Protists

Question 1

What are the unifying characteristics of eukaryotes?

Answer 1

cells have nuclei, “typical” mitochondria, cytoskeletal elements, some have flagella/cilia, chromosomes organized by histones, undergo mitosis, sexually reproduce, have cell walls

Question 1

Definition of Protist?

Answer 1

An informal term used to describe any eukaryote that doesn’t belong to phyla fungi, animal, or plant

Question 2

Endosymbiotic Theory?

Answer 2

Eukaryotes may have been a product of one cell engulfing another, and coevolving over time until the separate cells were no longer recognizable

Question 3

What is the evidence for endosymbiotic theory?

Answer 3

Mitochondria and chloroplasts have their own DNA molecule

Question 4

Describe the cell structure characteristics of protists

Answer 4

No common cell structure because of how diverse they are

Question 5

Describe the metabolic diversity of protists

Answer 5

Nutritionally diverse– contain literally everything
phagocytosis is how amoebas ingest organic matter

Question 6

Describe the reproduction and life cycle diversity of protists

Answer 6

Some reproduce solely asexually, others have both sexual and asexual cycles in their life. All 3 basic types of sexual life are represented among protists.

Question 7

Identify the evolutionary relationships of plants, animals, and fungi within the 4 presently recognized supergroups

Answer 7

Excavata is the least related to anything– are simply protists
SAR has photosynthetic, plant-like protists
Archaeplastida contains red and green algae and plants
Unikonta includes amoebas, fungi, and animals

Question 8

Describe representative organisms from each supergroup

Answer 8

Excavata– Giardia intestinalis, a diplomonads parasite that causes intestinal infections in mammals
SAR- globigerina, which are amoebas with threadlike pseudopods
Archaeplastida- volvox, a multicellular green algae
Unikonata- amoebas

Question 9

Identify defining characteristics of protists in each of the supergroups

Answer 9

Excavata- single-celled, asymmetrical with a feeding groove “excavated”
SAR- diverse, organized by DNA similarities
Archaeplastida- presence of chloroplasts
Unikonata-

Question 10

Describe the role protists play in the ecosystem

Answer 10

They can be either producers ( use energy from light to convert CO2 to organic compounds) or symbionts (harm or benefit their hosts)