Diseases caused by protozoa Questions in English

(D) In the life cycle of $Plasmodium$,sexual reproduction occurs in the gut of the female $Anopheles$ mosquito.
Gametes fuse to form a diploid zygote.
This zygote transforms into an elongated,motile form known as the $ookinete$.
The $ookinete$ penetrates the gut wall of the mosquito to form an oocyst.

(D) The life cycle of $Plasmodium$ involves several stages.
$1$. The $Sporozoite$ is the infective stage for humans,which enters the liver.
$2$. After liver schizogony,the $Merozoites$ are released into the blood.
$3$. These $Merozoites$ enter the red blood cells $(RBCs)$ and transform into the $Trophozoite$ stage.
$4$. The $Trophozoite$ stage is the active feeding stage that consumes the hemoglobin of the $RBCs$ to grow and multiply.
Therefore,the correct stage that derives nutrition from red blood cells is the $Trophozoite$.

(D) The life cycle of $Plasmodium$ in human liver cells (pre-erythrocytic cycle) follows a specific sequence:
$1$. The infective stage,$Sporozoite$,enters the liver cells.
$2$. Inside the liver cell,it transforms into a $Cryptoschizont$.
$3$. The $Cryptoschizont$ undergoes schizogony to produce $Cryptomerozoites$.
$4$. These $Cryptomerozoites$ can further infect other liver cells to form $Metacryptomerozoites$.
Thus,the correct sequence is $Sporozoite \rightarrow Cryptoschizont \rightarrow Cryptomerozoite \rightarrow Metacryptomerozoite$.

(D) Malaria is caused by different species of the protozoan $Plasmodium$.
$Plasmodium vivax$,$Plasmodium malariae$,and $Plasmodium ovale$ cause benign tertian or quartan malaria,which are generally less severe.
$Plasmodium falciparum$ is responsible for malignant or cerebral malaria,which is the most severe and potentially fatal form of the disease.
Therefore,the correct option is $D$.

(B) In the life cycle of $Plasmodium$,the gametocytes formed in the human blood are of two types: microgametocytes (male) and macrogametocytes (female).
Microgametocytes are characterized by their smaller size and a relatively larger nucleus,which facilitates the process of exflagellation during fertilization.
Macrogametocytes are larger in size and have a smaller,more compact nucleus.
Therefore,the male gametocytes are small in size and possess a large nucleus.

(B) In the life cycle of $Plasmodium$ (the malarial parasite),the sporozoites enter the human body through the bite of an infected female $Anopheles$ mosquito.
After initial development in the liver,the parasites enter the red blood cells $(RBCs)$.
Inside the $RBCs$,the parasite transforms into the $Trophozoite$ stage.
This $Trophozoite$ stage is characterized by an irregular,amoeboid shape,which allows it to feed on the host cell's hemoglobin.
Therefore,the amoeboid stage of $Plasmodium$ in human $RBCs$ is the $Trophozoite$ stage.

(D) The life cycle of $Plasmodium$ involves two hosts: humans and female $Anopheles$ mosquitoes.
In the human host,the parasite undergoes asexual reproduction in the liver cells and red blood cells $(RBCs)$.
As the parasite multiplies within the $RBCs$,some of them differentiate into sexual stages called gametocytes.
These gametocytes are formed within the human red blood cells before being ingested by the mosquito during a blood meal.

(C) In the life cycle of $Plasmodium$,the schizont undergoes multiple fission (a type of asexual reproduction) to produce merozoites,not gametocytes. Gametocytes are differentiated from merozoites that enter the red blood cells. Therefore,the statement that the schizont transforms into gametocytes through asexual reproduction is false.

(A) When the female $Anopheles$ mosquito bites a human,it injects the infectious stage of the malaria parasite,known as the $sporozoite$,into the bloodstream.
These $sporozoites$ reach the liver cells $(hepatocytes)$ via the blood.
Inside the liver cells,the $sporozoites$ undergo asexual reproduction (schizogony) and transform into a stage called the $cryptoschizont$.
This $cryptoschizont$ eventually ruptures to release $cryptomerozoites$ into the blood.

(C) When a female $Anopheles$ mosquito bites a human, it injects the infectious stage of the malaria parasite, known as $sporozoites$, into the bloodstream through its saliva.
These $sporozoites$ are then transported via the blood circulation to the liver.
In the liver, they invade the liver cells (hepatocytes) to multiply and undergo asexual reproduction, which is the first stage of the infection in the human body.

(C) The life cycle of $Plasmodium$ involves two hosts: humans and female $Anopheles$ mosquitoes.
In humans,$Plasmodium$ enters as sporozoites through the bite of an infected mosquito.
These sporozoites first infect the liver cells (hepatocytes),where they multiply asexually.
After the liver stage,they are released into the blood and infect the red blood cells (erythrocytes),causing the characteristic symptoms of malaria like chills and high fever.
Therefore,$Plasmodium$ acts as an endoparasite in both liver cells and red blood cells.

(A) The life cycle of $Plasmodium$ in the mosquito involves the following stages:
$1$. Gametocytes are ingested by the female $Anopheles$ mosquito during a blood meal.
$2$. Fertilization occurs in the mosquito's gut to form a zygote,which transforms into a motile $Ookinete$.
$3$. The $Ookinete$ penetrates the gut wall and develops into an $Oocyst$.
$4$. Inside the $Oocyst$,sporozoites are formed through multiple divisions.
$5$. These $Sporozoites$ migrate to the salivary glands of the mosquito,ready to infect a new human host.
Thus,the correct sequence is $Gametocyte \rightarrow Ookinete \rightarrow Oocyst \rightarrow Sporozoite$.

(C) In the life cycle of $Plasmodium$,the sporozoites enter the human liver cells through the blood. Inside the liver cells,they undergo asexual reproduction (schizogony) to form cryptozoites. These cryptozoites further divide to form metacryptozoites. Therefore,the development of metacryptozoites occurs within the liver cells.

(A) The life cycle of $Plasmodium$ is complex and involves two hosts: humans and female $Anopheles$ mosquitoes.
When an infected female $Anopheles$ mosquito bites a human,it injects the infectious stage of the parasite,known as the $Sporozoite$,into the human bloodstream along with its saliva.
These $Sporozoites$ then travel to the liver,where they undergo asexual reproduction to form $Merozoites$.
Therefore,the form that enters the human blood from the mosquito's saliva is the $Sporozoite$.

(B) The life cycle of $Plasmodium$ involves two hosts: humans and female $Anopheles$ mosquitoes.
$1$. The female $Anopheles$ mosquito acts as the vector.
$2$. When a mosquito bites an infected person,the parasites enter the mosquito's body.
$3$. Inside the mosquito,the parasites undergo fertilization and development to form sporozoites,which are stored in the salivary glands.
$4$. When this infected mosquito bites a healthy human,the sporozoites are injected into the human blood along with the mosquito's saliva.
$5$. Therefore,sporozoites are formed in the mosquito through sexual reproduction and enter the human blood during a bite.

(A) $1$. $Plasmodium$ parasites infect human red blood cells $(RBCs)$ during their life cycle.
$2$. Inside the $RBCs$,the parasite feeds on hemoglobin,breaking it down into toxic substances like hemozoin.
$3$. This process leads to the rupture of $RBCs$,which releases the parasite and toxic substances into the bloodstream,causing the characteristic chills and high fever.
$4$. The continuous destruction of $RBCs$ leads to a significant decrease in the number of red blood cells,resulting in anemia.
$5$. Anemia causes the patient to appear pale and feel weak due to reduced oxygen-carrying capacity of the blood. Therefore,both $A$ and $R$ are true,and $R$ is the correct explanation of $A$.

(C) In the life cycle of $Plasmodium$, the pre-erythrocytic cycle involves the formation of cryptoschizonts through schizogony in liver cells.
The exo-erythrocytic cycle involves the formation of metacryptoschizonts in liver cells.
The amoeboid form is a stage found during the endo-erythrocytic (erythrocytic) cycle within the red blood cells, not the exo-erythrocytic cycle.
Therefore, the pair "Exo-erythrocytic cycle - Amoeboid form" is mismatched.

(A) $Plasmodium$ is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The species $Plasmodium$ $\text{vivax}$ and $Plasmodium$ $\text{falciparum}$ are well-known causative agents of malaria in humans. Therefore, they belong to the category of protozoan parasites.

(A) The life cycle of $Plasmodium$ involves two hosts: humans and female $Anopheles$ mosquitoes.
$1$. When an infected mosquito bites a human,sporozoites are injected into the bloodstream.
$2$. These sporozoites first infect liver cells and then enter the $RBCs$.
$3$. Inside the $RBCs$,the parasite undergoes asexual reproduction (schizogony),which leads to the rupture of $RBCs$ and the release of toxins like hemozoin,causing fever.
$4$. After several cycles of asexual reproduction,some parasites differentiate into male and female gametocytes within the $RBCs$.
$5$. These gametocytes do not undergo sexual reproduction in humans; they are taken up by the mosquito during a blood meal,where sexual reproduction occurs.

(C) The life cycle of $Plasmodium$ involves two hosts: humans and mosquitoes. In humans,the parasite undergoes an asexual cycle.
$1$. The pre-erythrocytic and exo-erythrocytic cycles occur in the liver cells $(hepatocytes)$.
$2$. The erythrocytic cycle (also known as the endo-erythrocytic cycle) occurs within the red blood cells $(RBCs)$.
$3$. During this stage,the parasite multiplies,leading to the rupture of $RBCs$ and the release of toxins like $haemozoin$,which causes the characteristic chills and high fever associated with malaria.
Therefore,the cycle occurring in $RBCs$ is the endo-erythrocytic cycle.

(B) When an infected female $Anopheles$ mosquito bites a human,it releases sporozoites (the infectious stage of $Plasmodium$) into the bloodstream. These sporozoites travel through the blood and primarily target the liver cells (hepatocytes) to initiate the exo-erythrocytic cycle of the malaria parasite.

(D) In the life cycle of $Plasmodium$,the gametocytes (also known as gametocytes of $Plasmodium$ in human blood) are of two types: microgametocytes (male) and macrogametocytes (female).
$1$. The male gametocyte (microgametocyte) is smaller in size and contains a large,diffuse nucleus.
$2$. The female gametocyte (macrogametocyte) is larger in size and contains a small,compact nucleus.
Therefore,the correct description is that male gametocytes are smaller with a larger nucleus,and female gametocytes are larger with a smaller nucleus.

(B) $Plasmodium$ is indeed a microscopic protozoan that causes malaria in humans.
It is a digenetic parasite,meaning it requires two hosts to complete its life cycle: humans (intermediate host) and female $Anopheles$ mosquitoes (definitive host).
Since both statements are factually correct,but the fact that it is a protozoan is a biological classification and the fact that it has two hosts describes its life cycle,$R$ does not explain why it is a microscopic protozoan.
Therefore,both $A$ and $R$ are true,but $R$ is not the correct explanation of $A$.

(B) In the life cycle of the malaria parasite $(Plasmodium)$,the process of schizogony occurs within the human liver cells (exo-erythrocytic cycle) and red blood cells (erythrocytic cycle).
During this process,the parasite grows into a large multinucleated stage called a schizont.
Through asexual reproduction (multiple fission),the schizont undergoes cytoplasmic division to release numerous daughter cells known as merozoites.
These merozoites are then released into the bloodstream to infect new red blood cells.

(A) In the life cycle of $Plasmodium$,when the sporozoites enter the human liver cells through the blood,they undergo asexual reproduction.
This initial stage of development in the liver cells is known as the $pre-erythrocytic$ cycle.
During this phase,the sporozoites transform into $cryptoschizonts$,which then undergo multiple fission (asexual reproduction) to produce $cryptozoites$.

(B) The life cycle of $Plasmodium$ involves two hosts: humans and female $Anopheles$ mosquitoes.
When an infected female $Anopheles$ mosquito bites a human,it injects the infectious stage of the parasite,known as the $Sporozoite$,into the human bloodstream along with its saliva.
These $Sporozoites$ then travel to the liver to initiate the infection cycle.
Therefore,the correct stage is the $Sporozoite$.

(B) The diseases transmitted by mosquitoes are:
$1$. Malaria: Caused by Plasmodium species and transmitted by the female Anopheles mosquito.
$2$. Filariasis (Elephantiasis): Caused by Wuchereria bancrofti or Wuchereria malayi and transmitted by the Culex mosquito.
$3$. Pneumonia is a bacterial disease (Streptococcus pneumoniae) spread through droplets.
$4$. Hepatitis is a viral disease spread through contaminated water or blood.
Therefore,$(i)$ and $(iii)$ are the correct options.

(A) An endoparasite is an organism that lives inside the body of its host.
$Plasmodium$ is a protozoan parasite that causes malaria.
It is transmitted to humans by the female $Anopheles$ mosquito.
In this biological relationship,the mosquito acts as an ectoparasite (feeding on human blood),and the $Plasmodium$ lives inside the mosquito's body (specifically in the salivary glands and gut),making $Plasmodium$ an endoparasite living within an ectoparasite.
Therefore,the correct option is $A$.

(B) The disease caused by a protozoan in humans is $Malaria$.
$Malaria$ is caused by protozoan parasites of the genus $Plasmodium$ (e.g.,$Plasmodium$ $vivax$,$Plasmodium$ $falciparum$).
Common cold is caused by rhinoviruses.
Typhoid is caused by the bacterium $Salmonella$ $typhi$.
Pneumonia is caused by bacteria such as $Streptococcus$ $pneumoniae$ or $Haemophilus$ $influenzae$.

(D) Malaria is a protozoan disease caused by the genus $Plasmodium$.
Specifically, species such as $Plasmodium \text{ vivax}$, $Plasmodium \text{ malariae}$, and $Plasmodium \text{ falciparum}$ are responsible for different types of malaria in humans.
$Salmonella$ causes typhoid, $Haemophilus$ causes pneumonia, and $Rhinovirus$ causes the common cold.

(B) Malaria is caused by different species of the protozoan parasite $Plasmodium$.
$Plasmodium vivax$,$Plasmodium malariae$,and $Plasmodium falciparum$ are the common species that cause malaria in humans.
Among these,$Plasmodium falciparum$ is responsible for the most serious and fatal type of malaria,known as malignant malaria.
Therefore,the correct option is $(B)$.

(B) Malaria is caused by different species of the protozoan parasite $Plasmodium$.
Among these,$Plasmodium \ falciparum$ is responsible for malignant malaria,which is the most serious and often fatal form of the disease.
$Plasmodium \ vivax$ causes benign tertian malaria,which is less severe compared to $P. \ falciparum$.

(D) The life cycle of $Plasmodium$ is digenetic,meaning it requires two hosts to complete its life cycle.
$1$. The asexual phase occurs in the human host,where the parasite multiplies in the liver and red blood cells.
$2$. The sexual phase (gametogony,fertilization,and sporogony) occurs in the female $Anopheles$ mosquito,which acts as the definitive host.
Therefore,$Plasmodium$ completes its life cycle in both humans and female $Anopheles$ mosquitoes.

(B) The causative agent of malaria is the protozoan parasite $Plasmodium$.
$Plasmodium$ requires two hosts to complete its life cycle:
$1$. Humans: The asexual cycle (schizogony) occurs in the human liver and red blood cells.
$2$. Female Anopheles mosquito: The sexual cycle (gametogony and sporogony) occurs in the gut of the mosquito.
Therefore,the correct answer is $Malaria$.

(B) The life cycle of the malaria parasite $(Plasmodium)$ involves two hosts: humans and the female $Anopheles$ mosquito. In humans,the parasite undergoes two main phases of development:
$1$. The asexual cycle (exo-erythrocytic and erythrocytic schizogony) occurring in the liver and red blood cells.
$2$. The formation of gametocytes,which are the precursor stages for the sexual cycle that continues in the mosquito.
Therefore,the parasite completes its development in humans through these distinct phases.

(D) The life cycle of the malaria parasite $(Plasmodium)$ involves two hosts: humans and the female $Anopheles$ mosquito. Within the human host,the parasite undergoes several developmental stages in the liver and red blood cells. These include:
$1$. Pre-erythrocytic cycle: Occurs in the liver cells immediately after infection.
$2$. Exo-erythrocytic cycle: Further development in the liver cells.
$3$. Endo-erythrocytic (or Erythrocytic) cycle: Occurs in the red blood cells.
Since all these stages are essential parts of the $Plasmodium$ life cycle within the human host (which is transmitted by $Anopheles$),all the given options are correct.

(D) The life cycle of $Plasmodium$ in humans involves several stages within the liver and red blood cells (RBCs).
$1$. Pre-erythrocytic cycle: Occurs in the liver cells immediately after infection by sporozoites.
$2$. Exo-erythrocytic cycle: Refers to the multiplication of parasites in liver cells.
$3$. Erythrocytic cycle: Occurs within the red blood cells.
$4$. Post-erythrocytic cycle: This is a term sometimes used to describe secondary liver stages in certain species like $P. vivax$.
'Endo-erythrocytic cycle' is not a standard biological term used to describe any stage of the $Plasmodium$ life cycle.

(A) The life cycle of $Plasmodium$ (the malarial parasite) involves two hosts: humans and female $Anopheles$ mosquitoes.
When an infected female $Anopheles$ mosquito bites a healthy human,it injects the infectious stage of the parasite,known as the $Sporozoite$,into the human bloodstream along with its saliva.
These $Sporozoites$ then travel to the liver to initiate the infection cycle.
Therefore,the correct option is $A$.

(C) The life cycle of $Plasmodium$ involves two hosts: humans and female $Anopheles$ mosquitoes.
In the female $Anopheles$ mosquito,the parasite undergoes sexual reproduction in the gut.
The sporozoites,which are the infectious stage of the parasite,migrate from the gut to the salivary glands of the mosquito.
When the mosquito bites a human,these sporozoites are injected into the human bloodstream along with the mosquito's saliva.

(C) When an infected female $Anopheles$ mosquito bites a human,it injects the sporozoites (the infectious stage of $Plasmodium$) into the human bloodstream along with its saliva. Therefore,the sporozoites first enter the human body through the blood.

(A) The sporozoite is the infectious stage of the malaria parasite $(Plasmodium)$.
It is characterized by a slender,elongated,and spindle-shaped body,which allows it to penetrate the host cells efficiently.
Therefore,the correct shape is spindle-shaped.

(B) When an infected female $Anopheles$ mosquito bites a human,it injects the sporozoites into the human bloodstream.
These sporozoites do not stay in the blood for long; they are rapidly transported through the blood to the liver.
In the liver,they invade the hepatocytes (liver cells),where they multiply asexually to form merozoites.
Therefore,the correct destination after entering the blood is the liver cells.

(D) The life cycle of Plasmodium begins when an infected female Anopheles mosquito bites a human,injecting sporozoites into the bloodstream. These sporozoites quickly reach the liver cells (hepatocytes). Inside the liver cells,the sporozoites ingest nutrients from the host cell,grow in size,and transform into a spherical shape,eventually developing into schizonts. Therefore,the transformation into a spherical form occurs within the human liver cells.

(B) After the sporozoites of $Plasmodium$ enter the liver cells (hepatocytes),they feed on the host cytoplasm and become spherical in shape. This stage is known as the $Cryptozoite$ (or $Pre-erythrocytic$ schizont). Subsequently,these undergo schizogony to produce cryptomerozoites.

(A) In the life cycle of $Plasmodium$,the sporozoites enter the human liver cells. Inside the liver cells,they transform into a stage called the cryptoschizont. Within the cryptoschizont,the parasite undergoes multiple fission,a specific type of asexual reproduction known as $Schizogony$. This process results in the formation of numerous cryptomerozoites.

(D) Schizogony is a form of asexual reproduction in which a parasite,such as the malaria parasite $Plasmodium$,undergoes multiple fission within a host cell.
In the life cycle of $Plasmodium$,the stage where the parasite multiplies asexually inside the liver cells (hepatocytes) or red blood cells is known as schizogony.
The cryptoschizont is a stage in the liver cycle where this asexual multiplication occurs,leading to the production of merozoites.
Therefore,schizogony refers to the process of asexual reproduction occurring within the cryptoschizont stage.

(D) The life cycle of $Plasmodium$ involves two hosts: humans and mosquitoes.
$(i)$ The cryptozoite (the stage formed after the sporozoite enters the liver cell) ingests food and becomes spherical. This is a correct statement.
$(ii)$ Sporozoites are the infective stage that enters the human blood through the bite of an infected female $Anopheles$ mosquito. This is a correct statement.
$(iii)$ The life cycle of $Plasmodium$ is digenetic (involving two hosts),not just two stages. This statement is ambiguous or incomplete in this context.
$(iv)$ The cryptozoite undergoes schizogony to transform into cryptomerozoites. This is a correct statement.
Therefore,statements $(i)$,$(ii)$,and $(iv)$ are correct.

(B) In the life cycle of $Plasmodium$ (the malarial parasite),the $Sporozoites$ enter the human liver cells. Inside the liver cells,they transform into $Cryptoschizonts$. These $Cryptoschizonts$ then undergo a process called $Schizogony$ (asexual reproduction) to produce $Cryptomerozoites$. Therefore,the $Cryptoschizont$ transforms into $Cryptomerozoites$.

(A) In the life cycle of $Plasmodium$,the $Cryptomerozoites$ released from the liver cells (after the primary exo-erythrocytic cycle) infect new,healthy liver cells.
Inside these new liver cells,the $Cryptomerozoite$ grows in size and becomes spherical,a stage known as the $Metacryptoschizont$.
This stage eventually undergoes schizogony to produce $Metacryptomerozoites$.

(C) In the life cycle of the malaria parasite $(Plasmodium)$,the sporozoites enter the human liver cells.
Inside the liver,they undergo the pre-erythrocytic schizogony cycle.
The sporozoites transform into cryptoschizonts,which then produce cryptomerozoites.
Some of these cryptomerozoites infect other liver cells to form metacryptoschizonts.
These metacryptoschizonts undergo further asexual reproduction to produce metacryptomerozoites,which are then released into the blood to infect red blood cells.