1. Fundamental Units of Life – CELLS!

2. Living Compartments Organisms can exist as a single cells - amebas
Cells vary in size and shape; each is basically a fluid filled bag in which various structures are housed
Ok.. Why do have this fluid filled bag? Why is it’s composition similar to sea water?
Internal structures are called organelles (little organs in latin)

3. Living Compartments Intracellular = “inside of the cell”
Extracellular = “outside of the cell”
Organelles are small membrane bound structures that have specific functions within the cell
Prokaryotic = DO NOT have a membrane-bound nucleus or organelles
Eukaryotic = Have a membrane bound nucleus and membrane-bound organelles

4. Living Compartments

5. Prokaryotic vs. Eukaryotic

6. Plant Cells vs. Animal Cells
Cell Wall
Vacuole

7. Cell Structure Cell Wall PLANT CELLS ONLY!!
Composed of complex carbohydrate-cellulose
Humans are unable to digest cellulose because the appropriate enzymes to breakdown the beta acetal linkages it has are lacking. FIBER!
Support, rigidity, and protection
Surrounds plasma membrane
PLANT CELLS ONLY!!

8. Cell Structure Plasma membrane (cell skin?)
Double lipid bilayer (2 layers)
Composed of protein and phospholipids
The membrane regulates the exchange of substances (nutrients/waste/signaling molecules) between the cell and its surrounding
BOTH animal and plant cells
have a plasma membrane.

9. Cell Structure Cytoplasm (cell blood?) BOTH plant and animal cells
liquid substance inside the plasma membrane and outside the nucleus
Where biochemical reactions occur and organelles are suspended
BOTH plant and animal cells

10. Cell Structure Flagella / Cilia (cell feet/arms?)
Aid in locomotion
BOTH Plant and Animal cells can have these.
Flagella
Cilia

11. Cell Structure - Organelles
Nucleus (cell brain?)
Contains genetic instructions (DNA)
Controls cellular activities
BOTH plant and animal cells

12. Cell Structure - Organelles
Mitochondria (cell engine?)
Release of energy from sugars in the form of ATP through cellular respiration
BOTH plant and animal cells

13. Cell Structure - Organelles
Chloroplasts
Acquire energy through light (absorb photons!) and convert into chemical energy by photosynthesis
Contain green photosynthetic pigments - chlorophyll.
PLANT Cells ONLY!!!

14. Cell Structure - Organelles
Ribosomes
Protein synthesis
BOTH Plant and Animal Cells

15. Cell Structure - Organelles
Endoplasmic reticulum (cell circulatory system?)
Transport of proteins and synthesis of lipids
BOTH Plant and Animal cells

16. Cell Structure - Organelles
Golgi Bodies (cell post office)
Modification, packaging and shipping of proteins, lipids and carbohydrates
BOTH Plant and Animal cells

17. Cell Structure - Organelles
Central vacuoles (plant cell stomach?)
Storage of water, wastes, and nutrients
Influences cell size and shape – TURGOR PRESSURE
PLANT cells ONLY!!!

18. Cell Structure - Organelles
Lysosomes – (cell digestive tract?)
Contain enzymes for intracellular digestion of bacteria, cellular debris, and worn out cell parts
Animal Cells ONLY!!!
Centrioles (cell bones?)
Organize part of the cytoskeleton (protein filaments) in animal cells
Animal Cells ONLY!!!

19. Things to do Today Observing Unicellular organisms
Paramecium
Euglena
Volvox
Amoeba (from video)
Observing cells of multicellular organisms
Animal
Plant
Steps of the scientific method

20. Observing Unicellular organisms
Most bacteria and protists are usually unicellular organisms
All protists are eukaryotic; depending on their means of acquiring energy, they might have different organelles
Protists are particularly abundant in aquatic habitats
Preparation of a wet mount

21. Preparation of a Wet Mount
Put 1 small drop of sample from dropper onto the glass slide
Slowly lower the cover slip onto the drop of sample at an angle to avoid air bubbles between the slide and the cover slip
Find sample with the 10X and move onto the 40X (4x won’t give you any image)
Some organisms move rapidly; if it’s not moving or if you are using the 4x you probably aren’t looking at the right thing
After viewing each sample wash the slide with water at the sink and dry it with KIMWIPES
If you broke a cover slip or a slide, place the pieces in the red “sharps” box

22. Unicellular organisms

23. Observing the Cells of Multicellular Organisms
Multicellularity allows specialization of cells and division of labor
Example: Spermatocytes (“sperm”) are extremely specialized cells that transport chromosomes from a male’s reproductive system to an egg in a female’s reproductive system.
Plant cells produce their own food and thus are more stiff, green and stuck in one place
Animal cells are more mobile and are able to seek out and consume plants and other animals

24. Preparation of a Wet Mount
Pluck single leaf from the Elodea, place the leaf on the slide and put 1 drop of water on the leaf
Place a cover slip on the leaf slowly to avoid air bubbles
Make sure the leaf is spread flat against the slide as you add the cover slip
Locate the: cell wall, central vacuole, and chloroplasts

25. Preparation of a Wet Mount
Obtain human epithelial cells from inside of your mouth with a toothpick
Put a drop of methylene blue on a glass slide and dip the end of the toothpick with the sample into the drop and stir
Place the cover slip onto the slide and observe
Make sure you see the: Plasma membrane, cytoplasm and nucleus

26. Elodea vs. Epithelial Cells

27. The Study of Life
Scientific method: biologists used to study life in systematic way
Observation  Question  Hypotheses Predictions Experiment  Collect/Analyze data  Conclusions  Report findings
Hypothesis can be written in several forms
Null (no effect) statement/ hypothesis
Alternative hypothesis

28. The Study of Life
Predictions: often written as “If…, then…” statements
e.g. If I show up late to class, then my teacher will kill me.

29. The Study of Life Elements to consider in the design of experiments
Independent or experimental variables
Factors deliberately manipulated that will result in a measurable effect (water)
Dependent or measured variables
Dependent variables DEPEND upon the INDEPENDENT variable
Factors that are measurable (plant height)
e.g. My grade is dependent upon how much I study? Grade = dependent variable
Time Studying = independent variable

30. The Study of Life Elements to consider in the design of experiments
Confounding variables
Standardized variables
Factors that could influence the outcome of the exp. but are not of primary interest to the investigator. These are kept the same across all treatments.

31. The Study of Life Elements to consider in the design of experiments.
Experimental treatments
Independent (experimental) variable is manipulated.
Control treatments
Independent (experimental) is eliminated or set to standard

32. Test your understanding
Read the paragraph and identify the variables and different groups.
Exercise 3: Investigating what lives in pond water. (pg )