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Flashcards in Ch 7 Deck (64)
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0

What traits of prokaryotic cells may be considered limitations?

Small size, small genome, non-compartmentalized.

1

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)

2

How did compartmentalization evolve? (2 theories)

-> Plasma membrane pinching off to create nucleus
-> Endosymbiosis

3

What evidence supports the endosymbiotic theory?

Nucleus (nuclear envelope, etc) has a similar structure to a prokaryotic cell.

4

What is secondary endosymbiosis?

A cell that undergoes endosymbiosis multiple times creating layers.

5

What evidence is there for symbiosis in protistans?

Protists have plastids with multiple membranes.

6

Why are protistans considered paraphyletic?

Because they are unified by one common ancestor but do not include all of the descendants.

7

What are characteristics of protists?

-> Aquatic
-> Unicellular
-> Extremely Small
-> Eukaryotic

8

Why are protists difficult to characterize?

-> Small size
-> Diverse
-> Numerous

9

What are the major characteristics of Excavata?

-> Unicellular
-> Heterotrophic
-> Unique flagella
-> Modified mitochondria

10

Why are Diplomonads different from other excavates?

-> "double cells"
-> double nuclei
-> modified mitochondria performing fermentation

11

What characteristics in Giardia cause it to be considered ancient or primitive?

-> Ribosomal RNA (similar to bacteria)
-> double nuclei

12

How are Euglenozoa similar to diplomonads?

-> mixotrophic
-> nutritional function does not necessarily match structure

13

What derived characteristic helps distinguish Euglenozoa from other excavata?

-> Perform photosynthesis
-> Have crystalline rod structure in flagella

14

How do euglenid mitochondria distinguish them from other types?

They perform fermentation.

15

How do Euglenids appear to lead a double life?

Mixotrophic.

16

What distinguishes kinetoplastids from euglenoids?

Kinetoplastids: kDNA in single mitochondria
Euglenoids: Multiple mitochondria

17

What protozoan is responsible for sleeping sickness?

Trypanosoma.

18

What host(s) do Trypanosoma take advantage of?

Tsetse fly and human.

19

How is trypanosoma transmitted?

Bites from tsetse fly.

20

What 3 clades are included in the supergroup SAR?

-> Stramenopila
-> Alveolata
-> Rhizaria

21

How are the group of protistans known as SAR distinguished?

DNA similarities

22

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.

23

What is a major characteristic of Stramenopiles?

Has "hairy" and non hairy flagella.

24

What is characteristic among diatoms?

-> Shells containing silica.
-> Photozynthesize
-> Only have flagella in gametic state

25

What characteristics distinguish golden algae?

-> Extra pigment
-> Stores food as oil

26

What characteristics distinguish brown algae? Why is it so different?

-> Stores food as starch
-> Flagella in gametes
-> Colloidal substance in cell walls

27

What are the 3 major groups of stramenopiles?

-Diatoms
-Golden Algae
-Brown Algae (Phaeophytes)

28

What is the commercial use for alginate?

Thickening agent.

29

What nutritional function is mutual among stramenopiles?

Photosynthesis.