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Bellringer-2/4/15
What is a cell? Recall your work yesterday. When
classifying cells, what are the two groups scientists separate cells into?
USING A MICROSCOPELight Microscopes and Total Power Magnification
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
Parts of a Light Microscope
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
CELLSStructure and Function of Living Organisms
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!!!
Cell TheoryWhat do we know about cells?
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.”
Hooke’s Original Sketches
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.
Cell Theory
1. All living things are composed of cells.
2. Cells are the basic units of structure and function in living things.
3. New cells are produced from existing cells.
Types of Cells
Prokaryotic Simple Cells
Eukaryotic Complex Cells Plant and Animal Cells
Prokaryotic Cells
Prokaryotic cells are less complex than eukaryotic cells No membrane
bound organelles; smaller
Single-celled organisms (ex. Bacteria)
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!
Prokaryotic vs. EukaryoticPROKARYOTIC
No membrane bound organelles (no mitochondria, nucleus, vacuole, or chloroplasts)
Ribosomes DNA and RNA (not
enclosed) Circular DNA called
plasmids Smaller size
EUKARYOTIC
Contains membrane bound organelles
Ribosomes DNA and RNA
(enclosed by membrane)
DNA double-helix strands
Larger size
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
Eukaryotic CellsAnimal vs. Plant
Animal Cell
•Nucleus•Plasma Membrane•Mitochondria•Vacuoles•Ribosome•Cytoplasm•Lysosome
Plant Cell
•Nucleus•Plasma Membrane•Mitochondria•Ribosome•Cytoplasm•Vacuole (large)•Chloroplasts•Cell Wall
What differences do you see right away?
Nucleus
The “control center”
Holds the DNA Dark spot inside
nucleus is called the nucleolus (it helps makes the ribosomes)
Nucleus
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
Mitochondria
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
Ribosome
Protein producer The ribosome
makes proteins for the cell
Ribosome
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
Vacuole in Plants
Cytoplasm
Jelly/gel A liquid/gel like
substance that surrounds the organelles
Cytoplasm
Lysosome (Animal Only)
The “garbage cans”
Break down and digest waste products using enzymes
Lysosome
Cell Wall (Plant Only)
“Supporter/protector”
The cell wall shapes and protects the plant cell
Cell Wall
Chloroplasts (Plant Only) Food producers They are green Contain green
chlorophyll and trap energy from the sun for photosynthesis
Chloroplast
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?
Summary: Plant vs. Animal Cells
Bellringer-2/6/15
1. How are prokaryotic and eukaryotic cells similar?
a) Both contain a nucleusb) Both contain ribosomesc) Both contain membrane-bound organellesd) Both contain cell walls
2. This diagram shows a plant cell. Which structure is found in a plant cell but absent in an animal cell?
a) 1b) 2c) 3d) 4
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
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
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
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
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!
Where would you need more…
Mitochondria? Chloroplasts?
Cell organelles can be more concentrated based on needs!
Lab Time!!!
Candy Cells
Bellringer-2/9/15
Decide whether the cell is plant or animal. Next, label the parts with the appropriate name.
Question of the Day
Which cellular process is most closely related the presence of chloroplasts in eukaryotes?a) Metabolismb) Photosynthesisc) Aerobic respirationd) Lactic acid fermentation
Cell Organelles
Sepuplhs.org/high/sgi/teachers/cell_sim.html
UNICELLULAR ORGANISMSStructure and Adaptations
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
Structures of Unicellular Organisms
Unicellular organisms have many structures that help them survive Contractile vacuoles Cilia Flagella Psuedopods Eyespots
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 https://www.youtube.com/watch?
v=pahUt0RCKYc
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
Movement
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
https://www.youtube.com/watch?v=QGAm6hMysTA
Movement
Psuedopods “False feet” that help the unicellular
organism move about Sometimes used to obtain food
(phagocytosis)
https://www.youtube.com/watch?v=PsYpngBG394
Adaptive Behaviors
Recall that “taxis” is an innate behavior in response to an outside stimuli
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
Phototaxis
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
https://www.youtube.com/watch?v=2koAGkgmiqg