ORDINARY THINKING
Objective questions.
1. The DNA of E. Coli is
a) single stranded and linear
b) single stranded and circular
c) Double stranded and linear
d) Double stranded and circular
Answer. d) Double stranded and circular.
Reason.
The bacterium E. Coli have double stranded circular DNA. Many genetical researches are carried out on E. Coli for the study of genetic engineering.
2. The structure that help some bacteria to attach to rocks and for host tissues are
a) Fimbriae b) Mesosomes c) Holdfast d) Rhizoids
Answer. a) Fimbriae.
Reason.
Fimbriae are more in number, short thin straight bristle like appendages which function as organ of adhesion. Pili are similar to fimbriae but different in function.
3. Genes for antibiotic resistance are located in
a) Chromosome
b) Nucleus
c) Cell wall
d) Plasmid
Answer. d) plasmid.
Reason.
R factor is a type of plasmid which contains genes for antibiotic resistance.
4. Infloding of the plasma membrane of gram positive bacteria, gives rise to
a) Clathrin
b) Chondritin
c) Chondrioides
d) Chromatin
Answer. c) Chondrioides.
Reason.
Respiratory enzyme containing infloding of plasma membrane in bacteria called chondrioid.
5. The term glycocalyx is used for
a) A layer present between cell wall and membrane of bacteria.
b) cell wall of bacteria
c) Bacterial cell glyco- engineered to possess N- glycosylated proteins
d) A layer surrounding the cell wall of bacteria.
Answer. d) A layer surrounding the cell wall of bacteria.
Reason.
The cell envelope in bacteria consists of a tightly bound three layered structure ie) the glycocalyx followed by the cell wall and then plasma membrane.
6. Archaebacteria differ from eubacteria in
a) Cell shape
b) Mode of reproduction
c) cell membrane structure
d) Mode of nutrition
Answer. c) Cell membrane structure.
Reason.
Cell membrane of archaebacteria possesses branched chain lipids.
7. Which structures perform the function of mitochondria in bacteria.
a) cell wall
b) mesosomes
c) Nucleoid
d) Ribosomes
Answer. b) Mesosomes.
Reason.
Mesosomes help in respiration, secretion processes, to increase the surface area of the plasma membrane and enzymatic contact.
8. Which one of the following natching pairs is WRONG.
a) Bacterial cell wall- cellulose.
b) Bacterial ribosome- 16s rRNA
c) Bacterial flagella- protein
d) Bacterial glycocalyx- cellulose
Answer. a) Bacterial cell wall- cellulose.
Reason.
Bacterial cell wall is made of peptidoglycan.
9. Methanogens belong to
a) Slime moulds
b) Eubacteria
c) Archaebacteria
d) Dinoflagellates
Answer. c) Archaebacteria.
Reason.
Methanogens, halophiles and thermoacidophiles are archaebacteria.
10. Bacterial cell divides in every minute it takes one hour to fill up a cup. How much time will be taken to fill half the cup.
a) 59 minutes
b) 30 minutes
c) 60 minutes
d) 29 minutes
Answer. a) 59 minutes.
Reason.
The number of bacteria becomes double after each division.
Dr. A. KINGSLIN M.Sc, BEd, Phd
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