All stages of Plasmodium are digested in stomach of female Anopheles except [CPMT 2002]
(a) Sporozoites (b)Gametocytes
(c) Erythrocytes (d) Merozoites
Female Anopheles is [AMU 2002]
(a) Endogenous host for Plasmodium
(b) Exogenous host for Plasmodium
(c) Initial host for Plasmodium
(d)Both (a) and (b)
In which of the following binary fission is not seen
[Orissa JEE 2005]
(a) Plasmodium (b) Amoeba
(c)Euglena (d) Paramecium
Trichonympha is a symbiont in alimentary canal of
[APMEE 2002]
(a) Earthworm (b) Snails
(c) Hermit Crab (d)Termite
Paramaecium ingests food through [CMC 2002]
(a) Cytoproct (b) Cytopyge
(c) Cytopharynx (d)Cytostome
Maurer’s dots occurs in human RBCs infected by
[MP PMT 2002]
(a)Plasmodium falciparum (b) Plasmodium ovale
(c) Plasmodium vivax (d) Plasmodium malariae
Sexual mode of reproduction in protozoa is
[Orissa JEE 2005]
(a) Anisogamy (b) Plasmotomy
(c) Autogamy (d) Schizogony
Which of the following is not true for nutrition in Amoeba
[Orissa JEE 2005]
(a) Photoheterotrophic (b) Phagocytosis
(c) Intracellular (d) Holozoic
Which of the following unicellular organism has a macronucleus for trophic function and one or more micronuclei for reproduction [AMU 2005; CBSE PMT 2005]
(a) Euglena (b) Amoeba
(c) Paramecium (d) Trypanosoma
Man in the life cycle of Plasmodium is [AFMC 2005]
(a) Primary host (b) Secondary host
(c) Intermediate host (d) None of these
In life cycle of Plasmodium, exflagellation is seen in
[CPMT 2005]
(a) Microgametocytes (b) Trophozoites
(c) Macrogametocytes (d) Merozoites
Slipper animalcule is [Manipal 2005]
(a) Paramecium (b) Trypanosoma
(c) Entamoeba (d) Protozoa
The major function of contractile vacuole is
[BHU 1992; CBSE PMT 1995; CPMT 1996; RPMT 2000]
(a) Excretion (b) Circulation
(c) Osmoregulation (d) All the above
Centric discoid form of diatom is [Haryana PMT 2001]
(a) Diploneis (b) Coscinodiscus
(c) Stephanodiscus (d) Camphyloneis
Which of the following can be used as bacteriological filter
[JIPMER 2002]
(a) Gelidium (b) Batrachospermum
(c) Oscillatoria (d) Cymbella
Two species of Amoeba X and Y were kept in fresh water and got adapted. Species X developed contractile vacuole. When both were transferred to sea water and got adapted, both X and Y lost their contractile vacuole. From these observation we conclude that [AFMC 1983, AIIMS 1983]
(a) Both X and Y are marine species
(b) Species Y is marine and X is fresh water
(c)Species X is marine and Y is fresh water
(d) Both X and Y are fresh water
Amoeba reacts [CPMT 1987]
(a)Negatively to strong light and positively to weak light
(b) Positively to strong light and negatively to weak light
(c) Unaffected by light intensity
(d) Positive to both strong and weak light
Contractile vacuole of Amoeba placed in salt water will
[AFMC 1985]
(a) Burst (b)Disappear
(c) Enlarge (d) Multiply
Plasmodium, the malarial parasite, belongs to class
[CBSE PMT 1990]
(a) Sarcodina (b) Ciliata
(c)Sporozoa (d) Dinophyceae
Periodic appearance of malaria symptoms occurs due to periodic [AMU 1992]
(a) Entry of merozoites into erythrocytes
(b) Attack of liver cells by merozoites
(c) Formation of signet ring
(d)Release of pyrogen in blood
Amoeba taken downstream to estuary will show
[CPMT 1993]
(a)Disappearance of contractile vacuole
(b) Binary fission
(c) Encystment
(d) Stoppage of feeding
In Amoeba, pseudopodia are formed due to [RPMT 1995]
(a) Contact with food
(b)Sol ⇋ gel change
(c) Movement towards area of higher temeprature
(d) All the above
Which stage of Plasmodium is infective for Mosquito
[RPMT 1996]
(a) Trophozoite (b)Gametocyte
(c) Ookinete (d) Sporozoite
Chromatid bodies occurs in Entamoeba during
[APMEE 1996; Pb. PMT 1999; AIIMS 2002]
(a) Precyst stage (b)Early cysts
(c) Tetranucleate cysts (d) Trophozoites
Amoeba stops producing pseudopodia during
[Haryana PMT 2001]
(a) Alkaline condition (b)Starvation
(c) Acidic condition (d) Touch
Marine protozoans lack contractile vacuole because
[DPMT 2001]
(a) Their body cannot accommodate it
(b)They are hypo osmotic to their environment
(c) They are isotonic with their environment
(d) Osmoregulation is done by cell membrane
Microfossile often present in petroleum producing formation are those of [AMU 2001]
(a) Radiolarians (b) Diatoms
(c) Helizoans (d)Foraminiferans
Amoeba moves when [RPMT 2002]
(a) Upper part of plasma-gel changes to plasmasol
(b) Lower part of plasmasol changes into gel
(c)Upper part of plasmasol changes into plasmagel
(d) All the above
People recovering from long illness, are advised to include alga Spirulina in their diet because it [AIIMS 2003]
(a) Has antibiotic properties
(b) Restores intestinal flora
(c)Is rich in proteins
(d) Makes the food easy to digest
Histological differentiation is absent in [CPMT 1980]
(a)Amoeba (b) Hydra
(c) Cockroach (d) Earthworm
Exoerythrocytic schizogony of Plasmodium takes place in
[MP PMT 1987]
(a) RBC
(b) Leucocytes
(c) Liver in which cryptomerozoites are formed
(d)Liver in which metacryptomerozoites are formed
In Plasmodium, gametocytes are formed in man, but do not develop fully in the R.B.C. because of [CPMT 1983]
(a) Antibodies present in blood
(b) Antigens present in blood
(c)Higher temperature of blood
(d) Lower temperature of blood
Malarial parasite can best be obtained from a patient
[AFMC 1985; CPMT 1973]
(a) An hour before rise of temperature
(b)When temperature rises with rigor
(c) When temperature comes to normal
(d) Five hours after the temperature reaches to normal
The chill and fever recurring after 48 hours in benign tertian malaria is due to [CPMT 1987]
(a)Plasmodium vivax (b) P. malariae
(c) P. falciparum (d) None of the above
In malaria, shivering occurs when [MP PMT 1987, 89]
(a) Schizonts enter R.B.C.
(b) Sporozoites enter human body
(c) Merozoites are liberated from R.B.C. alongwith toxin
(d) Signet ring stage is attained
If all ponds and puddles are destroyed, the organism likely to be destroyed is [CBSE PMT 1993]
(a) Leishmania (b) Trypanosoma
(c) Ascaris (d)Plasmodium
In Plasmodium, gametocytes are formed from
[Bihar PMT 1994]
(a) Schizont (b) Trophozoite
(c) Sporozoite (d)Merozoite
Destruction of nucleus in Amoeba results in [RPMT 1995]
(a) Immediate death
(b) Slowing down of metabolic activity and ultimate death
(c) Quick locomotion
(d) No change
After how many days could a patient commonly feel malaria from the time of biting of mosquito [CPMT 1998]
(a) 2 – 8 days (b)8 – 10 days
(c) 10 – 20 days (d) 20 – 30 days
Motile elongate zygote of Plasmodium occurs in
[CPMT 1999]
(a) Human RBCs
(b) Human liver
(c) Salivary glands of mosquito
(d)Gut of mosquito
Which is wrong combination [AIIMS 2001]
(a) Haemocyanin – Prawn
(b) Haemoglobin in mammals – RBC
(c) Haemoglobin in plasma – Pheretima
(d)Haemozoin – Plasmodium cytoplasm
During conjugation in Paramecium
[BHU 1999; Pb. PMT 2004]
(a) Out of the four micronuclei formed, three nuclei degenerate
(b) Out of the twelve macronuclei formed, four nuclei degenerate
(c) Zygote nucleus undergoes eight successive divisions in each conjugant
(d) Out of the sixteen nuclei formed from zygote, 12 become macronuclei and 4 micronuclei
In humans, schizont stage of Plasmodium is found in
[MP PMT 2003]
(a) Liver cells only
(b) Liver, spleen and blood cells
(c) RBCs and liver cells
(d) RBCs only
Malaria parasite harm liver cells [RPMT 1999]
(a) In erythrocytic cycle (b) After erythrocytic cycle
(c) Before erythrocytic cycle (d) None of these
Read the assertion and reason carefully to mark the correct option out of the options given below :
(a) If both the assertion and the reason are true and the reason is a correct explanation of the assertion
(b) If both the assertion and reason are true but the reason is not a correct explanation of the assertion
(c) If the assertion is true but the reason is false
(d) If both the assertion and reason are false
(e) If the assertion is false but reason is true
Assertion : The plasmodium often possesses a number of branched “veins”.
Reason : The position of “veins” remains fixed.
Assertion : Sandfly transmits Kala-azar.
Reason : In Kala-azar, the parasite damages the brain.
Assertion : Trichomonas vaginalis causes infection only in women.
Reason : Trichomonas buccalis lives in the buccal cavity.
Assertion : The body of sarcodina bears a number of temporary pseudopodia.
Reason : New pseudopodia are formed in the direction of locomotion.
Assertion : Amoeba contains a contractile vacuole.
Reason : It helps in both digestion and osmoregulation.
Assertion : Amoebiasis is caused by Amoeba.
Reason : The protist feeds on red blood corpuscles.
Assertion : All sporozoans are ecotoparasites.
Reason : Locomotory organelles are absent.
Assertion : Plasmodium causes disease in female Anopheles
Reason : Female Anopheles mosquitoes feed on human blood.
Assertion : Malarial fever appear at merozoite stage of Plasmodium.
Reason : The infective stage of Plasmodium is sporozoite.
Assertion : Schizogony is an asexual reproduction of female Anopheles
Reason : It takes place only in human liver cells.
Assertion : Erythrocytic merozoites form gametocytes.
Reason : Gametocytes are of two types – male and female.
Assertion : The interval between the entry of the sporozoite into human blood and the appearance of the fever is called incubation period.
Reason : The incubation period of malaria in man is about 7 days.
Assertion : Paramecium contains two types of nuclei.
Reason : Paramecium contains two contractile vacuoles.
Assertion : Balantidium coli lives in colon of human beings, only.
Reason : The association is harmless.
Assertion : Euglena is studied as an animal as well as a plant.
Reason : The main function of the vacuole is contraction during digestion.
Assertion : Sexual reproduction in protozoan is not a frequent occurrence.
Reason : Sexual reproduction has no significance.
Assertion : There is no vaccination for malaria.
Reason : Plasmodium causes malaria.
Assertion : Slime moulds are excellent material for the study of protoplasm.
Reason : They lack cell organelles.
Assertion : Slime moulds show alternation of generation.
Reason : The sporangia bearing slime moulds represent haplophase.
Assertion : Cellular slime moulds are called communal slime moulds.
Reason : They show division of labour.
Assertion : Microcyst of myxamoebae lacks cell wall.
Reason : Microcyst is formed in sexual reproduction of slime moulds.
Photosynthetic and consumer protists
1
b
2
a
3
b
4
b
5
a
6
c
7
b
8
c
9
b
10
b
11
a
12
c
13
b
14
b
15
b
16
c
17
d
18
a
19
b
20
a
21
c
22
c
23
c
24
d
25
c
26
a
27
d
28
c
29
a
30
c
31
d
32
a
33
a
34
a
35
d
36
d
37
c
38
d
Protozoan protists
1
c
2
b
3
b
4
d
5
d
6
c
7
d
8
a
9
d
10
d
11
b
12
c
13
a
14
d
15
a
16
d
17
c
18
a
19
b
20
d
21
a
22
b
23
a
24
c
25
b
26
b
27
c
28
a
29
d
30
a
31
a
32
c
33
a
34
c
35
d
36
c
37
c
38
a
39
d
40
d
41
c
42
d
43
d
44
d
45
b
46
c
47
a
48
a
49
b
50
b
51
c
52
c
53
b
54
a
55
c
56
b
57
d
58
b
59
b
60
c
61
c
62
a
63
c
64
d
65
c
66
c
67
d
68
a
69
d
70
b
71
c
72
c
73
c
74
b
75
a
76
d
77
a
78
a
79
d
80
a
81
b
82
a
83
d
84
b
85
a
86
c
87
b
88
b
89
c
90
a
91
d
92
d
93
a
94
d
95
b
96
a
97
b
98
d
99
c
100
a
101
d
102
d
103
b
104
a
105
c
106
a
107
d
108
a
109
b
110
b
111
a
112
d
113
d
114
a
115
d
116
d
117
d
118
a
119
d
120
b
121
b
122
c
123
b
124
a
125
a
126
b
127
a
128
c
129
d
130
b
131
c
132
d
133
d
134
a
135
c
136
a
137
c
138
c
139
c
140
d
141
b
142
d
143
a
144
d
145
d
146
a
147
a
148
a
149
c
150
a
151
a
152
a
Critical Thinking Questions
1
c
2
b
3
d
4
c
5
a
6
b
7
c
8
d
9
a
10
b
11
b
12
b
13
b
14
b
15
d
16
c
17
c
18
a
19
d
20
c
21
b
22
a
23
c
24
d
25
d
26
b
27
b
28
d
29
d
30
a
31
c
32
c
Assertion and Reason
1
c
2
c
3
e
4
a
5
c
6
e
7
e
8
e
9
b
10
c
11
b
12
c
13
b
14
d
15
b
16
c
17
c
18
b
19
c
20
c
21
b
22
e
1
Photosynthetic and consumer protists
(b) In the five kingdom classification protista occupies intermediate position from phylogenetic point of view. Because all multicellular eukaryotes like plants, fungi and animals are originated from unicellular eukaryotic protista.
(b) Euglena having chlorophyll, photosynthesize and produce food while in reverse condition Euglena consume food and behave like animals.
(a) Free floating living protist are collectively called plankton, which are float on the water surface.
(c) Because in sea ecosystem, phytoplanktons are primary producers, if they are destroyed, naturally food chain will be disturbed.
(b) Euglena is a photosynthetic protist.
(b) Ernst Haeckel coined the term protista. In which include protozoans (animals), bacteria and algae (plants).
(a) Protozoans, unicellular algae and unicellular fungi are the members of protista.
(c) They are unicellular, photosynthetic, eukaryotes.
(b) Red tides of oceans are due to excessive growth of dinoflagellates like Gymnodinium and Gonyaulax.
(b) Contractile vacuole for regulation of water content are found in Paramecium, Amoeba etc.
(b) Slime moulds are consumer protist.
(c) In slime moulds the multinucleate protoplasma of a sporangium, undergoes cleavage to form spores.
(d) The cells of dinoflagellate are generally covered by theca or lorica. Theca contains two grooves, the longitudinal groove called sulcus and transverse groove known as cingulum or annulus or girdle.
(b) By binary fission the cells of Paramecium divide transversly. In conjugation two paramecia come in contact in the region their oral groove and establish protoplasmic bridge
(c) Enterobius vermicularis is a member of Nemathelminthes.
(c) They are solitary unicellular or colonial unicellular eukaryotic organisms.
(c) Auxospores are generally called rejuvenescent cells because they help in increasing diatom size to normal one. Auxospores are commonly formed form zygote.
(d) Mixotrophic nutrition found in Euglena, when light is available it is photosynthetic in darkness, it is saprophytic.
(a) Frustule of diatoms is made of silica, cellulose and pectic compounds.
(c) Store lipid drops of diatoms, help in the floating of water surface.
(d) Amoeba and Paramecium are protozoan protist while dinoflagellates are photosynthetic protist.
(c) Capillitium is a branched system of five tubes present in acellular slime moulds. Elaters and pseudoelaters are present in some bryophytes where as capitulum is a type of inflorescence.
Protozoan protists
(b) Because members of this class are exclusively endoparasites.
(c) They are present in some ciliates for defence and attachment.
(d) Parapodia is the locomotory organ of Nereis (Annelida).
(c) Contractile vacuole is an osmoregulatory organelle. When the internal and external media are isotonic, there is no necessity of contractile vacuole.
(a) Enterobius vermicularis is not a protozoan but a multicellular organism which causes enterobiosis.
(c) Amoeba is placed in the sub-class lobosia.
(a) Protozoans discharge all the body functions in one cell, therefore they are called unicellular.
(d) Euglena is autotrophic and has chloroplast. Rest are holozoic.
(b) Animals of class sarcodina or rhizopoda have pseudopodia as locomotory organ.
(c) Being unicellular, no specific excretory system develop so this function can be performed by plasmalemma by diffusion process.
(b) Pseudopodium is formed due to different viscosity of sol and gel.
(c) Members of this class are exclusively endoparasites.
(c) Amoeba was discovered by Rossenhoff (1755) and described by H.I. Hirshfield.
35, (d) Conjugation is shown by Paramecium which strictly belongs to ciliata of Protozoa.
(d) Protists are primitive single celled organism with well organised nucleus, which shows auto as well as heterotrophic mode of nutrition.
(d) Amobea is omnivorous and its mode of nutrition is holozoic. It feeds by phagocytosis. Amoeba captures and engulfs its prey by means of pseudopodia.
(a) Import involves passive sinking of food into body by rupture of plasmalemma, e.g., Ingestion of algae.
(b) Micronucleus is usually spherical, with a nuclear membrane and with diploid number of chromosomes. It controls the reproductive activities of the organism.
(b) Leishmania donovani cause kala-azar or visceral leishmaniasis.
(a) E. histolytica is a pathogenic intestinal parasite occuring in the colon of man and causes amoebic dysentery or amoebiasis.
(d) Absence of contractile vacuole in E.histolytica is a distinguish feature from Amoeba.
(c)The cilia of extreme posterior end are longer and form a bunch called caudal tuft.
(c) Infected R.B.Cs rupture that merozoites and haemozoin granules are liberated in blood. Haemozoin granules are toxic and bring about fever.
(d) Cyst is not formed in Entamoeba gingivalis and infection occurs by direct contact like kissing.
(a) Infection depends upon intake of food or water contaminated with faecal matter containing tetranucleated cyst of E. histolytica.
(b) Malarial parasite is digenetic because its life cycle completed in two different hosts. Primary or principal host is man and secondary intermediate or vector host is female Anopheles.
(a) Both type of gamete are formed during sexual cycle, which occurs in female Anopheles.
(b) Two different type of nucleus, present in ciliata group are micronucleus and macronucleus. Micronucleus take part in reproduction while macronucleus is large kidney shaped which control matabolism.
(a) Entamoeba coli inhabits human colon and feed only bacteria and debris which are present there. Hence Entamoeba coli neither harmful nor beneficial.
(d) Amoeba will move away from contact with a foreign object or a probe while crawling or resting.
(a) Metacyclic form is a infective stage of Trypanosomagambiense which are formed in lumen of salivary gland.
(d) All animals of sporozoa are endoparasite, so they have no any locomotory organs. It is a parasitic adaptation.
(d) Sporozoites are spindle or sickle shaped and uni-nucleated organism capable of wriggling movement. Each has a covering form but elastic pellicle containing longitudinal contractile microtubule.
(d) Inside R.B.Cs, the micro-metacryptomerozoite becomes rounded and modified into a young trophozoite.
(b) Asexual cycle passed in man by process termed schizogony (schizogony in liver and R.B.Cs). Schizogony is a type of multiple fission.
(b) Haemozoin is yellow brown to blackish and insoluble polymer of ferriprotoporphyrin. It is formed by haematin or breakdown product of haemoglobin. It collect in various tissues, e.g., spleen, skin.
(d) Plasmodium is inoculated in human by female Anopheles because female Anopheles injects saliva while puncturing human skin for obtaining a meal of blood. The infected mosquito possesses a large number of sporozoites in its salivary glands. The same are passed into human blood.
(d) Tetranucleate (= Quadri) cyst is infected stage of Entamoeba histolytica. Infection is oral through contaminated food and water.
(a) Leishmania donovani is the parasite of kala-azar or dum-dum fever. These parasite is transmitted by sand fly.
(d) Leishmania tropica produce skin ulcers known as oriental sore or Delhi sore, which is spread by sand fly.
(b) The central part of trophozoite possesses brown to black pigment granules of haemozoin or melanin. They are derived from haematin (iron part) part of haemoglobin.
(c) Chagas disease is caused by infection of Trypanosoma cruzi in south and central America
(c) Trichocysts are ejective organelles which are used for attachment and defence.
(d) Trypanosoma gambionse is a parasite of sleeping sickness, which is transmitted by Glossina palpalis.
(c) When kerosine, paraffin and petrolium oil is sprinkling over pond, then larva and pupa of mosquito die after some time due to difficulty of breathing. Difficulty of breathing is known as asphyxia.
(b) While female Anopheles suck the infected blood then various phases of malaria parasite are reach in their stomach, where digestive enzyme, digest all phases besides gametocyte.
(d) Trichonympha is a symbiont in alimentary canal of termites. Trichonympha secretes cellulose digesting enzyme glucosidase which convert cellulose into glucose.
(a) Maurer’s dots are green coloured structure which found in erythocytic cycle of Plasmodium falciparum.
Critical Thinking Questions
(c) The major function of contractile vacuole is osmoregulation, i.e., removal of excess of water.
(a) Amoeba responds to light, positive behaviour towards moderate lights, negative behaviour to strong light and darkness.
(b) If an Amoeba placed in salt water, its contractile vacuole will disappear, because endo-osmosis is not occurring due to isotonic condition.
(d) Paroxysm is the actual attack of malaria which initially begins after a few earliest erythrocytic cycles, but is, then repeated after every cycle. Obviously paroxysm result due to sufficient accumulation of haemozoin and other toxins in blood.
(a) When Amoeba taken down stream to estuary, it will show disappearence of contractile vacuole because, in isotonic solution or marine water, endosmosis does not occurs.
(b) According to pressure or ectoplasmic concentration or sol-gel theory, pseudopodia are formed and withdrawn due to cyclic viscosity change in the colloidal cytoplasm from ‘sol to gel’ and ‘gel to sol’ states.
(b) Gametocyte is infective stage for female anopheles mosquito because optimum temperature for growth of gametocyte is present in their body.
(b) Initial stage of cyst formation, two or more transparent rod like structure are present in cytoplasm called chromatid bodies. These chromatid bodies are made of ribonucleoprotein.
(b) During starvation, Amoeba stops producing pseudopodia and covered with hard impervious and chitinous protective layer or cyst wall for the protection and survival as well as dispersal of Amoeba.
(c) Amoeba move, when cytoplasm change from sol to gel or gel to sol state.
(c) Protein is a body building material, so extra amount of protein help in early recovery of destructive tissue during illness.
(d) The cryptomerozoite formed during pre-erythrocytic schizogony may enter the human RBCs to start the erythrocytic schizogony, while some of them enter new liver cells and reproduced asexually to give rise to a large number of meta-cryptomerozoites few are smaller in size and called micro-meta-cryptomerozoites.
(b) Haemozoin causes chill and body pain. Malarial parasites can be obtained in large number in blood from a person when temperature rises with rigour.
(d) Gametocytes of malarial parasite are developed from merozoites in RBCs of man.
(b) The patient displays symptoms of malaria fever after a period of 8-10 days from infectious bite.
(d) The motile zygote formed by fertilization of macrogamete by a microgamete is called ookinete. It occurs in gut of mosquito.
(d) Haemozoin liberated in blood plasma.
(a) The diploid micronucleus of each conjugant divides by meiosis. Thus, 4 haploid daughter micronuclei are produced of which 3 degenerates in each conjugant, while the remaining one divides by mitosis 2 unequal pronucleus.
(c) Schizont is a stage in the history of malarial parasite occuring in R.B.Cs and liver cells.
(c) The first cycle of plasmodium occurs in liver cells which is harm for liver cell because sporozoite phagocytes the cytoplasm of the liver cells.
Assertion and Reason
(c) The Plasmodium often possesses a number of branched “veins”. The protoplasm present in the veins show reversible streaming movement. The “veins” disappear and reappear as the Plasmodium moves about.
(c) Leishmania donovani causes kala-azar. The parasite is transmitted by sandfly. The parasite lives inside the cells of liver, spleen, lymph glands, white blood corpuscles and inner wall cells of blood capillaries. In sleeping sickness disease, the parasite damages the brain.
(e) Trichomonas vaginalis inhibits vagina of women and causes the disease known as leucorrhoea. In males the parasite produces irritation in urethra. Trichomonas buccalis resides in the buccal cavity, which is nearly harmless.
(a) Pseudopodia are temporary protoplasmic outgrowths. Locomotion in Sarcodina occurs by pseudopodia. New pseudopodia are formed in the direction of locomotion while pseudopodia of the other side are withdrawn.
(c) Contractile vacuole in Amoeba is a single, clear rounded pulsating structure which is filled with a watery fluid and enclosed by a unit membrane. It helps in the osmoregulation and excretory activities. Digestion in Amoeba occurs in the food vacuoles. These are spherical species small and large, contain water and food in various phases of digestion. As soon as the egestion of non digestible food occurs through body these get disappear.
(e) Person suffering from amoebic dysentry has repeated blood mixed, slimy and foul smelling motions and causes the disease known as amoebic dysentery or amoebiasis. This protist feeds on red blood corpuscles by damaging the wall of large intestine and reaching the blood capillaries.
(e) The sporozoan protists are adapted to parasitic mode of life. All of them are endoparasites. Locomotory organelles (cilia, flagella, pseudopodia etc.) are absent.
(e) The sexual phase of the malarial parasite occurs in the Anopheles As the female Anopheles mosquitoes feed on blood, only they can serve as vector hosts of malarial parasites. The parasite does not harm the mosquito.
(b) When the mosquito bites man, sporozoites present in the salivary gland of female Anopheles mosquito are injected into the blood of the man. The erythrocytic schizont gives rise to merozoites. Malaria fever occurs when shcizonts in red blood corpuscles burst and set free their contained merozoites and malarial pigment (haemozoin) in the blood plasma. Bursting of schizonts tends to be synchronous as hey all burst at the same time. Haemozoin is said to be toxic and so includes high fever and shivering (Haemozoin is a unused hematin, which is produced by the breakdown of haemoglobin). It is yellow brown to blackish in colour.
(c) Schizogony is an asexual reproduction in which schizont is formed. From the human blood sporozoites enter the liver cells. The sporozoite grows in size to become a rounded schizont called cryptozoite. The latter divides to form cryptomerozoites. The cryptomerozoites formed during pre-erythrocytic schizogony may enter the human RBCs to start the erythrocytic schizogony, while some of them enter new liver cells to repeat hepatic (liver) schizogony.
(b) Some erythrocytic merozoites enter fresh RBCs. And form rounded gametocytes (gamonts). The gametocytes are of two types – (i) Smaller male gametocytes or microgamete and (ii) Larger female gametocytes or macrogametocytes.
(c) The symptoms of malaria first appear about 14 days after the infection of the malarial parasite in man. This interval of time is known as incubation period. During this period, the parasites multiply to increase their number so that they can produce enough toxins to cause malaria.
(b) Paramecium contains two types of nuclei-one large macronucleus and one small micronucleus. Macronucleus is the somatic or vegetative nucleus and controls the day to day metabolic activities of the cell. micronucleus controls the reproductive activities of the organism. Paramecium contains two types of contractile vacuoles. One vacuole lies near each end of body, close to the dorsal surface.
(d) Balantidium coli is a ciliate protozoan parasite of colon and caecum of man, monkeys, pigs etc. It causes Balantidial dysentery in these organisms.
(b) Euglena is a typical examle of mastigophora. It is phytoflagellate as it possesses both chloroplast and flagella. It is autotrophic in sunlight, but becomes heterotrophic in dark. Because of its two fold nutritional abilties, it is usually studied as a plant as well as an animal. But it is more an animal than plant because of
(a) The absence of cellulose cell wall overlying the plasma membrane.
(b) Presence of centriole forming blepharoplasts.
(c) Reserve food is paramylon which is not a true starch.
(d) Response to various stimuli like an animal.
(c) One of the most important characteristics of protozoa is the possession of contractile vacuoles. The main function of contractile vacuole is in osmoregulation. The excess water of protozoan body is got rid off by means of contractile vacuole which contract and expand at regular intervals. As these help in passing exces water, the excretory products of their body get dissolved and eliminated with the fluid of contractile vacuoles. Numerous non contractile food vacuoles help in digestion.
(c) It is true that sexual reproduction (as for example, conjugation) is not a frequent occurrence in protozoa, because several factors are there to initiate this process. But it must have some significance. The following functions or effects are attributed to this process.
(b) Several species of Plasmodium cause malaria and it is a infectious disease. But, Plasmodium like germs of other infectious disease, (such as cholera and smallpox etc.) does not produce antibodies or antitoxins in human blood. Therefore, treatment of malaria by inoculations or vaccinations is out of question. Quinine is used for the cure of malaria for as long as 300 years.
(c) Slime moulds lack cell wall in somatic phase. However, the spore have the cellulose cell walls. They are surrounded by the plasma membrane only. They are shapeless mass of protoplasm. Therefore, they are considered for the study of structure and physiology of protoplasm. Slime moulds contain all membrane-bound cell organelles except chloroplasts.
(c) Slime moulds exhibit alternation of generation. The diploid plasmodium is a sporophyte. Under certain conditions it bears sporangia. The sporangia bearing plasmodium and spore producing sporangia constitute the sporophyte generation. It is diplophase reduction division takes place at the time of differentiation of resting spore. The resting spores germinate to produce the haploid, uninucleate swarm cells or myxamoebae. The latter meet and fuse in pairs to form a zygote. The haploid resting spores and the swarm cells or myxamoebae represent the haploid or gametophyte generation.
(b) When the food supply is exhausted, the amoeboid cells get aggregated without any fusion. This aggregated mass of cells is called pseudoplasmodium. It is a sort of community association. Because of this reason, cellular slime moulds are called the communal slime moulds. Pseudoplasmodium also shows division of labour as some cells form fruiting body (sporangium) while others form spores.
(e) Under unfavourable conditions, a myxamoeba secretes a rigid cellulose wall to form the microcyst. On the return of favourable conditions, the microcyst wall ruptures to release a myxamoeba. In the sexual reproduction process, the myxamoebae form clusters. The central myxamoeba of the cluster engulfs a surrounding myxamoeba to become larger structure which forms a thick wall to form the zygote. This zygote is called microcyst.
(a) Aseptate and multinucleate (b) Septate and multinucleate (c) Aseptate and uninucleate (d) Septate and uninucleate Answer. (b) The mycelium of Aspergillus consist of branch septate hyphae. Cells of hyphae are multinucleate. (185)
(a) Parenchyma (b) Chlorenchyma (c) Plectenchyma (d) Collenchyma Answer. (c) Plectenchyma (Pseudoparenchyma) is nothing but the interwoven mass of fungal mycelium which in cross-section look like parenchyma. (108)
(a) Colletotrichum falcatum (b) Phytophthora infestans (c) Potato mosiac virus (d) Alternaria solani Answer. (b) Late blight of potato is a seed born disease which is caused by Phytophthora infestans. The disease is characterised by brownish to blackish dead areas …
