Q: Which equation represents the photosynthetic process carried out by algae?

$$6\mathrm{CO_2$} + 6\mathrm{H_2O} + \text{light energy} \rightarrow \mathrm{C_6H_{12}O_6$} + 6\mathrm{O_2$}$$

Question 1

Which of the following best describes the role of autotrophic protists in aquatic ecosystems?

Accepted Answer

They serve as primary producers, converting light energy into chemical energy stored in biomass.

Question 2

During photosynthesis, algae convert light energy into which molecule, and what is the chemical formula for this molecule?

Accepted Answer

Glucose; $$\mathrm{C_6H_{12}O_6$}$$

Question 3

Which process performed by protists is essential for enabling aerobic cellular respiration in most aquatic organisms?

Accepted Answer

Production of oxygen ($$\mathrm{O_2$}) $$during photosynthesis

Question 4

How do heterotrophic protists contribute to nutrient cycling in ecosystems?

Accepted Answer

By sequestering nutrients from dead organisms and excreting nutrients, making them available to primary producers

Question 5

A sudden increase in nitrogen and phosphorus in a lake leads to a bloom of dinoflagellates. What is a potential consequence for human health?

Accepted Answer

Production of neurotoxins that can cause illness

Question 6

Which of the following best explains why kelp is considered an ecosystem engineer?

Accepted Answer

Kelp provides essential habitat for other species, supporting biodiversity.

Question 7

What is the primary ecological function of decomposer protists in nutrient flow pathways?

Accepted Answer

They sequester energy and nutrients from dead organisms, making resources available to other heterotrophs.

Question 8

Which equation represents the photosynthetic process carried out by algae?

Accepted Answer

$$6\mathrm{CO_2$} + 6\mathrm{H_2O} + 	ext{light energy} ightarrow \mathrm{C_6H_{12}O_6$} + 6\mathrm{O_2$}$$

Question 9

Why is the burial of algal cells in sediment important for global carbon cycling?

Accepted Answer

It locks up carbon, reducing atmospheric $$\mathrm{CO_2$}$$ and mitigating climate change.

Question 10

Which of the following scenarios best illustrates the transfer of energy and nutrients from primary producers to higher trophic levels in aquatic ecosystems?

Accepted Answer

Microscopic algae are consumed by small invertebrates, which are then eaten by fish.

Question 11

A researcher observes a decline in biodiversity in a coastal ecosystem following a protist bloom. Which of the following is the most likely explanation?

Accepted Answer

The bloom produced neurotoxins, causing illness and death in other organisms.

Question 12

Which of the following is a direct benefit to humans provided by kelp forests?

Accepted Answer

They enable the existence of harvestable species, supporting fisheries.

Question 13

Which trophic level do autotrophic protists primarily occupy in aquatic food webs?

Accepted Answer

Primary producer

Question 14

What is the main consequence of heterotrophic aerobic bacteria consuming large amounts of algae in aquatic ecosystems?

Accepted Answer

Depletion of oxygen, potentially leading to dead zones

Question 15

Which of the following best describes the dual role of protists in energy and nutrient flow pathways?

Accepted Answer

Protists can act as both primary producers and consumers, facilitating energy and nutrient transfer across trophic levels.

Question 16

Which of the following is a plausible multi-step impact of a dinoflagellate bloom in a coastal ecosystem?

Accepted Answer

Neurotoxin production causes fish kills, and subsequent decomposition by bacteria depletes oxygen, further reducing biodiversity.

Question 17

Which of the following is NOT a way protists contribute to human well-being?

Accepted Answer

Question 18

Which of the following best explains the importance of protists in the cycling of phosphorus in aquatic ecosystems?

Accepted Answer

Protists absorb phosphorus during photosynthesis and release it when decomposed, making it available to other organisms.

Question 19

A student claims that all protists are microscopic and do not affect large-scale ecosystem processes. Which evidence contradicts this claim?

Accepted Answer

Kelp, a macroscopic protist, forms underwater forests that provide habitat and influence nutrient cycling.

Importance of Protists in Ecosystems and Human Well-being

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