1. Cells and Tissues

2. Unicellular Organisms
“Single celled organisms carry out all functions of life in that cell”
What are the functions of life?
Why must a single celled organism carry out all functions in that cell?

3. Unicellular Organisms
Paramecium
How does the paramecium carry out the functions of life?
Video:

4. Unicellular Organisms
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/ Reproduction
Binary fission: 2 new cells formed when a parent cell divides. 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:

5. Unicellular Organisms
Chlamydomonas
How does the chlamydomonas carry out the functions of life?
Video:

6. Unicellular Organisms
Chlamydomonas
Function of Life
Chlamydomonas
Nutrition
Autotrophic. Photosynthesis occurs inside chloroplasts.
Metabolism
Takes place in the cytoplasm. Enzymes catalyze the reactions.
Growth / Reproduction
Nucleus can divide to produce genetically identical nuclei for 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.

7. Colonies Some unicellular organisms live in colonies
The cells cooperate but are not fused to form a single cell mass
Example: Volvox aureus

8. Multicellular
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
Example: C.elegans
959 cells: digestive parts, reproductive organs, nerve cells
(stop at 3:35)

9. What is their role?
Bone cell
Ovum/sperm cell
Nerve cell
Red Blood

10. How do cells specialize?
“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”

11. Stem cells
“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.”

12. Stem Cells Summary What are stem cells?
What are the sources of stem cells?
In what ways might they be useful?
What is stem cell research controversial?