Transcript The Early Years of Microbiology Bacteria

Bell Ringer
• Complete bell ringer on “Think-PairShare” worksheet silently
• Advertisements tell you that bacteria
and viruses are all over your home and
that you need to buy antibacterial
cleaning products. Should you?
Suspended Curriculum
Objectives
• By the end of the lesson, students will
be able to
– 1) Describe the general properties
and characteristics of bacteria, fungi,
parasites, and viruses.
– The will be demonstrated by the completion of
a concept map as an exit slip
Chapter 1
A Brief
History of
Microbiology
© 2012 Pearson Education Inc.
Lecture prepared by Mindy Miller-Kittrell
North Carolina State University
Microbiology
• Microorganisms (microbes)
– Tiny living things
– too small to see with naked eye
• Many are associated with disease
– Pathogens
• Roles of microbes in heath of living
organisms and environment
– Photosynthesis
– Recycle nutrients and make nutrients in
human body
– Protect against diseases
© 2012 Pearson Education Inc.
The Early Years of Microbiology
• What Does Life Really Look Like?
– Antoni Van Leeuwenhoek (Dutch)
– Began making and using simple microscopes
– new microscopes for each specimen
– Examined water and visualized tiny animals,
fungi, algae, and single-celled protozoa:
“animalcules”
– By end of 19th century, these organisms were
called microorganisms
© 2012 Pearson Education Inc.
Figure 1.2 Reproduction of Leeuwenhoek’s microscope
Lens Specimen holder
The Early Years of Microbiology
• How Can Microbes Be Classified?
– Linnaeus developed taxonomic system for
grouping similar organisms together
– Leeuwenhoek’s microorganisms grouped into six
categories:
– Bacteria
– Archaea
– Fungi
– Protozoa
– Algae
– Small multicellular animals
© 2012 Pearson Education Inc.
The Early Years of Microbiology
• Bacteria
– Unicellular and lack nuclei (prokaryotes)
– Much smaller than eukaryotes
– Reproduce asexually
– Binary fission
– Cell walls contain peptidoglycan
– Come in a variety of shapes
– Coccus (spherical)
– Bacillus (rodlike)
– Spiral (corkscrew or curved)
© 2012 Pearson Education Inc.
Figure 1.4 Cells of the bacterium Streptococcus
Nucleus of
Prokaryotic
bacterial cells eukaryotic cheek cell
The Early Years of Microbiology
• Archaea
–
–
–
–
Unicellular and lack nuclei
Much smaller than eukaryotes
Reproduce asexually
Cell walls composed of polymers other than
peptidoglycan
– Found in extreme conditions
– Methanogens
– Halophiles
– Thermophiles
© 2012 Pearson Education Inc.
The Early Years of Microbiology
• Fungi
– Eukaryotic (have membrane-bound nucleus)
– Obtain food from absorbing nutrients from
environment
– Cell walls made of chitin
– Include
– Molds – multicellular; grow as long
filaments; reproduce by sexual and asexual
spores
– Yeasts – unicellular; reproduce by budding
or sexual spores
© 2012 Pearson Education Inc.
Figure 1.5 Fungi-overview
The Early Years of Microbiology
• Protozoa
– Single-celled eukaryotes
– Similar to animals in nutrient needs and cellular
structure
– Live freely in water; some live in animal hosts
(parasites)
– Asexual (most) and sexual reproduction
– Most are capable of movement by
– Pseudopodia
– Cilia
– Flagella
© 2012 Pearson Education Inc.
Figure 1.6 Locomotive structures of protozoa-overview
The Early Years of Microbiology
• Algae
–
–
–
–
Unicellular or multicellular
Photosynthetic
Sexual and asexual reproduction
Categorized on the basis of pigmentation,
storage products, and composition of cell wall
– Chemicals from their cell walls are used to
make microbiology lab media
© 2012 Pearson Education Inc.
Figure 1.7 Algae-overview
Other Important Microorganisms
• Parasitic worms
– Helminths
– Flatworms and roundworms
– Eukaryotes
– Microscopic to 7 meters long
– Many cause disease
– Eggs can be found in blood, feces, urine,
lymph
© 2012 Pearson Education Inc.
Figure 1.8 An immature stage of a parasitic worm in blood
Red blood cell
Other Important Microorganisms
• Viruses
– Acellular
– Tiny, cannot be seen with light microscopes
– Obligate intracellular parasites
– Can only reproduce by controlling the cellular
machinery of other organisms
– Contain a core of nucleic acid surrounded by a
protein coat
© 2012 Pearson Education Inc.
Figure 1.9 Viruses infecting a bacterium
Virus
Bacterium
Viruses
assembling
inside cell
Cold Calling
• State one role of microorganisms in humans
or the environment
• What microorganism is not composed of
cells?
• Name one prokaryotic microbe.
• Which unicellular microbes lack a cell wall,
but have a nucleus?
Exit Slip
• Concept Map