Bacteria and protists are single-celled organisms. Bacteria come in different shapes - rod, spiral or sphere. They reproduce through binary fission. Protists are more complex than bacteria with organelles. They include algae, protozoans and other organisms. Protists obtain food through photosynthesis, consuming other organisms, or parasitism. They maintain water balance through osmosis and contractile vacuoles. Protists sense and react to their environment through structures like eyespots.
1. Bacteria and Protists
• Objectives: 7Sb.3
– Compare the body shapes of bacteria
• Detect differences among the shapes
• Be able to classify bacteria as spiral, coccus, or
bacillus
– Compare the body structures that protists use
for food gathering and locomotion
• Detect similarities and differences among the
structures of protists used for food obtainment and
locomotion
• Identify protits as a euglena, amoeba, or
paramecium based on structures for food gathering
and locomotion.
2. Bacteria
• Greatest number of
organisms in the
world
• Part of the monera
kingdom.
• Live almost
everywhere on Earth
3. Properties of Bacteria
• Single-celled organisms- usually very
small, seen using a microscope
• Simple organisms-lack organelles
• Biologist classify bacteria by their shape.
– Looks – rod, spiral or sphere
– Often form long chains or clusters that look
like a bunch of grapes.
5. Life Activities of Bacteria
• Each bacterial cell carries out all of the
basic life functions
– Ex. Break down dead organisms, some use
sunlight to make food
• Many need oxygen to carry out respiration:
aerobe
but some are poisoned by oxygen.
6. Methane producing Bacteria
• These bacteria live where oxygen is not
present such as the bottom of swamps.
• Anerobe: can live without oxygen
• They produce methane- a gas produced
by bacteria from hydrogen and carbon
dioxide.
Methane bubbles out of the
water as marsh gas.
Methane Bubbles
7. Binary Fission
• Bacteria reproduces
by a process called
binary fission.
• Binary Fission is
where the bacterial
cell divides into 2
cells that look the
same as the original
cell. Can reproduce
every 20 minutes.
8. Helpful Bacteria
Many are helpful in two ways.
1. Recycle nutrients such as carbon and
nitrogen. They breakdown dead organisms
or waster.
• Organisms that do this are called saprophytes.
• Some of the broken-down nutrients are returned to
the soil and plants use them. Animals eat the plants
to get the nutrients.
9. Helpful Bacteria
• 2. Help plants to get nitrogen.
– Nitrogen is plentiful in the atmosphere but
plants cannot absorb it from the air.
– The nitrogen must be changed to ammonia.
Some bacteria lives inside the roots of plants
and change the nitrogen to ammonia. In return
the plants provide food for the bacteria.
10.
11. Symbolic Relationships
• Mutualism- A • Commensalism- A
closeness in which relationship in which
two organisms live one organism benefits
together and help each and the other is not
other.
affected.
– Example- bacteria that
turns nitrogen into – Ex. Barnacles on
ammonia and the plant whales.
provides food for the
bacteria.
13. Useful to humans
• 1. Bacteria help to produce some food.
– Example- cheese, sour cream, yogurt, pickle
• 2. Bacteria can produce many different
materials that are helpful.
– Chemical companies use bacteria to make
vitamins. And some bacteria make antibiotics
to kill other kinds of bacteria.
14. Harmful Bacteria
• Some cause food to
spoil
– Ex. Cause mild to
spoil- refrigerating
food helps to prevent
spoiling because
bacteria grow slowly
at low temps.
– Food that looks or
tastes bad should be
thrown away.
15. FYI
• Doctors prescribe antibiotics such as penicillin to
fight bacterial disease.
• Bacteria often develops ways to resist the
antibiotic.
• Many household products contain antibacterial
agents- dish soap
– They also cause bacteria to become resistant.
– As more bacteria becomes resistant, scientists must
search for new ways to kill the bacteria.
16. Harmful Bacteria
• Some cause disease.
• Ex. Botulism, gonorrhea, strep
throat
• Some harm the body by producing
poisons called- toxins.
• A single gram of botulism can kill
a million people.
• Botulism is food poisoning.
– The bacteria can be inside
Notice can canned food. It produces
expanding
as the toxins.
Bacteria – Eating the contaminated food
grows.
causes botulism.
– Do not eat out of Expired cans
or cans that show bacterial
growth like the one to the left
17. Protists
• Is a kingdom
• Contains over 6,000 species
• Have many features like those of plants,
animals or fungi.
• Are single-celled
• Have organelles inside their cell.
18. Algae
• Plant-like protist are known as algae
• Use sunlight to make food
• Most are aquatic
• Important in 3 ways:
– 1. Produce nearly half the world’s carbohydrates
– 2. Provide food for other organisms
– 3. Release oxygen as they make food- about half the
world’s oxygen that enters the atmosphere comes
from algae.
19.
20. Euglena
• Euglena is a type of protist
• Has chloroplasts.
• Live in freshwater and moves with
a long, whiplike tail called a
flagellum.
• Has unique characteristics of both a plant
and a animal
• Contains chloroplasts that
photosynthesize
• Can consume other organisms as well.
21. Diatoms
• Diatoms are other kinds of protist
• Found in freshwater and in the ocean.
• Have hard shells that contain silica.
• As diatoms die, their shells build up in
deposits at the bottom of lakes and sea.
These deposits are mined to make metal
polish and soaps.
22. Seaweed
• Is many celled.
• Also called sea
lettuce.
• Giant seaweed is
called kelp- is
harvested and used to
thicken foods.
24. Protozoans
• Animal like protist
• Protozoan means first animal
• Live in water, on land or inside other
organisms.
• Cannot make their own food- eat bacteria
or other protists or dead organisms.
• Divided into 4 groups based on how they
move
25. Amoebas
• Move by pushing out
parts of the of their cell
called a pseudopod,
means “false foot.”
• Amoebas change their
shape
• Use pseudoposd to
surround and trap other
protists.
• Live on rocks and on
plants in ponds.
26. Paramecium
• Move with short,
hairlike structures
known as cilia.
• Cilia moves like oars.
When they move
back, the paramecium
moves forward.
• Often found in ponds.
27. Flegella
• Flegella- push or pull the protozoan
• Example is Giardia lamblia- is a parasite in the
intestines of animals.
• Get from water that contains waste from infected
animals. Causes tiredness, weight loss, but not
usually fatal.
• Ex. Sleeping sickness is more serious caused by
trypanosomes- a protozoan that is a parasite and
lives in blood. Spread by the bite of tsetse flies
which only live in Africa.
28. No means of moving
• Protozoans that reproduce
by forming spores.
• Called sporozonas. – a
protozoan that is a
parasite and lives in
blood, may cause malaria
• All sporozonas are
parasites
• Live in the blood of their
host
29. Malaria
• Sporozoan Plasmodium causes
malaria.
• Mosquitoes spread malaria
when they draw blood from an
infected person. The sporozoan
enters the mosquito and
reproduces. The mosquito
transfers the sporozoans when
it bites another person.
• Malaria can be deadly and it
affects ½ billion people every
year.
• It kills 1 –3 million a year.
30. Protists
• Carry out all of the basic life activities.
• Most are single-celled, but not simple
• Cells must perform the duties of tissues
and organs in a plant or an animal.
31. Getting and Digesting Food
• Algae makes their own food
• Protozoans do not
• Euglena does both
• Amoebas trap other protists
• Paramecia use their cilia to sweep food
particles over their surface.
– The food moves into an opening called the
gullet on the paramecium’s side. The gullet is
like the mouth of an animal
33. Paramecium eating
1. Enters gullet
2. The gullet encloses the food within a bubble like
structure called a food vacuole
3. Small packets of food travel all through the
paramecium and chemicals in the food vacuole
break down the food.
4. The food leaves the food vacuole to be used by
the paramecium.
5. Food that is not digested leaves the paramecium
through an opening called the anal pore.
Amoebas and other protozoan's also digest food
inside the food vacuoles.
35. Maintaining Water Balance
• Most protist live in a watery environment
• Water moves easily through the cell
membrane which causes a problem
• Think of a dry sponge. What happens to
the sponge as it gets wet?
• This is what happens to protists if they can
not control the water intake
36. Osmosis
• The water molecules outside the protists
are more concentrated and the chemical
molecules and water inside the protists are
not as concentrated.
• This difference in concentration causes
water to move into the protist from the
outside.
• Osmosis is the movement of water through
a cell membrane.
37. Passive Transport
• Water molecules move from an area of
high concentration to an area of low
concentration.
• This is a type of passive transport, or
movement, that doesn’t use cellular
energy.
38.
39. Cell’s burst
• Too much water causes a
protist to burst like a water
balloon.
• To avoid bursting, protists
release water that is not
needed.
• Structures called
contractible vacuoles
collect water. They contract
or pull together to squeeze
the water out of the protist.
• Contractile vacuoles carry
out the same functions as
your kidneys when you
drink too much water.
40. Sensing and Reacting
• All organisms must be able to sense and
react to signals in their environment.
• Many protists have an eyespot, which can
sense changes in the brightness of light.
• Eyespots allow algae to move to areas
where the light is brighter. With brighter
light they can make food more quickly.
42. Sensing and Reacting
• Protozoans can sense food in their
environment and move toward it.
• Protozoans can sense harmful chemicals
and move away from it.
• Can move away from objects in it’s way.
• Paramecium’s that bump into an object,
reverse by using their cilia.
43. Reproduction
• Single-celled protist reproduce by dividing
into 2 cells. The result is 2 protists that
look the same as the original cell and is an
example of asexual reproduction.
• Some reproduce in pairs. Each member of
the pair gives some hereditary material to
the offspring. The offspring is different
from either parent. This is an example of
sexual reproduction.
