Which of the following is a
characteristic of an organism belonging to kingdom Monera? (A) Most of these organisms are
large and multicellular. (B) The cells of these organisms
contain a cellulose cell wall. (C) These organisms only reproduce
sexually. Or (D) the cells of these organisms
do not contain a membrane-bound nucleus.
In order to answer this question,
we’ll recall what we know about the characteristics of the five kingdoms of
life. And then we’ll use this information
to determine which of the answer choices is specific to kingdom Monera. The American botanist Robert
Whittaker is credited with developing the five-kingdom system. The five kingdoms into which he
divided all living organisms are Monera, Plant, Animal, Fungus, and Protist.
The main difference that sets
members of kingdom Monera apart from the other four is that all monerans are
prokaryotic organisms, meaning that their cells do not possess a nucleus or other
membrane-bound organelles. All of the organisms in the other
four kingdoms of life are eukaryotic, meaning that their cells possess a nucleus in
which the genetic material, or DNA, is stored. If you’re able to remember that
monerans are prokaryotic and that pro- means no nucleus, then you have enough
information to answer this question. But we’ll investigate further and
determine why each of the other answer choices is incorrect.
All prokaryotic organisms are
unicellular, although some join together to form strands or colonies. This rules out the answer choice
that says these organisms are large and multicellular. The cell walls of monerans are made
of peptidoglycan or other similar molecules. The cell walls of plant cells are
made of cellulose, and the cell walls of fungal cells are made of chitin. So, we know that organisms
belonging to kingdom Monera do not possess a cellulose cell wall. Finally, prokaryotic organisms
reproduce through a process called binary fission.
In binary fission, one parent cell
replicates its genetic material and then reproduces into two identical daughter
cells. Since only one parent is involved,
this is a method of asexual reproduction. This allows us to eliminate the
answer choice that says that these organisms reproduce sexually. The answer choice that describes a
characteristic of an organism belonging to kingdom Monera is the cells of these
organisms do not contain a membrane-bound nucleus.