Mycobacteria

Characteristic features of mycobacteria are:

1. Slender rod shaped bacteria
2. Lipid rich cell wall
3. Acid fast

Major diseases caused by mycobacteria:
1. Leprosy
2. Tuberculosis

Viruses

Multiple Choice Questions from Viruses in Microbiology

1. Foot and mouth viruses are approximately of the size?

a. 10 µm

b. 100 µm

c. 150 µm

d. 250 µm

-----------------------

2. Influenza virus has which of the following symmetry?

a. Helical

b. Icosahedral

c. Complex

d. None of the above

------------------

3. Poliomyelitis virus has which of the following symmetry?

a. Helical

b. Icosahedral

c. Complex

d. None of the above

--------------------

4. Interferons are

a. Antigenic proteins of low molecular weight

b. Antigenic proteins of high molecular weight

c. Antibodies of low molecular weight

d. Antibodies of high molecular weight

-------------------

5. Viruses are classified according to

a. Type of nucleic acid

b. Symmetry of the capsomeres

c. Presence or absence of an envelope

d. All of the above

--------------------

6. Viruses related to geometrical factors are classified into

a. Orders

b. Families

c. Genus

d. Species

---------------------

7. Antigenic properties and  effects on living tissues are used to place viruses into

a. Orders

b. Families

c. Genus

d. Species

---------------------

8. Which of the following is RNA virus?

a. Napoviridae

b. Herpesviridae

c. Poxviridae

d. Both a and c

Answers of Multiple choice questions (MCQs) of Viruses in Microbiology

1. a
2. a
3. b
4. a
5. d
6. b
7. c
8. a

---------------------------
Further Reading:
Clinical Microbiology Made Ridiculously Simple (Medmaster) 

Microbiology the Easy Way (Barron's E-Z Series)


Microcards: Review Cards for Medical Students


Rapid Review Pathology: With STUDENT CONSULT Online Access


Deja Review Microbiology & Immunology

Ricketssiae

Multiple Choice Questions from Rickettsiae in Microbiology

1. Rickettsiae are much closely related to

a. Bacteria

b. Viruses

c. Yeast

d. Fungi

-------------------------

2. Rickettsiae are primarily parasites of

a. Annelida

b. Echinodermytes

c. Nematoda

d. Arthropoda

---------------------

Answers of Multiple choice questions (MCQs) of Rickettsiae in Microbiology

1. a
2. d

--------------------
Further Reading:
The cultivation of viruses and rickettsiæ in the chick embryo, (Medical research council)

Methods and Applications in Comparative Bacterial Genomics - Studying Microevolution in Action

Microbiology the Easy Way (Barron's E-Z Series)

Microbiology: Principles and Explorations

Microbiology: A Systems Approach

Prescott/Harley/Klein's Microbiology

Bacteria

Multiple Choice Questions from Bacteria in Microbiology

1. Which of the following structures is external to cell wall of bacteria?

a. Spheroplasts

b. Membranous Intrusions

c. Prosthecae

d. Both b and c

-------------------

2. Spherical shaped bacteria are referred to as 

a. Cocci

b. Bacilli

c. Spirilla

d. Pleomorph

--------------------

3. Straight rod shaped bacteria are referred to as 

a. Cocci

b. Bacilli

c. Spirilla

d. Pleomorph

---------------------

4. Rod shaped bacteria that are helically curved are referred to as

a. Cocci

b. Spirilla

c. Pleomorph

d. Bacilli

--------------------

5. Staphylococcus and lactobacillus are ________ in shape.

a. Bacilli and Spirilla respectively

b. Spirilla and Cocci respectively

c. Cocci and Bacilli respectively

d. Spirilla and Bacilli respectively

-------------------

6. Long branched, multinucleate filament called hyphae collectively form

a. Trichomes

b. Palisade Arrangement

c. Mycelium

d. Hypha

-----------------

7. A flagellum on bacteria is composed of 

a. 1 part

b. 2 parts

c. 3 parts

d. 4 parts

------------------

8. Directed swimming of bacteria towards various chemical compounds is referred to as 

a. Chemotaxis

b. Positive chemotaxis

c. Negative chemotaxis

d. Both a and b
-----------------
9. Which of the following statement regarding bacteria is true?

a. Slime layer is outside the capsule
b. Capsule is outside the slime layer
c. Cell wall is outside the capsule
d. Capsule is outside the cell wall
----------------
10. Capsule is made up of

a. Polysaccharide
b. Polypeptide
c. Both a or b
d. None of the above
---------------
11. Which of the following is the function of slime layer regarding bacteria?

a. It is important in immunity
b. It is important in dextran manufacture
c. It protects bacteria against changes of environment
d. All of the above
----------------
12. Which of the following form a matrix in the cell wall of bacteria?

a. Polypeptides and muramic acid
b. Polysaccharides and muramic acid
c. Polysaccharides and mucin
d. Polypeptides and mucin
-----------------
13. Flagellum is an outgrowth of

a. Cell wall
b. Cell membrane
c. Protoplasm
d. Nucleus
-----------------
14. Which of the following is the most important function of fimbria?

a. Attachment
b. Transfer of genetic material
c. Movement
d. Both a and b
-------------------
15. Certain bacteria can produce resting body (spores) in unfavorable conditions which is

a. Outside the cell wall
b. Within the cell wall
c. Outside the capsule
d. Within the cell membrane
----------------
16. Which of the following are the sites of protein synthesis?

a. Nucleus
b. Mitochondria
c. Ribosomes
d. Vacuoles
-----------------
17. Which of the following is required by bacteria in trace quantities?

a. Sulphur
b. Potassium
c. Iron
d. Zinc
------------------
18. Most of the bacteria pathogenic to man and animals belong to

a. Psychrotrophs
b. Mesophils
c. Thermophils
d. None of the above
------------------
19. The optimum temperature range for mesophils is

a. 0-25 C
b. 25-45 C
c. 45-55 C
d. 45-65 C
-------------------
20. Organisms that are very resistant to heat treatments are said to be

a. Psychrotrophs
b. Mesophils
c. Thermophils
d. Thermoduric
-------------------
21. Escherichia coli divides about every

a. 20 minutes
b. 30 minutes
c. 1 hours
d. 2 hours
------------------
22. Introduction of small portions of DNA into the nuclear material as a result of invasion by temperate phages, shows

a. Recombination
b. Conjugation
c. Transformation
d. Transduction

----------------------

Answers of Multiple choice questions (MCQs) of bacteria in Microbiology

1. c

2. a

3. b

4. b

5. c

6. c

7. c

8. d
9. d
10. c
11. d
12. a
13. c
14. d
15. b
16. c
17. d
18. b
19. b
20. d
21. a
22. d

----------------------

Further Reading:

Microbiology the Easy Way (Barron's E-Z Series)

Microbiology: A Systems Approach

Microbiology: Principles and Explorations

Microbiology: An Introduction, 9th Edition (Book & CD-ROM)

Microbiology: An Evolving Science

Fermentation

Introduction:
More commonly, fermentation is the conversion of biological materials, by enzymes, into carbon dioxide and alcohol. This is particularly for the utilization of foodstuffs.

The Merriam-webster Dictionary defines fermentation as:
"an enzymatically controlled anaerobic breakdown of an energy-rich compound (as a carbohydrate to carbon dioxide and alcohol or to an organic acid) ; broadly : an enzymatically controlled transformation of an organic compound".

Fermentation is the process of creating energy through the oxidative process of organic compounds, such as carbohydrates, by the use of endogenous electron acceptor. Fermentation is mostly carried out in an anaerobic environment. But some yeast cells also cause fermentation in the presence of oxygen (more or less) as long as sugar is there for consumption.

Reaction:
In the fermentation process, if we take the example of glucose, following reaction takes place:

Glucose (Sugar)----->Ethanol (Alcohol) + CO2 + Energy (in the form of ATP)

The early stages of this reaction follows part of the glycolysis pathway but most of the pathways depends on the sugar involved or used. The later stages of the pathway depends on the product obtained.

Processes of fermentation:
Primary fermentation: This is first step in the fermentation process, which involves the conversion of sugar to alcohol and carbon dioxide. This usually starts when we add yeast (or bacteria) to the organic compound and it starts to multiply and starts feeding on the fermentable sugars. Many of the aroma compounds are also produced durign the primary fermentation process. In human beings also, cells use fermentation as the first step in breaking down sugar.


Secondary fermentation: Stage of fermentation occuring from several weeks to several months. It is also referred to as "Malolactaic fermentation". Here, bacteria converts the malic acid to lactic acid. (2) This lactic acid in human beings is further broken down by the process of respiration and results in carbon dioxide and water. (This lactic acid accumulates in our muscles and causes pain, if we exert ourselves.)

Types of Fermentation:
Photofermentation: This is the type of fermentation that takes place by photosynthetic bacteria in the presence of light and involves the same steps as in the anaerobic conversion.

Dark fermentation: This fermentation takes place in the absence of light and involves the same steps as those of anaerobic conversion.

Thermophilic fermentation: Fermentation takes place in heating environment.

Uses of Fermentation:
(Michael D. Flythe et al.)Mankind has used fermentation to preserve animal feed for thousands of years. (1) Fermentation takes place in the large intestine of almost animals but in carnivores and omnivores, it produces very few calories but in case of herbivores this is the major cause of energy production. (2) Yeasts produce alcohols from sugars and this is used to produce spirits and ethanol. CO2 produced during the fermentation process is used to cause bubbles in bread. Bacteria which are used in the lactic acid formation are used in cheese making process and in making buttermilk, sour cream and yogurt.
(Ghasem Najafpour) In world war I, Germany found that glycerol can be generated from alcoholic fermentation. They developed an industrial scale fermentation process with a yield capacity of 1000 tons of glycerol per month.

References:
(1) http://www.vivo.colostate.edu/hbooks/pathphys/digestion/largegut/ferment.html

(2) http://www.historyoftheuniverse.com/ferment.html

Ghasem Najafpour. Chapter 10 - Application of Fermentation Processes. Biochemical Engineering and Biotechnology, 2007, Pages 252-262.

Michael D. Flythe, James B. Russell. Fermentation acids inhibit amino acid deamination by Clostridium sporogenes MD1 via a mechanism involving a decline in intracellular glutamate rather than protonmotive force. Microbiology 152 (2006), 2619-2624

Further Reading:
Fermentation Microbiology and Biotechnology, Second Edition by E. M. T. El-Mansi, C. F. A. Bryce, Arnold L. Demain and A. R. Allman

Practical Fermentation Technology by Brian McNeil and Linda Harvey

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