MCB3020 Exam 1 – Bacusmo UPDATED
Questions and CORRECT Answers
Microbes - CORRECT ANSWER - Organisms that cannot be seen by the naked eye;
usually less than 1mm in diameter
Described as "invisible hitchhikers"
Found everywhere on the planet and in the body
How can microbiology be distinguished from other fields of biology? - CORRECT
ANSWER - Based on the size of the organism studied and the techniques used to study
them.
Roles of microbes - CORRECT ANSWER - Recycling essential elements
Source of nutrients (e.g. synthesizing vitamins B and K)
Photosynthesis
Production of useful substances
Disease and disease resistance
Cellular organisms - CORRECT ANSWER - Made of of cells:
Fungi (e.g. yeasts and molds)
Protists (e.g. algae, protozoa, slime molds, and water molds)
Bacteria (e.g. E. coli)
Archaea (e.g. methanogens)
Acellular organisms - CORRECT ANSWER - Not made of cells:
Viruses
Viroids and virusoids
,Satellites
Prions
Virus - CORRECT ANSWER - Composed of protein, nucleic acid (DNA or RNA, and
sometimes a lipid membrane; smallest microbes; require a host for replication
Viroids and virusoids - CORRECT ANSWER - Infectious agents compsoed of RNA only
Satellites - CORRECT ANSWER - Composed of nucleic acids enclosed in a protein shell
Eukaryotes - CORRECT ANSWER - Organisms with cells that have DNA in a
membrane-bound organelle called a nucleus; contain organelles. More complex than
prokaryotes.
Prokaryotes - CORRECT ANSWER - Organisms made up of a single cell lacking a
membrane-bound nucleus.
Carl Woese - CORRECT ANSWER - Responsible for distinguishing between Archaea
and Bacteria by studying rRNA. After his work in the 1970s, the phylogenetic tree of life shifted
from two domains to three.
LUCA - CORRECT ANSWER - Last universal common ancestor; common ancestor of all
three domains of life
Where is the LUCA located? - CORRECT ANSWER - On the bacterial branch
True/False: All organisms share a prokaryotic ancestor, but archaea are more closely related to
eukaryotes than bacteria. - CORRECT ANSWER - True
, What is the difference between bacteria and archaea? - CORRECT ANSWER - Different
rRNA sequences
Bacteria have a structured cell wall made of peptidoglycan, while archaea cell walls do not
contain peptidoglycan.
Unique membrane lipids
Archaea live in extreme environments (e.g. deep sea) and have unusual metabolic characteristics
Do bacteria have peptidoglycan in their cell walls? - CORRECT ANSWER - Yes
Do archaea have peptidoglycan in their cell walls? - CORRECT ANSWER - No
How are phylogenetic tree relationships determined? - CORRECT ANSWER - By
examining rRNA sequences. This DOES NOT provide information about the timing of
divergence- only the relationships.
General timeline of the evolution of life - CORRECT ANSWER - First cells appeared 3.5-
3.8 billion years ago
First fossils of primitive microbes date back to between 3.5-3.7 billion years ago
First eukaryotic cells with mitochondria and chloroplasts evolved 2.0-2.5 billion years ago
First multicellular eukaryotes evolved 1.5 billion years ago.
First fossil discovered - CORRECT ANSWER - Swartkoppie chert
Central dogma of molecular biology - CORRECT ANSWER - DNA contains genetic
information, which is then transcribed into mRNA, which is then translated to make proteins.
Questions and CORRECT Answers
Microbes - CORRECT ANSWER - Organisms that cannot be seen by the naked eye;
usually less than 1mm in diameter
Described as "invisible hitchhikers"
Found everywhere on the planet and in the body
How can microbiology be distinguished from other fields of biology? - CORRECT
ANSWER - Based on the size of the organism studied and the techniques used to study
them.
Roles of microbes - CORRECT ANSWER - Recycling essential elements
Source of nutrients (e.g. synthesizing vitamins B and K)
Photosynthesis
Production of useful substances
Disease and disease resistance
Cellular organisms - CORRECT ANSWER - Made of of cells:
Fungi (e.g. yeasts and molds)
Protists (e.g. algae, protozoa, slime molds, and water molds)
Bacteria (e.g. E. coli)
Archaea (e.g. methanogens)
Acellular organisms - CORRECT ANSWER - Not made of cells:
Viruses
Viroids and virusoids
,Satellites
Prions
Virus - CORRECT ANSWER - Composed of protein, nucleic acid (DNA or RNA, and
sometimes a lipid membrane; smallest microbes; require a host for replication
Viroids and virusoids - CORRECT ANSWER - Infectious agents compsoed of RNA only
Satellites - CORRECT ANSWER - Composed of nucleic acids enclosed in a protein shell
Eukaryotes - CORRECT ANSWER - Organisms with cells that have DNA in a
membrane-bound organelle called a nucleus; contain organelles. More complex than
prokaryotes.
Prokaryotes - CORRECT ANSWER - Organisms made up of a single cell lacking a
membrane-bound nucleus.
Carl Woese - CORRECT ANSWER - Responsible for distinguishing between Archaea
and Bacteria by studying rRNA. After his work in the 1970s, the phylogenetic tree of life shifted
from two domains to three.
LUCA - CORRECT ANSWER - Last universal common ancestor; common ancestor of all
three domains of life
Where is the LUCA located? - CORRECT ANSWER - On the bacterial branch
True/False: All organisms share a prokaryotic ancestor, but archaea are more closely related to
eukaryotes than bacteria. - CORRECT ANSWER - True
, What is the difference between bacteria and archaea? - CORRECT ANSWER - Different
rRNA sequences
Bacteria have a structured cell wall made of peptidoglycan, while archaea cell walls do not
contain peptidoglycan.
Unique membrane lipids
Archaea live in extreme environments (e.g. deep sea) and have unusual metabolic characteristics
Do bacteria have peptidoglycan in their cell walls? - CORRECT ANSWER - Yes
Do archaea have peptidoglycan in their cell walls? - CORRECT ANSWER - No
How are phylogenetic tree relationships determined? - CORRECT ANSWER - By
examining rRNA sequences. This DOES NOT provide information about the timing of
divergence- only the relationships.
General timeline of the evolution of life - CORRECT ANSWER - First cells appeared 3.5-
3.8 billion years ago
First fossils of primitive microbes date back to between 3.5-3.7 billion years ago
First eukaryotic cells with mitochondria and chloroplasts evolved 2.0-2.5 billion years ago
First multicellular eukaryotes evolved 1.5 billion years ago.
First fossil discovered - CORRECT ANSWER - Swartkoppie chert
Central dogma of molecular biology - CORRECT ANSWER - DNA contains genetic
information, which is then transcribed into mRNA, which is then translated to make proteins.
