The morphology, or shape, of a bacteria is its most distinctive feature. Morphology is a distinctive trait of a specific species. The morphology of a bacterium cell dictates its shape, as well as the pathogenicity of the bacteria. Bacterial morphological traits influence their adaptation and evolution. The peptidoglycan (murein) is a sugar polymer in the bacterial cell wall that alternates N-acetylglucosamine (NAG) with N-acetylmuramic acid (NAM) & amino acids in the peptide chain. Changes in the structure and thickness of the polymer cause changes in the morphology and shape of bacteria.
Q1. Which of the following bacteria is resistant to penicillin since it lacks a cell wall?
- Spirochetes
- Mycoplasmas
- Cyanobacteria
- Bdellovibrios
Answer. Mycoplasmas is the correct answer as Mycoplasmas lacks a cell wall and is also resistant to penicillin.
Q2. Cluster of polar flagella are termed as-
- Peritrichous
- Amphitrichous
- Lophotrichous
- Monotrichous
Answer. Lophotrichous is the correct answer. Bacteria that have numerous flagella at 1 polar end or several flagella at one location are called lophotrichous.
Q3. Which of these is a single or double occuring cocci?
- Diplococci
- Tetracocci
- Streptococci
- None of the above
Answer. Diplococci is the correct answer as Diplococci occurs in single or in pairs.
Q4. Flagella in bacteria enable bacteria to
- reproduce
- locomote
- Adhere to the tissue surfaces
- Thrive in the nutrient agar
Answer.Locomotive is the correct answer as Flagella in bacteria enables bacteria to move.
Q5. Which of these is found on a gram-negative bacterium’s outer surface?
- Braun lipoprotein
- Polysaccharide portion of lipoteichoic acid (LTA)
- O- antigen of lipopolysaccharide (LPS)
- Components of Electron transport system
Answer. O – antigen of lipopolysaccharide (LPS) is the correct answer. Since it is found on a gram-negative bacterium’s outer surface.
Q6. Which of the following is true about gram-negative bacteria?
- Cell wall made up of various layers
- Cell wall made up of teichoic acids
- The cell wall is thicker as compared to the related gram-negative bacteria
- All the above
Answer. All the above is the correct answer. Since, the cell wall of gram-negative bacteria is made up of various layers & teichoic acids and also the cell wall is thicker than other gram-negative bacteria.
Q7. The covalent connection that connects the cell walls of gram-positive bacteria that contain two modified sugars, N-acetylmuramic acid (NAM) & N-acetyl glucosamine (NAG), is called-
- Glycosidic Bond
- 1,4-Glycosidic Bond
- Glycosidic Bond
- 1,6-Glycosidic Bond
Answer. 1,4-Glycosidic Bond is the correct answer. A covalent link between -OH group on carbon 1 of one sugar & -OH group on carbon 4 of another sugar is defined as a 1,4-glycosidic bond.
Q8. Which of the following has Chinese letter arrangement?
- Clostridium Tetani
- Corynebacterium Diphtheriae
- Bacillus Anthracis
- Mycobacterium Tuberculosis
Answer. Corynebacterium Diphtheriae is the correct answer. Corynebacterium Diphtheriae has Chinese letter arrangement.
Q9. Bacteria with helically curved rods are known as
- Cooci
- Bacillus
- Pleomorphic
- Spirilla
Ans. Spirilla is the correct answer. Spirilla is bacteria with helically curved rods.
Q10. Sterols are found in the cytoplasmic membrane of which of the following organisms?
- Mycoplasma
- Clostridium
- Proteus
- Bacillus
Answer. Mycoplasma is the correct answer. Sterols are found in the cytoplasmic membrane of Mycoplasma.
Q11. Lipopolysaccharide is a key element of the cell-wall’s outer membrane in which of the following?
- Gram-Negative Bacteria
- Gram-Positive Bacteria
- Fung
- None of these
Answer.Lipopolysaccharide is the correct answer. Lipopolysaccharide is a key element of the cell-wall’s outer membrane of Gram-Negative Bacteria.
Q12. Chemotaxis is a
- Moving in the direction of a bacteria
- Swimming away of the bacteria
- Swimming towards or away from a bacteria in the presence of a chemical substance
- None of the above
Answer. The right answer is Swimming towards or away from a bacteria in the presence of a chemical substance. Since, chemotaxis refers to the movement of cells away from repellent chemicals and toward attractant chemicals.
Q13. The analogous to mesosomes of the bacteria is
- Golgi apparatus of the Eukaryotes
- Lysosomes of the Eukaryotes
- Mitochondria of the Eukaryotes
- None of these
Answer. Mitochondria of the Eukaryotes is the right answer. Mesosomes carry out respiration in the bacterium since mitochondria are the site of the respiration.
Q14. Teichoic acids are basically found in
- Cell walls of the gram-positive bacteria
- Outer membrane of the gram-positive bacteria
- Outer membrane of the gram-negative bacteria
- Cell walls of the gram-negative bacteria
Answer. Cell walls of the gram-positive bacteria is the right answer.
The Gram +ve bacteria’s cell wall is made up of many layers of peptidoglycans with groups of teichoic acid molecules running perpendicular to them. Teichoic acids are responsible for providing stiffness to the cell wall by attracting cations like magnesium and sodium.
Q15. Fimbriae can be found in which of the following?
- Gram – Positive Bacteria
- Gram – Negative Bacteria
- Both (A) and (B)
- None of the above
Answer. The correct answer is Gram – Negative Bacteria. Fimbriae are tiny protein tubes that originate from cytoplasmic membrane of Gram-negative bacteria but are absent in Gram-positive bacteria.
Q16. The protein that makes up the hook and filaments of the flagella is called
- Keratin
- Gelatin
- Flagellin
- Casein
Answer. The correct answer is Flagellin. Flagellin is the protein that makes up the hook and filaments of the flagella.
Q17. The genetic system is found in prokaryotes in
- Nucleoid
- Chromatin
- Nuclear Material
- All of the above
Answer. The correct answer is all the above. The genetic system is found in prokaryotes in nucleoid, nuclear material and also chromatin.
Q18. The enzyme which may easily damage the cell walls of various gram – positive bacteria is termed as
- Lipase
- Pectinase
- Lysozyme
- Peroxidase
Answer. The correct answer is Lysozyme. Many gram-positive bacteria’s cell walls can be easily dissolved by the enzyme lysozyme.