1. Unit 1 Lesson 5 Homeostasis and Cell Processes
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2. Stayin’ Alive What is homeostasis?
Unit 1 Lesson 5 Homeostasis and Cell Processes
Stayin’ Alive
What is homeostasis?
Homeostasis is the maintenance of a constant internal state in a changing environment.
Homeostasis ensures that cells can obtain and use energy, make new cells, exchange materials, and eliminate wastes in a changing environment.
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3. Unit 1 Lesson 5 Homeostasis and Cell Processes
What is homeostasis?
Unicellular organisms exchange materials directly with the environment.
Multicellular organisms have systems that transport materials to cells from other places within the organism.
The cardiovascular system in humans and xylem and phloem in plants are transport systems.
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4. Get Growing! How do cells get energy?
Unit 1 Lesson 5 Homeostasis and Cell Processes
Get Growing!
How do cells get energy?
Cells get energy by breaking down materials.
Plants, algae, and some bacteria make their own food by a process called photosynthesis.
In the presence of sunlight, carbon dioxide and water are converted to sugar and oxygen in the chloroplasts.
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5. Unit 1 Lesson 5 Homeostasis and Cell Processes
How do cells get energy?
Plants and animals use oxygen during cellular respiration to produce energy from food.
Sugars and oxygen are converted to water, carbon dioxide, and energy during respiration.
Photosynthesis and respiration are linked because each process depends on the products of the other.
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6. Unit 1 Lesson 5 Homeostasis and Cell Processes
How do cells divide?
Cells grow, divide, and die at different rates and for different reasons.
In eukaryotes, DNA is copied before a cell can divide.
The nucleus and the rest of the cell divide to make two new cells.
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7. Unit 1 Lesson 5 Homeostasis and Cell Processes
How do cells divide?
Mitosis is cell division that forms two new nuclei that are identical to each other.
DNA is packaged as chromosomes in the cell.
During mitosis, the chromosomes are separated and genetic material is split evenly between the new, genetically identical cells.
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8. Move It! How do cells exchange materials?
Unit 1 Lesson 5 Homeostasis and Cell Processes
Move It!
How do cells exchange materials?
Cell membranes are semi-permeable, allowing only certain particles to move into or out of the cell.
The movement of materials across a cell membrane without the use of energy is called passive transport.
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9. How do cells exchange materials?
Unit 1 Lesson 5 Homeostasis and Cell Processes
How do cells exchange materials?
Diffusion is the movement of molecules from high concentrations to low concentrations.
Osmosis is the diffusion of water through a semi-permeable membrane.
Large molecules move into and out of cells through protein channels.
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10. How do cells exchange materials?
Unit 1 Lesson 5 Homeostasis and Cell Processes
How do cells exchange materials?
At some point, the movement of tea out of the bag stops or slows down considerably. Why?
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11. How do cells exchange materials?
Unit 1 Lesson 5 Homeostasis and Cell Processes
How do cells exchange materials?
Active transport is the movement of particles against a concentration gradient and requires energy.
Endocytosis and exocytosis are forms of active transport that move large particles into and out of cells.
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12. How do cells exchange materials?
Unit 1 Lesson 5 Homeostasis and Cell Processes
How do cells exchange materials?
Why are both active and passive transport necessary to move materials into and out of cells?
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13. How do cells exchange materials?
Unit 1 Lesson 5 Homeostasis and Cell Processes
How do cells exchange materials?
Endocytosis is a process by which a cell uses energy to surround and enclose a particle in a vesicle to bring the particle into the cell.
Exocytosis is a process by which particles are enclosed in a vesicle in a cell and released from the cell.
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14. How do organisms maintain homeostasis?
Unit 1 Lesson 5 Homeostasis and Cell Processes
How do organisms maintain homeostasis?
Cells and whole organisms must work to maintain homeostasis in a constantly changing environment.
Some animals adapt their behavior to control body temperature.
Trees can show seasonal responses to changes in the environment.
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