120 likes | 224 Views
Levels of Organization. Cell Specialization. Zygote: fertilized cell created by the union of the egg and sperm Embryonic stem cells Created during earliest divisions Potential to become any type of cell Average human: 100 trillion cells Over 200 types of human cells. Determination
E N D
Levels of Organization
Cell Specialization • Zygote: fertilized cell created by the union of the egg and sperm • Embryonic stem cells • Created during earliest divisions • Potential to become any type of cell • Average human: • 100 trillion cells • Over 200 types of human cells
Determination Stem cell genes program the cell to be a specific type Few weeks into development Irreversible Determination
Differentiation • Differentiation • Cells acquire the structures & functions of a specialized cell • Specific genes activated
Quick Questions • Do your muscle cells have the same DNA as your skin cells? Yes • Do your skin cells have the same DNA as your brain cells? Yes • Do your brain cells have the same DNA as your liver cells? Yes • So if all your cells have the same DNA, how do they know to do different jobs? Stay tuned for the answer
Stem cell programmed to become a muscle cell Gene A Gene B Gene C Gene D Gene E Gene F Gene G How will the top cell know to become a muscle cell…and the bottom to become a nerve cell if they have identical genes? If they have the same genes…how does one become a muscle and the other a nerve? Stem cell programmed to become a nerve cell Gene A Gene B Gene C Gene D Gene E Gene F Gene G
Stem cell programmed to become a muscle cell ON ON ON Gene A Gene B Gene C Gene D Gene E Gene F Gene G Remember that genes tell cells to create proteins. Muscle cells create different proteins from nerve cells based on the genes that are active. During “differentiation”, certain genes are activated in some cells, but deactivated in others. Stem cell programmed to become a nerve cell ON ON ON Gene A Gene B Gene C Gene D Gene E Gene F Gene G
Organization • Epithelial Tissue • protection sheet of cells • skin, stomach lining • Nerve Tissue • Transmit electric signals • Brain & Spinal Cord • Muscle Tissue • Contracting cells • Skeletal, cardiac cells • Connective Tissue • Support the body • Bone, fat, tendons • Cell: Basic unit • Tissue: Group of cells • 4 types • Organ: Groups of tissue • Ex: lung contains each tissue • Organ System: Group of organs working together • Digestive System • Organism: all organ systems working together
YouTube Review Video for help Click here if the video above does not work.
What is a zygote? What is the specific function of a stem cell? How does “determination” differ from “differentiation”? Cells are programmed to die during a process called ______. From smallest to largest, name the 5 levels of organization. Name the four types of tissues. Which tissue is able to stretch and contract? Which tissue transmits electric signals? Which tissue covers and protects the body? Which tissue connects the body? Kobe Kuiz