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Chapter 7: Cell Structure and Function. Section 7-1: Life is Cellular Harvard - Inner Life of the Cell. The observations and conclusions of many scientists helped to develop the current understanding of the cell. Put it in perspective: - PowerPoint PPT Presentation
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Chapter 7: Cell Structure and FunctionSection 7-1: Life is Cellular Harvard - Inner Life of the Cell
The observations and conclusions of many scientists helped to develop the current understanding of the cell
Put it in perspective:
1605 – English settlers found the colony at Jamestown, Virginia
The Cell TheoryRobert Hooke (1665)
English physicist used primitive compound microscope to look at plant tissue (cork).
He called the chambers
“cells” because they reminded him of the small rooms in a monastery
The Cell TheoryRudolph Virchow (1855) Proposes that all cells come from existing
cells Where did the first cell come from?
THE CELL THEORY1. All living things are composed of cells.
2. Cells are the basic unit of structure and function in living things.
3. New cells are produced from existing cells.
How small are cells?How much is a micrometer?
1 micrometer (µm) = 1/1,000,000 m
Typical cell size = 5 to 50 µm in diameter In a dice that is 1 cm3
We could fit 1,000,000 cells
Cells Alive
How small are cells?
Two categories of cells1. Prokaryotic Cells
pro = before; karyon = nucleus or kernel• contain cell membranes and cytoplasm but no
nucleus• DNA is scattered through cytoplasm
examples: bacteria
2. Eukaryotic Cells
eu = true; karyon = nucleus or kernel
contain a nucleus that holds DNA and membrane bound organelles that have specific functions
examples: all plants, animals, some fungi, some microorganisms
Two categories of cells
Two categories of cells
Prokaryotic Eukaryotic
-No Nucleus -Nucleus
-Smaller Ribosomes less complex
-Less complex
-DNA is linear
- Ribosomes larger and complex
-Membrane bound organelles
-Complex-Cell wall (plants and bacteria)
-DNA is circular
-Cell membrane-DNA-Cytoplasm-Ribosomes
Animal Cell - Eukaryotic
ProkaryoticPlant Cell - Eukaryotic
7-2 Cell Structures Organelle – a specialized structure that
performs a specific function inside a cell
Cytoplasm Found – between the nucleus and cell
membrane Structure – a clear jelly-like fluid Function – supports the organelles
The Nucleus Nuclear Envelope
Found: around the outside of the nucleus Structure: two thin membranes with
thousands of pores Function: allows materials to move in and
out of the nucleus.
The Nucleus
Chromatin
Nuclear Envelope
Nucleus
Found – In cytoplasm near middle of cell
Structure – filled with chromatin (tightly coiled DNA)
Function: Contains the cell’s DNA, the instructions for making protein and directing cell activities.
CytoskeletonFound: Throughout the cell
Structure: A network of protein filaments
Microtubules (25 nm) Microfilaments (7nm)
Function: Helps support the cell & maintain shape
Involved in several types of movement
Vacuoles Found: In the cytoplasm Structure: Saclike
Very large in plant cells Smaller in animal cells
Function: Storage (water proteins, carbs, salts)
Vesicles Found: In the cytoplasm Structure: membrane
bounded sac Function: transports
and/or stores cellular products
Lysosomes“The Cells Clean-up Crew” Found: In the cytoplasm Structure: Small enzyme filled organelles Function: Breakdown large organic
molecules, and old nonfunctioning organelles
Ribosomes Found: In the cytoplasm Structure: Small and grain-like, made of
large and small subunits Function: produce proteins from directions
given by DNA
Endoplasmic Reticulum
Found: just outside the nucleus
Structure: a maze of membranes
Rough ER: (ribosomes imbedded in membrane) produces and transports proteins.
Golgi Apparatus Found: In the cytoplasm Structure: A stack of membranes Function: to modify, sort and package
materials from the ER for storage or to be transported outside the cell.
Chloroplast
Found: In the cytoplasm of plant cells
Structure: Stack of membranes that contain photosynthetic pigments (chlorophyll)
Function: Use energy from the sun to make food (photosynthesis)
Mitochondria “Powerhouse of the Cell”Found: In the cytoplasm
Structure: Rod-shaped with a folded double membrane
Function: Provide the cell with energy.
Cell WallFound: Located outside the cell membrane
Structure: Fibers of carbohydrate, cellulose in plant cells
Function: Provide support and protection for the cell
Cell MembraneFound: Located around the perimeter of the
cell
Structure: Made of a phospholipid bilayer
Function: Regulates what leaves and enters the cell and provides protection and support
CentriolesFound: Within the cytoplasm only in animal
cells
Structure: Made of a microtubules (tubulin)
Function: Help organize the cell during cell during division.
Centrioles - Miosis
1. What are the three parts of the cell theory.
2. Who is credited with discovering cells?
3. What is the typical size range for cells in micrometers?
4. How did plant cells appear under the microscope?
5. What type of cell is this and name an organism it could have come from.
Warm up questions.
Read the passage about prokaryotic and eukaryotic cells.
Complete a Venn Diagram like the one in your notes detailing the similarities and differences between prokaryotic and eukaryotic cells.
Lastly, based on the passage write a short paragraph detailing how we think eukaryotic cells may have evolved from prokaryotic cells.
Eukaryotic and Prokaryotic Cells
Bryson Reading: Bacteria Multiplying White blood cell vs. bacterium Bonnie Bassler
According to endosymbiotic theory, what two eukaryotic organelles are believed to have been former prokaryotic cells?
Bonus question (3 pts.)
Get a book from the back and turn to pages 162-163. In your notebook construct a Venn diagram that compares and contrasts prokaryotic and eukaryotic cells
After exam:
Prokaryotic Eukaryotic
3.
2.1.