Plasmodium Introduction

Question 1

What characteristics do members of the phylum Apicomplexa share?

Answer 1

1. all parasitic
2. apical complex
3. complex life cycles

Question 2

What is the function of each of the components of the apical complex?

Answer 2

rhoptries & micronemes - secretory organelles penetrating host cells
conoid & polar rings - structural

Question 3

Worldwide, how many people are infected with & how many die from Plasmodium?

Answer 3

~200 million cases

~650,000 deaths

Question 4

What are the 4 species of Plasmodium which infect humans?

Answer 4

1. P. vivax
2. P. ovale
3. P. mlariae
4. P. falciparaum

Question 5

What species of mosquito transmits malaria?

Answer 5

Anophels

Question 6

Is the mosquito male or female?

Answer 6

female

Question 7

What stage of the parasite is infective to humans?

Answer 7

sporozoites

Question 8

Why do sporozoites invade hepatocytes and no other cells?

Answer 8

binds specifically to receptors on hepatocytes

Question 9

What is the exoerythrocytic cycle?

Answer 9

trophozoite feeds on host cell cytoplasm
schizogony - asexual reproduction
merozoites burst out of hepatocyte

Question 10

How does the mosquito transmit the parasite to the human host?

Answer 10

takes a blood meal

Question 11

Once the sporozoite invades the hepatocyte, it transforms into a __.

Answer 11

trophozoite

Question 12

This stage feeds for approximately one week and then undergoes a process of asexual reproduction known as ___.

Answer 12

schizogony

Question 13

What occurs in the two steps of schizogony?

Answer 13

1. nuclear division

2. cytoplasmic division

Question 14

This stage leaves the liver, enters the blood and initiates which cycle?

Answer 14

merozoite

Erythrocytic cycle

Question 15

What is the function of MSP-1?

Answer 15

binds to proteins on RBC surface & orients apical complex to RBC membrane

Question 16

How does the apical complex function during the invasion of a RBC?

Answer 16

secretions from apical complex push merozoite into RBC membrane forming a pit
creates parasitophorous vacuole

Question 17

How did the signet ring stage get its name?

Answer 17

large food vacuole is main characteristic

Question 18

What is hemozoin?

Answer 18

end product of trophooite’s digestion of host Hb

Question 19

Does schizogony occur during the erythrocytic cycle?

Answer 19

yes

Question 20

What is released when an infected RBC ruptures?

Answer 20

merozoites & hemozoine

Question 21

What does synchrony mean in a malaria infection? How is this related to the fevers associated with infection?

Answer 21

in an infected individual merozoites develop at the same time & released of merozoites & hemozoin is at the same time
causes fever & chills

Question 22

What is the fate of micro- and macrogametocytes?

Answer 22

ingested by mosquito

Question 23

What stage of Plasmodium is infective to the vector?

Answer 23

gametocyte

Question 24

What happens to the marcogametocyte in the vector?

Answer 24

nucleus shifts

macrogametocyte = female

Question 25

Name and explain the process which the microgametocyte undergoes in the vector.

Answer 25

exflagellation -
nucleus divides
8 daughter cells
each develops member & flagellum
8 microgametes (males)

Question 26

What 2 cells join during fertilization & which stage is produced?

Answer 26

microgamete + macrogamete = ookinete

Question 27

Where does the ookinete go?

Answer 27

penetrates stomach wall

attaches to hemocoel side

Question 28

Ookinete transforms into a(n) ___ on the hemocoel side of the mosquito stomach.

Answer 28

oocyst

Question 29

How many sporozoites develop in one oocyst?

Answer 29

> 10,000

Question 30

How do the sporozoites get to the salivary glands?

Answer 30

migrate

Question 31

How does feeding behavoir change in an infected mosquito?

Answer 31

feeds more frequently

PITT