Transcript eukaryotic cells

Microbiology
It’s a small world…
Chapters 7 and 19
LIFE IS CELLULAR
• Cell Theory
– All living things are made up of
cells.
– Cells are the basic units of
both structure and function in
living things.
– New cells are made only from
existing cells.
BASIC CELL STRUCTURE
• All cells have:
– Cell membrane – thin layer that
surrounds cells
– Cytoplasm – gel like material inside
cells (the “juice”)
– Genetic material (DNA and/or RNA)
– Ribosomes – make proteins
• Some cells have:
– Cell wall – more rigid structure on
outside of some cell membranes
– Nucleus – contains genetic material
(brain of the cell)
– Mitochondria – make energy
(powerhouse)
– Chloroplasts – make sugar
(photosynthesis)
DIVERSITY OF LIFE
• All cells fall into two categories of
cells:
1.Prokaryotes
• Includes bacteria
2.Eukaryotes
• Includes animals, plants, fungi,
and protists (like amoebas and
paramecium)
CHARACTERISTIC OF PROKARYOTES
• No membrane-bound
organelles (“little organs” in
cells)
• No nucleus, mitochondria, or
chloroplasts
• Have DNA, ribosomes,
cytoplasm, cell membrane, and
cell wall
Bacterium
• Fossil evidence shows that
bacteria have been on the
earth for over 3.5 billion
years
• Three major shapes
– Cocci (round)
– Bacilli (rod-like)
– Spirilla (spiral)
HARMFUL BACTERIA
• Some bacteria are pathogens (disease
causing)
• Some bacteria can make endospores, which
allow bacteria to survive long periods of time
(even in bad conditions)
• Diseases caused by bacteria:
•Pneumonia
•Strep throat
•Ear infections
•Salmonella
•Cholera
•E. coli infections
•Lyme
•Tetanus
•Tuberculosis
•Leprosy
Botulism
Strep throat
Leprosy
HELPFUL BACTERIA
• In your intestine, E. coli help to
digest food
• Used to make yogurt
• Can be used to degrade oil and
toxic waste spills
• Used to make certain medicines
• Used as “gene” factories
• Help plants fix nitrogen
• Major decomposers
Decomposition over 2 weeks
Legumes with nitrogen fixing
bacteria in their roots
KILLING BACTERIA
• Antibiotics- drugs that kill bacteria by
blocking growth or reproduction
– Antibiotics do NOT kill any viruses so they
do not cure the common cold or flu
– Some bacteria are now resistant to
antibiotics (ex. MRSA)
– We must always take antibiotics as
prescribed!
• Sterilization – destroying bacteria by
heating or with chemicals
Archaea
• Extremophiles activity.
• List seven different types of
extremophiles from the archaea
domain and explain their habitat
requirements.
CHARACTERISTICS OF EUKARYOTES
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Cell membrane
Cytoplasm
Cytoskeleton
Ribosomes
Organelles that are membrane bound
(ex. mitochondria and chloroplasts)
• Fossil evidence shows that eukaryotic
cells have been on the earth for
approximately 1 billion years.
Animal Cell
Plant Cell
VIRUSES
• Viruses are particles made up of
nucleic acid (DNA and/or RNA),
protein, and sometimes lipids.
• Viruses are NOT living because they
cannot reproduce by themselves.
• All viruses enter (infect) living cells
and once inside of a cell, they make
more viruses.
• All viruses are pathogens.
• Viruses are thought to have evolved
from pieces or fragments of cells.
VIRUS STRUCTURE
• Viruses have a core of genetic
material surrounded by a capsid
(protein coat)
• They are much smaller than
bacteria and animal cells.
• They come in many shapes.
VIRAL INFECTIONS
• All cells can be infected by viruses
including bacteria, animals, and plants.
• Bacteriophage – a virus that infects a
bacterial cell
• There are two main methods of
infection:
1.Lysogenic
2.Lytic
Bacteriophage (virus) infecting a bacterium
LYTIC CYCLE
• Viruses inject their genetic material
(DNA or RNA) into the host cell.
• This genetic material gives
instructions to make viruses.
• The viruses are released by causing
the cell to burst (lyse), which kills
the cell.
LYSOGENIC CYCLE
• A virus injects its genetic material
(DNA or RNA) into the host cell.
• The virus’s genetic material is mixed
in with the host DNA.
• Viral DNA can stay embedded in the
host DNA for long periods of time.
• Sometimes, the viral DNA will
instruct new viruses to be made and
the lytic cycle begins.
VIRAL DISEASES
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Polio
AIDS
Influenza (the flu)
Yellow fever
Rabies
Common cold
Some cancers like cervical cancer
Measles
Small pox
Small Pox
Measles
Polio
1918 Flu Pandemic
Herpes
VACCINES
• Vaccines – made from weakened or
“killed” viruses
• Vaccines stimulate the immune
system to fight a specific disease
• Vaccines help prevent viral and
bacterial diseases from developing,
but cannot help someone already
infected
• Examples include: HPV, MMR, Hep A
PRIONS
• Prions - possibly infectious proteins that
can change brain proteins causing brain
damage
• Diseases caused by prions progress
rapidly and are almost always fatal
• Diseases caused by prions include:
– Mad Cow Disease
– Creutzfeldt-Jakob Disease (CJD)
Creutzfeld-Jakob Disease
Spread the word, not the germs!
1) WASH your hands when they are dirty and
BEFORE eating.
2) DO NOT cough into your hands.
3) DO NOT sneeze into your hands.
4) DO NOT put your fingers into your eyes, nose,
or mouth.
• Regular soap and water are best. Antibacterial
soaps are not necessary if you have spent enough
time (at least 20 seconds) cleaning your hands with
regular soap and water.
• (Source: www.henrythehand.com)