Tag: world of virus

Questions Related to world of virus

$NH _3$ in amoeba is excreted through

  1. Food vacuole.

  2. Contractile vacuole.

  3. Plasma membrane.

  4. Both B and C.


Correct Option: D
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.

Entamoeba histolytica is transmitted through

  1. Insect bite

  2. Bird dropping

  3. Improperly cooked pork meat

  4. Food or water contaminated with cysts


Correct Option: D
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.

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

  1. One

  2. Two

  3. Four

  4. Six


Correct Option: A
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.

Which one of the following is the most important criterion used to classify living organisms into three primary kingdoms, namely-Archaea, Eubacteria and Eukarya?

  1. Genetic relatedness

  2. Morphological characters

  3. Physiological characters

  4. Phenotypic characters


Correct Option: A

Rhodopseudomonas and Rhodospirillum are ______________.

  1. Purple non-sulphur bacteria

  2. Green non-sulphur bacteria

  3. Green sulphur bacteria

  4. Purple sulphur bacteria


Correct Option: A

Yeast die when alcohol concentration reaches about $13$%, still yeast perform alcholic fermentation why?

  1. To obtain ATP

  2. Utilization of $O _{2}$

  3. For oxidation of $NADH _{2}$

  4. Obligate aerobic


Correct Option: A

Cell division is a type of reproduction in 

  1. Unicellular organisms

  2. Multicellular organisms

  3. Both A and B

  4. None of the above


Correct Option: A
Explanation:

Cell division is the process in which a parent cell divides into two or more daughter cells. The unicellular organism divides and results in the formation of daughter cells and hence, cell division is a type of reproduction in unicellular organisms. Thus, the correct answer is option A.

Choose the correct answers from the alternatives given.
Surface appendages used by -bacteria to attach to one another and to host organisms are called:

  1. thylakoids

  2. mesosomes

  3. pili

  4. spirilla


Correct Option: C
Explanation:
A pilus is a thin, rigid fiber made of protein that protrudes from the cell surface. The primary function of pili is to attach a bacterial cell to specific surfaces or to other cells. So, the correct option is 'pili'.

Which of the following organisms do not depend on reproduction to exchange genetic information?

  1. Animals

  2. Plants

  3. Bacteria

  4. Fungi


Correct Option: C
Explanation:

Bacteria have three mechanism for genetic information transfer without undergoing reproduction-
1. Transformation- take up free fragment of DNA floating in medium. 
2. Transduction- transfer of DNA by a virus bacteriophage.
3. Conjugation- direct cell to cell transfer of DNA mediated by plasmid. So, option C is correct, all other options depend on reproduction for exchange of genetic material.

Select the pair that shows the same relationship as the animals in the box.
Amoeba : Paramecium.

  1. Rhizopus : Chlamydomonas

  2. Candida : Saccharomyces

  3. Pteridium : Fasciola

  4. Albugo : Adiantum


Correct Option: A