Download Features of Life and the Cell

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I. Cell Theory
A. Early studies led to the development of the
cell theory
• It was the result of the collective work of many
scientists.
• 1665 Robert Hooke used the word “cell” to
describe the spaces in cork
• 1674 Anton Von Leeuwenhoek observed
living cells and called them “animalcules”
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I. Cell Theory (continued)
• 1838 Matthias Schleiden was the first
to note that plants were made of cells
• 1839 Theodor Schwann concluded
that animals are made of cells
• 1855 Rudolf Virchow reported that all
cells come from other cells
Cell Theory video
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Cell Theory
 All organisms are made of cells.
 The cell is the most basic unit of life.
Structure and function
 All cells are produced by other cells
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Levels of Organization in Living Things
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CELLS
ORGAN SYSTEMS
TISSUES
ORGANS
ORGANISM
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2 Categories of Cells
1. Prokaryotic Cells lack a nucleus and most internal
structures of eukaryotic cells
Pro = Before
Karyotic = nucleus
• All prokaryotic cells are microscopic singlecelled organisms whose DNA is suspended in
the cytoplasm
• Bacteria are the ONLY examples of
prokaryotes.
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2 Categories of Cells
2. Eukaryotic cells have a nucleus with DNA
Eu = True Karyotic = nucleus
- Have other membrane bound organelles
Organelles = specialized structures that
perform specific jobs “tiny organs”
- There are 2 types: Animal and Plant Cells
- Eukaryotic cells are found in:
animals, plants, fungi and protists.
Prokaryote vs eukaryote video
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II. Cell Organelles - Animal Cell
6. Ribosomes on ER
4. Nucleolus
6. Ribosomes in cytoplasm
2. Nucleus
1. Cell Membrane
3. Nuclear Membrane
8. Mitochondria
5. Smooth ER
5. Rough ER
10. Vacuole
3. Nuclear pore
11. Centrioles
7. Golgi
12. Cytoplasm
9. Lysosome
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II. Cell Organelles (continued)
A. Cells have an internal structure
•
Cells are highly organized structures
1. Cytoskeleton
- Cyto = cell
 Network of proteins and fibers that is constantly
changing to meet the needs of the cell
 Like the support beams or infrastructure of the school
2. Cytoplasm
Cyto = cell
Plasm = fluid
 The fluid portion of the cell that fills the space
between the nucleus and the cell membrane
in eukaryotic cells
 Like the inside of the school “air”
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II.
Cell Organelles (continued)
B. Several organelles are involved in making and processing
protein
1. Nucleus – the brain of the cell
 Located at the center of the cell
 Contains our genetic information,
 Controls all of the cell’s activities
 Determines what proteins are made
 “Like the principal’s office”
2. Nuclear Envelope/Membrane:
 Double Membrane that surrounds the nucleus
 Contains nuclear pores that allow certain materials to
move in and out of the nucleus
 “Like the walls and doors surrounding the principal’s
office”
3. Nucleolus:
 Located inside of the nucleus
 Made of DNA
 Makes ribosomes
 “Like the principal”
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4. Endoplasmic Reticulum –
• interconnected network of thin folded membranes
 helps move materials within cell
 Passageways
• “Like hallways and staircases”
Two types
 It’s called rough ER when it
has ribosomes on it.
- Site of protein making
- “Like the staircases and hallways”
 It’s called smooth ER when there
are no ribosomes on it.
- Site of lipid making and other functions
- “Like the elevators”
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5. Ribosome:
 Made from the nucleolus
 Job is to make protein
 Ribosomes are found in three places:
1. Nucleolus
2. Attached to the Rough Endoplasmic Reticulum.
3. Freely floating throughout the cytoplasm
 “The information of the school”
6. Golgi Apparatus
 packs, stores and ships out proteins to the
cell membrane so they can be released from the cell and
distributed to the body.
 “Like the mailroom or guidance office”
7. Vesicles
• Tiny sacs that isolate and transport specific
molecules out of the cell.
 “Like envelopes”
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C. Other organelles have various functions
1. Mitochondria:
 The “Powerhouses” of the cell because they
produce energy from food that was digested.
 This is where the process of cellular respiration is
carried out.
 Cellular respiration is a
process that breaks down
food (glucose) into energy
(ATP) that can
be used by the cell.
 “Like the generators of the
school”
Glucose + Oxygen ATP+ Carbon dioxide + water
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2. Lysosomes:
 membrane bound organelles that contain enzymes
 Digestive sacs – destroy damaged or worn out cell
parts and get rid of
bacteria.
 “Like the clean-up crew”
3. Vacuole:
 Fluid filled sac that stores water, food, ions,
minerals, protein and carbohydrates.
 “Like kitchens”
 These are much larger in plant cells – central
vacuole
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Why is the vacuole larger in a
plant cell?
 Because plants rely on rain in order to
receive water. Therefore the vacuole needs
to be much larger because the plant has to
be able to store its water for long periods of
time when there is no rain.
 Without water a plant can not perform
photosynthesis!
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4. Centrosome
 it contains the centrioles
5. Centrioles:
 Help with cell division in a
process known as mitosis form of reproduction.
 Found in pairs
 Small cylinder shaped organelle
 Only found in animal cells
“like the students”
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Virtual Cell Tour
 Take a Virtual Cell Tour
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Movement of Animal Cells
 Animal cells can move by either cilia or flagella.
 Both composed of microtubules.
 Cilia - short, hair-like projections that produce
movement.
 Flagella – a whip-like tail used for locomotion.
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Plant cell
Vacuole
Smooth endoplasmic
reticulum
Ribosome
(free)
Chloroplast
Ribosome
(attached)
Cell
Membrane
Nuclear
envelope
Cell wall
Nucleolus
Golgi apparatus
Nucleus
Mitochondrion
Rough endoplasmic reticulum
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Plant Cell
 A plant cell contains every organelle of an animal cell
EXCEPT the centrioles!
 Plant cells also have 2 additional organelles that are not
found in an animal cell.
 What are the 2 organelles of a plant cell that are not found
in an animal cell?
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1. Chloroplasts:
 Found only in plant cells
 Are needed for photosynthesis
 Contain the green pigment chlorophyll
 Chlorophyll can trap energy from the sun and use it
for photosynthesis, so plants can make their own
food( glucose) through photosynthesis.
Carbon dioxide + Water  Glucose + Oxygen
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2. Cell wall:
 Found in cells of plants, algae, fungi, and
bacteria
 It is a thick outer covering surrounding the cell
membrane
 Provides support and protection
 Allows the stem of the plant to stand upright in order to
carry out photosynthesis.
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Virtual Cell Tour
 Take a Virtual Cell Tour
Travel through the cell video
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3.3 Cell Membrane
3.4 Diffusion and Osmosis
3.5 Active Transport
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3.3. Cell Membrane
Cell membranes are composed of two phospholipid layers.
• The cell membrane has two major functions.
– forms a boundary between inside and outside of the
cell
– Allows materials to pass in and out of the cell
Lipid bilayer
(selectively permeable)
cholesterol
protein
channel
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Phospholipid from the cell
membrane
• Fluid Mosaic Model - describes the arrangement of molecules that
make up a cell membrane.
• Flexible membrane
• Moves from side to side like a fluid
• Has a variety of molecules in it like a mosaic (different
textures/patterns)
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3.3. Cell Membrane (continued)
• Cell Membrane is selectively permeable
• Some molecules can pass while others can
not
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Movement across a cell membrane
• Passive Transport
Requires no energy for molecules to move across a cell
membrane.
• Two types of Passive Transport
1. Diffusion
2. Osmosis
3. Facilitated Diffusion
• Active Transport
Requires energy in order for molecules to move across a cell
membrane.
• Two types of Active Transport
1. Protein Pumps
2. Endocytosis
3. Exocytosis
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IV. Diffusion and Osmosis
Movement across a cell membrane
A.
Diffusion: Movement of substances from an area where there
are more to where there is less along a concentration gradient.
- This occurs until there is a balance of substances called
equilibrium
- The moving substance has to be smaller than the
cellular pore
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Osmosis – Diffusion of water across a membrane from an
area where there is more water to an area where there is
less water in order to reach equilibrium.
*This occurs when a solute or substance is too large to
pass through the cell membrane.
*Water moves to dilute the substance that is too large!
B.
video
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3 types of osmotic solutions
 Hypertonic solution – when there is more
water inside the cell, water will move out
of the cell in order to dilute the higher
substance.
- Causes a cell to shrink
 Hypotonic solution – when there is more
water outside the cell, water will move
into the cell in order to dilute the higher
substance.
- Causes a cell to swell or expand
 Isotonic solution – when both sides of the
cell membrane are at equilibrium
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Osmosis
Hypertonic - Because the solution
outside the cell is greater than inside the
cell – Water will leave; causing the cell
to shrink
Hypotonic - Because the solution
outside the cell is less than inside the
cell – Water will enter; causing the cell to
swell
Isotonic - Because the solution outside
the cell is equal or the same as inside
the cell – Water will move back and forth
at an equal rate
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Facilitated Diffusion
 Some particles can not diffuse through the membrane
because of their size, or their charge
 They need to pass through a carrier protein
 Diffusion with help (High to low)
Osmosis rap
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Active transport – molecular
pumps
 Move things AGAINST
the concentration
gradient: low to high
 Requires energy! ATP!!
 A transport protein
PUMPS the molecule to
the other side of the
membrane
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Active Transport
 Endocytosis – process of
taking molecules into a cell
by engulfing them in a
membrane
 Exocytosis – process of
releasing a substance out a
cell by the fusion of a vesicle
with the cell membrane.
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Pin the Organelle on the Animal Cell
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Pin the Organelle on the Plant Cell
Smooth endoplasmic
reticulum
Ribosome
(free)
Ribosome
(attached)
Cell
Membrane
Nuclear
envelope
Nucleolus
Golgi apparatus
Nucleus
Mitochondrion
Rough endoplasmic reticulum
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