Protists Info

Question 1

Protists and humans

Answer 1

• Irish potato famine of 1845

- Malaria

Question 2

Algal Blooms

Answer 2

• Red tide
• Dinoflagellates
• Poisoning in humans

Question 3

Aquatic food chains

Answer 3

-Protists fix half of world’s carbon

Question 4

Protists and climate change

Answer 4

• Global carbon cycle

- Phytoplankton act as key carbon sink

Question 5

Diversification of Protista

Answer 5

• Paraphyletic

- Earliest eukaryotes must have had unicelluar, nucleus, mitochondria, no cell wall

Question 6

Protista

Answer 6

• Includes all eukaryotes (not land plants, fungi, and animals)
• no single trait found in Protista but not in other groups
• low species diversity
• extremely abundant
• not monophyletic

Question 7

Origin of the nuclear envelope

Answer 7

• Leading hypothesis: cell membrane folded in on itself; also creating ER
• Evidence: infoldings are present in some bacteria; nuclear envelopes is continuous with ER
• Advantage: separation of transcription of and translation

Question 8

Origin of mitochondria

Answer 8

• Endosymbiosis theory: mitochondrion took up residence in eukaryotic cell; 2 billion years ago; eukaryote engulfs bacteria but did not consume; eukaryote provided protection; bacterium supplied ATP
• Symbiosis: mutually beneficial for 2 species when in contact
• Endosymbiosis: symbiosis when 1 lives inside another
• Evidence: same size as bacterium; have own genes (self-replicate); manufacture own proteins; have double membranes

Question 9

Origin of the chloroplast

Answer 9

-photosynthesis originated in bacteria; protist engulfed cyanobactera; another protist engulfed that protist (secondary endosymbiosis); chloroplasts: have 4 membranes

Question 10

How do protists eat?

Answer 10

• Phagocytosis: ingest packets of food; eat bacteria, archaea, and other protists
• Absorptive feeding: nutrient taken directly from environment; common; decomposers; parasites

Question 11

Protist motion

Answer 11

• Amoeboid motion via pseudopodia
• Swimming via flagella
• Swimming via cilia

Question 12

Amoebozoa

Answer 12

• Phagocytosis
• Amoeboid motion: lobose pseudopods (blunt)
• includes amoebae and slime molds

Question 13

Rhizaria

Answer 13

• Amoeba-like
• Lack cell walls
• Amoeboid motion: long, slender pseudopodia

Question 14

Excavata

Answer 14

• “excavated” feeding groove
• lacks mitochondria
• e.g. Giardia
• Have flagella

Question 15

Excavata: Euglenida

Answer 15

• 1/3 are photosynthetic

- some have light sensitive eyespots: swim towards light

Question 16

Plantae

Answer 16

• red algae, green algae, and land plants
• mostly multicellular
• cell walls: cellulose
• mostly photosynthetic
• no flagella

Question 17

Alveolata

Answer 17

• Small sacs: alveoli
• Unicellular
• Diverse in morphology

Question 18

Stramenopila

Answer 18

• Some stage: distinctive hollow hairs

- Types: oomycota (cell wall: cellulose); diatoms; brown algae