Protists

Question 1

What are protists

Answer 1

-Older text books use the term “Protozoa”, but newer name reflects changes in understanding of evolution of the organisms.
-A large and diverse group of
unicellular, eucaryotic microorganisms.
-Inhabitants of water, soil, and animal digestive tracts.
-Individual species have specific habitats.
Some Free-living
Some Host-associated
-Many exhibit complex life cycles and undergo differentiation during growth and reproduction

Question 2

what are examples of protists

Answer 2

fungi, algae and slime moulds

Question 3

what are some protist shapes

Answer 3

Euglena is spindle shaped, Amoeba has an irregular shape, and Paramecium is slipper shaped

Question 4

how do protists move and what is their nutrtion

Answer 4

Protists commonly move with the help of pseudopodia, flagella, or cilia and Nutrition may be photosynthetic, or heterotrophic

Question 5

what are the nutritional stratgies for protists

Answer 5

Absorptive nutrition. (osmotrophy)= Uptake of soluble nutrients= Myxomycota, Dictyostelida, Acrasida

Ingestive nutrition. (phagotrophy)= Predation on bacteria or other protists, Need to digest complex macromolecules= Amoeba, Actinopoda, Apicomplexa, Formanifera, Ciliophora, Flagellates

Question 6

what is absorptive nutrtion

Answer 6

-Nutrient uptake across the plasma membrane
-Passive diffusion with soluble nutrients on one side
-Active transport between soluble nutrients on the other end

Question 7

What is ingestive nutrition

Answer 7

-Particulate nutrients engulfed
e.g. bacteria
-Digestion within a membrane vesicle inside the cell

Question 8

How is protist reproduction diverse

Answer 8

-Asexual= binary fission, multiple fission and budding
-Sexual= fusion of male and female gametes or Conjugation (unique to cilliates)
-All methods of reproduction are characteristic of individual species and help in their identification.

Question 9

what happens in asexual reproduction

Answer 9

Binary fission is a commonly observed system= one cell divides into two equal cells, plane of division varies with different organisms and Paramecium

Question 10

what is Schizogony

Answer 10

-is a common method of asexual reproduction
-nucleus and intracellular organelles divide repeatedly prior to cell division
-large numbers of progeny released at once
-Dividing cell is a Schizont
-Daughter cells are Merozoites

Question 11

What is the protist diversity of organisms

Answer 11

->200,000 named species
~10,000 parasites
~human pathogens

Question 12

what are 2 examples from the protist kingdom

Answer 12

1. Euglenophyta- one-celled, make or take in food and most have one flagellum
2. Ciliophora- one-celled, take in food and have cilia

Question 13

Explain protist taxonomy

Answer 13

Classification based upon size, physiology and mechanism of motility:
-Sarcodina- amoeboid movement
-Ciliophora- cilia on outer surface
-Mastigophora- flagella (whiplash)
-Apicomplexa- no external organelles of motility
gliding
-Eugelenoids- phototrophic flagellates

Question 14

what is Sarcodina: amoebas

Answer 14

-Amoeboid organisms= no fixed cell shape and Diameter from 10-60 mm
-Cytoplasm subdivided =ectoplasm and endoplasm
-Asexual reproduction by mitotic cell division.
-Cells in constant motion along surfaces= Move by generating pseudopods
-Survives adverse conditions by forming cysts.

Question 15

look at differences between endo and ectoplasm

Answer 15

Echo= the more vicious clear outer of the cytoplasm in amoeboid cells
Endo= the more fluid, granular, inner layer of the cytoplasm in amoeboid cells

Question 16

what is Acanthamoeba

Answer 16

grows in water, infects cornea and can cause blindness.

Question 17

what does Entamoeba histolytica cause

Answer 17

causes amoebic dysentery, destruction of intestinal lining with diarrhea

Question 18

what % of people have Sarcodina: amoeba in the population

Answer 18

1-40% of population in developing countries and Up to 10% of population in endemic areas of developed countries

Question 19

what is Entamoeba histolytica

Answer 19

-amoebic dysentery
-Cysts ingested with contaminated food or water= 1-40% of diarrhoeal disease in developing countries and 1-10% of diarrhoeal disease in developed countries
-Germination and growth in the intestine, attached to the epithelial cell layer= diarrhoea and bowel destruction
Complications when trophzoites migrate:
Liver
Brain
-no accurate global prevalence data for E histolytica infection and amoebic dysentery

Question 20

what does Acanthamoeba spp. act as reservoirs for

Answer 20

the bacterium
-Ingest the bacterium (phagocytosis)
-Unable to digest the bacterium
Trojan Horse!

Question 20

what is Acanthamoeba spp.

Answer 20

-Legionella pneumophila is a BACTERIUM that causes a serious lung infection, High fever, Chest pain and breathing difficulties -15% fatality and Septic shock
-Organism contracted via contaminated water

Question 21

what is Mastigophora

Answer 21

-Haemoflagellates- Leishmania and Trypanosoma
-human pathogens
-replicate within the blood stream of infected individuals.
-They are injected into the blood stream by biting insects.
-Single flagella.
-Multiple developmental stages.

Question 22

what is sleeping sickness

Answer 22

• life threatening disease caused by reated parasite strains and transmitted by the tsetse fly
  -people in early stages often arent diagnosed

Question 23

what are the symptoms of sleeping sickness

Answer 23

-fever
-chills
-headaches
-loss of appetite
-enlargment of spleen, liver and lymph nodes

Question 24

how do humans have an efficient response to the Trypanosoma species

Answer 24

Antibodies sproduced that result in killing of the parasite

Question 25

what is Apicomplexa

Answer 25

-Obligate parasites
-Apical Complex for penetrating host cells
-Many spread by biting insects.

Question 26

what are the developmental stages in Apicomplexa

Answer 26

asexual in host (Schizogony)
sexual in insect

Question 27

what is a definitive host

Answer 27

host in which sexual stage resides

Question 28

what are the 2 kinds of nuclei in ciliates

Answer 28

-Macronuclei: large polyploid nucleus that regulates daily metabolic activities
-Micronuclei: one or more small nucleus which are genetic reserve of the cell

Question 29

how can ciliates reproduce asexually

Answer 29

transverse binary fission and occasionally budding

Question 30

how can ciliates reproduce sexually

Answer 30

in conjugation

Question 31

what are Ciliophora (ciliates)

Answer 31

-move by cilia
-Complex cells
-Balantidium coli is the only human parasite that is a ciliate
-Causes a rare, though severe type of dysentery

Question 32

what is cilia

Answer 32

small hair-like protuberances on the outside of every eucaryotic cell
-responsible for locomotion and mechanoreception

Question 33

what is dysentery

Answer 33

-a gastrointestinal disease
-caused by bacterial or parastitic infections
-causes diarrhea, fever, vomiting and nausea, weight loss, cramps
-Diagnosed with stool culture
-Treated with antibiotics

Question 34

what is an example of a multicellular parasite

Answer 34

helminth- parastatic worms

Question 35

are protists multicellular

Answer 35

no, unicellular

Question 36

what is Dracunculiasis

Answer 36

-Guinea worm infection caused by Dracunculus mediensis
Nematode (round worm)
->3 million cases in 1992 prior to start of eradication program
-Now down to < 500

Question 37

what happens in dracunculiasis

Answer 37

-Formation of a blister which can burn or itch strongly
-The blister bursts and gives rise to an ulcer with the female protruding (triggered by cooling through water contact)
-Embryos are squeezed out in response to cold water

Question 38

how is dracunculiasis a preventable disease

Answer 38

-No reservoir outside of humans
-Prevent contact of infected people with water sources
-Filter water to remove intermediate host
-relavtively low cost educational campaigns have been made