Transcript Cells and Tissues

Cells and Tissues
Unicellular Organisms
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“Single celled organisms carry out all
functions of life in that cell”
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What are the functions of life?
Why must a single celled organism carry out all
functions in that cell?
Unicellular Organisms
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Paramecium
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How does the paramecium carry out the functions
of life?
Video: http://www.youtube.com/watch?v=sn3MTYNe8mM
Unicellular Organisms
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Paramecium
Function of Life
Paramecium
Nutrition
Heterotrophic. Cilia moves food into oral groove. Slowly
digested in vacuoles. Nutrients absorbed into cytoplasm.
Metabolism
Takes place in cytoplasm. Enzymes catalyze the reactions.
Growth/
Binary fission: 2 new cells formed when a parent cell divides.
Reproduction Can reproduce sexually by conjugation.
Response
Cilia move the paramecium through the water in response to
changes in the environment.
Excretion
Waste products diffuse out through the membrane.
Homeostasis
Cell membrane determines what gets in and out. Contractile
vacuole fills with water and expels it to maintain tolerable
water content.
Videos: http://en.wikipedia.org/wiki/Paramecium
Unicellular Organisms
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Chlamydomonas
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How does the chlamydomonas carry out the
functions of life?
Video: http://www.youtube.com/watch?v=EMNFZnDt75c
Unicellular Organisms
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Chlamydomonas
Function of Life
Chlamydomonas
Nutrition
Autotrophic. Photosynthesis occurs inside chloroplasts.
Metabolism
Takes place in the cytoplasm. Enzymes catalyze the
reactions.
Growth /
Nucleus can divide to produce genetically identical nuclei for
Reproduction asexual reproduction or fuse and divide sexually.
Response
Flagella move the cell through water. A light-sensitive
“eyespot” allows cell to sense the brightest light.
Excretion
Oxygen, a waste product of photosynthesis, diffuses out
through the membrane.
Homeostasis
Cell wall is freely permeable. The cell membrane controls
what chemicals enter and leave. Contractile vacuole fills with
water and expels it to maintain tolerable water content.
Colonies
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Some unicellular
organisms live in
colonies
The cells cooperate
but are not fused to
form a single cell
mass
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Example: Volvox
aureus
Multicellular
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Organisms consisting of a
mass of cells fused together
are multicellular
The cells form interdependent
cooperative groups
The groups work together to
form a living organism with
distinctive overall properties
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Example: C.elegans
959 cells: digestive parts,
reproductive organs, nerve cells
http://education-portal.com/academy/lesson/animal-tissue-types-connectiveand-epithelial-tissues.html#lesson (stop at 3:35)
What is their role?
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Bone cell
Ovum/sperm cell
Nerve cell
Red Blood
How do cells specialize?
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“Specialized tissues can develop by cell
differentiation in multicellular organisms”
“Differentiation involves the expression of
come genes and not others in a cell’s
genome”
http://ns.umich.edu/stemcells/C_030206.html
Stem cells
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“The capacity of stem cells to divide and
differentiate along different pathways is
necessary in embryonic development. It also
makes stem cells suitable for therapeutic
uses.”
http://ns.umich.edu/stemcells/022706_TabA.html
Stem Cells Summary
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What are stem cells?
What are the sources of stem cells?
In what ways might they be useful?
What is stem cell research controversial?