Question:
I. Identify 2 ways in which red algae are different from brown algae.
Answer:
a) Brown Algae: color results from the carotenoid FUCOXANTHIN; carbohydrate storage product: LAMINARIN
Red Algae: color results from PHYCOERYTHRIN; carbohydrate storage product: FLORIDEAN STARCH
b) many red algae contain an accessory pigment called phycoerythrin, which gives them a reddish color and allows them to carry out photosynthesis in relatively deep coastal water. Also unlike brown algae, red algae have no flagellated stages in their life cycle and must depend on water currents to bring gametes together for fertilization.
Question:
II. Why is it accurate to say that Ulva has true multicellularity but Caulerpa does not?
Answer:
a) Ulva's thallus contains many cells and is differentiated into leaflike blades and a rootlike holdfast. Caulerpa's thallus is composed of multinucleate filaments without cross-walls, so it is essentially one large cell.
Saturday, December 1, 2007
Concept 28.7
Question:
I. Contrast the pseudopodia of amoebozoans and forams.
Answer:
a) Amoebozoans have lobe-shaped pseudopodia, whereas forams have threadlike pseudopodia.
Question:
II. In what sense is 'fungus animal' a fitting description of a slime mold? In what sense is it not a fitting description?
Answer:
a) Slime molds are fungus-like in that they produce fruiting bodies that aid in the dispersal of spores, and they are animal-like in that they are motile and ingest food. However, slime molds are more closely related to gymnamoebas and entamoebas that to fungi or animals.
Question:
III. Does cooperation between cells exist in amoebozoans? Explain.
Answer:
a) Yes, in the life cycle of a cellular slime mold, individual amoebas may congregate in response to a chemical signal, forming a slug-like aggregate from that can move. Then some of the cells from a stalk that supports an asexual fruiting body.
I. Contrast the pseudopodia of amoebozoans and forams.
Answer:
a) Amoebozoans have lobe-shaped pseudopodia, whereas forams have threadlike pseudopodia.
Question:
II. In what sense is 'fungus animal' a fitting description of a slime mold? In what sense is it not a fitting description?
Answer:
a) Slime molds are fungus-like in that they produce fruiting bodies that aid in the dispersal of spores, and they are animal-like in that they are motile and ingest food. However, slime molds are more closely related to gymnamoebas and entamoebas that to fungi or animals.
Question:
III. Does cooperation between cells exist in amoebozoans? Explain.
Answer:
a) Yes, in the life cycle of a cellular slime mold, individual amoebas may congregate in response to a chemical signal, forming a slug-like aggregate from that can move. Then some of the cells from a stalk that supports an asexual fruiting body.
Concept 28.6
Question:
I. Why do forams have such a well-preserved fossil record?
Answer:
a) Because foram tests are hardened with calcium carbonate, they form long-lasting fossils in marine sediments and sedimentary rocks.
Question:
II. Compare feeding forams and radiolarians.
Answer:
a) Forams feed by extending their pseudopodia through pores in therir tests. Radiolarians ingest smaller microorganisms by phagocytosis using their pseudopodia; cytoplasmic streaming carries the engulfed prey to the main part of the cell.
I. Why do forams have such a well-preserved fossil record?
Answer:
a) Because foram tests are hardened with calcium carbonate, they form long-lasting fossils in marine sediments and sedimentary rocks.
Question:
II. Compare feeding forams and radiolarians.
Answer:
a) Forams feed by extending their pseudopodia through pores in therir tests. Radiolarians ingest smaller microorganisms by phagocytosis using their pseudopodia; cytoplasmic streaming carries the engulfed prey to the main part of the cell.
Concept 28.5
Question:
I. What unique cellular feature is common to all stramenopiles?
Answer:
a) Stramenopiles have "hairy" and smooth flagella. In some stramenopile groups, the only flagellated cells are motile reproductive cells.
b) A pair of flagella, one hairy and one smooth.
Question:
II. Compare the nutrition of oomycetes with that of golden algae.
Answer:
a) Golden Algae: all are photosynthetic, some are mixotrophic, & can also absorb dissolved organic compounds or ingest food particles and prokaryotes by phagocytosis. While, Oomycetes: do not carry out photosynthesis, instead they acuire nutrients as decomposers or parasites.
b) Oomycetes acquire nutrition mainly as decomposers or parasites; golden algae are photosynthetic, but some also absob dissolved organic compounds or ingest food particles and prokaryotes by phagocytosis.
Question:
III. How is the structure of a borwn alga such as Laminaria well suited to its intertidal zone habitat?
Answer:
a) They have unique adaptations that enable them to withstand the waves & the intense heat of the sun. For example, their cell walls are composed of cellulose and gel-forming polysaccharides that help cushion the thalli from waves and reduce drying when the algae are exposed.
b) The holdfast anchors tha alga to the rocks, while the wide, flat blades provide photosynthesis surfaces. The cellulose and algin in the alga's cell walls cushion the thallus from waves and protect it from drying out.
I. What unique cellular feature is common to all stramenopiles?
Answer:
a) Stramenopiles have "hairy" and smooth flagella. In some stramenopile groups, the only flagellated cells are motile reproductive cells.
b) A pair of flagella, one hairy and one smooth.
Question:
II. Compare the nutrition of oomycetes with that of golden algae.
Answer:
a) Golden Algae: all are photosynthetic, some are mixotrophic, & can also absorb dissolved organic compounds or ingest food particles and prokaryotes by phagocytosis. While, Oomycetes: do not carry out photosynthesis, instead they acuire nutrients as decomposers or parasites.
b) Oomycetes acquire nutrition mainly as decomposers or parasites; golden algae are photosynthetic, but some also absob dissolved organic compounds or ingest food particles and prokaryotes by phagocytosis.
Question:
III. How is the structure of a borwn alga such as Laminaria well suited to its intertidal zone habitat?
Answer:
a) They have unique adaptations that enable them to withstand the waves & the intense heat of the sun. For example, their cell walls are composed of cellulose and gel-forming polysaccharides that help cushion the thalli from waves and reduce drying when the algae are exposed.
b) The holdfast anchors tha alga to the rocks, while the wide, flat blades provide photosynthesis surfaces. The cellulose and algin in the alga's cell walls cushion the thallus from waves and protect it from drying out.
Concept 28.4
Question:
I. What morphological feature supports molecular data that suggest dinoflagellates, apicomplexans, and ciliates are members of a single clade?
Answer:
a) Membrane-bounded sacs under the plasma membrane
Question:
II. Why is a 'red tide' a cause for concern to people who eat locally caught seafood?
Answer:
a) Red Tide is a microorganism containing a concentrated toxin and occasionally washes onshore. Though not all people are susceptible to the effects of red tide, it can be absorbed by humans directly, as well as be absorbed in shellfish. Red tide can also affect humans if they consume contaminated molluscan shellfish. During a red tide, bivalve shellfish, including clams and oysters, concentrate the toxin. This concentrated toxin can cause neurotoxic shellfish poisoning (NSP) in humans who eat bivalve shellfish. Both mild gastrointestinal and neurological symptoms occur in NSP.
b) A red tide is a bloom of dinoflagellates, some of which produce deadly toxins that accumulate in molluscs and can affect people who eat molluscs.
Question:
III. Why is it incorrect to refer to conjugation in ciliates as a form of reproduction?
Answer:
a) During conjugation, two ciliates exchange micronuclei, but no new individuals are produced.
I. What morphological feature supports molecular data that suggest dinoflagellates, apicomplexans, and ciliates are members of a single clade?
Answer:
a) Membrane-bounded sacs under the plasma membrane
Question:
II. Why is a 'red tide' a cause for concern to people who eat locally caught seafood?
Answer:
a) Red Tide is a microorganism containing a concentrated toxin and occasionally washes onshore. Though not all people are susceptible to the effects of red tide, it can be absorbed by humans directly, as well as be absorbed in shellfish. Red tide can also affect humans if they consume contaminated molluscan shellfish. During a red tide, bivalve shellfish, including clams and oysters, concentrate the toxin. This concentrated toxin can cause neurotoxic shellfish poisoning (NSP) in humans who eat bivalve shellfish. Both mild gastrointestinal and neurological symptoms occur in NSP.
b) A red tide is a bloom of dinoflagellates, some of which produce deadly toxins that accumulate in molluscs and can affect people who eat molluscs.
Question:
III. Why is it incorrect to refer to conjugation in ciliates as a form of reproduction?
Answer:
a) During conjugation, two ciliates exchange micronuclei, but no new individuals are produced.
Concept 28.3
Question:
I. How is Trypanosoma's ability to produce an array of cell-surface proteins advantageous to its survival?
Answers:
a) The surface of a trypanosome is coated with millions and millions of copies of a single protein. Before, a host's immune system could mount an attack, new generations of the parasite switch to another surface protein with a slightly different molecular structure. Frequent changes in the structure of the surface of the protein prevent the host from developing immunity, thus contributing to its (Trypanosoma) survival.
b) The proteins have slightly different structures, but only one protein at a time is expressed. Frequent changes in expression prevent the host from developing immunity.
Question:
II. Is Euglena an alga? Explain your answer.
Answer:
a) Euglena could be considered an alga because it is a photosynthetic autotroph; however, it could also be considered a fungus-like protist because it can absorb organic nutrients from its environment.
I. How is Trypanosoma's ability to produce an array of cell-surface proteins advantageous to its survival?
Answers:
a) The surface of a trypanosome is coated with millions and millions of copies of a single protein. Before, a host's immune system could mount an attack, new generations of the parasite switch to another surface protein with a slightly different molecular structure. Frequent changes in the structure of the surface of the protein prevent the host from developing immunity, thus contributing to its (Trypanosoma) survival.
b) The proteins have slightly different structures, but only one protein at a time is expressed. Frequent changes in expression prevent the host from developing immunity.
Question:
II. Is Euglena an alga? Explain your answer.
Answer:
a) Euglena could be considered an alga because it is a photosynthetic autotroph; however, it could also be considered a fungus-like protist because it can absorb organic nutrients from its environment.
Concept 28.2
Question:
I. Why do some biologists describe the mitochondria of diplomonads and parabasalids as "highly reduced"?
Anwers:
a) Diplomonads and parabasalids are adapted to anaerobic environments. They lack plastids, and their mitochondria do not contain DNA, an electron transport chain, or citric-acid cycle enzymes.
b) Their mitochondria do not have DNA, an electron transport chain, or citric-acid cycle enzymes.
Question:
II. How is the structure of Trichomonas vaginalis well suited to its parasitic lifestyle inside its host's reproductive and urinary tracts?
Answer:
a) Diplomonads have multiple flagella and 2 nuclei. Parabasalids, include trichomonads, which move by means of flagella and an undulating part of the plasma membrane.
b) Its flagella and undulating membrane enable it to move along the mucus-coated lining of these tracts inside its host.
I. Why do some biologists describe the mitochondria of diplomonads and parabasalids as "highly reduced"?
Anwers:
a) Diplomonads and parabasalids are adapted to anaerobic environments. They lack plastids, and their mitochondria do not contain DNA, an electron transport chain, or citric-acid cycle enzymes.
b) Their mitochondria do not have DNA, an electron transport chain, or citric-acid cycle enzymes.
Question:
II. How is the structure of Trichomonas vaginalis well suited to its parasitic lifestyle inside its host's reproductive and urinary tracts?
Answer:
a) Diplomonads have multiple flagella and 2 nuclei. Parabasalids, include trichomonads, which move by means of flagella and an undulating part of the plasma membrane.
b) Its flagella and undulating membrane enable it to move along the mucus-coated lining of these tracts inside its host.
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