Zoology - Chapter 25: Protozoa

study study study

What is a protist?

single celled microscopic organisms that can move independently

Describe a hypothesis for the origin of eukaryotic cells

Through endosymbiosis, eukaryotic cells (1.5 BYA) came after prokaryotic cells (3.5 BYA).

What are the four phylums of the protista kingdom? Give an example of an organism found in each.

• Phylum Sarcodina - Amoeba

• Phylum Ciliophora - Paramecium

• Phylum Zoomastigina - Euglenophyta

• Phylum Sporozoa - Apicomplexa

What are the three structures that protists use for movement?

Flagella, Cillia, and Psuedopodia (non-structure, but a movement type)

What are the two types of reproduction in protozoans?

Asexual reproduction, sexual reproduction

What is a “test”?

A shell

What are Foraminiferans?

An ancient group of shelled sarcodines - calcium carbonate test

What are “Radiolarians”?

Oldest known group of sarcodines

How does amoebic dystentry work in a Sarcodina?

1. Enters the body through contaminated food

2. Lives in the large intestines where they breakdown the intestinal wall for food

What allows Ciliophora to move through the water? Describe the appearance.

Cillia are hair-like structures that cover the body and propel the organism through the water.

How does paramecium absorb nutrients and excrete waste?

1. Bacteria (food) enters through the mouth pore

2. Food vacuole forms

3. Bacteria is digested

4. Waste exits anal pore

What is a pellicle and what purpose does it serve?

the pellicle is the elastic protein surrounding the cell membrane protecting the Ciliophora

How do paramecium capture their food?

paramecium float around and wait for bacteria to enter through the mouth pore

What are the three key structures that play a role in a paramecium’s food absorption?

• Oral groove

• Mouth pore

• Gullet

• Food vacuole (developing)

What is the name of the whip-like structure used to propel some protozoans through the water?

flagella

What are the names of the three flagellates that cause disease, and what do they do?

1. Trypanosomiasis: african sleeping sickness

2. Chagas’ Disease: fever and heart damage

3. Giardiasis: diarrhea and intestinal cramps

What mosquito transfers malaria?

anopheles mosquito

What are sporozoites and what is their function in Malaria?

Sporozoites are spore like bodies that divide into merozoites. It is the infectious stage of Malaria when the plasmodia infects the human host, spreading Malaria.

What does it mean to be “free-living”?

to swim free in the water

What is the term for when one animal lives on or in another animal?

parasitic

What is a zooplankton?

a population of microscopic animal

What are the two types of asexual reproduction and what occurs during each?

Binary Fission: a protozoans divides into two identical cells

Multiple Fission: cell division that results in a number of identical cells

What is conjugation?

Conjugation: protozoans pair and exchange genetic material.

What two ways can a protozoans monitor or sense conditions in its environment?

• Eyespot: detects quantity and quality of light

• Cyst: hardened external covering of a dormant protozoa

What is a cyst and what is it used for in protozoans?

A cyst is a hardened external covering of dormant Protozoa, and it’s used to monitor conditions in the environment

What occurs during endosymbiosis, and what is it used to explain?

Endosymbiosis is a process in which one prokaryote comes to live inside another. This is used to explain the evolution of the origin of protozoa’s.

What are cytoplasmic extensions called in moving amoeba?

pseudopodia

What is the difference between endoplasm and ectoplasm?

• Endoplasm: Inner cytoplasm

• Ectoplasm: outer layer of cytoplasm

What causes amoeboid movement?

cytoplasmic streaming that leads to locomotion

What is the function of a contractile vacuole?

expels fluid from the cell (prevents popping)

What is phagocytosis?

the process in which sarcodinas feed

What are the four steps of phagocytosis in the Sarcodina feeding process?

1. Psuedopodia surround prey

2. Food vacuole forms via cell membrane

3. Digestive enzymes in food vacuole break down prey

4. Empty food vacuole reemerges with cell membrane to empty wastes

What are food vacuoles?

membrane bound chambers containing digestive enzymes