Chapter 4 Cell Structure and Function

Chapter 4
Cell Structure and Function
Chapter 4, Sections 5­19
Cell Structure
Cell as a Factory
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Cell Organization
• The Cell is like a Factory:
Many different workers performing different functions in order to maintain homeostasis/life!
These Workers are the Specialized Organelles
Organelle is a "Tiny Organ"
Responsible for Information, Energy, Maintenance, and Production of Cellular Activity 2
Classwork:
Go to following website and complete your cellular organelles worksheet
http://www.cellsalive.com/cells/3dcell.htm
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4.4. Cytoplasm (Workspace/Factory Floor)
Fluid Filled Space within the Cell Membrane where Float the Organelles Cytosol­ Fluid in the Cytoplasm
Function­ a. Acts like blood to circulate materials within the cell
"Cytoplasmic Streaming"
b. Site of Cellular Metabolism
c. Locomotion:
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A. Organelles: General Function: Manufacturing
4.5. The Nucleus: (Control center/Brain of Cell)
Function: Membrane Bound Organelle that contains DNA­ Instructions for creating the products= Proteins
Membrane is called Nuclear Envelope­
has pores which limit what enters and exits
Dense central region called
Nucleolus­ tiny nucleus
builds the ribosomes
(MAD IMPORTANT!)
DNA is attached to proteins=Chromatin
Each strand of Chromatin is called a Chromosome
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RIBOSOMES: PROTEIN FACTORIES
Function: Responsible for assembling Amino Acids in the correct
order and binding them together!
Polypeptide synthesis
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Can be free flowing in cytoplasm or bound to
ENDOPLASMIC RETICULUM
Ribosomes
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ENDOMEMBRANE SYSTEM:
Inter­related membrane channels that transport and
synthesize macromolecules
4.7 Smooth Endoplasmic Reticulum (ER): Transport Tunnels
Function: No Ribosomes
Synthesis of Lipids, Phospholipids, and Steroids, and enzymes for chemical reactions e.g­liver cell enzymes process drugs and alcohol
4.8 Rough Endoplasmic Reticulum (ER): Transport Tunnels
Function: Ribosomes on outer wall
1. Produces more membranes for other organelles
2. modifies proteins that will be secreted from cell
"secretory proteins" ie insulin, melanin
Quaternary Structure
Transport Vesicle­ to Golgi Apparatus
Secretory Vesicle­ carries a protein to outer cell membrane to release it from the cell
Ribosomes
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4.9 Golgi Apparatus: Shipping Station
Function: 1. Packages the Proteins and other macromolecules
so they can be delivered
2. Lysosome formation
3. Transport Vesicles
A Protein will not work until it is processed here. This is where it is given its final shape!
Quaternary Structure
Remember
__________ Dictates ____________
Has "Receiving" end­ accepts transport vesicles from ER
and a "Shipping" end­ Transport vesicles destined for the cell membrane
Golgi Apparatus Proteins 8
B. General Function: Breakdown
4.10 Lysosomes and Peroxisomes(Animal Cells only)
Consist of Hydrolytic Enzymes or hydrogen peroxide
Function: 1. Digestion of food particles by joining with food vacuoles
2. White blood cells kill bacteria
3. Recycle materials by digesting malfunctioning organelles
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4.12 VACUOLES –(Both Plant and Animal Cells)
Large membrane bound sacs used for the storage of water, salt, protein, and carbs
a. Central Vacuole­ found in plants­ used for water and food storage­ Makes plant firm­ Turgor Pressure
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b. Contractile Vacuole­ more common in animal cells­ acts like a pump to suck in fluids and food from outside environment­
Osmoregulation­ prevents it from bursting or being crushed
Also aids in Locomotion
c. Food Vacuole­ substances of nutrition enter through the
membrane and are encapsulated
Phagocytosis­cell eating
Pinocytosis­ cell drinking
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Webquest: Define these two diseases and discuss which organelles of the Endomembrane system cause their mechanism of disease.
What is the cause of each disease?
What effects do these conditions have on the life of the cell and the affected organism?
a. Pompe's Disease
b. Tay­Sachs Disease
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C. Organelles: General Function: Energy Conversion
Organelles Responsible for Energy Conversion
4.14. Chloroplast
Found only in Plant Cells
Contain Chlorophyll­ Green Color/Main Photosynthetic Pigment
Membrane Bound Organelle
Function: **Where Photosynthesis Happens!!!** (Photoautotroph)
Photosynthesis is the process by which plants convert the energy in sunlight into food (glucose)
Thylakoid: Disc shaped unit that is made of chlorophyll­ Site of photosynthesis
Granum: Stack of Thylakoids.
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4.15. Mitochondria (Power Plant)
Membrane Bound Organelle Found in both Plant Animal Cells
and Function: Breakdown food (chemical energy) into ATP which is also energy that can be used by the cell
Process is called RESPIRATION
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D. General Function: Support, Movement, and Communication
4.16 Cytoskeleton: Framework of Proteins that give a cell its shape and structure and hold organelles in place
a. Microfilaments­ connect microtubules­ comprised of a globular protein called ACTIN (Crossbeams)
b. Intermediate filaments­ fibrous protein rather than globular
c. Microtubules­ Main support beams ­Composed of globular proteins called TUBULINS­ hollow
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Play a role in movement of cells and muscular contractions as well.
Actin and myosin form bridges­ act as anchors for actin
The more actin and myosin the stronger you are!!!
Lifting weights tears muscles and replaces tears with more actin and myosin filaments called sarcomeres aka. muscle cells­
more sarcomeres­ greater load capacity of muscles
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4.17 Locomotion:
Cilia and Flagella a. Cilia­ Tiny hairlike projections composed of microtubules
Propel organism through fluid medium
Paramecium
Cilia
Lung tissue
b. Flagella­ Long whiplike tail composed of microtubules for motion
Structure:
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C. Pseudopodia:
"False Feet" Amoeba will extend its pseudopods in the direction it wants to move and the rest of its body will catch up.
Pseudopods
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Microtubule Microfilament Microtubule Microfilament Microfilament Microtubule Men eating Lunch on a Microfilament
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4.18. Cell surfaces protect, support, and join cells: A. Types of Cell Surfaces
1. Cell Walls: (Found only in Plants)
Support, Shape, and Protection
Allow water, oxygen, and CO2 and other materials necessary to cell life to pass easily!
Prevent the Plant cell from absorbing too much water
2. Cell/Plasma Membrane:
Selectively Permeable Membrane
Limits what enters and exits the cell
Phospholipid Bilayer
Double Layer of Phospholipids
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3. Extracellular Matrix
a. Holds cells together
b. protect and support
c. regulate cell behavior
B. Cell Junctions allow communication and exchange between adjacent cells
1. Plasmodesmata: (Plant Cells only)
Circulatory and communication system of cells in a plant tissue
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2. Tight Junctions: (Animal Cells only)
provide tight leakproof seals between cells
3. Demsosomes aka Adhesion junctions or adherens (Animal Cells only)
4. Gap Junctions: (Animal Cells only)
Similar to Plasmodesmata
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