Chapter 20

Question 0

Most protists are single celled.

Answer 0

Beautiful shapes, forms, lifestyles, diverse modes of reproduction and the structural and physiological innovations that are possible within the limits of a single cell. Some are Single celled - some are visible to the naked eye, and a few are large. Some are multicellular organisms.

Question 1

What are protists?

Answer 1

Eukarya Domain; Protists do not form a clade- a group consisting of all the descendants of a particular common ancestor.- So systematics do not use the term “protist” as a formal group name. Its more of a term used to describe that is not a plant, animal or fungus.

Question 2

Modes of nutrition

Answer 2

Three major modes of nutrition: Ingest their food (predators), absorb nutrients from surroundings , or capture solar energy directly by photosynthesis.

Question 3

Predator protists can do what?

Answer 3

Single- celled protists may have flexible cell membranes that can change shape to surround and engulf food such as bacteria. Protists that feed in this manner use finger-like extensions called pseudopods to engulf prey.

Question 4

What is food vacuole for digestion?

Answer 4

Tiny currents that sweep food particles into mouth-like openings in the cell. Once inside the protist cell, it is packaged in for digestion.

Question 5

Free living, or inside host protists

Answer 5

Live in soil, and other environments that contain dead organic matter, where they act as decomposers. Most absorptive feeders, however, live inside other organisms. Protists are parasites whose feeding activity harms the host species. Abundant in oceans, lakes and ponds. Float suspended in the water, but some live in close association with corals.

Question 6

Mutual benefit from protists

Answer 6

Some of the solar energy captured by the photosynthetic protists is used by the host organism, which provides shelter and protection for the protist. Takes place in chloroplasts. Descendants of ancient photosynthetic bacteria that took up residence inside a larger cell in a process called endosymbiosis.

Question 7

Endosymbiosis and secondary endosymbiosis.

Answer 7

Endosymbiosis is that which created the first protist chloroplast; Secondary in which a non photosynthesis protist engulfed a photosynthetic protist. Chloroplast surrounded by four disappear. Leaving only the chloroplast surrounded by four membranes. Two of these membranes are from the original, bacteria-derived chloroplasts;

Question 8

Protists Use diverse modes of reproduction

Answer 8

Most reproduce asexually; an individual divides by mitotic cell division to yield two individuals that are genetically identical to the parent cell. Many are capable of sexual reproduction in which two individuals contribute genetic material to an offspring that is genetically different from either parent.

Question 9

Algae

Answer 9

Photosynthetic protist

Question 10

Protozoa

Answer 10

Sincle-celled, non photosynthetic protists

Question 11

Excavates

Answer 11

Named for a feeding groove that gives the appearance of having been excavated. They lack mitochondria. The two largest groups of excavates are the diplomonads and the parabasalids.

Question 12

Diplomonads

Answer 12

have two nuclei and move about the means of multiple flagella. A parasitic diplomonad, Giardia, is an increasing problem in the US, particularly hikers who drink from apparently pure mountain streams.

Question 13

Cysts

Answer 13

Tough structures that enclose the organism during one phase of its life cycle. when this diplomonad is released in the feces of infected humans, dogs, or other animals; a single gram of feces may contain 300 million cysts. small intestine cysts.

Question 14

Parabasalids

Answer 14

Are anaerobic, flagellated protists named for the presence in their cells of a distinctive structure called the para basal body. Trichomonas vaginalis

Question 15

Euglenozoans

Answer 15

The folds of the inner membrane of the cell’s mitochondria have a distinctive shape that appears under the microscope, as a stack of disks. 2 major groups: Euglenids and kinetopastic.

Question 16

Euglenids

Answer 16

Single celled protists that live in fresh water- named after the groups’ best known representative , euglena, a complex single cell that moves about by whipping its flagellum through water. Photosynthetic , but some absorb or engulf food.

Question 17

Kinetoplastids

Answer 17

DNA in the mitochondria is arranged in distinctive structures called kinetoplasts. Most Kinetoplasts posses one flagellum, which may propel the organisms, the sense of the environment, or ensnare the food.

Question 18

stramenopiles *(chromists)

Answer 18

form a clade whose shared ancestry was discovered through genetic comparison. All members of the group have fine, hair -like projections on their flagella. Despite their shared evolutionary history, stramenopiules display a wide range of forms. Some are photosynthetic and some are not. Most are single celled, but some are multicelled. water molds, diatoms, and brown algae.