Lesson Overview

Homeostasis and Cells

Lesson Overview

7.4 Homeostasis and Cells

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Lesson Overview

Homeostasis and Cells

THINK ABOUT IT

All living cell are not the same. Differences arise from the ways in which cells are specialized Cells also have to associate with one another in multicellular organisms.

How do they communicate?

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Lesson Overview

Homeostasis and Cells

The Cell as an Organism

A single-celled-

unicellular

-Do everything a living thing needs to do. unicellular organisms must achieve homeostasis

Homeostasis

-relatively constant internal physical and chemical conditions. To maintain homeostasis, unicellular organisms: grow respond to the environment transform energy reproduce.

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Lesson Overview

Homeostasis and Cells

The Cell as an Organism

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Unicelluar organisms dominate life on Earth.

Unicellular organisms include both prokaryotes and eukaryotes. Prokaryotes ( no nucleus), especially bacteria, are remarkably adaptable and live almost everywhere — soil on leaves in the ocean in the air even within & on the human body.

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Lesson Overview

Homeostasis and Cells

The Cell as an Organism

Many eukaryotes(with Nucleus) also spend their lives as single cells. Algae, which contain chloroplasts and are found in oceans, lakes, and streams around the world, are single celled. Yeasts, or unicellular fungi, are also widespread. QuickTime™ and a decompressor are needed to see this picture.

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Lesson Overview

Homeostasis and Cells

The Cell as an Organism

Whether prokaryote or a eukaryote, homeostasis is an issue for each unicellular organism. Every unicellular organism needs to: - find sources of energy or food -keep concentrations of water & minerals within certain levels -respond quickly to changes in its environment QuickTime™ and a decompressor are needed to see this picture.

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Lesson Overview

Homeostasis and Cells

The Cell as an Organism

How do individual cells maintain homeostasis?

Lesson Overview

Homeostasis and Cells

The Cell as an Organism

How do individual cells maintain homeostasis?

To maintain homeostasis, unicellular organisms grow, respond to the environment, transform energy, and reproduce.

Lesson Overview

Homeostasis and Cells

Multicellular Life

Multi-Many Cellular Cells Multicellular-Oranism made up of many cells QuickTime™ and a decompressor are needed to see this picture.

The cells of multicellular organisms are interdependent *like the members of a team, they work together. Cells take on a particular roles The cells of multicellular organisms become specialized for particular tasks.

Cells communicate with one another in order to maintain homeostasis.

I am a multicellular creature!

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Lesson Overview

Homeostasis and Cells

Cell Specialization

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The cells of multicellular organisms are

specialized

-different cell types playing different roles. Some cells are specialized to move Other Cells are specialized to react to the environment Other Cells are specialized to produce substances that the organism needs.

Specialized

cell contributes to the overall

homeostasis

organism.

of the

Lesson Overview

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Lesson Overview

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Lesson Overview

Homeostasis and Cells

Levels of Organization

The specialized cells of multicellular organisms are organized into Cell Tissues, Organs organ systems.

Lesson Overview

Homeostasis and Cells

Levels of Organization

A cell is the basic unit of living things QuickTime™ and a decompressor are needed to see this picture.

Lesson Overview

Homeostasis and Cells

Levels of Organization

A

tissue

is a group of similar cells that performs a particular function. QuickTime™ and a decompressor are needed to see this picture.

Lesson Overview

Homeostasis and Cells

Levels of Organization

To perform complicated tasks, many groups of tissues work together as an

organ

. Each type of tissue performs an essential task to help the organ function. In most cases, an organ completes a series of specialized tasks.

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Homeostasis and Cells

Levels of Organization

A group of organs that work together to perform a specific function is called an

organ system.

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Homeostasis and Cells

Levels of Organization

The organization of the body’s cells, tissues, organs, and organ systems creates a division of labor among those cells that allows the organism to maintain homeostasis.

Lesson Overview

Homeostasis and Cells

Cellular Communication

Cells in a large organism communicate by chemical signals that are passed from one cell to another. Signals can speed up or slow down the activities of the cells that receive them, and can cause a cell to change what it is doing.

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Lesson Overview

Homeostasis and Cells

Cellular Communication

Some cells form connections, or cellular junctions, to neighboring cells. Some junctions hold cells firmly together.

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Lesson Overview

Homeostasis and Cells

Cellular Communication

Other junctions allow chemical messages to pass directly from one cell to the next.

Receptor

are places where signaling molecule can bind. Sometimes receptors are on the cell membrane Sometimes receptors are inside the cytoplasm. QuickTime™ and a decompressor are needed to see this picture.

Lesson Overview

Homeostasis and Cells

Multicellular Life

How do the cells of multicellular organisms work together to maintain homeostasis?

Lesson Overview

Homeostasis and Cells

Multicellular Life

How do the cells of multicellular organisms work together to maintain homeostasis?

The cells of multicellular organisms become specialized for particular tasks and communicate with one another to maintain homeostasis.

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