FYI One bacteria cell in a colony looks like all the others. The human body contains several hundred different cells and each possess a different set of proteins that allow it to carry out specialized activities. All of us began life as a single fertilized egg that divided by mitosis to produce trillions of cells containing the same genes.

Key Idea #10 Following fertilization, cells divide and become specialized for specific functions.

What do you want to be when you grow up? There are many important jobs that grown ups do to keep our world running smoothly. Whether doctors, teachers, builders, engineers, farmers, etc, everyone learns a specific skill which they can then use to help everyone else. Just like people, cells specialize in important jobs.

During early embryonic development, the cells of the body became specialized for different activities in a process called cell differentiation.

How Living Things are Structured

Following fertilization, cell division produces a small cluster of cells that then differentiate by appearance and function to form the basic tissues, organs, and organ systems of multi- cellular organisms. Googleimages.com

Specialized Cells are very different from each other in size and structure are found in multi-celled organisms and carry out different functions from each other are genetically programmed for a particular function have a unique structure to facilitate its function –Cells that become liver cells express a specific set of “liver genes” –Each cell type has specific genes that can be "switched on" or "switched off" as it carries out its particular function. are specialized to take in nutrients, which are used to make the materials that a cell or organisms needs to survive make up different kinds of body tissues, organs, and organ systems that function together

Specialized Animal Cells

Specialized Plant Cells

Epidermis and cuticle: prevents dehydration. Green chlorophyll containing cells: perform photosynthesis Guard Cells: help to regulate the rate of transpiration by opening and closing the stomata.

Tissues are made up of groups of similar specialized cells.

A variety of specialized cells formed through cell division make up different tissues, performing different functions.

Types of Animal Tissues epithelial tissue –outer skin cells connective tissue –cartilage cells –fat cells –blood cells –bone cells –inner skin cells muscular tissue –muscle cells nervous tissue –nerve cells

Types of Plant Tissues Vascular (conductive) –transportation system –Xylem/phloem cells Epidermal –protective covering –outer surface of leaf cells Ground –storage and support Photosynthetic layers of cells

Organs are a group of different tissues working together performing a specific job.

Plant organs include roots stems leaves flower

Animal organs include stomach liver kidney heart lungs skin skeleton muscles, etc…

Organs are made of different tissues: The heart is an organ that includes muscle, epithelial, connective (blood) tissue. Leaves, stems, and roots are organs made up of dermal, vascular, and ground tissue.

Cells – Tissues – Organs – Organ Systems

Organ System An organ system is a group of organs that work together to perform a certain task.

Humans have multiple organ systems including:

Plants have two organ systems:

The Shoot System Above ground (usually) Elevates the plant above the soil Many functions including: –photosynthesis –reproduction & dispersal –food and water conduction

The Root System Underground (usually) Anchor the plant in the soil Absorb water and nutrients Conduct water and nutrients Food Storage

From atoms and molecules to organisms:

Think about it: Why do multicelled organisms like plants and animals make specialized cells, considering that every cell contains the same genetic information?

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