Question

True (a) or false (b) 14. An acidic dye will bind more readily to the nucleic acids of a bacterial cell than a basic dye. d) 15. Bacterial cells divide by a process known as: a) meiosis b) mutation c)binary fission Osmosis 16-18. Match the following components of a stain with their correct descriptions A Benzene B. Ionachrome C. Auxochrome D. Chromophore 16. 17. 18. Conveys ionization to the colored component of the stain Colorless solvent of dye Colored component of the stain 19. Which type of staining does NOT require heat fixation? a) simple staining b) spore staining c) Grom staining d) negative staining 20. What factors are necessary for a spore to accept a primary stain? a) rinsing b) application of heat c) first decolorizing d) adding a mordant 21. What is the significance of the heating during the primary stain step in the acid fast a) to kill the cells b)to soften the waxy cell wall c) to decolonized) to create a positive charee the cell 22. Carbol fuschin is a soluble stain that is used for the staining procedure a) peptidoglycan, Gram b) lipid, spore c) lipid, acid fast d) water, acid fast 23. The causative agent of which of the following diseases can be harvested as spores? a) smallpox b) anthrax c) tuberculosis d) leprosy 24. Which of the following sugars in found in peptidoglycan? a) N-acetylmuramic acid b) N-acetylsalicylic acid c) N-acteylglycogen d) choice aande 25. The most accurate Gram Stain are made from cultures that approximately a) 2 hours old b) 24 hours old c) 3 days old d) one week old 26. The act of a free spore reverting to a metabolically active cell is: a) endosporogenesis b)sporogenesis c) germination d) sporulation 27. Extremely cold temperature and depletion of nutrients source may prompt which of the following in a bacterial cell? a) germination b) sporogenesis c) vegetation d) endosporulation

Answer 1

14. The statement is False(b).

Acidic dyes have negatively charged and can bind to positively charged structures. On the other hand, basic dyes have positively charged and can bind to negatively charged structures. Nucleic acid such as DNA is negatively charged and only positively charged basic dyes can bind rapidly to it.

15. The correct statement is c) binary fission

Binary fission is the process by which bacteria divide asexually to produce daughter cells.

16. C) Auxochrome conveys ionization to the colored component of the stain.

Auxochrome cause the ionization of the chromophore which convert them to salts and enable it to bind to tissues.

17. Colorless solvent of the dye is A) Benzene

Benzene doesnot display color because it doesnot have chromophore.

18. Colored component of the stain is D) chromophore.

Chromophore is the component of a stain that give color to the stain.

19. The correct answer is d) negative staining.

A negative staining doesnot stain the cells but they stain the background of cells.They donot require heat fixation. It is used to determine cell size and used for cells that are too delicate to be heat fixed.

20. The correct answer is b) application of heat.

Spores are highly resistant to normal staining procedure because of the tough protein coat. The primary stain for spore is malachite green and is made to enter the cells with application of heat.

21. The correct answer is b) to soften the waxy cell wall.

Heat soften the cell wall and allow the dye to penetrate the cell wall.

22. The correct answer is c) lipid, acid fast.

Carbol fuschin is lipid soluble and is used as a primary stain to detect acid fast bacteria.

23. The correct answer is b) anthrax

Anthrax is caused by Bacillus anthracis and spores can be harvested.

24. The correct answer is a) N- acetylmuramic acid.

Peptidoglycan layer makes the cell wall of bacteria .The peptidoglycan layer is composed of N-acetylglucosamine and N-acetylmuramic acid.

25. The correct answer is b) 24 hours old

The preparations for gram stain are made from fresh culture less than 24 hours old. The ability to retain stain decreases with age of culture.

26. The correct answer is c) germination.

Germination is the process of transition of spore from dormant state to metabolically active cell.

27. The correct answer is d) endosporulation

Endospores enable the bacterial cell to survive in extreme cold temperature, depleted nutrient condition and at high temperature. Endosporulation is the process of formation of spores.