(1) Chapter 12 Pt. 2

What kingdom do algae belong to?

Kingdom Protista.

What domain do algae belong to?

Domain Eukarya.

Why are algae considered plant-like?

They are photosynthetic and contain chloroplasts.

Why are algae not considered true plants?

They lack true roots, stems, and leaves.

What structures do algae have instead of roots and stems?

Stipes, blades, and gas bladders.

What is the function of gas bladders in algae?

They provide buoyancy so algae float closer to sunlight.

What pigment do all algae contain?

Chlorophyll.

Can algae be unicellular or multicellular?

Yes. Some are unicellular, filamentous, or multicellular.

How do algae reproduce asexually?

By spores, fragmentation, or fission.

How do algae reproduce sexually?

By conjugation or fusion of gametes.

Why are green algae found near the surface of water?

Their pigments absorb wavelengths that penetrate shallow water.

Why are brown algae found deeper than green algae?

Gas bladders help position them where they receive adequate sunlight.

Why are red algae found deepest in the ocean?

Their pigments absorb blue and violet light, which penetrates deepest.

What phylum contains brown algae?

Phaeophyta.

What is another name for brown algae?

Kelp.

What are the cell walls of brown algae made of?

Cellulose and algin.

What is algin?

A thickening agent obtained from brown algae.

How is algin used?

As a thickener in foods such as ice cream and other products.

Are brown algae unicellular or multicellular?

Multicellular.

Which brown alga was mentioned in lecture?

Laminaria japonica.

How is Laminaria japonica used medically?

To dilate the vaginal tract before certain surgical procedures.

What phylum contains red algae?

Rhodophyta.

What are the cell walls of red algae composed of?

Cellulose.

What important laboratory substance comes from red algae?

Agar.

Why is agar important in microbiology?

It solidifies media and does not melt at 37°C.

What other product is obtained from red algae?

Carrageenan.

How is carrageenan used?

As a thickening agent in food products.

What phylum contains green algae?

Chlorophyta.

Can green algae be unicellular or multicellular?

Yes.

Which green alga was discussed in lecture?

Euglena.

Why is Euglena considered both plant-like and animal-like?

It has chloroplasts but also moves with a flagellum and can ingest food.

What structure allows Euglena to move?

A flagellum.

What is the red eyespot of Euglena?

A light-detecting pigment that senses light.

What is the function of chloroplasts in Euglena?

Photosynthesis.

What happens if Euglena remains in darkness?

It loses the ability to photosynthesize and begins feeding on organic material.

Does Euglena have a cell wall?

No.

What surrounds Euglena instead of a cell wall?

A flexible pellicle.

What is a pellicle?

A tough but flexible outer covering.

What are diatoms?

Single-celled algae with silica cell walls.

What phylum contains diatoms?

Bacillariophyta.

What unique material is found in diatom cell walls?

Silica (glass).

What shape do diatoms resemble?

A Petri dish with a top and bottom fitting together.

What energy storage molecule do diatoms use?

Oil (hydrocarbons).

What toxin can some diatoms produce?

Domoic acid.

What illness is caused by domoic acid?

Domoic acid intoxication.

How do humans become infected with domoic acid?

Eating shellfish that have consumed toxic diatoms.

What are symptoms of domoic acid intoxication?

Diarrhea and memory loss.

What serious complication of domoic acid intoxication did the professor mention?

Permanent brain damage.

What are dinoflagellates?

Single-celled algae that often possess flagella.

Which dinoflagellate genus produces saxitoxin?

Alexandrium.

What toxin is produced by Alexandrium?

Saxitoxin.

What disease does saxitoxin cause?

Paralytic shellfish poisoning.

How do humans develop paralytic shellfish poisoning?

Eating contaminated shellfish.

What muscles are paralyzed by saxitoxin?

Respiratory muscles.

Why can paralytic shellfish poisoning be fatal?

Respiratory paralysis causes suffocation.

What environmental event is associated with toxic dinoflagellates?

Red tide.

Why should shellfish not be harvested during red tide?

They may contain dangerous toxins.

Which dinoflagellate causes massive fish kills?

Karenia brevis.

How does Karenia brevis kill fish?

It produces a neurotoxin that paralyzes fish gills.

What organism caused the Irish Potato Famine?

Phytophthora infestans.

What historical event was caused by Phytophthora infestans?

The Irish Potato Famine.

What is an algal bloom?

Rapid overgrowth of algae due to excess nutrients.

What causes algal blooms?

Runoff containing nitrates and phosphates from farms, factories, and pollution.

Why are algal blooms harmful?

They block sunlight and eventually deplete oxygen during decomposition.

What organisms usually survive severe algal blooms?

Obligate anaerobes living in sediments.

What kingdom do protozoa belong to?

Kingdom Protista.

Are protozoa unicellular or multicellular?

Unicellular.

Why are protozoa considered animal-like?

They lack cell walls and are motile.

Where are protozoa commonly found?

Aquatic environments and moist soil.

How do protozoa reproduce asexually?

Binary fission, budding, or schizogony.

What is schizogony?

Asexual reproduction in which the nucleus divides many times before the cell splits into many daughter cells.

How do protozoa reproduce sexually?

Conjugation or fusion of gametes.

What is conjugation?

Exchange of genetic material between cells.

What is the active feeding stage of protozoa called?

Trophozoite.

What is the dormant resistant stage of protozoa called?

Cyst.

Why are cysts important?

They survive harsh conditions and are usually the infective stage.