Transcript From Single Cells to Body Systems

From Single Cells to
Body Systems
Cells
The Discovery of Cells
Microscopes allow you to see objects that are
too small for see with your eyes (magnification)
Robert Hooke built and used a microscope to
discover cells (tiny rooms) in a piece of cork
Cell = the basic unit of structure and function of
all living things
Robert Hooke
Drawing of cork
in Hooke’s
sketch book
Kinds of Cells
All plants and animals are made up of cells
Some organisms have only one cell (bacteria); other organisms have many
cells
If an organism has many cells, there are usually different kinds of cells
which have special jobs or functions
The function of a cell determines its size and shape
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Red blood cells are small and oval
Muscle cells are long and thin (contract as they move)
Nerve cells are very long
Plants have different kinds of cells that do different tasks (take in water,
help in the making of food, protect the plant)
Cells keep organisms alive in the jobs that they do
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Release energy from food
Get rid of body wastes
Make new cells
BUT…all cells can perform all these process for itself
Pictures of Kinds of Cells
Nerve Cell
Plant and Animal Cells
Cells are made up of even smaller structures called organelles, which have
functions to keep the cells alive.
Cell Membrane = a thin covering around the cell that holds the cell together and
separates the cell from its surroundings
Nucleus = controls the cells activities
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is in the center
is surrounded by its own membrane
is responsible for reproduction because cells only grow to a certain size
Chromosomes are threadlike structures that contain the characteristics of an
organisms. New cells of the same organism have the same chromosomes.
Cytoplasm = jellylike substance containing chemicals to keep the cell functioning
Organelles in the cytoplasm
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Mitochondria – releases food
Vacuoles – used for storage (food, water, and waste)
Plant cells have…
Cell wall – gives it strength
Chloroplasts – make food
Plant & Animal Cells
Animal Cell
Plant Cell
Cell Transport
Mitochondria supplies the energy for the
cells
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Need food, oxygen, and water
Carbon Dioxide is the waste of the cell
Diffusion = movement of materials in and
out of the cells…moves from where there
are a lot of particles to where there are
fewer particles
Diffusion
Red blood cells have lots of oxygen so the oxygen
diffuses out of the red blood cells into the body cells
Carbon dioxide diffuses out of the body cells into the red
blood cells
Diffusion takes places through the cell membrane like a
filter and does not need energy.
Energy-free movement is called passive transport.
Osmosis = the movement of water and dissolved
materials through the cell membrane
Diffusion
Osmosis is used in plants getting water.
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More water in the soil so the water flows to
the plant cells and fills up the vacuoles.
This pushes against the cytoplasm and
causes the plant to stand up straight
If the soil is dry, the water leaves the plant
cells causing the vacuoles to shrink
This causes the cytoplasm to shrink and the
plant cannot stand up straight
Cell Transport
Not all cells are small enough for diffusion
A swimmer’s muscle cells might need more sugar than
there is in the blood in order to have the energy he/she
needs for a swim meet
Active transport uses a carrier to transport materials that
are too large to pass through a cell membrane
A channel is used in the cell membrane to transport
materials
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To do this a cell needs energy from the cell
1/3 of the energy in the cell is used to transport materials through
active transport
Tissues, Organs, and Systems
Tissue = cells that work together to perform a specific function
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Muscle tissue – contraction and relaxation of the muscle to move the skeleton
Nervous tissue – brain, spinal cord, sight, hearing, taste, smell touch
Connective tissue (bone, cartilage, tendons, and blood)
Epithelial tissue (body and organ coverings)
Organ = tissues that work together (stomach, heart, etc.). Each organ is
made up of several kinds of tissue
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Skin is an organ that is made up of epithelial tissue, music tissue, nervous tissue
& connective tissue
Each organ performs a major function to keep the animal alive.
System = organs that work together
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Human body has 10 systems
Plant tissues work together to form organs (roots & leaves)
Video – The Living Cell (20 minutes)