required for growth

· Moderate halophiles-5-20% salt required for growth

· Extreme halophiles-20-30% salt required for growth

Write the correct term for bacteria growing under the following conditions

15. Based in your knowledge about tonicity, for cells to survive they have to be surrounded by ______tonic environment.

 

16. Why would cells not survive in hypotonic or hypertonic environment?

2420-Lab 7- Microbial Growth: Temperature, Oxygen and Osmotic Balance

Directions:

Answer following questions after reading the information and watching the video from the link below. Use color RED or BLUE for your answers. Submit the completed document on eCampus for grading. Refer to

· the textbook chapter 4 (sections 4.1, 4.3 and 4.4) (Nester- McGraw Hill)

· Lab Manual by Dr. Su, pages (optional)

· Link: Environmental Influences of Bacterial Growth, Virtual Edge Experiment- 5A-B

· pH Requirement of bacteria

Bacterial Growth:

Read the information from textbook from chapter 4 review sections 4.1, 4.3 and 4.4 to answer the following questions.

Watch the following video:

· For background: Bacterial Growth

1. Label the phases of growth on the following curve:

2. What happens to bacteria in the phases labeled as A, B, C and D in the above figure?

A:

B:

C:

D:

3. If we add more nutrients and space at the end of the exponential phase for a growing bacterial culture, what will happen?

Oxygen Requirement of bacteria

Read the information from textbook from chapter 4 review sections 4.3-4.4 to answer the following questions.

Watch the following videos:

· For background: Oxygen Requirement of bacteria

· For experiment: Oxygen requirement of bacteria using soft agar

Results of the bacterial oxygen requirement of bacteria:

4. Why can only some organisms tolerate oxygen?

 

5. Describe the kind of bacteria shown in the figure above in terms of oxygen (concentration) requirement and special enzymes.

 

6. Which oxygen related enzymes are present or absent in the bacteria from tubes A-E?

 

Temperature Requirements of Bacteria:

Read the information from textbook from chapter 4 review sections 4.3-4.4 to answer the following questions.

Watch the following videos:

· For background: Temperature Requirement of bacteria

· For experiment: Temperature Influence on bacterial growth

Temperature tolerance of bacteria

Write the correct term for bacteria growing under the following conditions

7. Most medically important bacteria

8. Bacteria growing on or inside your body

9. Bacteria growing in your refrigerator

10. Bacteria growing in the arctic ocean in winter

11. Bacteria growing in hot springs in Arkansas

12. Bacteria growing in geysers

13. Why are bacteria not able to grow at temperature higher than the maximum tolerance limit?

14. Do bacteria grow at the temperatures lower than the minimum tolerance limit? Why or why not? Explain

Osmotic Balance Requirements of Bacteria:

Read the information from textbook from chapter 4 review sections 4.3-4.4 to answer the following questions.

Read the following:

· For experiment: Osmotic Influences

Osmotic tolerance of bacteria

Halophiles : On human body, Staphylococcus aureus is known to tolerate sweat. These bacteria may cause skin infections if athletic gear is shared among athletes without proper sanitization. In nature we will find bacteria, algae and fungi in water bodies or soil with higher salt concentrations. These organisms come under a group called “halophiles”.

Habitat : Halophiles are usually found in salt lakes, salt marshes, subterranean salt deposits, dry soil, salted meat and hypersaline seas.

3 groups based on the salt concentration tolerance :

· Halophiles-2-5% salt required for growth

· Moderate halophiles-5-20% salt required for growth

· Extreme halophiles-20-30% salt required for growth

Write the correct term for bacteria growing under the following conditions

15. Based in your knowledge about tonicity, for cells to survive they have to be surrounded by ______tonic environment.

 

16. Why would cells not survive in hypotonic or hypertonic environment?

 
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Infectious Disease Society of America

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Please respond to both students on seperate pages with a minimum of 100 words each

please follo directions or I will dispute!!!

Page1- original Forum and references

page2- student Response

page 3- studen Response

Original Forum

Antibiotics are commonly used to treat infections. We seldom think about what occurs when we take this medication other than the fact that we will or should get better after a few days. Most are aware that antibiotics have been used for some time and their effectiveness is beginning to wane. In fact, today we have strains of microbes that have developed resistance to antibiotics such that we have named them Superbugs. One such Superbug, methicillin-resistant Staphylococcus aureus (MRSA) has become resistant to most antibiotics available and is a problem in many hospital settings.

Review chapters 14 and 15 of your textbook for a review of Antimicrobial Drugs and Microbial Mechanisms of Pathogenicity.

And then visit the Infectious Disease Society of America

For this forum, please choose to take ONE role in the following scenario.

A patient has arrived in the ER critically ill. She had a minor surgery the week previously and was discharged home with antibiotics. Upon arrival to the ER, the patient presented gravely ill, the surgical wound red, swollen, puss filled and her temperature elevated. A post surgical infection is suspected.

Choose only ONE (Topic) role in this scenario:

Topic 1. You are the patient

Topic 2. You are the spouse of the patient (the person who may be or may become responsible for making decisions)

Topic 3. You are the nurse caring for the patient.

Topic 4. You are the primary physician caring for the patient.

Topic 5. You are the infectious disease specialist on call for the hospital where the patient has arrived.

Compose an exposition to address the following questions;

1. Is this infection likely MRSA?

2. What would a MRSA infection look like on a patient; for example, describe how the wound presents.

3. Was the patient exposed to MRSA in the hospital prep, during the surgery the week previously or sometime afterwards (post-discharge)?

4. Where does liability for this (potential) infection rest? Is it the responsibility of the patient (making sure she followed her discharge instructions, etc), nurse(s), scrub technicians, physicians, surgeons and/or infectious disease specialists to ensure resistant diseases are kept in check in hospitals?

Student Responses

Eric

As the nurse treating the patient, Here are my answers.

1. Is this infection likely MRSA?

This infection has a probability of being MRSA due to the signs and symptoms which are present. The patient may have been prescribed a broad-spectrum medicine that did not target the intended pathogens to prevent the infection or there could be other possibilities. The patient could have also developed a super infection in which the protective microbiota of the body were killed allowing added exposure to bacteria. Lastly, it is possible that the patient was over prescribed medication in which the body became resistant to and had less effect which the bacteria was able to overcome <w:sdt>(Parker, 2016).

2. What would a MRSA infection look like on a patient; for example, describe how the wound presents.

A MRSA infection appears to look like a large bump on the skin which is red, swollen, and warm to the touch. It is sometimes painful, full of pus, and most of the time accompanied by a fever. The common areas in which the infection is usually located include the legs, buttocks, groin, and back of the neck <w:sdt>(CDC).

3. Was the patient exposed to MRSA in the hospital prep, during the surgery the week previously or sometime afterwards (post-discharge)?

All of these options are a possibility as MRSA can be contracted either in the community or in the hospital setting due to improper sterilization of medical equipment or areas in the hospital <w:sdt>(Parker, 2016). Another possibility is that the patient was even given the wrong medication to treat the wound. The patient could have also become resistant due to previous medications which were over prescribed, or perhaps even not following proper instructions for taking enough medication or the correct doses.

4. Where does liability for this (potential) infection rest? Is it the responsibility of the patient (making sure she followed her discharge instructions, etc), nurse(s), scrub technicians, physicians, surgeons and/or infectious disease specialists to ensure resistant diseases are kept in check in hospitals?

The liability of this infection rests ultimately on the hospital and staff members because of the protocols for cleaning and sterilizing equipment properly <w:sdt>(Parker, 2016). There may be other factors such as manufacturers fault in which the equipment allowed for pathogen to enter a persons body and the patient themselves to not follow proper instruction. However, the hospital is the liable one. MRSA used to be known to be contracted through just the hospital setting as a common thing.
-Eric

<w:sdt>

References<w:sdtpr>

<w:sdt>

CDC. (n.d.). MRSA Skin Infection Signs and Symptoms.Retrieved October 2018, from cdc.gov: https://www.cdc.gov/mrsa/pdf/MRSA_Broch_Parent.pdf<w:sdtpr>

Parker, N. (2016). Microbiology. OpenStax. Retrieved 2018

Jennifer

Hello everyone,

I will play the Physician for this topic.

How you determine if an infection is MRSA related is by first examining the wound. A MRSA infection displays at the wound site; warm to the touch, red, swollen, painful, full of pus and can also cause you to have a fever. The possible infection site looks awful to say the least and is discolored most times. It almost looks like a nasty “super” pimple.

The patient presents a surgical wound that is red, swollen, filled with pus, and even has a temperature increase or a fever. These point to MRSA, but the description of being gravely ill is suspicious. One of the few ways to definitely diagnose MRSA is to swab the nose or skin.

It does say that the patient was discharged with antibiotics to potentially kill of any impending infections. Although, MRSA can become resistant to antibiotics due to the many different advances in the strain.

It is very possible that the patient could have been exposed during surgery. Everyone involved with surgery scrubs diligently to prevent the spread of harmful microbes. The patient is also advised to keep the wound clean, covered and to not share any personal items. This is to help prevent infections.

The liability for this infection can rest on either the hospital or the patient. The hospital can run tests to confirm if their facility has MRSA or if their staff is carrying it. If those test come back negative then that is on the patient’s lack of self-care and following post-operation instruction.

Personally for me I had surgery at an out-patient facility and I had no issues. My incision site was wrapped up for about 2-3 weeks. I was instructed to keep the dressing dry at all times. Someone I work with had surgery at a hospital and developed staph infection. I am not sure who was at fault for that.

General Information About MRSA in the Community. (2016, March 25). Retrieved October 23, 2018, from https://www.cdc.gov/mrsa/community/index.html

-Jenny

 
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