Section 25.2 (Exam 1)

Question 1

Within Eukaryota, how many major groups of protists are there? Most of them are _______________.

Answer 1

5; Unicellular and small

Question 2

One example of a large multicellular protist is ____________.

Answer 2

giant kelp

Question 3

Name some characteristics of Alveolates.

Answer 3

Have alveoli beneath the cell membrane, unicellular, most are photosynthetic

Question 4

Name the three types of Alveolates.

Answer 4

Dinoflagellates, Apicomplexans, and Ciliates.

Question 5

Dinoflagellates are protists. Some species of them cause red tides. What are some characteristics of dinoflagellates?

Answer 5

Most are marine, photosynthetic, important primary producers.
Some are photosynthetic endosymbionts that live in the cells of other organisms, such as corals.
Some are parasites in other marine organisms.

Question 6

What are some characteristics of Apicomplexans?

Answer 6

All are parasites.

Have Apical Complex.

Complex life cycle with two hosts.

Question 7

What is an Apical Complex?

Answer 7

A mass of organelles at one tip helps parasites enter host cells.

Question 8

Describe the Apicomplexans complex life cycle.

Answer 8

Two examples are plasmodium (malaria) which cycles between humans and mosquitos, and toxoplasma which is a parasite that can circulate between cats and rats, and sometimes even infect humans.

Question 9

What are Ciliates?

Answer 9

They have numerous cilia.

Almost all are heterotrophic but some have photosynthetic endosymbionts.

Have complex body forms and two types of nuclei.

Question 10

Paramecium is a type of __________, which is a type of ____________, which is a type of protist.

Answer 10

Ciliate; Alveolate

Question 11

Describe paramecium’s structure.

Answer 11

Composed of an outer membrane and an inner layer of alveoli that surround cilia bases.

Trichocysts (sharp darts) in the pellicle, a thin layer of film or skin, are defensive

Question 12

Locomotion by cilia is more _______ than flagella.

Answer 12

precise

Question 13

Which structures within protists excrete excess water?

Answer 13

Contractile vacuoles

Question 14

What is formed when protists such as paramecium ingest solid food particles through endocystosis?

Answer 14

Digestive vacuoles

Question 15

What is the function of digestive vacuoles?

Answer 15

Digestive vacuoles digest the food, and then smaller vesicles pinch off from it to absorb the nutrients faster by increasing surface area.

Question 16

Stramenopiles are types of protists. Name three types of stramenopiles.

Answer 16

Diatoms, Brown algae, and Oomycetes

Question 17

Name some characteristics of diatoms.

Answer 17

Unicellular, but many form filaments.

Only male gametes have flagella

They are either radially or bilaterally symmetric.

Photosynthetic; carotenoids give them a yellow or brownish color.

Diatoms are major primary producers in both the ocean and freshwater ecosystems.

Make carbohydrates and oils as storage products.

Question 18

Diatoms deposit _________ in cell walls. Their cell walls are constructed in two pieces.

Answer 18

silicon

Question 19

Diatoms perform asexual reproduction by binary fission. The top and bottom pieces of the cell wall become the tops of the new daughter cells. This leads to which problem?

Answer 19

The cells formed from the smaller plates get smaller and smaller over time.

Question 20

In larger diatoms, sexual reproduction occurs. The ___________ fuse to form a zygote which grows substantially before a new cell wall is laid down.

Answer 20

gametes

Question 21

Brown algae are stramenopiles. Name some of their characteristics.

Answer 21

multicellular; some get very large (like giant kelp).

They have the carotenoid fucoxanthin, which imparts the brown color.

Almost exclusively marine. Sargassum forms dense mats in the Sargasso Sea in the mid-Atlantic.

Question 22

Brown algae attaches to rocks by a holdfast that glues it to the rocks. The “glue” is called _________, its a gummy polymer that also holds cells and filaments together.

Answer 22

carrageenan

It’s used as an emulsifier in ice cream and cosmetics.

Question 23

What are Oomycetes?

Answer 23

Water molds and downy mildews.

Question 24

Water molds are ___________________. They secrete enzymes to digest large food molecules into smaller molecules that can be absorbed.

Answer 24

absorptive heterotrophs

Question 25

Some oomycetes like water molds are saprobic. What does this mean?

Answer 25

They feed on dead organic matter.

Question 26

What does the cell wall of oomycetes have as its main component?

Answer 26

Cellulose

Question 27

What are the characteristics of downy mildews and other terrestrial oomycetes?

Answer 27

Some are decomposers.

Some are plant parasites that attack avocados, grapes, potatoes, and other plants.