Organization of Life Cell Tissue Organ Organ System Organism

Cells All living organisms on Earth are divided in pieces called cells. There are smaller pieces to cells that include proteins and organelles. Cells hold all of the biological equipment necessary to keep an organism alive and successful on Earth.

Organelles Means “little organ” Small parts of the cell Each with their own special job in the cell

Examples of Organelles Nucleus Rough Endoplasmic Reticulum (ER) Smooth ER Ribosomes Golgi apparatus Cell Membrane Cytoskeleton Mitochondria Lysosomes Plants Only: Chloroplast Vacuoles Cell Wall

Prokaryote Unicellular organism Lack membrane bound organelles No nucleus Ex: bacteria

Eukaryote Unicellular or Multi-cellular organism Contain a true nucleus and membrane bound organelles Ex: yeast, plants and animals

Nucleus The nucleus is the brain of the cell. Contains the genetic material – DNA. (Code for making proteins) Not all organisms have a nucleus. Nucleus (yellow)

Nucleus The nucleolus is a small section of the nucleus. (usually in the center) The nuclear membrane is a thin membrane around the nucleus.

Cell Membrane Also called the plasma membrane The boundary between the cell and its environment. 1 Protein

Cell Membrane It’s Function: Protection of the cell –Keeps bad things from coming in –Allows needed materials in –Keeps good things in –Allows wastes out This is called selective permeability – allows some molecules to pass through while keeping others out. 2

Cell Membrane The cell membrane allows the cell to maintain homeostasis. –Homeostasis- the ability of an organism to maintain equilibrium and survive. 3

Cell Membrane Structure Made of 2 phospholipids back to back. The membrane is NOT water soluble. One phospholipid Bilayer of the Membrane 4 Head Tail

Cell Wall Surrounds a plant cell Inflexible compared to cell membrane Provides support and protection Permeable to all molecules

Cell Wall Cell Membrane Inside of Cell All plant cells have BOTH a cell wall and a cell membrane

Jelly-like fluid that fills a cell All organelles are suspended in the cytoplasm Cytoplasm

Cytoskeleton Scaffolding or skeleton structure in the cytoplasm Maintains cell shape, protects the cell, & enables the cell to move

Endoplasmic Reticulum (ER) Interconnected tubes & vesicles Responsible for: –Protein transport –Production & storage of biomolecules Usually found near the nucleus

Endoplasmic Reticulum (ER) Smooth ER –Has no Ribosomes Rough ER –Has ribosomes on the surface

Ribosomes Location of protein production in the cell. Small structure made of RNA and protein that is NOT membrane bound (no membrane). Use the “recipe” written on DNA to make proteins. *Remember: DNA can’t leave the nucleus so RNA is the messenger.

Ribosomes Attached to the ER (Endoplasmic Reticulum) Can be free floating in cytoplasm Or

Golgi Body Function is to modify, sort and package biomolecules for use inside or outside the cell. Think of the Golgi Body as a post office.

Lysosomes Contain digestive enzymes They digest excess or worn out organelles, food particles and invaders (virus & bacteria)

Mitochondria Found in both plants and animals. Location of cellular respiration. Energy converter … converts sugars/food into energy (ATP) for the cell

Chloroplast Found only in plants. Location of Photosynthesis. Full of chlorophyll a green pigment.

Vacuole Membrane bound sac Storage for food, water & waste –Small in animals –Larger in plants

Multiple Cells –Stained to show the difference between the nucleus (green) and the membrane (red)

Red Blood Cells

Nerve Cell

White Blood Cell & Bacteria

Red Blood Cells flowing through blood vessels

Brain Cancer Cell

Organisms Simple Organisms: –Are unicellular –Very basic –Growth is restricted Complex Organisms: –Are multi-cellular –Can be basic or complex –Have the ability to grow Salmonella typhimurium invading human cells

Cells Alive! Size? – Cell Animation –

Resources Wikipedia Cells Alive! Biology4Kids.com