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Bellringer-2/4/15 What is a cell?

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1 Bellringer-2/4/15 What is a cell?
Recall your work yesterday. When classifying cells, what are the two groups scientists separate cells into?

2 USING A MICROSCOPE Light Microscopes and Total Power Magnification

3 Uses We can use microscopes to observe cells in greater detail
Light microscopes are what we will use in class More complicated microscopes, like scanning and electron transmission microscopes, allow us to see prokaryotic and eukaryotic cell differences in greater detail

4 Parts of a Light Microscope

5 Microscope: Total Power Magnification
To find this, multiply the power of the objective lens (4X, 10X, 40X), by the power of the eyepiece (usually 10X) Example: A student is viewing a slide using an objective lens with a power of 4X. What is the total power magnification? 4 x 10 = 40X

6 CELLS Structure and Function of Living Organisms

7 What is a Cell? A cell is the basic structural, functional, and biological unit of all living organisms “The building block of life” You are made up of about 37 trillion cells!!!

8 Cell Theory What do we know about cells?

9 Robert Hooke In 1665, Robert Hooke used an early microscope to look at a thin slice of cork, a plant material. Cork looked like thousands of tiny, empty chambers. Hooke called these chambers “cells.”

10 Hooke’s Original Sketches

11 History In 1838, Matthias Schleiden concluded that all plants were made of cells. In 1839, Theodor Schwann stated that all animals were made of cells. In 1855, Rudolph Virchow concluded that new cells were created only from division of existing cells. These discoveries led to the cell theory.

12 Cell Theory All living things are composed of cells.
Cells are the basic units of structure and function in living things. New cells are produced from existing cells.

13 Types of Cells Prokaryotic Eukaryotic Simple Cells Complex Cells
Plant and Animal Cells

14 Prokaryotic Cells Prokaryotic cells are less complex than eukaryotic cells No membrane bound organelles; smaller Single-celled organisms (ex. Bacteria)

15 Eukaryotic Cells Eukaryotic cells are complex cells made up of membrane bound organelles Each organelle within the cell carries out different roles Eukaryotic cells make up complex organisms (mostly multicellular)…like insects, fish, and mammals like you!

16 Prokaryotic vs. Eukaryotic
No membrane bound organelles (no mitochondria, nucleus, vacuole, or chloroplasts) Ribosomes DNA and RNA (not enclosed) Circular DNA called plasmids Smaller size Contains membrane bound organelles Ribosomes DNA and RNA (enclosed by membrane) DNA double-helix strands Larger size

17 Bellringer-2/5/15 What is a cell? What does cell theory tell us about cells? Fill in the chart comparing the two basic categories of cells. PROKARYOTIC EUKARYOTIC

18 Eukaryotic Cells Animal vs. Plant

19 Animal Cell Nucleus Plasma Membrane Mitochondria Vacuoles Ribosome
Cytoplasm Lysosome

20 Plant Cell Nucleus Plasma Membrane Mitochondria Ribosome Cytoplasm
Vacuole (large) Chloroplasts Cell Wall

21 What differences do you see right away?

22 Nucleus The “control center” Holds the DNA
Dark spot inside nucleus is called the nucleolus (it helps makes the ribosomes) Nucleus

23 Mitochondria The “powerhouse” of the cell
It produces most of the energy for the cell Breaks down food to make ATP ATP is major fuel for all cell activities that require energy Folded inner membrane increase the surface area for energy production during respiration

24 Plasma Membrane The “gate” of the cell
Double membrane structure controls what comes in and out of the cell “YOU SHALL NOT PASS” Plasma Membrane

25 Ribosome Protein producer The ribosome makes proteins for the cell

26 Vacuole “Storage tanks” of the cell
It stores food, water, and chemicals in the cell Plant cell vacuole is much larger; controls Turgor Pressure-keeps plant upright (no water=wilting) Vacuole

27 Vacuole in Plants

28 Cytoplasm Jelly/gel A liquid/gel like substance that surrounds the organelles Cytoplasm

29 Lysosome (Animal Only)
The “garbage cans” Break down and digest waste products using enzymes Lysosome

30 Cell Wall (Plant Only) “Supporter/protector”
The cell wall shapes and protects the plant cell Cell Wall

31 Chloroplasts (Plant Only)
Food producers They are green Contain green chlorophyll and trap energy from the sun for photosynthesis Chloroplast

32 Organelle Interactions
All these organelles work together to keep the cell running!! What do you think would happen if… The Mitochondria or chloroplasts stopped working? The Plasma Membrane didn’t do it’s job? The Nucleus stopped directing activities?

33 Summary: Plant vs. Animal Cells

34 Bellringer-2/6/15 How are prokaryotic and eukaryotic cells similar?
Both contain a nucleus Both contain ribosomes Both contain membrane-bound organelles Both contain cell walls This diagram shows a plant cell. Which structure is found in a plant cell but absent in an animal cell? 1 2 3 4

35 Review-Cell Organelles
Nucleus “Brain of the cell”-controls cell functions and stores DNA Mitochondria “Powerhouse of the cell”-makes energy through cellular respiration; folded inner membrane provides lots of surface area for cell processes Cell membrane “Gate of the cell”-Double membrane structure composed of lipids-controls what goes in and out

36 Review-Cell Organelles
Ribosomes Site of protein synthesis (makes proteins); attached or free floating Cytoplasm Gelly/jel that surrounds cells-keeps organelles where they should be Vacuole “Storage center”-holds water, food, etc.-large in plants due to Turgor Pressure

37 Review-Cell Organelles
Chloroplast Plants only-uses sunlight to convert to sugar through process of photosynthesis Cell wall Plants only-carbohydrate called cellulose provides rigid structure that protects and supports cell Lysosome “Garbage can”-animals only. Uses enzymes to digest waste products

38 Just a Note…Other Organelles
Endoplasmic Reticulum-Network of membranes that fold, modify, and transports proteins throughout the cell Golgi Apparatus-receives proteins and lipids (fats); modifies, sorts, and packs them; works closely with the ER rec

39 Specialization of Cells
Cells all begin as undifferentiated-DNA and genetics play a role in determining the type of cell (ex. nerve cell, muscle, blood…) We will talk more about this later!

40 Where would you need more…
Mitochondria? Chloroplasts? Cell organelles can be more concentrated based on needs!

41 Lab Time!!! Candy Cells 

42 Bellringer-2/9/15 Decide whether the cell is plant or animal. Next, label the parts with the appropriate name.

43 Question of the Day Which cellular process is most closely related the presence of chloroplasts in eukaryotes? Metabolism Photosynthesis Aerobic respiration Lactic acid fermentation

44 Cell Organelles Sepuplhs.org/high/sgi/teachers/cell_sim.html

45 UNICELLULAR ORGANISMS
Structure and Adaptations

46 Unicellular Organisms
A “multicellular” organism is composed of many cells (ex. You are composed of many animal cells; plants are composed of many plant cells) “Unicellular” means they are composed of a single cell! Ex. Bacteria, protozoa, euglena

47 Structures of Unicellular Organisms
Unicellular organisms have many structures that help them survive Contractile vacuoles Cilia Flagella Psuedopods Eyespots

48 Contractile Vacuoles Stores excess water that enters the cell, and expels it to the exterior It expands when filling with water, then contracts, expelling the contents back out Found in: protists + unicellular algae

49 Eyespots A dark area that functions in light reception; influences motion so that the organism can move toward/ away from light Toward (positive phototaxis) Away (negative phototaxis) Found in: green algae; photosynthetic unicellular organisms

50 Movement Cilia Flagella Many hair like structures
Cilia Many hair like structures Often used for movement Non-motile cilia serve as sensory organelles Flagella Single, whip like tail used for movement Found in: bacteria, protists, specialized plant, animal and fungi cells

51 Movement Psuedopods “False feet” that help the unicellular organism move about Sometimes used to obtain food (phagocytosis)

52 Adaptive Behaviors Recall that “taxis” is an innate behavior in response to an outside stimuli

53 Chemotaxis Movement in response to chemicals (“chemo”).
Some single celled organisms direct their movement according to chemicals in their environment Found in bacteria and single-cell or multicellular organisms Find food (e.g., glucose) Flee from poisons (e.g., phenol) Critical to early development

54 Phototaxis Movement toward or away from light.
Movement toward or away from light. Many plant-like unicellular organisms will move toward light to better photosynthesize, just like plants will tilt toward the window Positive phototaxis: if the movement is in the direction of increasing light intensity Negative phototaxis: if the movement is in the opposite direction of light intensity


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