1. Microbiology is the study of what?
My answer: Microbiology is the study of microorganisms and their biological processes at what is called the "micro" or "microscopic" level.
Answer Key: Microbiology is the study of microbes (microorganisms and viruses) and their biological processes.
BIOD 171 Module 1-6 Exams Questions With Answers
2. True or False: A virus is considered a microorganism.
False. Viruses are not living and as such are not considered microorganisms. Viruses can, however, be classified as microbes, a more general term that includes microorganisms and viruses.
3. Explain why the flu shot given each year may not be 100% effective at preventing the flu?
It is possible to receive a flu vaccine and yet (unfortunately) still get the flu in the same season if you are exposed to a viral strain that was not included in the vaccine. There are a large number of variants and the flu vaccine is unable to vaccinate against all subtypes. Medical researchers predict and then distribute flu vaccines based current trends and the available data relative to the most common circulating strains. Unfortunately, this model is not always 100% accurate.
4. How many turns (or repetitions) of the Calvin Cycle are required to generate one molecule of glucose?
Six
5. Which subtype of Influenza is the most virulent?
Influenza A
6. Define an essential amino acid.
An essential amino acid cannot be produced by the human body and as such must be taken in from the environment through alternative sources (i.e) food.
7. Which one of the following is an efferent vessel?
Pulmonary Artery
Pulmonary vein
Ascending Aorta
Inferior vena cava
Ans. Pulmonary Artery and Ascending Aorta
8. What is the primary function of enzymes, and how are they regulated?
Enzymes speed up chemical reactions. Most notably, the enzyme is not consumed during the reaction and can be used repeatedly by the cell. Enzymes can also be regulated by a cofactor such that in the absence of the proper cofactor, enzymes are inactive while in its presence enzymes are active.
9. What are the two main strategies for replenishing cellular concentrations of NAD+, and when these strategies be utilized?
Fermentation and Respiration are the two strategies used by the cell to convert NADH (end product of glycolysis) back to NAD+. Fermentation occurs in the absence of oxygen (anaerobic conditions) while respiration occurs under aerobic (presence of oxygen) conditions. Notably, respiration is more efficient that fermentation.
10. An individual infected with HIV is placed on anti-retroviral medication. What is the general purpose of this medication?
As the name suggests, anti-retrovirals are intended to inhibit (anti) the life cycle of retroviruses (retro). By inhibiting steps in the HIV’s lifecycle, anti-retroviral medications effectively block the production of new virus particles and lower the viral load of the patient.
11. T/F: The reactants of the TCA cycle directly enter and fuel the electron transport system
False. The products of the TCA cycle (reduced electron carriers) enter and drive the production of ATP via the electron transport system.
12. Which of the following microorganisms are considered to be Eukarya? Select all that apply.
Animalia
Plantae
Fungi
Protista
Answer: All of them
13. The combination of the cell membrane and the outer membrane is referred to as the
Cellular envelope
14. Microorganisms classified as _________ obtain most of their energy by converting light energy into chemical energy.
Plantae
15. What is an obligate intracellular parasite?
Viruses cannot replicate unless inside a living host cell. As a parasite, a virus depends on its living host to provide the framework (proteins, etc) to replicate—to make additional copies of itself.
16. Describe the main underlining differences between the Salk and Sabin polio vaccine.
The Salk vaccine contained an inactivated form of the virus and was injected while the Sabin vaccine contained a live attenuated (weakened) form of the virus and was administered orally.
17. What happens if valves inside the veins do not work? Why?
Answer: If the valves do not work and do not close, then the blood is able to flow in the wrong direction. This can cause blood pooling in the legs. Reasons why valves may be damaged are age, long sitting, or reduced mobility overall.
Varicose veins due to backflow of blood which then becomes visible in the skin.
18. Match the following symptoms with their respective diseases:
1. Folliculitis
2. Scalded-skin syndrome
3. Impetigo
4. Conjunctivitis
5. Ophthalmia Neonatorum
A. Childhood skin disease near mouth/nose
B. Infection of thin, transparent scleral tissue
C. Infection occurs at time of birth
D. Pus-filled lesions on skin or hair
E. Ruptured pustules; treated with Penicillin
Answer.
1. - D
2. - E
3. - A
4. - B
5. - C
19. Complete the following RNA strand and indicate how many bonds are formed for each complementary pair:
3’ GGUCAUCG 5’
5’ CC AGC 3’
3’ GGUCAUCG 5’
5’ CCAGUAGC 3’
There are 2 bonds formed between A and U, and 3 bonds between G and C.
20. How is the total magnification of an object calculated?
Total magnification is calculated by multiplying the power of the objective and the power of the eyepiece. For instance, a 40x objective with a 10x eyepiece would make an object appear (40 x 10) 400 times larger (400x).
21. Describe the symptoms and treatment regimen for someone infected with Clostridium perfringens.
Clostridium perfringens (also known as Gas gangrene) presents with muscle necrosis, swelling of infected areas, fever and intense gas production. Treatment entails removal of all infected tissue, often resulting in amputation of the affected areas, in conjunction with heavy antibiotic therapies.
22. True or False. You would expect to see a viral envelope on a virus infecting a plant cell.
False. The overwhelming majority of animal viruses are enveloped whereas the majority of plant or bacteria-infecting viruses are not.
23. What is a cofactor? And give a general example.
Answer: metal ions are cofactors. Cofactors assist enzymes in the catalysis of reactions.
Rationale: a cofactor is a small chemical component that helps an enzyme during the catalysis reactions. A cofactor is usually metal ions.
24. Assuming a fixed ocular, identify the part of the microscope you would adjust to enhance the magnification of a sample.
A. Objective
B. Condenser
C. Iris diaphragm
D. Eye piece
Answer: A. Only the oculars (eyepiece) and the objectives contribute to the magnification of the sample. Since the eyepiece is fixed, only the objectives could be altered.
25. Identify the following disease:
A. Tetanus
B. Anthrax
C. Gas gangrene
D. Frost bite
B. Anthrax—the distinct black center at the site of infection is a hallmark of anthrax infection.
26. Place the following viral life cycle steps in order beginning with viral attachment and provide a description of each step.
Uncoating
Release
Replication
Attachment
Entry
New infection
Answer:
3- Uncoating: the viral capsid disassembles
5-Release: New virus particles are produced and leave the cell
4-Replication: the viral genome is the ‘blueprint’ to make copies of itself
1-Attachment: viral receptors bind to host proteins on the surface of the cell
2-Entry: the virus fuses with the host membrane and enters the cell
6-New infection: newly produced viruses that left the host cell now go on to infect new cells.
27. True or False. Pathogenic strains of bacteria tend to grow slower than normal non-pathogenic bacterial strains.
False. Pathogenic strains of bacteria tend to grow faster than non-pathogenic strains at 37°C, which is why researchers may set incubators at 25°C to restrict its growth.
28. While traveling abroad, should you be worried about coming into contact with either the Variola major or Variola minor viruses?
No. Both viruses are variants of smallpox and were eradicated in 1977. You would not need to worry about coming into contact with the virus.
29. Identify the enzyme associated with the following enzymatic reactions:
A-B → B-A
Ab + C → A + Cb
Answer: Isomerases and Transferases
30. The plasma membrane (select all that are true):
A. Restricts movement of materials in and out of the cell
B. Is often a triple layer comprised of lipids
C. Prevents essential nutrients from escaping
D. Contains hydrophobic tails pointing outward?
A;C
31. Why does the alpha toxin (perfringolysin) produced during an infection of gas gangrene cause cell death?
The toxin perforates the membrane. It forms pores in the plasma membrane of host cells resulting in uncontrolled ion fluxes and eventually cell lysis and death.
32. The function of the mitochondria is (select all that apply):
A. Lipid synthesis
B. Protein synthesis
C. To produce energy (ATP)
D. Protein modification and distribution
E. Waste disposal via hydrolytic enzymes
C
33. Which of the following would not qualify as a macro molecule.
A. Triglyceride
B. Sucrose
C. Phosphatidylinositol
D. Transthyretin
E. Cellulose
Answer: B. Sucrose
Sucrose is a disaccharide.
34. In a three-phase dilution gradient, which phase most likely contains individual colonies: phase 1 (P1) or phase 3 (P3)?
Individual colonies are most likely going to appear within the phase 3 streaks. You begin with P1 (highest concentration), dilute during P2 and then further dilute the sample in P3. However, it is possible to see individual colonies in P2 if only a small portion of P1 was carried over into P2.
35. The binding of an allosteric inhibitor to an enzyme causes the rate of production formation by the enzyme to decrease. Which of the following best explains why this decrease occurs?
A. The allosteric inhibitor binds to the substrate and prevents it from binding at the active site.
B. The allosteric inhibitor includes a structural change in the enzyme that prevents the substrate from binding at the active site.
C. The allosteric inhibitor causes free energy change of the reaction to decrease.
D. The allosteric inhibitor lower the activation energy of the enzyme.
E. The allosteric inhibitor binds to the active site, preventing the substrate from binding.
B. The allosteric inhibitor includes a structural change in the enzyme that prevents the substrate from binding at the active site.
36. True or False: Viral replication occurs after it attaches and enters the host cell. True. The viral genome is never replicated before attachment and entry.
True. The viral genome is never replicated before attachment and entry.
37. Describe the main differences between lytic and temperate phages.
Lytic bacteriophages replicate within the host bacteria until it ruptures, whereas temperate
(Or lysogenic) phages primarily exist in a non-replicative state that does not kill the host cell.
Lytic phages replicate all viral proteins needed for the assembly of new virus particles whereas lysogenic phage genomes are integrated into the host genome but production of viral proteins is suppressed.
38. Identify what type of electron microscope was used to capture the following image and explain your choice.
The image was captured using a Scanning Electron Microscope (SEM). The above image shows the trademark ‘shell’ image (no subcellular organelles are visible) reminiscent of SEM. Only TEM is capable of visualizing subcellular substructures.
39. True or False . The viral capsid of HIV is dumbbell shaped and contains -2,000 copies of the viral protein p24
False
40. How are the TCA and ETC related?
The end products of the Kreb's (TCA) cycle are used to fuel the electron transport chain. In other words, as the Kreb's cycle (TCA) produces an abundance of reduced electron carriers (NADH and FADH2), it fuels the ETC. As the electrons are transferred from NADH/FADH2 to terminal electron acceptors a proton motor force is generated, ATP synthase is activated and up to 34 molecules of ATP can be produced.
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