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Structure and FunctionChapter 4
What importance do cells have to life?
THE CELL
-Mid 1600’s Started using microscopes
-Robert Hooke- used the scope to look at cork-Coined the term cells, because of what the cork looked like under the scope.
-Van Leeuwenhoek- 1st to look at living cells.-Looked at pond water and saw organisms (very tiny) living in the water.
1. All living things are made of cells.2. Basic unit of structure and function.3. New cells come from existing cells.
The Cell Theory
- Use fluorescent labels to follow molecules through cells.
- Can build 3-D cells images of cells and their parts.
-Use light, electrons and high resolution scopes to see cells, structures, DNA, proteins and other molecules.
Exploring the Cell
CELL TYPES
Prokaryote1.1st to evolve2.Lacking
Nucleus3.Simple Cell4.Ex: Bacteria
Eukaryote1.Cells contain
Nucleus2.Larger and more
complex3.Highly
Specialized
BothHave DNA and CellMembranes
2 Parts1. Nucleus- Brain of the cell2. Cytoplasm- Entire cell outside of the nucleus.Holds organelles for cell.
Eukaryote Cell Structure
Animal Cell
Plant Cell
1. Cell Membrane--thin, flexible outer layer- lipid bilayer (2 layers of lipids)- Integral proteins(in membrane)- Peripheral Protein (touch membrane)-Mosaic because molecules in
membrane.
Cell Structures
Semi-Permeable Cell Membrane (fluid)
Gate Keeper- controls what comes in and out of cell. (picky)
2. Cell Wall- - Plant Cells- made of cellulose- rigid support for cell/plant- outside of the membrane
3. Cytoplasm-- area between nucleus and membrane-contains organelles-jelly-like substance
4. Nucleus- - brain of the cell- surrounded by the nuclear envelope
- double membrane- contains nuclear pores (sm holes)
- Main Function- store DNA in form of chromatin.- during cell division chromatin coils up to form chromosomes.
- Contains nucleolus- synthesizes and partially assembles
ribosomes.
5. Cytoskeleton-- framework of the cell, made of proteins- 2 structures:
1. microfilaments- (“threads”)- aid in movement and muscle
contraction2. microtubules- (“straws”)
- assemble/disassemble to form spindle fibers during cell division.
(extremely important to cells)
6. Cilia and Flagella-- hairlike- on cell surface- aid movement
Cilia- shorter and numerous (respiratory system)
Flagella- longer and less numerous(protists)
- small structures with specialized function- Found in the cytoplasm7. Mitochondrion- mitochondria (plural)- “powerhouse” of the cell- Converts energy from nutrients to ATP- Double membrane –inner membrane cristae- has its own DNA (from mother)-more in active tissue (muscle, liver)
Organelles
8. Ribosomes- - protein synthesis (proteins are made)- most numerous organelle- NOT membrane bound- synthesized and partially made in
nucleolus- finished being made in cytoplasm
when proteins are made.- may be “free-standing” or attached to
Endoplasmic Reticulum.
9. Endoplasmic Reticulum (ER)- “subway” of the cell- Transports material within cell- Rough ER- covered with ribosomes
and prepares proteins for transport.- Smooth ER- no ribosomes
- synthesizes steroids (glands)- regulates calcium (muscle)- breaks down toxins (liver)
10. Golgi Apparatus- - Made of a series of parallel
compartments.- Modifies/ repackages proteins- manufactures lysosomes- plays a role in secretion
11. Lysosomes-- most common in animals, not plants- contains digestive enzymes- help to break down carbs, proteins, lipids
12. Centrioles- - found in a pair- near nucleus- aid in cell division by aligning chromosomes
13. Vacuoles- - store food, water, waste (not at same time)- plant cells have a large central vacuole- animals have numerous, smaller
vacuoles - plant vacuoles perform lysosome job.
14. Chloroplasts- - exclusive to plants- have a double membrane- captures energy from sunlight and
converts it into chemical energy during photosynthesis.
- “solar power” in plants- contains green pigment called
chlorophyll.- Type of Chromoplasts- colored plastids
- orange- carotene
Plant Cells Animal CellsCell Wall No Cell Wall
Cell Membrane
Chloroplasts Mitochondria
NO Centrioles Centrioles
Single Large Vacuole Many small lysosomes
Oblong Shape Round/Irregular Shape
Nucleus not centrally located Nucleus usually centrally located
Endoplasmic Reticulum Endoplasmic Reticulum
Relationships Between Organelles1. Nucleus (DNA makes RNA)
- Nucleolus – Makes Ribosomes- Cytoplasm- Holds Organelles
2. ER- ribosomes attach, transports proteins3. Proteins modified by GOLGI4. Golgi manufactures LYSOSOMES5. Lysosome digest particles, worn out organelles6. Spare parts from lysosome, ready to use in future
from directions from NUCLEUS7. MITOCHONDRIA provides energy for ALL
7.3- Cell Boundaries
What is the cell boundary of animal cells?What is the cell boundary of plant cells?
What role do these structures have?
Cell Boundaries Functions
Cell Membrane- regulates what enters and leaves the cell.
Cell Wall- Provides support and protection for the cell.
2 Types of Transport
1. Passive Transport- movement of molecules/material through the cell membrane and requires NO energy.
2. Active Transport- movement of molecules/material through the cell membrane and REQUIRES energy.
Passive Transport1. Diffusion- movement of molecules from an
area of high concentration to low concentration.
2. Osmosis- movement of solutions across a membrane.
3. Facilitated Diffusion- form of diffusion which requires a carrier protein. Ex: Glucose
Diffusion- Concentration- amount of solute dissolved in a
solution- Concentration Gradient- difference in molecule
concentration across a space.- Movement of molecules from an area of HIGH
concentration to LOW concentration.- Ex: Match being lit.
- Movement is ‘with’ or ‘down’ the gradient- Molecules move to reach equilibrium.
Diffusion Continued
Movement from high Equilibriumto low Reached
Diffusion ContinuedKinetic Energy- powers diffusion
- energy of moving particles
Examples:- ink dropped into water- gas exchange in cells (oxygen)- fragrance of candles in a room
Osmosis- Movement of water (solutions)- Cell must have a selectively permeable
membrane.- Movement depends on concentration.
(use salt water as an example)- Hypertonic- more solute (salt) [OVER]- Hypotonic- less solute (salt) [Below]- Isotonic- same amounts of solute (equal salt in
the cell and outside of the cell)
Osmosis ContinuedOutside Outside Outside
Inside of Cell
Inside of Cell
Inside of Cell
Solutions are:
HYPOTONIC HYPERTONICISOTONIC - ate salt, need water - no salt to absorb water
Osmosis ExamplesPlants- “like” HYPOTONIC
- turgor pressure- membrane pushing against cell wall. Gives us crisp veggies.
Protists- often in HYPOTONIC environment.- contractile vacuole pumps out excess water
Animals- can be in HYPOTONIC environment.- cells take on water until they burst- CYTOLYSIS
If in HYPERTONIC environment- Plasmolysis- cells lose water and shrink.
Facilitated Diffusion- Form of diffusion- Requires a carrier protein (protein channel)- Carrier protein binds to molecule and
changes shape to carry molecule across.- Protein returns to normal shape when
finished.- No ATP (energy) used- Glucose is best example.
Active Transport1. Molecular Transport- movement of
molecules from area of lesser to greater concentrations.
2. Endocytosis- taking in of material into the cell by infolding of the cell membranes.
3. Exocytosis- forces material out of the cell through the cell membrane.
Molecular Transport-Movement of molecules from an area of lesser
concentration higher concentration- Movement is ‘up’ or ‘against’ the gradient
- Paddling up stream- Normally moves calcium, potassium, and
sodium ions across cell membrane.- Uses ATP- Ex: Na/K pumps
- moves 3 Na+ OUT and 2 K+ IN
EndocytosisEndocytosis- “infolding” to allow cells to bring molecules
into it. Cell membrane pinches around a molecule or fluid.
2 types1. Phagocytosis- membranes surround LARGE PARTICLES and pull it in.
2. Pinocytosis- membranes surround FLUIDS and pull it into the cell
Exocytosis
Exocytosis- cells release large amounts of material from the cell.- vacuole attaches to cell membrane and dumps its contents out of the cell.
7-4 Diversity of Cellular Life
- What are the different types of life found on Earth?
Living Organisms
Unicellular Organisms- a cell is the entire organism. 1 cell does everything multicellular organisms do.
Multicellular Organisms- made of many cellsCell specialization- cells develop in different ways to perform different tasks.
Cell Specialization
Animal Cells- Red Blood Cells- transport oxygen- Pancreatic Cells- produce proteins (enzymes)- Muscle Cells- humans ability to move
Plant Cells- Guard Cells- regulates how much carbon dioxide, oxygen, water vapor is released through the stomata.
Levels of Organization
Cells- Tissues- similar cells grouped into units that perform
a particular function. Ex: muscle, epithelial, nervous and connective
Organs- groups of tissues working together.Ex: heart
Organ Systems- group of organs that work together.Ex: Pulmonary system- heart and lungs