Chapter 7 Cells and Transport
Hooke 1665
• Observed pieces of cork under a simple
microscope.
Describe the structure of cork.
•Hooke named the structures “CELLS”.
•He named them after the rooms that monks lived in
at monasteries, because they looked like empty
rooms.
Leeuwenhoek 1674
•He used a primitive microscope
to look at many objects.
•He saw tiny creatures swimming
around and called them
“animalcules”.
Schleiden 1838
• Concluded that all
plants were made of
cells.
→
Schwann 1839
• Concluded that all
animals were made
of cells.
→
Virchow 1855
• Proposed that all cells
must come from
existing cells.
The cell theory
1st States that……..
•ALL LIVING THINGS ARE
COMPOSED OF CELLS.
2nd States that….
•CELLS ARE THE BASIC UNIT
OF STRUCTURE AND
FUNCTION IN LIVING
THINGS.
3rd and Finally states that…..
•NEW CELLS ARE PRODUCED
FROM EXISTING CELLS.
Let’s Look at Some Cells!
A plant cell taken with a transmission electron microscope
Red blood cells taken with a scanning electron microscope
Bacterial cells taken with a scanning electron microscope
A paramecium taken with a compound light microscope
List at least 5 differences between
these two types of cells.
Prokaryotes vs. Eukaryotes
• Prokaryotes – Smaller, more primitive
cells. Lack a nucleus and organelles.
Examples: Bacteria and cyanobacteria
• Eukaryotes – “True nucleus”. Have
membrane-bound DNA and complex
organelles. Examples: Animals, plants,
fungi, protists (amoeba).
Eukaryotes vs. Prokaryotes:
Size
A macrophage eating E. coli and human cheek cells with bacteria.
Plant and Animal Cells
Plant cells have:
• A cell wall
• Chloroplasts
• No centrioles
• Large vacuoles
(some)
Animal cells have:
• No cell walls
• Centrioles
Plant and Animal
cells have:
•Mitochondria
•Cell membranes
•Nucleus
•All other organelles
Cellular Organelles:
Organelles found in Eukaryotes
Cell membranemade of a phospholipid bi-layer, the
membrane protects
the cell and regulates
what enters and exits
the cell
Cell membrane illustrations:
Endoplasmic
Reticulum:
• An extension of the
•
nucleus inside the
cell, the ER transports
materials inside the
cell and serves as a
place for protein
synthesis (Rough ER).
Ribosomes: sites of
protein synthesis.
Golgi Body:
• “flattened pancakes”
that take material
traveling on the ER
and package it and
label it for
intracellular or
extracellular
transport.
Nuclear
membrane:
• Surrounds the
•
nucleus and has pores
which allow RNA to
pass through the
cytoplasm
Regulates protein
messages to the rest
of the cell
Nucleus:
• Contains the DNA on
chromosomes. Site of
the replication of DNA
in the beginning of
mitosis.
Mitochondria:
• The “powerhouse” of
the cell. Mitochondria
are kidney bean/oval
shaped with a wavy
internal membrane.
ATP (the cell’s energy
currency) is formed
on this membrane.
(Once bacteria??)
Chloroplast:
• Found only in plants,
chloroplasts are oval
shaped organelles
that gather the sun’s
energy to create ATP
and assemble
carbohydrates for
plants to use in the
future.
Cell Wall:
• Also found only in
plants (and fungi),
the cell wall is a rigid
structure made of
cellulose and lignin
that protects a plant
cell and gives it
shape.
Peroxizomes:
• Small vesicles (bags)
that contain various
enzymes that convert
fats to carbohydrates
and convert H2O2 into
water and oxygen.
Lysosomes:
• Vesicles that contain
digestive enzymes.
Vacuole:
• A large internal
storage place for
wastes, food, or
water. Common in
plant cells.
Cytoskeleton:
• The internal
framework of the cell
composed of
microtubules that give
the cell its shape.
Centrioles:
• Found only in animal
cells, the centrioles
set up the framework
that moves the
chromosomes to
opposite sides of the
cell during cell
division.
Flagella and Cilia:
• Flagella: Complex
cables of microtubules
that allow for cellular
movement.
http://www.microscopyu.com/mov
iegallery/pondscum/protozoa/pera
nema/t1/peranema03.html
• Cilia: Smaller, more
numerous flagella in a
large area of the cell.
http://www.microscopyu.com/moviegallery/pondscum/protozoa/stentor/t1/stentor0
1.html
Cellular Organelles:
• Organelles work together to allow the cell to
•
•
carry out important life functions.
Use your notes and your diagrams to help you
study.
Complete your cell models/activities for side
dishes. Include: cell membrane, nucleus,
nuclear membrane, rough ER, smooth ER, Golgi
body, mitochondria, lysosomes, and centrioles.
The cell membrane regulates
what enters and exits the cell.
• Active transport – the movement of
particles across the membrane using
energy (ATP). Examples: gated channels,
endocytosis.
• Passive transport – the movement of
particles without using energy. Examples:
osmosis, diffusion.
A review:
• Solution – a mixture of two or more
substances
• Solutes – the substances dissolved in the
solution.
• Water – the universal solvent.
• Concentration – the mass of solvent in a
given volume of solution.
Passive transport:
• Diffusion – the
•
movement of particles
from an area of high
concentration to an area
of low concentration.
When the concentration
of the solvent is even
throughout, the system
has reached
equilibrium.
Simulation B.K. hot/cold
Passive transport, continued…
• Osmosis – the
diffusion of water
through a selectively
permeable
membrane.
• Selectively
permeable – some
•
particles can pass
through while others
cannot.
Water wants to reach
an equilibrium!
Osmosis continued…
• Water moves to “dilute” out the more
concentrated solution so the free water content
is equal on both sides of the membrane.
• Isotonic solution – when the amount of solutes
and water is the same on both sides of the
membrane. Example: RBC’s and plasma.
• Hypertonic – more concentrated solution.
Example: Salt water.
• Hypotonic – the less concentrated solution.
Example: Red blood cell in salt water
Red blood cells in various solutions:
Passive transport, Continued…
• Facilitated diffusion –
•
•
•
Protein channels in the
cell help certain
molecules (glucose)
through the membrane.
No energy used.
Animation
What diffuses?
Water, oxygen, carbon
dioxide, glucose…
Active Transport:
• Endocytosis – Uses ATP to “engulf” or take
in food/water through the cell membrane.
Examples:
Pinocytosis – taking in water by
pinching in around it.
Phagocytosis – taking in food/solids
by pinching in.
• Exocytosis- Uses ATP to expel vesicles
(proteins, solids)