BSC 2011 Exam 2 Learning Objectives | UPDATED
Questions with 100% Verified Answers
Q1: Identify the differences between Bacteria, Archaea, Eukarya
and the relationships between the 3 groups
A: Bacteria and Archaea are subgroups of Prokaryotes
Eukarya contains eukaryotes (protists, animals, plants and fungi)
Archaea is more closely related to Eukarya than Bacteria
Bacteria and eukaryotes developed the flagella analogously
Plant and fungi contain cellulose and chitin in their cell walls, while bacteria contain
peptidoglycan and archaea contain polysaccharides and proteins
Prokaryotes lack a nucleus, and membrane enclosed organelles
Prokaryotes have circular DNA, while eukaryotes have linear DNA
Prokaryotes reproduce asexually only
Both Archaea and Eukarya contain histones
The first prokaryotes were extremophiles; lived in both highly saline and highly hot
environments
Q2: Explain the ecological roles of prokaryotes: decomposers,
producers, nitrogen fixers, pathogens and various symbioses
A: Ecosystems depend on the continual recycling of chemical elements between the living
and nonliving components of the environment
Q3: Explain the ecological role as decomposers
A: Release CO2 into the atmosphere and breaks down dead organisms into carbon to be
recycled in the environment
Q4: Explain the ecological role as producers
A: Convert CO2 into O2 and sugar to be used as a form of energy
Provide energy to other organisms by being eaten directly or indirectly
Q5: Explain the ecological role as nitrogen fixers
A: Uses nitrogen fixation to convert atmosphere N2 into ammonium to be used for plants
for metabolism
, Q6: Explain the ecological role as pathogens
A: Some prokaryotes are parasites that cause diseases by either invading the host cell or
producing toxins
Q7: Explain the ecological role of various symbioses
A: 1. Host- the larger organism in a symbiotic relationship
2. Symbiont- the smaller organism that resides in the host
3. Mutualism- an ecological interaction between two species in which both benefit 4.
Commensalism- an ecological relationship in which one species benefits while the other
is not harmed or helped in any significant way.
4. Parasitism- an ecological relationship in which a parasite eats the cell contents, tissues,
or body fluids of its host
Q8: Discuss the mechanisms of horizontal gene transfer, the
widespread nature of this process in prokaryotes and its
importance in the evolution of eukaryotic groups.
A: Three mechanisms: transformation, conjugation and transduction
Allows transfer of genes between two different species, by making the genes either
immune or pathogenic
HGT is common in both archaea and bacteria and 80% of prokaryotic genes have been
involved in HGT at some point in their history
Q9: Describe major shapes, cell wall types, modes of nutrition
used by bacteria and different responses to oxygen
A:
Q10: Major shapes
A: Coccus - spherical
Bacillus - Rod-shaped
Spirrillus - Spiral shaped
Q11: Cell Walls
A: Gram Negative and Gram positive
1. Gram positive- thick layer of peptidoglycan with an inner membrane; stains purple
2. Gram negative - thin layer of peptidoglycan with no inner membrane; stains pink (gram
Questions with 100% Verified Answers
Q1: Identify the differences between Bacteria, Archaea, Eukarya
and the relationships between the 3 groups
A: Bacteria and Archaea are subgroups of Prokaryotes
Eukarya contains eukaryotes (protists, animals, plants and fungi)
Archaea is more closely related to Eukarya than Bacteria
Bacteria and eukaryotes developed the flagella analogously
Plant and fungi contain cellulose and chitin in their cell walls, while bacteria contain
peptidoglycan and archaea contain polysaccharides and proteins
Prokaryotes lack a nucleus, and membrane enclosed organelles
Prokaryotes have circular DNA, while eukaryotes have linear DNA
Prokaryotes reproduce asexually only
Both Archaea and Eukarya contain histones
The first prokaryotes were extremophiles; lived in both highly saline and highly hot
environments
Q2: Explain the ecological roles of prokaryotes: decomposers,
producers, nitrogen fixers, pathogens and various symbioses
A: Ecosystems depend on the continual recycling of chemical elements between the living
and nonliving components of the environment
Q3: Explain the ecological role as decomposers
A: Release CO2 into the atmosphere and breaks down dead organisms into carbon to be
recycled in the environment
Q4: Explain the ecological role as producers
A: Convert CO2 into O2 and sugar to be used as a form of energy
Provide energy to other organisms by being eaten directly or indirectly
Q5: Explain the ecological role as nitrogen fixers
A: Uses nitrogen fixation to convert atmosphere N2 into ammonium to be used for plants
for metabolism
, Q6: Explain the ecological role as pathogens
A: Some prokaryotes are parasites that cause diseases by either invading the host cell or
producing toxins
Q7: Explain the ecological role of various symbioses
A: 1. Host- the larger organism in a symbiotic relationship
2. Symbiont- the smaller organism that resides in the host
3. Mutualism- an ecological interaction between two species in which both benefit 4.
Commensalism- an ecological relationship in which one species benefits while the other
is not harmed or helped in any significant way.
4. Parasitism- an ecological relationship in which a parasite eats the cell contents, tissues,
or body fluids of its host
Q8: Discuss the mechanisms of horizontal gene transfer, the
widespread nature of this process in prokaryotes and its
importance in the evolution of eukaryotic groups.
A: Three mechanisms: transformation, conjugation and transduction
Allows transfer of genes between two different species, by making the genes either
immune or pathogenic
HGT is common in both archaea and bacteria and 80% of prokaryotic genes have been
involved in HGT at some point in their history
Q9: Describe major shapes, cell wall types, modes of nutrition
used by bacteria and different responses to oxygen
A:
Q10: Major shapes
A: Coccus - spherical
Bacillus - Rod-shaped
Spirrillus - Spiral shaped
Q11: Cell Walls
A: Gram Negative and Gram positive
1. Gram positive- thick layer of peptidoglycan with an inner membrane; stains purple
2. Gram negative - thin layer of peptidoglycan with no inner membrane; stains pink (gram
