Topic 4 - Eukaryotes - Clickers Flashcards
What would you predict for the cell wall of a microorganism that makes bread, beer, and wine?
a) Peptidoglycan: Found in bacterial cell walls; composed of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM) linked by β-(1,4)-glycosidic bonds.
b) Pseudomurein: Found in some archaeal cell walls; composed of N-acetyltalosaminuronic acid and N-acetylglucosamine (NAG) linked by β-(1,3)-glycosidic bonds.
c) Simplified peptidoglycan-like structure: Found in certain archaeal species, with alternative arrangements of structural components.
d) Polysaccharides and proteins: Found in halophilic archaea; does not include peptidoglycan or pseudomurein but is adapted for survival in extreme saline conditions.
a) is correct because it represents the β-1,4 linkage of N-acetylglucosamine (NAG), which is a key structural component of chitin. Chitin is a major constituent of fungal cell walls, including those of microorganisms that produce bread, beer, and wine, such as Saccharomyces cerevisiae (yeast).
Where would you find this?
Choose all that apply.
a) fungi
b) archaea
c) bacteria
d) viruses
a) fungi
Explanation: This structure represents chitin, a polymer of N-acetylglucosamine, which is a characteristic component of fungal cell walls. Chitin provides structural integrity and rigidity to fungi, similar to the role of cellulose in plants or peptidoglycan in bacterial cell walls. It is a critical feature that distinguishes fungal cell walls from those of other organisms.
Incorrect match?
a) MreB and actin
b) FtsZ and tubulin
c) Algae and cellulose
d) Chitin and NAM
e) ParM and plasmids
d) Chitin and NAM
Explanation: Chitin is a polysaccharide found in fungal cell walls, not associated with N-acetylmuramic acid (NAM), which is specific to bacterial peptidoglycan.
Why does Dictyostelium generate macrocysts?
a) Generating new genetic combinations and minimizing the impact of detrimental genes.
b) Generating large numbers of gametes and new genetic combinations.
c) Generating large numbers of gametes that are genetically identical.
d) Generating diploid gametes and new genetic combinations.
a) Generating new genetic combinations and minimizing the impact of detrimental genes.
Explanation: Macrocysts allow Dictyostelium to undergo sexual reproduction, promoting genetic diversity and reducing the impact of harmful genes.
A million people died, mostly in Ireland, due to loss of a primary food crop. Why?
a) Saccharomyces
b) Plasmodium
c) Rhytisma
d) Cordyceps
e) Phytophthora
e) Phytophthora
Explanation: Phytophthora infestans caused the Irish potato famine by destroying potato crops.
Phytophthora is a strange one…
a) algae – cellulose
b) algae – chitin
c) fungi – chitin
d) fungi – cellulose
d) fungi – cellulose
Explanation: Although Phytophthora resembles fungi, it has cellulose in its cell walls like algae.
Why is it a sad day for Sarah’s bread? (what is the most likely cause of the fungal growth)
a) Basidiomycota
b) Chytridiomycota
c) Glomeromycota
d) Zygomycota
e) Ascomycota
d) Zygomycota
Explanation: Zygomycota, such as Rhizopus, is responsible for bread mold.
Your friend (a human) feels sick and asks you about the pathogen’s cell wall. Which cell wall composition can you rule out?
a) [NAG NAT]n
b) [NAG NAG]n
c) [NAG NAM]n
a) [NAG NAT]n
Explanation: [NAG NAT]n is found in archaeal cell walls, not in bacterial or fungal pathogens.
All of these are haploid EXCEPT…
a) Dictyostelium in a fruiting body
b) Escherichia coli
c) Dictyostelium in a macrocyst
d) Motile Chlamydomonas in favourable conditions
e) Saccharomyces released from an ascus
c) Dictyostelium in a macrocyst
Explanation: A macrocyst is a diploid structure formed during the sexual cycle of Dictyostelium, making it the exception among the haploid examples listed.
A million people died, mostly in Ireland, due to loss of a primary food crop. Why?
a) Phytophthora
b) Cordyceps
c) Rhytisma
d) Saccharomyces
e) Plasmodium
a) Phytophthora
Explanation: Phytophthora infestans caused the Irish Potato Famine by infecting potato crops with late blight, leading to widespread famine and death.
The fly agaric (Amanita muscaria) is an iconic (yet toxic) fungi. Surprisingly, the strain of this species that you find in Ontario produce yellow mushrooms. What are they?
a) Phototrophs
b) Lithotrophs
c) Autotrophs
d) Primary producers
e) Heterotrophs
e) Heterotrophs
Explanation: Amanita muscaria, like all fungi, are heterotrophs, obtaining nutrients by breaking down organic matter rather than producing it themselves.
Which is true?
a) An axoneme is an array where nine pairs of microtubules are wrapped around a core pair of microtubules.
b) Cilia and flagella of eukaryotes are made of the same protein subunits as bacterial flagella.
c) Mitochondria are completely autonomous, with their own genome encoding all proteins needed to function.
d) Kinesins are molecular motors for flagella.
e) Evidence for prokaryotic origin for mitochondria and chloroplasts include a peptidoglycan layer around these organelles.
a) An axoneme is an array where nine pairs of microtubules are wrapped around a core pair of microtubules.
Explanation: This structure is a defining feature of the axoneme, which is found in eukaryotic cilia and flagella.
Pizza night! Oh no, we’re fresh out of (mushroom topping)…
a) Zygomycota
b) Glomeromycota
c) Chytridiomycota
d) Basidiomycota
e) Ascomycota
d) Basidiomycota
Explanation: Most edible mushrooms belong to the phylum Basidiomycota, making it the correct answer.
Pizza night! Oh no, we’re fresh out of (what makes dough rise)…
a) Glomeromycota
b) Ascomycota
c) Zygomycota
d) Chytridiomycota
e) Basidiomycota
b) Ascomycota
Explanation: Yeasts like Saccharomyces, which are responsible for making dough rise, belong to the phylum Ascomycota.
Find the INCORRECT association.
a) Protozoa and termite guts
b) Cordyceps and arthropods
c) x-bacteria and amoeba
d) Dictyostelium and potato blight
e) Nanoarchaeum and Ignicoccus
d) Dictyostelium and potato blight
Explanation: Dictyostelium is a slime mold and does not cause potato blight, which is caused by Phytophthora.
