Life Sciences 11- Cell Organization

Cells

Specialized cells that are similar in shape and function ( ex. Muscle cells)

Tissues

Groups of cells that are similar in shape and function (ex. Skin is all epithelial tissue)

Organs

Tissues that are organized into large structures that have one function. (Ex. Heart pumps blood through body)

Organ Systems

Groups of organs that have related functions (ex. Circulatory system)

Organism

An individual animal, plant, or single-celled life form that is either multicellular or unicellular

Prokaryotes

Simple, unicellular organisms

No membrane bound organelles

No nucleus

All bacteria

Eukaryotes

Complex organisms

Can be multicellular or unicellular

Contain organelles surrounded by membranes (including nucleus)

Unicellular Organism

Consists of only one cell

Can be a prokaryote or a eukaryote

That one cell carries out all the required functions for life for the organisms

There is no cell specialization

Multicellular organisms

Made of more than one cell

Have cell specialization due to a process called cell differentiation

Cell Differentiation

A result of gene expression, a process in which a gene is switched on or off, resulting in different proteins being made.

Most cells in your body have the same DNA, however, cells only use the needed DNA, leaving the rest inactive

They look different because of this process

(ex. skin cells use DNA that codes for MELANIN (a skin pigment that protects from UV light)

Cell Specialization

A term that states cells are specialized to perform certain functions

Neuron

Known as a Nerve Cell

Sends important information from one part of the body to another

Very long and thin

Red Blood Cells

Carry oxygen throughout the body

Shaped like flattened disks so they can ease through blood vessels

Sickle Red Blood Cell

In patients who have sickle cell anemia

Because the structure of the cell has changed, the function to carry oxygen is negatively affected

Sperm Cell

Fertilizes egg cell

Strong tail for quick swimming in the race

Distinct head that helps it enter the egg cell

Gene

They are DNA

They give instructions to the ribosome in order to make proteins

Different proteins result in different cell appearances

Stem Cells

Can become any cell in your body because they have yet to undergo Cell Differentiation

Can be used to repair damaged organs and cure some diseases

Gene expression

A process in which a gene is switched on or off, resulting in different proteins being used

No genes expressed = no proteins made

no proteins made