MCB 3023 Exam 1 Questions with Correct Answers Latest Version 2025
In which of these are Archaea and Bacteria significantly different?
lack of a membrane-enclosed nucleus
possession of membrane enclosed organelles
cell size
membrane lipid structure
chromosome size and organization - Answers membrane lipid structure
Several Archaea have a lipid monolayer instead of a lipid bilayer comprising their cytoplasmic
membrane. Why could this be an advantage?
This type of structure is permeable to protons
This type of structure offers considerable protection against osmotic pressure
This type of chemical lipid structure is more stable at very high temperatures
Proteins are able to integrate more easily into this type of structure
,Carbohydrates can easily diffuse across this structure to provide nutrients for the cell - Answers This
type of chemical lipid structure is more stable at very high temperatures
What is the primary reason that Woese and Fox choose the rRNA molecule to study phylogenetic
relationships between organisms?
Ribosomal RNA is abundant in the cell
Ribosomal RNA sequencing was very easy to perform at the time
Ribosomal RNA is very easy to isolate and manipulate
Ribosomal RNA is a molecule found in all living organisms
Ribosomal RNA is a very stable molecule - Answers Ribosomal RNA is a molecule found in all living
organisms
Chaperone proteins in hyperthermophilic archaeal cells are known as
thermosomes
desmosomes
ribosomes
chaperonins
,hyperthermosomes - Answers thermosomes
Why might the process of chemotaxis in the archaeon Halobacterium be similar to chemotaxis in
Bacteria?
Fagellum assembly is identical in both Halobacterium and Bacteria
Both Halobacterium and Bacteria use ATP to turn the flagellum
Genes that encode proteins for flagellum assembly are found in both Halobacterium and Bacteria
The flagellin protein is almost identical in sequence for both Halobacterium and Bacteria
Similar proteins in the chemotaxis signaling pathway are found in both Halobacterium and Bacteria -
Answers Similar proteins in the chemotaxis signaling pathway are found in both Halobacterium and
Bacteria
Eukaryal microbes play a very important role in the digestion of ___ in the gut of ruminants
nucleic acids
phospholipids
lactose
proteins
, cellulose - Answers cellulose
Giardia lamblia is of significance because:
it is a respiratory pathogen
its ancestry is one of the most recent among protozoa
its locomotion permits study of the mechanism by which cilia operate
its metabolism is typical of all protists using aerobic respiration
it causes disease in around one billion individuals around the world - Answers It causes disease in
around one billion individuals around the world
Which of these comprises the viral genome?
double-stranded DNA
double-stranded RNA
All of these choices are seen in viruses.
single-stranded DNA
single-stranded RNA - Answers All of these choices are seen in viruses
In which of these are Archaea and Bacteria significantly different?
lack of a membrane-enclosed nucleus
possession of membrane enclosed organelles
cell size
membrane lipid structure
chromosome size and organization - Answers membrane lipid structure
Several Archaea have a lipid monolayer instead of a lipid bilayer comprising their cytoplasmic
membrane. Why could this be an advantage?
This type of structure is permeable to protons
This type of structure offers considerable protection against osmotic pressure
This type of chemical lipid structure is more stable at very high temperatures
Proteins are able to integrate more easily into this type of structure
,Carbohydrates can easily diffuse across this structure to provide nutrients for the cell - Answers This
type of chemical lipid structure is more stable at very high temperatures
What is the primary reason that Woese and Fox choose the rRNA molecule to study phylogenetic
relationships between organisms?
Ribosomal RNA is abundant in the cell
Ribosomal RNA sequencing was very easy to perform at the time
Ribosomal RNA is very easy to isolate and manipulate
Ribosomal RNA is a molecule found in all living organisms
Ribosomal RNA is a very stable molecule - Answers Ribosomal RNA is a molecule found in all living
organisms
Chaperone proteins in hyperthermophilic archaeal cells are known as
thermosomes
desmosomes
ribosomes
chaperonins
,hyperthermosomes - Answers thermosomes
Why might the process of chemotaxis in the archaeon Halobacterium be similar to chemotaxis in
Bacteria?
Fagellum assembly is identical in both Halobacterium and Bacteria
Both Halobacterium and Bacteria use ATP to turn the flagellum
Genes that encode proteins for flagellum assembly are found in both Halobacterium and Bacteria
The flagellin protein is almost identical in sequence for both Halobacterium and Bacteria
Similar proteins in the chemotaxis signaling pathway are found in both Halobacterium and Bacteria -
Answers Similar proteins in the chemotaxis signaling pathway are found in both Halobacterium and
Bacteria
Eukaryal microbes play a very important role in the digestion of ___ in the gut of ruminants
nucleic acids
phospholipids
lactose
proteins
, cellulose - Answers cellulose
Giardia lamblia is of significance because:
it is a respiratory pathogen
its ancestry is one of the most recent among protozoa
its locomotion permits study of the mechanism by which cilia operate
its metabolism is typical of all protists using aerobic respiration
it causes disease in around one billion individuals around the world - Answers It causes disease in
around one billion individuals around the world
Which of these comprises the viral genome?
double-stranded DNA
double-stranded RNA
All of these choices are seen in viruses.
single-stranded DNA
single-stranded RNA - Answers All of these choices are seen in viruses
