Lecture 3

Question 1

Can a low power microscope reveal a great variety of organisms in a drop of pond water?

Answer 1

Yes

Question 2

Define Protist

Answer 2

The informal name of the group of mostly unicellular eukaryotes.

Question 3

What kind of a Cladistic group do protists constitute?

Answer 3

Polyphyletic

Question 4

Protists are _____ and thus have organelles and more complex than prokaryotes.

Answer 4

Eukaryotes

Question 5

Most protists are _____, but there are some colonial and multicellular species.

Answer 5

Unicellular

Question 6

Which group of eukaryotes can be considered the most nutritionally diverse?

Answer 6

Protists

Question 7

What does the diversity of nutrition in protists consist of?

Answer 7

Photoautotroph-Heterotroph-Mixotroph PHM

Question 8

Define Mixtotroph

Answer 8

The combination of photosynthesis and heterotrophic nutrition.

Question 9

In what ways can protists reproduce?

Answer 9

Some protists reproduce asexually, while others reproduce sexually, or by the sexual processes of meiosis and fertilization.

Question 10

What are the 4 supergroups of eukaryotes?

Answer 10

Excavata-SAR-Archaeplastida-Unikonta ESAU

Question 11

Explain everything important about Unikonta

Answer 11

Gymnamoebas are free living in many habitats and Entamoebas are parasites.

The Unikonta do not contain a shell, cilia, or flagella; instead has pseudopodia, extensions of cytoplasm shared by micro tubules and micro filaments.

Grows by cytoplasmic steaming; cytoplasm undergoes reversible phase change from solution to gel.

Used for locomotion, and to trap food particles which are then internalized by infolding of the cell membrane (phagocytosis).

It has food vacuoles (responsible for the ingestion of phagocytoses food) and contractile vacuoles (removal of water and wastes). It removes water and conserves solutes. Diffusion and osmosis and constantly changing cytoplasmic composition; organism must regulate.

Question 12

What can be said about Slime Molds in the Unikonta Supergroup?

Answer 12

They were once thought to be fungi due to the production of fruiting bodies and spores. But, this is a case of convergent evolution and the different types of slime molds include Plasmodial and Cellular Slime Molds.

Question 13

Explain everything important about the Excavata Supergroup

Answer 13

Characterized by a rod with spiral or crystalline structure inside each of their flagella. Two best studied groups are the kinetoplastdis and euglenids. EKE

Question 14

What are some important things to note about the Kinetoplastids under the Excavata Supergroup?

Answer 14

Some are free-living and some are parasitic.
African Trypanosomiasis, Chagas’ Disease, and Leishmaniasis are all diseases that can be caused by these kinetoplastids.

Question 15

What happens in the African Trypanosomiasis Disease?

Answer 15

Sleeping sickness; fatal if untreated, difficult to treat.

Question 16

What happens in Chagas’ Disease?

Answer 16

It is American Trypanosomiasis; causes lingering illness and sometimes death.

Question 17

What happens in Leishmaniasis?

Answer 17

It usually happens in the tropics, causes organ damage and nasty skin sores.

Question 18

How are the diseases from Kinetoplastids transmitted?

Answer 18

They are ALL transmitted through insects that bite vertebrates (tsetse flies for sleeping sickness, reduviid bugs for Chagas, and sand flies for Leishmaniasis). TRS

Question 19

Have there been any vaccines developed for trypanosome cause diseases? What happens upon infection?

Answer 19

No; the organisms rapidly change cell surface antigens, so it’s impossible to prevent infection. Once infected, this also challenges the hosts’ immune system.

Question 20

How is treating trypanosome diseases?

Answer 20

It is difficult; antibiotics dont work and both host and parasite are eukaryotes, so anti-Protozoan drugs often have a harmful side effect.

Question 21

Explain everything about Arcaheplastida

Answer 21

They’re the closest relative to land plants and developed from Cyanobacterial endosymbiosis.

Question 22

What are the different types of endosymbiosis?

Answer 22

Primary and Secondary

Question 23

What does SAR stand for? (What is included in it)

Answer 23

Stramenopiles-Alveolates-Rhizarians

Question 24

Explain everything about Rhizarians

Answer 24

They move and feed with pseudopodia; there are bulging extensions form the cell and the cytoplasm streams to form these extensions.

Question 25

Explain everything about Alveolates (specifically ciliates)

Answer 25

Cilia usually occur in large numbers; often in bands or discrete regions.

Ciliary beating is coordinated (metachronal) so they don’t work against each other; direction of the power stroke can be reversed.

On free-swimming ciliates, direction of swimming is opposite of the direction of power strokes.

Question 26

Explain everything about Apicomplexans

Answer 26

All parasites in animals; name refers to a set of apex organelles in the infective stage (sporozoite) that accomplishes penetration into the host.

Often must infect a series of hosts and change between sexual and asexual phases to complete the life cycle.

Often a complex variety of life stages within and between hosts.

Indicates a long, shared evolutionary history between parasite and host (co-evolution).

Question 27

What is an extremely important example of Apicomplexans? Explain

Answer 27

Plasmodium, the cause of malaria; there are two hosts: mosquitoes and vertebrates (including humans). In the past, insecticides killed mosquito populations and anti-malarial drugs like chloroquine cured infections.

However, both control methods now compromised: mosquitoes have evolved resistance to insecticides and Plasmodium has evolved resistance to many drugs.

Question 28

Define Malarial Disease

Answer 28

It is largely due to one life stage that reproduces asexually in the host’s red blood cells; periodically, it causes the red blood cells to lyse, leading to anemia.

Question 29

Why is there no effective vaccine for Malaria yet?

Answer 29

Because it “hides” within the host cells for most of its life cycle; there is only a few minutes in between the injection off sporozoites during a mosquito bite and their entry into the liver cell. Like Trypanosoma, Plasmodium changes its surface proteins, making immune system attack difficult.