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Cell Structure and Function
Chapter 7
Conversion Review
K H D ___ d c m
12.4m = ________cm
0.765L = ________mL
10,432ms = ________s
Going Further
1 Milimeter (mm) = 0.001m 1 micrometer (μm) = 0.00001m (10-6m) 1 nanometer(nm)=0.00000001m
(10-9m)
7.1 Life is CellularSizes of Objects and Magnifying Power of Microscopes
Compound Light Microscope
Guidelines for using Light Microscopes Carry the microscope with one hand holding
the arm and the other hand supporting the base.
Never slide the microscope across the lab table.
Clean lenses with lens paper only. Always begin AND end with the lowest power
objective in place and the stage at its lowest level.
Use the coarse adjustment knob on low power objectives.
Use ONLY the fine adjustment knob on high power objectives.
The Discovery of the Cell
Robert Hooke • Looked at cells in cork and named them cells
Anton van Leeuwenhoek• Observed pond water
Schleiden and Schwann• All plants and animals are made of cells
Oken and Virchow• Cells are produced from division of existing cells
Three Parts of the Cell Theory:
1. All living things are made up of cells.
2. The cell is the most basic unit of life.
3. New cells are produced from existing cells.
Why are cells so small?
Small cells function more efficiently than large cells.• All substances that enter and leave the cell
must cross the cell surface.
• Cells need a high surface area to volume ratio in order to exchange substances more readily.
Prokaryotes
Single-celled organism that lacks a nucleus and other internal compartments.
Bacteria are common prokaryotes.
Pearson Education inc. 2010
Common Features of Cells• Cell membrane – thin flexible barrier that
encloses and separates the cell from it’s external environment.
• Cytoplasm – the cell’s interior
• Ribosomes – where proteins are made
• Genetic Material – instructions for making proteins, regulate cellular activities, and enable reproduction
Eukaryotes
Cells that contain a nucleus and internal compartments called organelles.
Eukaryotic organisms can be one-celled (unicellular) or contain many cells (multicellular).
7.2 Cell Structure
supports and shapes cell helps position and transport organelles provides strength assists in cell division aids in cell movement
Three types of cytoskeleton fibers:• Microfilaments – made up of protein and actin
• Microtubules – made up of protein and tubulin
• Intermediate fibers – thick ropes of protein
The Cytoskeleton
The Nucleus
Controls most functions of the cell.
Most of the cell’s DNA is contained in the nucleus.
Surrounded by the nuclear envelope, which separates the nucleus from the cytoplasm.
• The nuclear envelope contains small channels called nuclear pores which allow substances to move in and out of the nucleus.
Nucleolus
Region inside the nucleus where ribosomes are assembled.
Nucleolus
Ribosomes
Located free in the cytoplasm or attached to the rough endoplasmic reticulum
Produce proteins
2 types of endoplasmic reticulum (ER):
• Rough ER – has attached ribosomes and thus has a rough appearance.– Helps transport proteins from ribosomes in
vesicles.
• Smooth ER – performs various functions such as making lipids and breaking down toxic substances.
Rough ER
Smooth ER
Golgi Apparatus
Modifies proteins received in vesicles from the ER.• Some vesicles will
remain in the cytoplasm and become lysosomes, which work to remove waste in the cell.
Vesicle
Vacuoles
Used for storage of water, salts, proteins, and sugars.
Mitochondria
Harvest energy from organic compounds to make ATP.
Cell Membrane
Made of a double layer of phospholipids• lipid bilayer
Protects and supports the cell
Regulates what enters and leaves the cell• Selectively permeable
Unique features of plant cells
Cell wall • thick layer of protein and cellulose
surrounding the cell membrane. Chloroplast
• use light energy to make carbohydrates from carbon dioxide and water.
Central vacuole • takes up much of the plant cell’s volume
• Stores water and nutrients.
Plant Cells
Plant Cell
Cell Specialization• Cell Diversity
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