Question

26.

Which of the following statements is TRUE?

	A.	All eukaryotic cells contain both DNA and RNA, while prokaryotic cells contain only DNA.
	B.	A slime layer is a rigid, organized form of glycocalyx produced by some bacteria.
	C.	A bacterium classified as atrichous has one flagellum at each pole.
	D.	Runs result from flagella turning in a counterclockwise motion.
	E.	All of the above are true.

30.

Both skin and mucous membranes function well as barriers to infection because their cells are constantly shed and replaced.

True

False

33.

Which of the following statements concerning development of antibiotic resistance is  FALSE?

		Resistance genes can be acquired through transformation, transduction, or conjugation.
		Antibiotic resistance is often mediated by R-plasmids.
		Antibiotics cause bacteria to create new resistance genes.
		Resistant cells are normally in the minority in a bacterial population.
		Resistance can occur through mutation of existing bacterial genes.

34.

Which of the following is FALSE?

	A.	The most dangerous pathogens would require BSL-1.
	B.	Physical controls are the usual choice for disinfection, antisepsis, and preservation.
	C.	There are many antibacterial drugs because there are so many differences between pro- and eukaryotic cells.
	D.	Once viruses complete the Entry phase, they cannot be harmed by antibodies or antivirals.
	E.	Both A and B are false.

Answer 1

26.

A) false. eukaryotes and prokaryotes both have rna as well as dna. in prokaryotes rna is formed after transcription and also present with protein as ribosomes.

B) FALSE. slime layer is not rigid infact it is an easily removable layer which is an unorganised structure. it contains exopolysaccharide, glycoprotein and glycolipid.

C) FALSE. bacteria which have one flagella at each pole is known as Amphitrichious. Atrichous are those which do not have any falgella.

D) TRUE. When the flagella rotate counter-clockwise, they cause a swimming motion or a run, and when they rotate clockwise, they cause a tumble.

30. TRUE. but apart from this skin also has keratin which inhibits the growth of bacteria and make it resistant to get degraded by bacterial enzyme.mucous is thick so its traps the pathogen and remove it.

33.

A) TRUE. these three methods are ways by which genes get transferd among bacteria. transformation- foreign DNA is acquired from surroundings transduction- foreign DNA is acquired by viral infection conjugation. by temporary union of two bacteria.

B) TRUE. R plasmid have r determinatns or r factor which contain the genes for antibiotic resistant.

C) The statement is debatable wether antibiotic creates resistant or they already have tha power which become observable during selection by antibiotic.

D) TRUE. resistant cells are present in minority they become numerous only when selection by antibiotics occur because antibiotic kills the non resistant cells.

E) TRUE. random mutation can alter the genetic code which can make new molecule or enzyme which can provide the resistant to the bacterial cells.

34

A) FALSE . BSL stands for bio saftey level. BSL 1 is the lowest bio saftey level which does not provide any protection against harmful bacteria. FOR most dangerous bacteria BSL 4 is used which have equipments with latest technology and provide highest saftey level.

B) FALSE. physical control means controlling microorganisms by regulating the physical paramters like heat , temperature and pressure. Disinfectant and antiseptics come under chemical control. anti

C) FALSE . Virus can be harmed by antivirals such as  zidovudine  lamivudine act after the entry during replication.