1. Which statement is FALSE regarding bacterial and archaeal cells? Select one:
ID: 93385 • Letter: 1
Question
1. Which statement is FALSE regarding bacterial and archaeal cells?
Select one:
A. Archaeal and bacterial plasma membranes consist of a thin bilayer of lipid molecules penetrated by proteins.
B. Bacteria and archaea have group specific specializations in their cell envelope.
C. Archaea can have a single- or double-layered membrane.
D. Bacteria can have a single- or double-layered membrane.
E. Both bacteria and archaea have a layer of peptidoglycan in their cell envelope.
2.Which reason is MOST probable for why carbon is used in living organisms but not silicon?
Select one:
A. Carbon can make four bonds, whereas silicon can only make three.
B. Silicon is heavier, and therefore its bonds are stronger.
C. Carbon can form more preferred geometries when bonding.
D. Carbon is lighter, and therefore its bonds are stronger.
E. Carbon can make double bonds, but silicon cannot.
3.
Which statement is TRUE regarding energy sources used by organisms?
Select one:
A. All phototrophs are autotrophs that can use carbon dioxide as a carbon source.
B. Phototrophs can use carbon dioxide as an energy source.
C. Phototrophs can use carbon dioxide as a carbon source.
D. All phototrophs are autotrophs.
E. All chemotrophs are heterotrophs.
Explanation / Answer
1. Which statement is FALSE regarding bacterial and archaeal cells?
Answer) E. Both bacteria and archaea have a layer of peptidoglycan in their cell envelope.
The cell envelope of archaea lacks peptidoglycan. It is covered by a paracrystalline protein layer known as S-layer and is made up of polysaccharides and proteins.
2. Which reason is MOST probable for why carbon is used in living organisms but not silicon?
Answer) D. Carbon is lighter, and therefore its bonds are stronger.
Carbon and silicon both can make four bonds, hence option A is incorrect.
Silicon is heavier than carbon but forms weak bonds, hence option B is incorrect.
Carbon and silicon both can make double bonds, hence option E is incorrect.
Carbon is much lighter and more flexible, hence it is more reactive than silicon and therefore its bonds are stronger.
3. Which statement is TRUE regarding energy sources used by organisms?
Answer ) C. Phototrophs can use carbon dioxide as a carbon source.
Phototrophs can be photoautotrophs and photoheterotrophs. Similarly, chemotrophs can be chemoautotrophs and chemoheterotrophs. Phototrophs use light as an energy source and carbon dioxide as a carbon source.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.