Tag: bacteria; benefits and harmful effects

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Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

DNA of Escherichia coli is

  1. dsDNA and circular

  2. dsDNA and linear

  3. ssDNA and linear

  4. ssDNA and circular.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Escherichia coli is a Gram-negative, facultatively anaerobic bacteria. It is found in the intestine of warm-blooded organisms. It has one circular chromosome. The chromosome contains double-stranded DNA. It may contain some circular plasmids as well as extrachromosomal material.

Thus, the correct answer is option A.

Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Mitochondria are absent in

  1. Bacteria

  2. Red Algae

  3. Green Algae

  4. Brown Algae.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
  • Mitochondria are absent in bacteria and blue-green algae.
  • A prokaryotic cell lacks membrane-bound cell organelles and nucleus whereas, a eukaryotic cell consists of membrane-bound cellular organelles and well-defined nucleus.
  • Red algae, green algae and brown algae have eukaryotic cells (well-defined nucleus and cellular organelles).
  • So, the correct answer is 'Bacteria'.
Multiple choice botany bacteria bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Alga Acetobularia is

  1. Unicellular prokaryote.

  2. Multicellular prokaryote.

  3. Unicellular eukaryote.

  4. Multicellular eukaryote.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Acetabularia is a single-celled green photosynthetic algae which contain chloroplasts of the photosynthetic function. Being unicellular it has a complex shape and has been a model organism for the study of gene expression with morphogenesis. It has a large nucleus which contains a genetic material. Because of the presence of nucleus which is absent in prokaryote, these algae is classified in eukaryotes. hence algae Acetabularia is a unicellular eukaryote.

Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Bacteria with tuft of flagella at one pole are

  1. Amphitrichous

  2. Peritrichous

  3. Atrichous

  4. Lophotrichous
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A. Amphitrichous bacteria have flagella (single or multiple) extending from both ends of the cell.

B. Peritrichous bacteria have flagella projecting in all directions around the cell.
C. Atrichous bacteria lack flagella. 
D. Lophotrichous bacteria have a tuft of flagella located at the same point on the bacterial cell.
So, the correct answer is 'Lophotrichous'.

Multiple choice botany the world of microbes bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Bacteria having a tuft of flagella at both the poles are

  1. Atrichous

  2. Peritrichous

  3. Lophotrichous

  4. Amphitrichous.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Amphitrichous bacteria possess a single flagellum or a tuft of flagella at both poles of the cell. This distinguishes them from peritrichous (all over) or lophotrichous (tuft at one end) arrangements.

Multiple choice botany bacteria bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects

Which one of the following statements correctly disguises Nitrosamines and Nitrobacteria?

  1. Nitrosamines is nitrifying bacterium whereas Nitrobacteria is a denitrifying bacterium

  2. Nitrosamine oxidizes ammonia to nitrite while Nitrobacteria oxidizes nitrite to nitrate

  3. Nitrosamine fixes atmospheric nitrogen into ammonia while Nitrobacteria oxidizes ammonia to nitrate

  4. Nitrosamines is responsible for amino acid synthesis while Nitrobacteria is responsible for protein synthesis
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice botany bacteria bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

$NH _3$ in amoeba is excreted through

  1. Food vacuole.

  2. Contractile vacuole.

  3. Plasma membrane.

  4. Both B and C.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Amoeba is a unicellular organism. The main waste material in amoeba ammonia (NH$ _3$) along with carbon dioxide (CO$ _2$). The waste material is excreted through body surface (plasmalema) by the process of diffusion. In this process, contractile vacuoles play important role.

Thus, the correct answer is option B.

Multiple choice botany bacteria bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

Entamoeba histolytica is transmitted through

  1. Insect bite

  2. Bird dropping

  3. Improperly cooked pork meat

  4. Food or water contaminated with cysts
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Entamoeba histolytica is a protozoan protist. It is pathogenic in nature. It resides in the upper part of the human large intestine and causes the disease known as amoebic dysentery or amoebiasis. The symptoms of the disease are abdominal pain, repeated motions with blood and mucus. Entamoeba histolytica is transmitted through food or water contaminated with cysts. A mature cyst is called quadri-nucleate cyst. It has four nuclei and two chromatid bodies. Quadrinucleate cyst is the infective stage.

Multiple choice botany bacteria bacteria - introduction, shape and structure bacteria: types and structure bacteria; benefits and harmful effects non cellular organism : virus world of virus

How many young Amoebae hatch out from a cyst of E. histolytica?

  1. One

  2. Two

  3. Four

  4. Six
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Entamoeba histolytica is a protozoan protist. It is pathogenic in nature. The type of nutrition present in Entamoeba is parasitic. The parasite is generally with one pseudopodium. The contractile vacuole is absent as there is no need of osmoregulation. It feeds on red blood corpuscles by damaging the wall of the large intestine and reaching the blood capillaries. It produces ulcers. It resides in the upper part of the human large intestine and causes the disease known as amoebic dysentery or amoebiasis. Entamoeba histolytica is transmitted through food or water contaminated with cysts. A mature cyst is called quadri-nucleate cyst. It has four nuclei and two chromatid bodies. Quadrinucleate cyst is the infective stage. Only one young Amoeba with four nuclei hatches out from a cyst of Entamoeba histolytica. However, single cyst of Entamoeba histolytica produces eight Amoebae.