MICROBES
Chapter 11
Standard Course of Study
6.03: Compare the life functions of
protists.
 7.01: Compare and contrast microbes.
 Students will be able to explain the
differences between protists, bacteria,
and viruses.
 VOCABULARY: virus, bacteria, protist,
euglena, amoeba, paramecium, volvox

What is a microbe?
A microbe is an organism that
can only be seen with the help of
a microscope.
 Microbes include:

 Viruses
 Bacteria
 Protists
 Fungi
Protists
Protists are eukaryotes
because they have a nucleus,
but cannot be classified as
plants, animals, or fungi.
 Single- or multi-celled
 May move with cilia, flagella,
or pseudopods.
 Size: 10 micrometers to 100
meters

Three Types of Protists
1. Plant-like: get energy from sun
 2. Animal-like: move through the
environment & eat other organisms
 3. Fungus-like: absorb nutrients from
the environment

Examples of Protists
Euglena: plant-like, but can
be autotroph or heterotroph
 Volvox: plant-like, lives in
colonies
 Amoeba: animal-like, moves
with pseudopods
 Paramecium: animal-like,
moves with cilia

Diagram of a Protist
•Nucleus
•Nucleolus
•Vacuoles
•Mitochondria
•Chloroplasts
Which statement best
explains the movement of
Euglena?
A) It expands and contracts its
muscles.
B) It sways its tentacles.
C) It floats in its environment.
D) It swings its flagella.

How do Amoebae move?
A) They move by using cilia.
 B) They move by using pseudopods.
 C) They move by using a flagellum.
 D) The cells move by swimming
together.

What is one way Amoebae are
different from Paramecia?
A) Amoebae move in a way different from
that of Paramecia.
 B) Amoebae are decomposers, but
Paramecia are producers.
 C) Amoebae produce their own food, but
Paramecia do not.
 D) Amoebae have cilia, but Paramecia do
not.

Bacteria
Single-celled
 Bacteria are prokaryotes. Their genetic
material is not found in a nucleus.
 Size: 1-2 micrometers
 Three main shapes: spherical, rodlike, or
spiral.

Examples of Bacteria
Cyanobacteria
 E. coli
 Lyme disease
 Pneumonia
 Syphilis
 Strep throat
 Anthrax
 Tetanus

Bacteria Diagram
•Genetic
material
•Ribosomes
•Cell wall
•Cell
membrane
•Cytoplasm
•Flagella
Viruses
A virus is a tiny, non-living particle that
enters and then reproduces inside of a
living cell.
 A virus may have DNA or RNA
 Many shapes of viruses.
 Size: 10-1,000 nanometers

Examples of Viruses
Ebola
 HIV
 Influenza (flu)
 Chicken pox
 Hepatitis
 Rabies
 Polio

Virus Structure

Viruses
have two
parts:
Genetic
material
(DNA or
RNA)
Protein
coat
Virus Reproduction
Which microorganisms are
generally classified as nonliving?
A) bacteria
B) fungi
C) protists
D) viruses

Which would be the most
complex to study due to its
changing structure?
A) polio virus
 B) influenza virus
 C) leprosy bacteria
 D) pneumonia bacteria

Which list of microbes is
arranged in order of increasing
size?
A) virus, protist, bacteria
 B) virus, bacteria, protist
 C) bacteria, virus, protist
 D) bacteria, protist, virus

Which is a microbe that contains
genetic material and protein
and is unable to reproduce
outside a living cell?
A) virus
 B) fungus
 C) protist
 D) bacteria

Which structure is found only
in eukaryotes?
A) nucleus
 B) ribosome
 C) cell wall
 D) cell membrane

Which best describes the main structural
difference between viruses and bacteria?
A) Bacteria have DNA only; viruses have a cell
wall and DNA.
 B) Bacteria have a cell membrane and DNA;
viruses have DNA only.
 C) Bacteria have a protein coat and DNA;
viruses have a cell membrane and DNA.
 D) Bacteria have a cell wall, DNA, cytoplasm,
and ribsomes; viruses consist of a protein coat
and DNA.

Influenza is caused by which
microbe?
A) bacterium
B) fungus
C) parasite
D) virus

Why are viruses not considered
living organisms?
A) They cannot grow.
 B) They do not require oxygen.
 C) They cannot reproduce on their own.
 D) They do not have a semi-permeable
membrane.

Which statement best contrasts a
bacterium and a virus?
A) A bacterium can reproduce, whereas a virus
will not reproduce.
 B) A bacterium does not live on living things,
whereas a virus does.
 C) A bacterium is a one-celled living organism,
whereas a virus is a nonliving organism.
 D) A bacterium is a nonliving organism,
whereas a virus is a one-celled living organism.

How does the size of bacteria
compare to the size of viruses?
A) Bacteria are larger than viruses.
 B) Bacteria are smaller than viruses.
 C) They are both relatively the same
size.
 D) The size depends on the specific
virus or bacteria.
