Bacteria, Archaea & Protists- Moodle Questions

Question 1

Which of the following traits do archaea and bacteria share?

a. composition of the cell wall
b. composition of the cell wall and lack of a nuclear envelope
c. presence of plasma membrane and composition of the cell wall
d. lack of a nuclear envelope but do have of plasma membrane

Answer 1

D

Question 2

Which of the following describe all existing bacteria?

a. extremophiles, tiny, abundant
b. tiny, ubiquitous (found nearly everywhere), metabolically diverse
c. morphologically diverse, metabolically diverse, extremophiles
d. pathogenic, ubiquitous (found nearly everywhere), morphologically diverse

Answer 2

B

Question 3

You have found a new prokaryote. What line of evidence would support your hypothesis that the organism is a cyanobacterium?

a. It lacks cell walls
b. It is able to form colonies and produce oxygen
c. It is an endosymbiont
d. It forms chains called mycelia

Answer 3

B

Question 4

Bacteria perform each of the following ecological roles. Which role typically does NOT involve symbiosis?

a. decomposer
b. skin commensalist
c. gut mutualist
d. aggregates with methane-consuming archaea

Answer 4

A

Question 5

If a bacterium regenerates from an endospore that did not possess any of the plasmids that were contained in its original parent cell, the regenerated bacterium will probably also …

a. lack a cell wall
b. lack water in its cytoplasm
c. lack a chromosome
d. lack antibiotic-resistant genes

Answer 5

D

Question 6

A particular species of protist has obtained a chloroplast via secondary endosymbiosis. You know this because the chloroplasts ________.

a. are exceptionally small
b. have only a single pigment
c. have three or four membranes
d. have nuclear and cyanobacterial genes

Answer 6

C

Question 7

Chloramphenicol is an antibiotic that targets prokaryotic ribosomes, but not eukaryotic ribosomes. Which of these questions could you ask about this antibiotic that shows an understanding of the origin of the eukaryote cell?

a. Why aren’t prokaryotic ribosomes identical to eukaryotic ribosomes?
b. If chloramphenicol inhibits prokaryotic ribosomes, should it not also inhibit mitochondrial ribosomes?
c. Can chloramphenicol pass through the capsules possessed by many cyanobacteria?
d. Can chloramphenicol also be used to control human diseases that are caused by archaeans?

Answer 7

B

Question 8

Broad-spectrum antibiotics inhibit growth of most normal beneficial intestinal bacteria. Assuming that nothing is done to counter the reduction of intestinal bacteria, a hospital patient who is receiving broad-spectrum antibiotics is most likely to become ________.

a. deficient in certain vitamins and nutrients
b. antibiotic resistant
c. unable to fix carbon dioxide
d. unable to synthesise peptidoglycan

Answer 8

A

Question 9

Which of the following extremophiles might researchers most likely use as a model for the earliest organisms on Earth?

a. an anaerobic archaean species
b. an archaean capable of surviving in the polar ice caps
c. a bacterium that thrives in a highly acidic environment
d. a bacterium found on another planet or moon

Answer 9

A

Question 10

Mitochondria are thought to be the descendants of certain alpha proteobacteria. They are, however, no longer able to lead independent lives because most genes originally present on their chromosomes have moved to the nuclear genome. Which phenomenon accounts for the movement of these genes?

a. plasmolysis
b. conjugation
c. horizontal gene transfer
d. translation

Answer 10

C

Question 11

Previously understood similarities that seemed to connect slime moulds and fungi are now considered to be ________.

a. examples of convergent evolution
b. adaptations for much different functions
c. homologies
d. variations of common ancestral traits

Answer 11

A

Question 12

Which of the following is responsible for nearly 100,000 human deaths worldwide every year?

a. Dictyostelium discoideum
b. plasmodial slime moulds
c. Amoeba proteus
d. Entamoeba histolytica

Answer 12

D

Question 13

A large seaweed that floats freely on the surface of deep bodies of water would be expected to lack which of the following?

a. thalli
b. gel-forming polysaccharides
c. bladders
d. holdfasts

Answer 13

D

Question 14

Which protist clade usually lack typical mitochondria and posses feeding grooves?

a. Excavata
b. SAR
c. Archaeplastida
d. Unikonta

Answer 14

A

Question 15

Assume that some members of an aquatic species of motile, photosynthetic protists evolve to become parasitic to fish. They gain the ability to live in the fish gut, absorbing nutrients as the fish digests food. Over time, which of the following phenotypic changes would you expect to observe in this population of protists?

a. loss of chloroplasts
b. loss of motility
c. gain of a rigid cell wall
d. gain of meiosis

Answer 15

A

Question 16

What is the goal of bioremediation?

a. to improve human health with the help of living organisms such as bacteria
b. to improve soil quality for plant growth by using bacteria
c. to clean up areas polluted with toxic compounds by using bacteria
d. to improve bacteria for production of useful chemicals

Answer 16

C

Question 17

If all prokaryotes on Earth suddenly vanished, which of the following would be the most likely and most direct result?

a. Human populations would thrive in the absence of disease
b. The recycling of nutrients would be greatly reduced, at least initially
c. Bacteriophage numbers would dramatically increase
d. There would be no more pathogens on Earth

Answer 17

B

Question 18

Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods should be LEAST effective at inhibiting bacterial growth?

a. Pickling: creates a pH at which most bacterial enzymes cannot function
b. Closing previously opened containers: prevents more bacteria from entering, and excludes oxygen
c. Refrigeration: slows bacterial metabolism and growth
d. Canning in heavy sugar syrup: creates osmotic conditions that remove water from most bacterial cells

Answer 18

B

Question 19

All protists are ________.

a. unicellular
b. mixotrophic
c. symbionts
d. eukaryotic

Answer 19

D

Question 20

Biologists sometimes divide living organisms into two groups: autotrophs and heterotrophs. These two groups differ in:

a. the way that they generate ATP
b. their electron acceptors
c. their sources of energy
d. their mode of nutrition (carbon source)

Answer 20

D

Question 21

A fish that has been salt-cured subsequently develops a reddish colour. You suspect that the fish has been contaminated by the extreme halophile Halobacterium. Which of these features of cells removed from the surface of the fish, if confirmed, would support your suspicion?

1. the presence of the same photosynthetic pigments found in cyanobacteria
2. cell walls that lack peptidoglycan
3. cells that are isotonic (equal in salt concentration) to conditions on the surface of the fish
4. cells unable to survive salt concentrations lower than 9%
5. the presence of very large numbers of ion pumps in its plasma membrane
   a. 1, 4, and 5
   b. 2, 3, 4, and 5
   c. 2 and 5
   d. 3 and 4

Answer 21

B

Question 22

In prokaryotes new mutations accumulate quickly in populations, while in eukaryotes new mutations accumulate much more slowly. The primary reasons for this are ________.

a. the DNA in prokaryotes is not as stable as eukaryotic DNA and is thus more likely to mutate
b. prokaryote mutations are less effective than eukaryote mutations in providing variation for evolution
c. prokaryotes have random mutations while eukaryotes can target genes for mutations; thus mutations may not accumulate as quickly in eukaryotes but they are more useful to the organism
d. prokaryotes have short generation times and large population sizes

Answer 22

D

Question 23

Which statement is true regarding archae and bacteria?

a. Bacteria have peptidoglycan in the cell wall while archae do not
b. Archae are only found in extreme environments (such as hot springs) but bacteria live in diverse habitats
c. All archae have flagella but not all bacteria have flagella
d. All answers are correct

Answer 23

A

Question 24

The chloroplasts of land plants are thought to have been derived according to which evolutionary sequence?

a. cyanobacteria → green algae → fungi → land plants
b. red algae → brown algae → green algae → land plants
c. cyanobacteria → red algae → green algae → land plants
d. cyanobacteria → green algae → land plants

Answer 24

D

Question 25

According to the endosymbiotic theory, why was it adaptive for the larger (host) cell to keep the engulfed cell alive, rather than digesting it as food?

a. The engulfed cell provided the host cell with adenosine triphosphate (ATP)
b. The host cell was able to survive anaerobic conditions with the engulfed cell alive
c. The engulfed cell allowed the host cell to metabolise glucose
d. The engulfed cell provided the host cell with carbon dioxide

Answer 25

A

Question 26

Dinoflagellates ________.

a. possess two flagella
b. include species that cause malaria
c. lack mitochondria
d. are all autotrophic

Answer 26

A

Question 27

Which two genera have members that can evade the human immune system by frequently changing their surface proteins? 1. Plasmodium; 2. Trichomonas; 3. Paramecium; 4. Trypanosoma; 5. Entamoeba

a. 2 and 4
b. 2 and 3
c. 4 and 5
d. 1 and 4

Answer 27

D

Question 28

Living diatoms contain brownish plastids. If global warming causes blooms of diatoms in the surface waters of Earth’s oceans, how might this be harmful to the animals that build coral reefs?

a. The diatoms’ photosynthetic output may over-oxygenate the water
b. The coral animals may die from overeating the plentiful diatoms with their cases of silica
c. The coral animals, which capture planktonic organisms, may be outcompeted by the diatoms
d. The coral animals’ endosymbiotic dinoflagellates may get “shaded out” (not able to get enough light) by the diatoms

Answer 28

D

Question 29

Why are protists important?

a. They can be symbionts and producers
b. They are eukaryotes
c. They are pathogenic
d. They provide scientists an easy way to study evolution

Answer 29

A

Question 30

Unikonta is a supergroup that includes all of the following except ________.

a. protists
b. fungi
c. animals
d. plants

Answer 30

D

Question 31

The thermoacidophile Sulfolobus acidocaldarius lacks peptidoglycan, but still possesses a cell wall. What is likely to be true of this species?

1. It is a bacterium.
2. It is an archaean.
3. The optimal pH of its enzymes will lie above pH 7 (alkaline)
4. The optimal pH of its enzymes will lie below pH 7 (acidic)
5. It could inhabit certain hydrothermal springs.
6. It could inhabit alkaline hot springs.
   a. 1, 3, and 5
   b. 1, 3, and 6
   c. 1, 4, and 5
   d. 2, 4, and 5

Answer 31

D

Question 32

When a mosquito infected with Plasmodium first bites a human, the Plasmodium ________

a. cells cause lysing of the human red blood cells
b. gametes fuse, forming an oocyst
c. cells infect the human liver cells
d. oocyst undergoes meiosis

Answer 32

C

Question 33

Mitochondria are thought to be the descendants of certain alpha proteobacteria (early bacteria) that were engulfed by host cells. Why are they no longer able to survive outside of the cell?

a. Many mitochondrial chromosomes have moved to the nuclear genome
b. Mitochondria are trapped in the second host cell membrane
c. Mitochondria have DNA but no mRNA
d. Mitochondria cannot process glucose, they need the host cells to undertake glycolysis first

Answer 33

A

Question 34

While examining a rock surface, you have discovered an interesting new organism. Which of the following criteria will allow you to classify the organism as belonging to Bacteria but not Archaea or Eukarya?

a. The lipids in its plasma membrane consist of glycerol bonded to straight-chain fatty acids
b. It can survive at a temperature over 100°C
c. Cell walls are made primarily of peptidoglycan
d. The organism does not have nucleus

Answer 34

C

Question 35

Which of the following have chloroplasts (or structures since evolved from chloroplasts) thought to be derived from ancestral green algae?

a. stramenopiles
b. apicomplexans (an alveolate)
c. chlorarachniophytes (archaeplastida clade)
d. dinoflagellates (an alveolate)

Answer 35

C

Question 36

Which protists have membrane enclosed air sacs?

a. alveolates
b. stramenopiles
c. rhizarians
d. unikonta

Answer 36

A

Question 37

The genome of modern chloroplasts is roughly 50% the size of the genome of the cyanobacterium from which it is thought to have been derived. In comparison, the genome of Paulinella chromatophora’s chromatophore is only slightly reduced relative to the size of the genome of the cyanobacterium from which it is thought to have been derived. What is a valid hypothesis that can be drawn from this comparison?

a. The genome of the cyanobacteria was smaller than the genome of P. chromatophora
b. P. chromatophora’s chromatophore is the result of a more recent evolutionarily endosymbiosis
c. The genome of the chloroplast ancestor contained many more introns that could be lost without harm, compared to the chromatophore’s genome
d. Lytic phage infections have targeted the chloroplast genome more often than the P. chromatophora genome

Answer 37

B

Question 38

The pathogenic prokaryotes that cause cholera are ________.

a. archaea that release an exotoxin
b. bacteria that release an endotoxin
c. bacteria that release an exotoxin
d. archaea that release an endotoxin

Answer 38

C

Question 39

What is the best description of endosymbiosis?

a. One organism lives inside another, to the benefit of both
b. One organism live on another organism, to the benefit of both
c. One organism lives inside another, to the benefit of only one of the organisms
d. One organism live on another organism, to the benefit of only one of the organisms

Answer 39

A