CHAPTER 1 LESSON 2 NOTES:
SINGLE-CELLED ORGANISMS
MAIN IDEA:
• IN SINGLE-CELLED ORGANISMS, ALL LIFE PROCESSES ARE CARRIED OUT IN JUST
ONE CELL.
Bacteria
Paramecium
Amoeba
I. LIFE AS A SINGLE-CELLED ORGANISM:
1.) ALL LIVING CELLS TAKE IN FOOD AND GET RID OF WASTE
2.) SINGLE-CELLED ORGANISMS CAN ONLY BE SEEN USING A MICROSCOPE, KNOWN
AS MICRO-ORGANISMS
A.) EXAMPLES: AMOEBAS, PARAMECIA, BACTERIA
3.) THEY ALSO NEED TO STORE ENERGY FROM FOOD TAKEN IN
4.) DIATOM-PROTISTS: SAND DOLLAR
II. INTERACTIONS W/ LARGER ORGANISMS:
1.) BACTERIA BREAK DOWN THE REMAINS OF DEAD PLANTS AND ANIMALS
RETURNING NUTRIENTS BACK INTO THE ENVIRONMENT FOR OTHER LIVING
ORGANISMS TO USE
A.) EXAMPLES: YOGURT, SOUR CREAM, BUTTERMILK, PICKLES, SAUERKRAUT, &
COTTAGE CHEESE
2.) STREP THROAT, LYME DISEASE, & TUBERCULOSIS COME FROM
BACTERIAL INFECTIONS
II. INTERACTIONS W/ LARGER ORGANISMS:
(CONTINUED)
3.) ANTIBIOTICS- DRUGS THAT TREAT BACTERIAL INFECTIONS
4.) YEAST AND ALGAE ARE TWO MORE SINGLE-CELLED ORGANISMS: BREAD, VINEGAR,
AND ETHANOL
5.) A FEW TYPES OF YEASTS CAUSE DISEASE IN PLANTS, ANIMALS, AND HUMANS
* QUESTION: WHY ARE BACTERIA IMPORTANT FOR ALL LIVING THINGS?
III. GETTING FOOD: SINGLE-CELLED ORGANISMS:
1.) DIFFERENT WAYS: ( ALL ORGANISMS NEED ENERGY )
A.) TAKE IN FOOD FROM THE OUTSIDE
B.) MAKE THEIR OWN
2.) AMOEBAS: DOES NOT HAVE “CILIA”
A.) FIRST: STRETCHES AROUND THE FOOD PARTICLE
B.) SECOND: FORMS A SAC OR VACUOLE AROUND THE FOOD
C.) THIRD: FOOD IS DIGESTED IN THE VACUOLE AND THEN RELEASED INTO THE CYTOPLASM
D.) LASTLY: WASTES ARE WASHED AWAY THROUGH THE CELL MEMBRANE AS THE ORGANISM
MOVES THROUGH THE WATER
IV. PARAMECIUM
1st:
Small hairs sweep food
particles into a groove called
the oral groove.
2nd:
Once the oral groove is
filled, it breaks off and
submerges into the cell
carrying food to parts of the
cell
3rd:
The vacuole delivers the
food and gathers waste
to get rid of
V. PROCESS: DIFFUSION & OSMOSIS
1. DIFFUSION:
A. MOVEMENT FROM A HIGHER CONCENTRATION TO A LOWER CONCENTRATION
B. PARTICLES TRAVEL FROM A CROWDED AREA TO A LESS CROWDED AREA.
2. OSMOSIS:
A. HAPPENS WHEN WATER MOVES THROUGH THE CELL MEMBRANE
B. OSMOSIS ALONE CANNOT ALWAYS CONTROL THE AMOUNT OF H2O IN THE CELL
C. SINGLE-CELLED ORGANISMS USE VACUOLES TO HELP WITH EXCESS WATER
D. IN AN AMOEBA, LARGE VACUOLES RELEASE THE WATER THROUGH THE CELL MEMBRANE
E. IN A PARAMECIUM, SMALL CHANNELS DIRECT EXCESS WATER INTO A CONTRACTILE
VACUOLE
VI. MOVEMENT
1. AMOEBA:
• MOVES BY PUSHING ITS MEMBRANE FORWARD ; THIS CREATES A PSEUDOPOD, OR “FALSE
FOOT”
2. PARAMECIA:
• MOVES BY USING CILIA (SMALL HAIR LIKE STRUCTURES THAT MOVE BACK AND FORTH)
3. EUGLENA:
* HAS A LONG TAIL THAT ACTS LIKE A WHIP (FLAGELLUM); IT SPINS LIKE A PROPELLER OF A
BOAT
* QUESTION: WHY DO AMOEBAS AND PARAMECIA NEED MOVING PARTS?
VII. REPRODUCTION: BINARY FISSION
* The new organism will have the same trait as the parent organism.
Example: Bacteria
A
A
Parent Cell
A
Cell
A
Identical
Cell
Divides
A
A:A
Genetic
Information
Copied (DNA)
Identical
Cell
IIX. REPRODUCTION: BUDDING
1. IN THE PROCESS OF BUDDING, A GROWTH OF A BUD OR KNOB IS
FORMED ON THE OUTSIDE OF THE SINGLE-CELLED ORGANISM.
2. WHEN THE CELL GROWS TO THE SAME SIZE AS THE PARENT CELL IT BREAKS
OFF.
3. THE NEW CELL FORMED IS IDENTICAL TO THE PARENT CELL.
• *HOW DOES YEAST AND BACTERIA REPRODUCE?