CH. 7 – CELLS. I. CELLS A. What is a cell? 1. Cell – the smallest unit of matter that can carry...
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Transcript of CH. 7 – CELLS. I. CELLS A. What is a cell? 1. Cell – the smallest unit of matter that can carry...
CH. 7 –
CELLS
I. CELLSA. What is a cell?
1. Cell – the smallest unit of matter that can carry on all the processes of life
I. CELLSB. Who first discovered the cell?
1. Anton van Leeuwenhoek – first to observe cells
2. Robert Hooke – used the light microscope to observe cork
a. First person to call the shapes inside of organisms “cells”
I. CELLS3. Rudolph Virchow – studied cell reproduction and discovered that all cells come from other pre-existing cells.
http://www.youtube.com/watch?v=5fg3Q-hbSsI
I. CELLS4. Mathias Schleiden – studied plants and discovered that all plants are made of cells 5. Theodor Schwann – studied animals and discovered that all animals are made of cells
I. CELLSC. What is the cell theory?
1. The cell theory was developed by theories of Hooke, Virchow, Schleiden, and Schwann.
a. The cell is the basic unit of organization for organisms.
b. All organisms are made of one or more cells.
c. All cells come from other pre-existing cells.
I. CELLS2. With better microscopes, scientists observed that cells contained specialized structures.
a. Organelles – cells parts that perform a specific job or function for the cell
I. CELLSD. Cell Diversity!
1. Your body alone contains 200 different cell types!2. Cells Organisms can be classified by the number of cells they are made up of.
a. Unicellular Organism – single celled organismExample: bacteria, yeast
b. Multicellular Organism – organism made up of many cells
Example: plants, animals
I. CELLSE. How are cells classified based upon the presence/absence of
organelles?
1. Eukaryotic Cells – cells with a membrane-bound nucleus and organelles
a. Examples: plant and animal cells
4. Cell membrane
1. Nucleus
2. Nucleolus
3. Chromatin
5. Organelles
I. CELLS2. Prokaryotic Cells – cells with no membrane-bound nucleus or organelles (except ribosomes)
a. Examples: bacteria
1. Ribosomes
2. DNA 3. Cell membrane
4. Cell wall
I. CELLS
Left: Colorized micrograph of a prokaryotic cell of the bacterium.
Right: Colorized micrograph of a eukaryotic cell of the green algae.
I. CELLS
Cell Type Nucleus? Organelles? Uni or Multicellular?
Prokaryotic
Eukaryotic
3. Review:
II. CELL BOUNDARIESPlasma (Cell) MembraneFunction:
Surrounds cellAllows things in and out (homeostasis)
Fact: Selectively permeable – allows water and nutrients in and
waste outMade of phospholipids
Found in: ProkaryotesEukaryotes
Cell WallFunction:
Surrounds cell membrane to provide extra support and protection
Fact: Made of cellulose in plants
Found in: ProkaryotesEukaryotes (plants)
1. Cell membrane
2. Cell wall
II. CELL BOUNDARIES
NucleusFunction:
Controls the organellesContains DNA
Fact: “Command center” or “brain” of the cellMost prominent structure
Found in: Eukaryotes
Nucleus
NucleusIII. CELL CONTROL
III. CELL CONTROLChromatinFunction:
Condense to form chromosomes in nucleus
Fact: Strands of DNA that look like spaghetti
Found in: Eukaryotes
III. CELL CONTROLNucleolusFunction:
Makes ribosomes
Fact: Found inside the nucleus
Found in: Eukaryotes
Nucleolus
Nucleolus
III. CELL CONTROLRibosomesFunction:
Makes proteins
Fact: Made of RNACan be free or attached to ER
Found in: EukaryotesProkaryotes
Ribosomes
III. CELL CONTROLNuclear Envelope/MembraneFunction:
Controls what enters/exits the nucleus
Fact: Surrounds the nucleus
Found in: Eukaryotes
IV. CELL ASSEMBLYCytoplasmFunction:
Suspends/holds organellesSite of chemical reactions
Fact: Contains clear gel-like fluid called cytosol
Found in: EukaryotesProkaryotes
IV. CELL ASSEMBLYRough Endoplasmic Reticulum (ER)Function:
Produces proteins
Fact: Helps move molecules throughout the cell
Found in: Eukaryotes
IV. CELL ASSEMBLYSmooth Endoplasmic Reticulum (ER)Function:
Produces lipids (steroids)Detoxifies poisons
Fact: Helps move molecules throughout the cell
Found in: Eukaryotes
IV. CELL ASSEMBLYGolgi ApparatusFunction:
Processes, packs, and secretes proteins and lipids
Fact: Works closely with ERFlattened stack of membranes
Found in: Eukaryotes
Golgi
IV. CELL ASSEMBLYVacuoleFunction:
Stores food, water, waste, proteins, carbs
Fact: Helps maintain homeostasis
Found in: Eukaryotes (plants have a LARGE vacuole)
Vacuole
IV. CELL ASSEMBLYLysosomesFunction:
Uses enzymes to digest old organelles and foreign objects (bacteria, viruses)
Fact: “Suicide sacs”
Found in: Eukaryotes
Lysosome
IV. CELL ASSEMBLYEver wonder how a tadpole gets rid of its tail and
grows legs????
It’s lysosomes digest the cells in the tail, and these molecules are released to build different cells, like legs!
V. ENERGY TRANSFORMERSChloroplastFunction:
Capture light (solar energy) and convert it to chemical energy during photosynthesis
Fact: Glucose is the sugar made
Found in: Eukaryotes (plants)
Chloroplast
Mitochondria
V. ENERGY TRANSFORMERSMitochondriaFunction:
Breaks down food into ATP energy during cellular respiration
Fact: “Powerhouse” of the cell
Found in: Eukaryotes
VI. SUPPORT & LOCOMOTIONCytoskeletonFunction:
Maintains the shape & supports the cell
Fact: Made of microfilaments &
microtubulesFound throughout the cytoplasm
Found in: EukaryotesProkaryotes
VI. SUPPORT & LOCOMOTIONCiliaFunction:
Movement of cells or fluids
Fact: Short hair-like fibers
Found in: EukaryotesProkaryotes
VI. SUPPORT & LOCOMOTIONFlagellaFunction:
Movement of cells
Fact: Long hair-like fibers
Found in: EukaryotesProkaryotes
Flagella
Cilia
http://www.youtube.com/user/ecrouch7#p/a/f/0/1IqsE8CVTms
http://www.youtube.com/watch?v=rABKB5aS2Zg&feature=related
VII. LEVELS OF ORGANIZATIONA. Organization: Organelles Cells
Tissues Organs Organ systems Organisms
VIII. THE CELL MEMBRANE
A. A cell’s survival depends on the cell’s ability to maintain the necessary conditions inside itself.1. Maintaining these constant internal conditions is called homeostasis.
VIII. THE CELL MEMBRANE
B. Cell Membrane – flexible boundary between the cell and its outside environment1. Allows water and nutrients to enter the cell and wastes to leave the cell.
Water
Cell Membrane
VIII. THE CELL MEMBRANE
2. Selectively Permeable – allowing some materials to pass while keeping others out
a. Example: A spaghetti strainer allows water, but not spaghetti to pass through
VIII. THE CELL MEMBRANE
C. What is the cell membrane made up of?1. Phospholipids – diglyceride with a phosphate group attached
VIII. THE CELL MEMBRANE
a. Phospholipid Bilayer – the cell membrane is TWO layers thick
VIII. THE CELL MEMBRANE
b. Phospholipids have a polar “head” and non polar “tail”.
- Polar “heads” are attracted to water, sugars, and proteins.
VIII. THE CELL MEMBRANE
- Non-polar “tails” repel water,sugars, and proteins.- Resulting in a selectively permeable membrane.
VIII. THE CELL MEMBRANE
2. Proteins are embedded in the cell membrane to recognize substances that can enter and exit the cell.
VIII. THE CELL MEMBRANE
3. Cholesterol stabilizes the membrane by preventing lipids from sticking together.
VIII. THE CELL MEMBRANE
D. Fluid Mosaic Model - describes how phospholipids can move around like a fluid and the proteins make a pattern
VIIII. CELL TRANSPORT
A. What types of materials need to cross the cells membrane? Water, nutrients, oxygen, waste
B. In cells, particles always move to reach equal concentrations.1. Concentration Gradient – unequal distribution of particles
VIIII. CELL TRANSPORTC. Types of Transport
1. Passive Transport – movement of any substance across a membrane WITHOUT the use of chemical energy.
a. Occurs from high to low concentration, with the concentration gradient.
VIIII. CELL TRANSPORT
b. Types of Passive Transport- Diffusion – movement of molecules across a selectively permeable
membrane; occurs from high to low concentration, with the concentration gradient.
VIIII. CELL TRANSPORT
- Example: Oxygen diffuses into the bloodstream because of a high pressure in the lungs.
VIIII. CELL TRANSPORT
- Osmosis – movement of water across a selectively permeable membrane; occurs from high to low concentration, with the
concentration gradient.
VIIII. CELL TRANSPORTc. How are larger and strongly charged molecules, such as
glucose, able to pass through the cell membrane more quickly than they should?
- Facilitated diffusion – passive transport of large particles across a membrane with the help of
proteins; occurs from a high to low concentration, with the concentration gradient
- Example: Sugars, Amino Acids
Glucosemolecules
LowConcentration
CellMembrane
HighConcentration
Proteinchannel
VIIII. CELL TRANSPORT
VIIII. CELL TRANSPORT2. Types of Solution – How does the water “know” which way to move?
a. Hypertonic Solution – (high solute concentration) more water on the inside of the cell than the outside of the cell.
- Water moves OUT of the cell.- Size of the cell = shrinks (plasmolysis)
H2O + NaCl Solution
VIIII. CELL TRANSPORTb. Hypotonic Solution – (low solute concentration) more
water on the outside of the cell than the inside of the cell.
- Water moves INTO the cell.
- Size of the cell = swells
- Cytolysis = animal cells burst
- Turgor Pressure = water pushes against cell wall in plants
H2O + NaCl Solution
VIIII. CELL TRANSPORTc. Isotonic Solution – equal concentration of water and solute inside and outside the cell
- Water moves in and out of cell equally.- Size of cell = stays the same
H2O + NaCl Solution
VIIII. CELL TRANSPORT
Criteria Inside Cell
Outside Cell
Where is there more solvent (water)?
hypertonic
hypotonic
Where is there more solute (salts, dissolved substances)?
hypotonic hypertonic
CELL TRANSPORT
VIIII. CELL TRANSPORT3. Diffusion is a powerful process, however, sometimes cells need to move materials in the opposite direction.
a. Active Transport – proteins are used to move ions or molecules against the concentration gradient, using ATP energy.
- Occurs from areas of low to high concentrations.
- Examples: minerals, nutrients
VIIII. CELL TRANSPORT4. Types of Active Transport
a. Endocytosis – process when a cell surrounds and takes in materials from the environment
- Example: White blood cell engulfing a bacterium.
VIIII. CELL TRANSPORT- Two types of Endocytosis
- Pinocytosis – movement of liquids into a cell
- Phagocytosis – movement of solids in a cell
VIIII. CELL TRANSPORTb. Exocytosis – the explusion (exit) or secretion of
material out a cell - Example: Cell getting rid of waste.
VIIII. CELL TRANSPORTc. Although endocytosis and exocytosis are different, the two processes often work TOGETHER.
http://www.youtube.com/watch?v=dPKvHrD1eS4