BIO 102 | Study Mode

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Question 1
A
Trypanosoma cruzi 
B
T. rhodesiense 
C
T. tangela 
D
T. gambiense. 
Explanation.
Share Answer Trypanosoma gambiense was first observed by Forde in 1901. It causes African sleeping sickness. The disease, also called trypanosomiasis, is found in western and central parts of Africa. The parasite is transmitted by blood sucking tse-tse fly, Glossina palpalis. Mouth and contractile vacuole are absent. Food is absorbed through the body surface.

The parasite multiplies by fission. In human beings the parasite lives in the blood plasma. It causes trypanosoma fever. It is accompanied by glandular swelling. Later the parasite enters cerebrospinal fluid and damages the brain. It makes the patient lethargic and unconscious. Because of it, the disease is called sleeping sickness. If untreated, the disease leads to death.


Correct Option:
D
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Question 2
A
sarcodina 
B
zoofiagellata 
C
ciliata 
D
sporozoa. 
Explanation.
Share Answer On the basis of locomotory organelles the protozoan protists are divided into four groups : Mastigophora, Sarcodina, Sporozoa and Ciliata. Trypanosoma belongs to class zooflagellata which comes under the group mastigophora. The characteristics are:

(i) These zooflagellates are generally uninucleate, occasionally multinucleate.

(ii) The body is covered by a firm pellicle.

(iii) Nutrition is holozoic, parasitic and saprobic.

(iv) Reserved food is glycogen.


Correct Option:
B
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Question 3
A
Leishmania donovani 
B
Trypanosoma gambiense 
C
Entamoeba histolytica 
D
Plasmodium vivax. 
Explanation.
Share Answer The main vertebrate host is human. The principle invertebrates hosts are tsetse fly of the genus Glossina. T. gambiense is transmitted to human by biting of an infected tsetse fly after the cyclic development of the parasite.

Correct Option:
B
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Question 4
A
Linnaeus 
B
De Candolle 
C
Pliny the Edkr 
D
Bentham and Hooker 
Explanation.
Share Answer Artificial system of classification was first used by Linnaeus. The cryptogams were included in flowering plants. Linnaeus system is known as sexual system of classification. He classified on the basis of number, size and union of sex organs.

Correct Option:
A
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Question 5
A
natural system 
B
artificial system 
C
phylogenetic system 
D
asexual system 
Explanation.
Share Answer Linnaeus put forward an Artificial system of plant classification which was based on sexual characters like cryptogamia, monoecia, monandria, diandria, polyandria etc. It is commonly also called as sexual system of plant classification.

Correct Option:
B
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Question 6
A
housefly 
B
tsetse fly 
C
sandfly 
D
fruit fly. 
Explanation.
Share Answer Trypanosoma gambiense was first observed by Forde in 1901. It causes African sleeping sickness. The disease, also called trypanosomiasis, is found in western and central parts of Africa. The parasite is transmitted by blood sucking tse-tse fly, Glossina palpalis. Mouth and contractile vacuole are absent. Food is absorbed through the body surface.

The parasite multiplies by fission. In human beings the parasite lives in the blood plasma. It causes trypanosoma fever. It is accompanied by glandular swelling. Later the parasite enters cerebrospinal fluid and damages the brain. It makes the patient lethargic and unconscious. Because of it, the disease is called sleeping sickness. If untreated, the disease leads to death.


Correct Option:
B
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Question 7
A
cryptomerozoties 
B
metacryptomerozoites 
C
merozoites 
D
trophozoites. 
Explanation.
Share Answer Symptoms of malaria first appear several days after the infection of the malaria parasite in man. This interval of time or the incubation period is utilized by the parasites to increase their progeny. To establish malarial symptoms, it is necessary that a large number of organisms must continue erythrocytic cycle at a time.

A healthy person acquires infection when a female Anopheles mosquito, containing infective stages of parasite (sporozoites) in its salivary glands, bites him for sucking his blood. Once within the numan blood, the sporozoites get into liverto invade the hepatic cells. Here they multiply asexually by schizogony.

Liver schizogony has two phases, pre-erythrocytic and exo-erythrocytic: Pre-crythrocytic phase: After penetrating a hepatic cell each sporozoite becomes a cryptozoite. It grows for a number of days and becomes a spherical and non- pigmented schizont.

It divides by schizogony (multiple fission) and forms a large number of uninucleate cells, the cryptomerozoites. During pre-erythrocytic schi7ogony, blood remains sterile and its inoculation does not produce infection.

Exo-erythrocvic phase: Cryptomerozoites enter fresh liver cells to become metacryptozoites. They undergo schizogony similar to the previous one producing enormous number of metacrypto-merozoites. Metacryptonierozoites, after escaping into blood stream, invade the erythrocytes or red blood corpuscles. This starts the erythrocytic schizogony. With erythrocytic schizogony, the symptom of malaria starts appearing.


Correct Option:
B
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Question 8
A
merozoite 
B
sporozoite 
C
trophozoite 
D
minuta form. 
Explanation.
Share Answer The infective stage of Plasmodium is a minute organism called sporozoite. When the mosquito bites man, sporozoites present in the salivary gland of female Anopheles mosquito are injected into the blood of the man. These sporozoites are spindle-shaped or sickle- shaped uninucleate organisms capable of wrigging (wormlike) movements. Each sporozoite consists of elastic pellicle, cytoplasm and nucleus.

Correct Option:
B
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Question 9
A
micronucleus 
B
macronucleus 
C
both micronucleus and macronucleus 
D
mitochondria. 
Explanation.
Share Answer Paramaecium contains a single large macronucleus and one small micronucleus. The macronucleus controls metabolism such as feeding and maintaenance, whereas the macronucleus takes and important role in reproduction and stores genetic information, hence it is also termed as reproductive nucleus whereas macronucleus is termed as vegetative nucleus.

Correct Option:
A
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Question 10
A
polymorphic 
B
monogenetic 
C
facultative parasite 
D
non-pathogenic. 
Explanation.
Share Answer Trypanosoma is polymorphic i.e. it has more than one form. It has at least four forms that are recognized on the basis of the positions of kinetoplast and blepharoplast and the course taken by the tlagellum. Two or more such forms occur either in one or both the hosts in the life cycles of various species of Trypanosoma. These i forms are

(i) Leishmanial (amastigote): Round or oval form with a nucleus, blepharoplast and kinetoplast. Flagellum reduced and fibril-like embedded in cytoplasm.

(ii) Leptomonad (promastigote): Body elongate, nucleus large and anteriorly located blepharoplast and kinetoplast. Flagellum short and unattached.

(iii) Crithidial (epimastigote): Body elongate. Blepharoplast and kinetoplast placed immediately anterior to nucleus. Undulating membrane inconspicuous.

(iv) Trypanosomid (trypomastigote): Body elongate and slender. Blepharoplast and kinetoplast situated at or near posterior end. Undulating membrane conspicuous.

Tiypanosoma is digenetic i.e. it completes its life cycle in two hosts. It is an obligate parasite and is pathogenic.


Correct Option:
A
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