Ch 7 Flashcards
What are some natural selective trends toward life’s increase in complexity?
- Communities (competition with other organisms)
- Multicellularity (Division of labor)
- Compartmentalization (increased cellular efficiency)
What traits of prokaryotic cells may be considered limitations?
Small size, small genome, non-compartmentalized.
How did compartmentalization evolve? (2 theories)
- > Plasma membrane pinching off to create nucleus
- > Endosymbiosis
What evidence supports the endosymbiotic theory?
Nucleus (nuclear envelope, etc) has a similar structure to a prokaryotic cell.
What is secondary endosymbiosis?
A cell that undergoes endosymbiosis multiple times creating layers.
What evidence is there for symbiosis in protistans?
Protists have plastids with multiple membranes.
Why are protistans considered paraphyletic?
Because they are unified by one common ancestor but do not include all of the descendants.
What are characteristics of protists?
- > Aquatic
- > Unicellular
- > Extremely Small
- > Eukaryotic
Why are protists difficult to characterize?
- > Small size
- > Diverse
- > Numerous
What are the major characteristics of Excavata?
- > Unicellular
- > Heterotrophic
- > Unique flagella
- > Modified mitochondria
Why are Diplomonads different from other excavates?
- > “double cells”
- > double nuclei
- > modified mitochondria performing fermentation
What characteristics in Giardia cause it to be considered ancient or primitive?
- > Ribosomal RNA (similar to bacteria)
- > double nuclei
How are Euglenozoa similar to diplomonads?
- > mixotrophic
- > nutritional function does not necessarily match structure
What derived characteristic helps distinguish Euglenozoa from other excavata?
- > Perform photosynthesis
- > Have crystalline rod structure in flagella
How do euglenid mitochondria distinguish them from other types?
They perform fermentation.
How do Euglenids appear to lead a double life?
Mixotrophic.
What distinguishes kinetoplastids from euglenoids?
Kinetoplastids: kDNA in single mitochondria
Euglenoids: Multiple mitochondria
What protozoan is responsible for sleeping sickness?
Trypanosoma.
What host(s) do Trypanosoma take advantage of?
Tsetse fly and human.
How is trypanosoma transmitted?
Bites from tsetse fly.
What 3 clades are included in the supergroup SAR?
- > Stramenopila
- > Alveolata
- > Rhizaria
How are the group of protistans known as SAR distinguished?
DNA similarities
Why is the grouping of SAR controversial?
Because it is only the best guess for the phylogeny of the three major groups of protists (Stramenopiles, Alveolates, Rhizarians). There are many diversities among the organisms.
What is a major characteristic of Stramenopiles?
Has “hairy” and non hairy flagella.
What is characteristic among diatoms?
- > Shells containing silica.
- > Photozynthesize
- > Only have flagella in gametic state
What characteristics distinguish golden algae?
- > Extra pigment
- > Stores food as oil
What characteristics distinguish brown algae? Why is it so different?
- > Stores food as starch
- > Flagella in gametes
- > Colloidal substance in cell walls
What are the 3 major groups of stramenopiles?
- Diatoms
- Golden Algae
- Brown Algae (Phaeophytes)
What is the commercial use for alginate?
Thickening agent.
What nutritional function is mutual among stramenopiles?
Photosynthesis.
The three main groups of Alveolates are:
- > Ciliates
- > Dinoflagellates
- > Apicomplexans
What commercial use does alginate (found in cell walls of brown algae) have?
Thickening agent due to colloidal property of cell walls.
What are the three main groups of Alveolates?
- > Ciliates
- > Dinoflagellates
- > Apicomplexans
What type of motility is utilized by Ciliates?
Cilia
What kind of motility is used by dinoflagellates?
Flagella
What form of motility is used by Apicomplexans?
They are non motile.
What mode of nutrition is used by ciliates?
chemotrophic
What mode of nutrition is used by dinoflagellates?
Photosynthesis
What mode of nutrition is used by apicomplexans?
Parasitic
Why does paramecium have two different nuclei?
1 for reproduction, 1 for metabolic function
What organelle does Paramecium have the differ from human cells?
Oral groove
What is a red tide and why does it occur?
When excess resources in the water become available, dinoflagellates can rapidly overbreed and have a red colour.
How many hosts are required in the life cycle of Trypanosoma? What are they?
- Human and Mosquito.
What is examined in a host of Trypanosoma to detect its presence?
Antigens.
What distinguishes Rhizaria from the other SAR protists?
- > Have a hard outer shell (called the test)
- > Have thin cytoplasmic projections
What characteristics distinguish actinopods?
thin extensions of microtubules covered with cytoplasmic sheath used to obtain food
What are characteristics that distinguish foraminiferans?
have pored tests with many chambers. receive food from symbiotic algae
Foraminiferans are historically important to what country? Why?
England. These protists created the limestone that causes the cliffs of Dover to be white.
What does Unikonta mean?
Uni - ___
Konta - ________
One
Movement
What characteristic unifies this group?
1 flagellum.
Why are amoebozoans different from other Unikonta?
Pseudopodia
How are slime molds different from other amoeba types? (entamoeba)
Act as fungi and have sexual reproduction with a haploid stage
Plasmodial slime molds are _________ (uni/multi cellular) while cellular slime molds are _______ (uni/multi cellular)
unicellular
multicellular
What higher group of organisms do slime molds most closely resemble?
Fungi
Connect the following:
A)Axopodia 1)Cytoplasmic
B) Reticulopodia 2) Psuedopodia
C) Lobopodia 3) Microtubules
A) Axopodia 3) Microtubules
B) Reticulopodia 1) Cytoplasmic
C) Lobopodia 2) Psuedopodia
What does opisthokont mean?
Opistho:
Kont:
Posterior, movement
Do all opisthokonts have a posterior flagella?
Yes, it is a monophyletic group.
How are choanoflagellates distinguished from fungi and animals?
Free living
Describe the lifestyle of choanoflagellates
put out flagella to aid phagocytosis
What characterizes Archaeoplastida?
Double membrane chloroplasts (endosymbiotic cyanobacteria)
What is different about Rhodophytes (red algae)?
Has chlorophyll a&d as well as ohycoerythins which gives it color.
What characteristics distinguish green algae?
Chlorophyll a+b, store food as starch.
Why are green algae more closely related to plants?
Store food as starch.
Why is red algae different from any other algae?
Accessory pigments
