1.3 Algae, Viruses, & Multicellular Animal Parasites

Are algae prokaryotes or eukaryotes?

Algae are eukaryotes.

How do algae obtain energy?

Algae are photosynthetic; they use light to produce energy.

What do algae need for food production and growth?

Light, water, and CO₂.

Do algae require organic compounds from the environment?

No, they produce their own food via photosynthesis.

Q: What are the products of algal photosynthesis, and why are they important?

Oxygen and carbohydrates, which are used by other organisms.

What role do algae play in nature?

They are important for maintaining ecological balance.

Can algae reproduce sexually, asexually, or both?

Both — algae have sexual and asexual forms.

What are algae cell walls made of?

Cellulose.

Where are algae commonly found?

Freshwater, saltwater, soil, and in association with plants.

Are viruses cellular or acellular?

Viruses are acellular; they are not made of cells.

How small are viruses?

Some are so small they can only be seen with an electron microscope.

What does the core of a virus consist of?

DNA or RNA, never both.

What surrounds the viral core?

A protein coat, which may be further encased by a lipid envelope.

Can viruses reproduce on their own?

No, they can only reproduce using the cellular machinery of other organisms.

When are viruses considered “living”?

When they multiply inside the host cells they infect.

Why are viruses not considered living outside hosts?

Because they are inert and cannot carry out metabolic processes on their own.

Are multicellular animal parasites considered microorganisms?

Not strictly, but they are of medical importance.

Are helminths prokaryotic or eukaryotic?

They are eukaryotes.

Are helminths unicellular or multicellular?

Multicellular.

What are the two major groups of helminths?

Flatworms and roundworms.

What is another term for helminths?

Helminths collectively refers to both flatworms and roundworms.

Are helminths always macroscopic?

No, during some stages of their life cycle, they are microscopic.

How are helminths identified in the laboratory?

Using techniques similar to those for identifying microbes.